FFmpeg/libavformat/movenc.c

/*
 * MOV, 3GP, MP4 muxer
 * Copyright (c) 2003 Thomas Raivio
 * Copyright (c) 2004 Gildas Bazin <gbazin at videolan dot org>
 * Copyright (c) 2009 Baptiste Coudurier <baptiste dot coudurier at gmail dot com>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>

#include "movenc.h"
#include "avformat.h"
#include "avio_internal.h"
#include "riff.h"
#include "avio.h"
#include "isom.h"
#include "avc.h"
#include "libavcodec/get_bits.h"
#include "libavcodec/put_bits.h"
#include "libavcodec/vc1.h"
#include "internal.h"
#include "libavutil/avstring.h"
#include "libavutil/intfloat.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/dict.h"
#include "hevc.h"
#include "rtpenc.h"
#include "mov_chan.h"

#undef NDEBUG
#include <assert.h>

static const AVOption options[] = {
    { "movflags", "MOV muxer flags", offsetof(MOVMuxContext, flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "rtphint", "Add RTP hint tracks", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_RTP_HINT}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "moov_size", "maximum moov size so it can be placed at the begin", offsetof(MOVMuxContext, reserved_moov_size), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, 0 },
    { "empty_moov", "Make the initial moov atom empty (not supported by QuickTime)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_EMPTY_MOOV}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "frag_keyframe", "Fragment at video keyframes", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FRAG_KEYFRAME}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "separate_moof", "Write separate moof/mdat atoms for each track", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_SEPARATE_MOOF}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "frag_custom", "Flush fragments on caller requests", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FRAG_CUSTOM}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "isml", "Create a live smooth streaming feed (for pushing to a publishing point)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_ISML}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "faststart", "Run a second pass to put the index (moov atom) at the beginning of the file", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FASTSTART}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    { "omit_tfhd_offset", "Omit the base data offset in tfhd atoms", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_OMIT_TFHD_OFFSET}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
    FF_RTP_FLAG_OPTS(MOVMuxContext, rtp_flags),
    { "skip_iods", "Skip writing iods atom.", offsetof(MOVMuxContext, iods_skip), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
    { "iods_audio_profile", "iods audio profile atom.", offsetof(MOVMuxContext, iods_audio_profile), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, AV_OPT_FLAG_ENCODING_PARAM},
    { "iods_video_profile", "iods video profile atom.", offsetof(MOVMuxContext, iods_video_profile), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, AV_OPT_FLAG_ENCODING_PARAM},
    { "frag_duration", "Maximum fragment duration", offsetof(MOVMuxContext, max_fragment_duration), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
    { "min_frag_duration", "Minimum fragment duration", offsetof(MOVMuxContext, min_fragment_duration), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
    { "frag_size", "Maximum fragment size", offsetof(MOVMuxContext, max_fragment_size), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
    { "ism_lookahead", "Number of lookahead entries for ISM files", offsetof(MOVMuxContext, ism_lookahead), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
    { "use_editlist", "use edit list", offsetof(MOVMuxContext, use_editlist), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, AV_OPT_FLAG_ENCODING_PARAM},
    { "video_track_timescale", "set timescale of all video tracks", offsetof(MOVMuxContext, video_track_timescale), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
    { NULL },
};

#define MOV_CLASS(flavor)\
static const AVClass flavor ## _muxer_class = {\
    .class_name = #flavor " muxer",\
    .item_name  = av_default_item_name,\
    .option     = options,\
    .version    = LIBAVUTIL_VERSION_INT,\
};

static int get_moov_size(AVFormatContext *s);

//FIXME support 64 bit variant with wide placeholders
static int64_t update_size(AVIOContext *pb, int64_t pos)
{
    int64_t curpos = avio_tell(pb);
    avio_seek(pb, pos, SEEK_SET);
    avio_wb32(pb, curpos - pos); /* rewrite size */
    avio_seek(pb, curpos, SEEK_SET);

    return curpos - pos;
}

static int supports_edts(MOVMuxContext *mov)
{
    // EDTS with fragments is tricky as we don't know the duration when its written
    return (mov->use_editlist<0 && !(mov->flags & FF_MOV_FLAG_FRAGMENT)) || mov->use_editlist>0;
}

static int co64_required(const MOVTrack *track)
{
    if (track->entry > 0 && track->cluster[track->entry - 1].pos + track->data_offset > UINT32_MAX)
        return 1;
    return 0;
}

/* Chunk offset atom */
static int mov_write_stco_tag(AVIOContext *pb, MOVTrack *track)
{
    int i;
    int mode64 = co64_required(track); // use 32 bit size variant if possible
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    if (mode64)
        ffio_wfourcc(pb, "co64");
    else
        ffio_wfourcc(pb, "stco");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, track->chunkCount); /* entry count */
    for (i = 0; i < track->entry; i++) {
        if (!track->cluster[i].chunkNum)
            continue;
        if (mode64 == 1)
            avio_wb64(pb, track->cluster[i].pos + track->data_offset);
        else
            avio_wb32(pb, track->cluster[i].pos + track->data_offset);
    }
    return update_size(pb, pos);
}

/* Sample size atom */
static int mov_write_stsz_tag(AVIOContext *pb, MOVTrack *track)
{
    int equalChunks = 1;
    int i, j, entries = 0, tst = -1, oldtst = -1;

    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "stsz");
    avio_wb32(pb, 0); /* version & flags */

    for (i = 0; i < track->entry; i++) {
        tst = track->cluster[i].size / track->cluster[i].entries;
        if (oldtst != -1 && tst != oldtst)
            equalChunks = 0;
        oldtst = tst;
        entries += track->cluster[i].entries;
    }
    if (equalChunks && track->entry) {
        int sSize = track->entry ? track->cluster[0].size / track->cluster[0].entries : 0;
        sSize = FFMAX(1, sSize); // adpcm mono case could make sSize == 0
        avio_wb32(pb, sSize); // sample size
        avio_wb32(pb, entries); // sample count
    } else {
        avio_wb32(pb, 0); // sample size
        avio_wb32(pb, entries); // sample count
        for (i = 0; i < track->entry; i++) {
            for (j = 0; j < track->cluster[i].entries; j++) {
                avio_wb32(pb, track->cluster[i].size /
                          track->cluster[i].entries);
            }
        }
    }
    return update_size(pb, pos);
}

/* Sample to chunk atom */
static int mov_write_stsc_tag(AVIOContext *pb, MOVTrack *track)
{
    int index = 0, oldval = -1, i;
    int64_t entryPos, curpos;

    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "stsc");
    avio_wb32(pb, 0); // version & flags
    entryPos = avio_tell(pb);
    avio_wb32(pb, track->chunkCount); // entry count
    for (i = 0; i < track->entry; i++) {
        if (oldval != track->cluster[i].samples_in_chunk && track->cluster[i].chunkNum) {
            avio_wb32(pb, track->cluster[i].chunkNum); // first chunk
            avio_wb32(pb, track->cluster[i].samples_in_chunk); // samples per chunk
            avio_wb32(pb, 0x1); // sample description index
            oldval = track->cluster[i].samples_in_chunk;
            index++;
        }
    }
    curpos = avio_tell(pb);
    avio_seek(pb, entryPos, SEEK_SET);
    avio_wb32(pb, index); // rewrite size
    avio_seek(pb, curpos, SEEK_SET);

    return update_size(pb, pos);
}

/* Sync sample atom */
static int mov_write_stss_tag(AVIOContext *pb, MOVTrack *track, uint32_t flag)
{
    int64_t curpos, entryPos;
    int i, index = 0;
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); // size
    ffio_wfourcc(pb, flag == MOV_SYNC_SAMPLE ? "stss" : "stps");
    avio_wb32(pb, 0); // version & flags
    entryPos = avio_tell(pb);
    avio_wb32(pb, track->entry); // entry count
    for (i = 0; i < track->entry; i++) {
        if (track->cluster[i].flags & flag) {
            avio_wb32(pb, i + 1);
            index++;
        }
    }
    curpos = avio_tell(pb);
    avio_seek(pb, entryPos, SEEK_SET);
    avio_wb32(pb, index); // rewrite size
    avio_seek(pb, curpos, SEEK_SET);
    return update_size(pb, pos);
}

static int mov_write_amr_tag(AVIOContext *pb, MOVTrack *track)
{
    avio_wb32(pb, 0x11); /* size */
    if (track->mode == MODE_MOV) ffio_wfourcc(pb, "samr");
    else                         ffio_wfourcc(pb, "damr");
    ffio_wfourcc(pb, "FFMP");
    avio_w8(pb, 0); /* decoder version */

    avio_wb16(pb, 0x81FF); /* Mode set (all modes for AMR_NB) */
    avio_w8(pb, 0x00); /* Mode change period (no restriction) */
    avio_w8(pb, 0x01); /* Frames per sample */
    return 0x11;
}

static int mov_write_ac3_tag(AVIOContext *pb, MOVTrack *track)
{
    GetBitContext gbc;
    PutBitContext pbc;
    uint8_t buf[3];
    int fscod, bsid, bsmod, acmod, lfeon, frmsizecod;

    if (track->vos_len < 7)
        return -1;

    avio_wb32(pb, 11);
    ffio_wfourcc(pb, "dac3");

    init_get_bits(&gbc, track->vos_data + 4, (track->vos_len - 4) * 8);
    fscod      = get_bits(&gbc, 2);
    frmsizecod = get_bits(&gbc, 6);
    bsid       = get_bits(&gbc, 5);
    bsmod      = get_bits(&gbc, 3);
    acmod      = get_bits(&gbc, 3);
    if (acmod == 2) {
        skip_bits(&gbc, 2); // dsurmod
    } else {
        if ((acmod & 1) && acmod != 1)
            skip_bits(&gbc, 2); // cmixlev
        if (acmod & 4)
            skip_bits(&gbc, 2); // surmixlev
    }
    lfeon = get_bits1(&gbc);

    init_put_bits(&pbc, buf, sizeof(buf));
    put_bits(&pbc, 2, fscod);
    put_bits(&pbc, 5, bsid);
    put_bits(&pbc, 3, bsmod);
    put_bits(&pbc, 3, acmod);
    put_bits(&pbc, 1, lfeon);
    put_bits(&pbc, 5, frmsizecod >> 1); // bit_rate_code
    put_bits(&pbc, 5, 0); // reserved

    flush_put_bits(&pbc);
    avio_write(pb, buf, sizeof(buf));

    return 11;
}

/**
 * This function writes extradata "as is".
 * Extradata must be formatted like a valid atom (with size and tag).
 */
static int mov_write_extradata_tag(AVIOContext *pb, MOVTrack *track)
{
    avio_write(pb, track->enc->extradata, track->enc->extradata_size);
    return track->enc->extradata_size;
}

static int mov_write_enda_tag(AVIOContext *pb)
{
    avio_wb32(pb, 10);
    ffio_wfourcc(pb, "enda");
    avio_wb16(pb, 1); /* little endian */
    return 10;
}

static int mov_write_enda_tag_be(AVIOContext *pb)
{
  avio_wb32(pb, 10);
  ffio_wfourcc(pb, "enda");
  avio_wb16(pb, 0); /* big endian */
  return 10;
}

static void put_descr(AVIOContext *pb, int tag, unsigned int size)
{
    int i = 3;
    avio_w8(pb, tag);
    for (; i > 0; i--)
        avio_w8(pb, (size >> (7 * i)) | 0x80);
    avio_w8(pb, size & 0x7F);
}

static unsigned compute_avg_bitrate(MOVTrack *track)
{
    uint64_t size = 0;
    int i;
    if (!track->track_duration)
        return 0;
    for (i = 0; i < track->entry; i++)
        size += track->cluster[i].size;
    return size * 8 * track->timescale / track->track_duration;
}

static int mov_write_esds_tag(AVIOContext *pb, MOVTrack *track) // Basic
{
    int64_t pos = avio_tell(pb);
    int decoder_specific_info_len = track->vos_len ? 5 + track->vos_len : 0;
    unsigned avg_bitrate;

    avio_wb32(pb, 0); // size
    ffio_wfourcc(pb, "esds");
    avio_wb32(pb, 0); // Version

    // ES descriptor
    put_descr(pb, 0x03, 3 + 5+13 + decoder_specific_info_len + 5+1);
    avio_wb16(pb, track->track_id);
    avio_w8(pb, 0x00); // flags (= no flags)

    // DecoderConfig descriptor
    put_descr(pb, 0x04, 13 + decoder_specific_info_len);

    // Object type indication
    if ((track->enc->codec_id == AV_CODEC_ID_MP2 ||
         track->enc->codec_id == AV_CODEC_ID_MP3) &&
        track->enc->sample_rate > 24000)
        avio_w8(pb, 0x6B); // 11172-3
    else
        avio_w8(pb, ff_codec_get_tag(ff_mp4_obj_type, track->enc->codec_id));

    // the following fields is made of 6 bits to identify the streamtype (4 for video, 5 for audio)
    // plus 1 bit to indicate upstream and 1 bit set to 1 (reserved)
    if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
        avio_w8(pb, 0x15); // flags (= Audiostream)
    else
        avio_w8(pb, 0x11); // flags (= Visualstream)

    avio_wb24(pb, track->enc->rc_buffer_size >> 3); // Buffersize DB

    avg_bitrate = compute_avg_bitrate(track);
    // maxbitrate (FIXME should be max rate in any 1 sec window)
    avio_wb32(pb, FFMAX3(track->enc->bit_rate, track->enc->rc_max_rate, avg_bitrate));
    avio_wb32(pb, avg_bitrate);

    if (track->vos_len) {
        // DecoderSpecific info descriptor
        put_descr(pb, 0x05, track->vos_len);
        avio_write(pb, track->vos_data, track->vos_len);
    }

    // SL descriptor
    put_descr(pb, 0x06, 1);
    avio_w8(pb, 0x02);
    return update_size(pb, pos);
}

static int mov_pcm_le_gt16(enum AVCodecID codec_id)
{
    return codec_id == AV_CODEC_ID_PCM_S24LE ||
           codec_id == AV_CODEC_ID_PCM_S32LE ||
           codec_id == AV_CODEC_ID_PCM_F32LE ||
           codec_id == AV_CODEC_ID_PCM_F64LE;
}

static int mov_pcm_be_gt16(enum AVCodecID codec_id)
{
    return codec_id == AV_CODEC_ID_PCM_S24BE ||
           codec_id == AV_CODEC_ID_PCM_S32BE ||
           codec_id == AV_CODEC_ID_PCM_F32BE ||
           codec_id == AV_CODEC_ID_PCM_F64BE;
}

static int mov_write_ms_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0);
    avio_wl32(pb, track->tag); // store it byteswapped
    track->enc->codec_tag = av_bswap16(track->tag >> 16);
    ff_put_wav_header(pb, track->enc);
    return update_size(pb, pos);
}

static int mov_write_wfex_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0);
    ffio_wfourcc(pb, "wfex");
    ff_put_wav_header(pb, track->enc);
    return update_size(pb, pos);
}

static int mov_write_chan_tag(AVIOContext *pb, MOVTrack *track)
{
    uint32_t layout_tag, bitmap;
    int64_t pos = avio_tell(pb);

    layout_tag = ff_mov_get_channel_layout_tag(track->enc->codec_id,
                                               track->enc->channel_layout,
                                               &bitmap);
    if (!layout_tag) {
        av_log(track->enc, AV_LOG_WARNING, "not writing 'chan' tag due to "
               "lack of channel information\n");
        return 0;
    }

    avio_wb32(pb, 0);           // Size
    ffio_wfourcc(pb, "chan");   // Type
    avio_w8(pb, 0);             // Version
    avio_wb24(pb, 0);           // Flags
    avio_wb32(pb, layout_tag);  // mChannelLayoutTag
    avio_wb32(pb, bitmap);      // mChannelBitmap
    avio_wb32(pb, 0);           // mNumberChannelDescriptions

    return update_size(pb, pos);
}

static int mov_write_wave_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);

    avio_wb32(pb, 0);     /* size */
    ffio_wfourcc(pb, "wave");

    if (track->enc->codec_id != AV_CODEC_ID_QDM2) {
    avio_wb32(pb, 12);    /* size */
    ffio_wfourcc(pb, "frma");
    avio_wl32(pb, track->tag);
    }

    if (track->enc->codec_id == AV_CODEC_ID_AAC) {
        /* useless atom needed by mplayer, ipod, not needed by quicktime */
        avio_wb32(pb, 12); /* size */
        ffio_wfourcc(pb, "mp4a");
        avio_wb32(pb, 0);
        mov_write_esds_tag(pb, track);
    } else if (mov_pcm_le_gt16(track->enc->codec_id))  {
      mov_write_enda_tag(pb);
    } else if (mov_pcm_be_gt16(track->enc->codec_id))  {
      mov_write_enda_tag_be(pb);
    } else if (track->enc->codec_id == AV_CODEC_ID_AMR_NB) {
        mov_write_amr_tag(pb, track);
    } else if (track->enc->codec_id == AV_CODEC_ID_AC3) {
        mov_write_ac3_tag(pb, track);
    } else if (track->enc->codec_id == AV_CODEC_ID_ALAC ||
               track->enc->codec_id == AV_CODEC_ID_QDM2) {
        mov_write_extradata_tag(pb, track);
    } else if (track->enc->codec_id == AV_CODEC_ID_ADPCM_MS ||
               track->enc->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV) {
        mov_write_ms_tag(pb, track);
    }

    avio_wb32(pb, 8);     /* size */
    avio_wb32(pb, 0);     /* null tag */

    return update_size(pb, pos);
}

static int mov_write_dvc1_structs(MOVTrack *track, uint8_t *buf)
{
    uint8_t *unescaped;
    const uint8_t *start, *next, *end = track->vos_data + track->vos_len;
    int unescaped_size, seq_found = 0;
    int level = 0, interlace = 0;
    int packet_seq   = track->vc1_info.packet_seq;
    int packet_entry = track->vc1_info.packet_entry;
    int slices       = track->vc1_info.slices;
    PutBitContext pbc;

    if (track->start_dts == AV_NOPTS_VALUE) {
        /* No packets written yet, vc1_info isn't authoritative yet. */
        /* Assume inline sequence and entry headers. This will be
         * overwritten at the end if the file is seekable. */
        packet_seq = packet_entry = 1;
    }

    unescaped = av_mallocz(track->vos_len + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!unescaped)
        return AVERROR(ENOMEM);
    start = find_next_marker(track->vos_data, end);
    for (next = start; next < end; start = next) {
        GetBitContext gb;
        int size;
        next = find_next_marker(start + 4, end);
        size = next - start - 4;
        if (size <= 0)
            continue;
        unescaped_size = vc1_unescape_buffer(start + 4, size, unescaped);
        init_get_bits(&gb, unescaped, 8 * unescaped_size);
        if (AV_RB32(start) == VC1_CODE_SEQHDR) {
            int profile = get_bits(&gb, 2);
            if (profile != PROFILE_ADVANCED) {
                av_free(unescaped);
                return AVERROR(ENOSYS);
            }
            seq_found = 1;
            level = get_bits(&gb, 3);
            /* chromaformat, frmrtq_postproc, bitrtq_postproc, postprocflag,
             * width, height */
            skip_bits_long(&gb, 2 + 3 + 5 + 1 + 2*12);
            skip_bits(&gb, 1); /* broadcast */
            interlace = get_bits1(&gb);
            skip_bits(&gb, 4); /* tfcntrflag, finterpflag, reserved, psf */
        }
    }
    if (!seq_found) {
        av_free(unescaped);
        return AVERROR(ENOSYS);
    }

    init_put_bits(&pbc, buf, 7);
    /* VC1DecSpecStruc */
    put_bits(&pbc, 4, 12); /* profile - advanced */
    put_bits(&pbc, 3, level);
    put_bits(&pbc, 1, 0); /* reserved */
    /* VC1AdvDecSpecStruc */
    put_bits(&pbc, 3, level);
    put_bits(&pbc, 1, 0); /* cbr */
    put_bits(&pbc, 6, 0); /* reserved */
    put_bits(&pbc, 1, !interlace); /* no interlace */
    put_bits(&pbc, 1, !packet_seq); /* no multiple seq */
    put_bits(&pbc, 1, !packet_entry); /* no multiple entry */
    put_bits(&pbc, 1, !slices); /* no slice code */
    put_bits(&pbc, 1, 0); /* no bframe */
    put_bits(&pbc, 1, 0); /* reserved */
    put_bits32(&pbc, track->enc->time_base.den); /* framerate */
    flush_put_bits(&pbc);

    av_free(unescaped);

    return 0;
}

static int mov_write_dvc1_tag(AVIOContext *pb, MOVTrack *track)
{
    uint8_t buf[7] = { 0 };
    int ret;

    if ((ret = mov_write_dvc1_structs(track, buf)) < 0)
        return ret;

    avio_wb32(pb, track->vos_len + 8 + sizeof(buf));
    ffio_wfourcc(pb, "dvc1");
    track->vc1_info.struct_offset = avio_tell(pb);
    avio_write(pb, buf, sizeof(buf));
    avio_write(pb, track->vos_data, track->vos_len);

    return 0;
}

static int mov_write_glbl_tag(AVIOContext *pb, MOVTrack *track)
{
    avio_wb32(pb, track->vos_len + 8);
    ffio_wfourcc(pb, "glbl");
    avio_write(pb, track->vos_data, track->vos_len);
    return 8 + track->vos_len;
}

/**
 * Compute flags for 'lpcm' tag.
 * See CoreAudioTypes and AudioStreamBasicDescription at Apple.
 */
static int mov_get_lpcm_flags(enum AVCodecID codec_id)
{
    switch (codec_id) {
    case AV_CODEC_ID_PCM_F32BE:
    case AV_CODEC_ID_PCM_F64BE:
        return 11;
    case AV_CODEC_ID_PCM_F32LE:
    case AV_CODEC_ID_PCM_F64LE:
        return 9;
    case AV_CODEC_ID_PCM_U8:
        return 10;
    case AV_CODEC_ID_PCM_S16BE:
    case AV_CODEC_ID_PCM_S24BE:
    case AV_CODEC_ID_PCM_S32BE:
        return 14;
    case AV_CODEC_ID_PCM_S8:
    case AV_CODEC_ID_PCM_S16LE:
    case AV_CODEC_ID_PCM_S24LE:
    case AV_CODEC_ID_PCM_S32LE:
        return 12;
    default:
        return 0;
    }
}

static int get_cluster_duration(MOVTrack *track, int cluster_idx)
{
    int64_t next_dts;

    if (cluster_idx >= track->entry)
        return 0;

    if (cluster_idx + 1 == track->entry)
        next_dts = track->track_duration + track->start_dts;
    else
        next_dts = track->cluster[cluster_idx + 1].dts;

    next_dts -= track->cluster[cluster_idx].dts;

    av_assert0(next_dts >= 0);
    av_assert0(next_dts <= INT_MAX);

    return next_dts;
}

static int get_samples_per_packet(MOVTrack *track)
{
    int i, first_duration;

// return track->enc->frame_size;

    /* use 1 for raw PCM */
    if (!track->audio_vbr)
        return 1;

    /* check to see if duration is constant for all clusters */
    if (!track->entry)
        return 0;
    first_duration = get_cluster_duration(track, 0);
    for (i = 1; i < track->entry; i++) {
        if (get_cluster_duration(track, i) != first_duration)
            return 0;
    }
    return first_duration;
}

static int mov_write_audio_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    int version = 0;
    uint32_t tag = track->tag;

    if (track->mode == MODE_MOV) {
        if (track->timescale > UINT16_MAX) {
            if (mov_get_lpcm_flags(track->enc->codec_id))
                tag = AV_RL32("lpcm");
            version = 2;
        } else if (track->audio_vbr || mov_pcm_le_gt16(track->enc->codec_id) ||
                   mov_pcm_be_gt16(track->enc->codec_id) ||
                   track->enc->codec_id == AV_CODEC_ID_ADPCM_MS ||
                   track->enc->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV ||
                   track->enc->codec_id == AV_CODEC_ID_QDM2) {
            version = 1;
        }
    }

    avio_wb32(pb, 0); /* size */
    avio_wl32(pb, tag); // store it byteswapped
    avio_wb32(pb, 0); /* Reserved */
    avio_wb16(pb, 0); /* Reserved */
    avio_wb16(pb, 1); /* Data-reference index, XXX  == 1 */

    /* SoundDescription */
    avio_wb16(pb, version); /* Version */
    avio_wb16(pb, 0); /* Revision level */
    avio_wb32(pb, 0); /* Reserved */

    if (version == 2) {
        avio_wb16(pb, 3);
        avio_wb16(pb, 16);
        avio_wb16(pb, 0xfffe);
        avio_wb16(pb, 0);
        avio_wb32(pb, 0x00010000);
        avio_wb32(pb, 72);
        avio_wb64(pb, av_double2int(track->enc->sample_rate));
        avio_wb32(pb, track->enc->channels);
        avio_wb32(pb, 0x7F000000);
        avio_wb32(pb, av_get_bits_per_sample(track->enc->codec_id));
        avio_wb32(pb, mov_get_lpcm_flags(track->enc->codec_id));
        avio_wb32(pb, track->sample_size);
        avio_wb32(pb, get_samples_per_packet(track));
    } else {
        if (track->mode == MODE_MOV) {
            avio_wb16(pb, track->enc->channels);
            if (track->enc->codec_id == AV_CODEC_ID_PCM_U8 ||
                track->enc->codec_id == AV_CODEC_ID_PCM_S8)
                avio_wb16(pb, 8); /* bits per sample */
            else
                avio_wb16(pb, 16);
            avio_wb16(pb, track->audio_vbr ? -2 : 0); /* compression ID */
        } else { /* reserved for mp4/3gp */
            avio_wb16(pb, 2);
            avio_wb16(pb, 16);
            avio_wb16(pb, 0);
        }

        avio_wb16(pb, 0); /* packet size (= 0) */
        avio_wb16(pb, track->enc->sample_rate <= UINT16_MAX ?
                      track->enc->sample_rate : 0);
        avio_wb16(pb, 0); /* Reserved */
    }

    if (version == 1) { /* SoundDescription V1 extended info */
        if (mov_pcm_le_gt16(track->enc->codec_id) ||
            mov_pcm_be_gt16(track->enc->codec_id))
            avio_wb32(pb, 1); /*  must be 1 for  uncompressed formats */
        else
            avio_wb32(pb, track->enc->frame_size); /* Samples per packet */
        avio_wb32(pb, track->sample_size / track->enc->channels); /* Bytes per packet */
        avio_wb32(pb, track->sample_size); /* Bytes per frame */
        avio_wb32(pb, 2); /* Bytes per sample */
    }

    if (track->mode == MODE_MOV &&
        (track->enc->codec_id == AV_CODEC_ID_AAC           ||
         track->enc->codec_id == AV_CODEC_ID_AC3           ||
         track->enc->codec_id == AV_CODEC_ID_AMR_NB        ||
         track->enc->codec_id == AV_CODEC_ID_ALAC          ||
         track->enc->codec_id == AV_CODEC_ID_ADPCM_MS      ||
         track->enc->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV ||
         track->enc->codec_id == AV_CODEC_ID_QDM2          ||
         (mov_pcm_le_gt16(track->enc->codec_id) && version==1) ||
         (mov_pcm_be_gt16(track->enc->codec_id) && version==1)))
        mov_write_wave_tag(pb, track);
    else if (track->tag == MKTAG('m','p','4','a'))
        mov_write_esds_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_AMR_NB)
        mov_write_amr_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_AC3)
        mov_write_ac3_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_ALAC)
        mov_write_extradata_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_WMAPRO)
        mov_write_wfex_tag(pb, track);
    else if (track->vos_len > 0)
        mov_write_glbl_tag(pb, track);

    if (track->mode == MODE_MOV && track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
        mov_write_chan_tag(pb, track);

    return update_size(pb, pos);
}

static int mov_write_d263_tag(AVIOContext *pb)
{
    avio_wb32(pb, 0xf); /* size */
    ffio_wfourcc(pb, "d263");
    ffio_wfourcc(pb, "FFMP");
    avio_w8(pb, 0); /* decoder version */
    /* FIXME use AVCodecContext level/profile, when encoder will set values */
    avio_w8(pb, 0xa); /* level */
    avio_w8(pb, 0); /* profile */
    return 0xf;
}

static int mov_write_avcc_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);

    avio_wb32(pb, 0);
    ffio_wfourcc(pb, "avcC");
    ff_isom_write_avcc(pb, track->vos_data, track->vos_len);
    return update_size(pb, pos);
}

static int mov_write_hvcc_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);

    avio_wb32(pb, 0);
    ffio_wfourcc(pb, "hvcC");
    ff_isom_write_hvcc(pb, track->vos_data, track->vos_len, 0);
    return update_size(pb, pos);
}

/* also used by all avid codecs (dv, imx, meridien) and their variants */
static int mov_write_avid_tag(AVIOContext *pb, MOVTrack *track)
{
    int i;
    avio_wb32(pb, 24); /* size */
    ffio_wfourcc(pb, "ACLR");
    ffio_wfourcc(pb, "ACLR");
    ffio_wfourcc(pb, "0001");
    avio_wb32(pb, 2); /* yuv range: full 1 / normal 2 */
    avio_wb32(pb, 0); /* unknown */

    avio_wb32(pb, 24); /* size */
    ffio_wfourcc(pb, "APRG");
    ffio_wfourcc(pb, "APRG");
    ffio_wfourcc(pb, "0001");
    avio_wb32(pb, 1); /* unknown */
    avio_wb32(pb, 0); /* unknown */

    avio_wb32(pb, 120); /* size */
    ffio_wfourcc(pb, "ARES");
    ffio_wfourcc(pb, "ARES");
    ffio_wfourcc(pb, "0001");
    avio_wb32(pb, AV_RB32(track->vos_data + 0x28)); /* dnxhd cid, some id ? */
    avio_wb32(pb, track->enc->width);
    /* values below are based on samples created with quicktime and avid codecs */
    if (track->vos_data[5] & 2) { // interlaced
        avio_wb32(pb, track->enc->height / 2);
        avio_wb32(pb, 2); /* unknown */
        avio_wb32(pb, 0); /* unknown */
        avio_wb32(pb, 4); /* unknown */
    } else {
        avio_wb32(pb, track->enc->height);
        avio_wb32(pb, 1); /* unknown */
        avio_wb32(pb, 0); /* unknown */
        if (track->enc->height == 1080)
            avio_wb32(pb, 5); /* unknown */
        else
            avio_wb32(pb, 6); /* unknown */
    }
    /* padding */
    for (i = 0; i < 10; i++)
        avio_wb64(pb, 0);

    /* extra padding for stsd needed */
    avio_wb32(pb, 0);
    return 0;
}

static int mp4_get_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag = track->enc->codec_tag;

    if (!ff_codec_get_tag(ff_mp4_obj_type, track->enc->codec_id))
        return 0;

    if      (track->enc->codec_id == AV_CODEC_ID_H264)      tag = MKTAG('a','v','c','1');
    else if (track->enc->codec_id == AV_CODEC_ID_HEVC)      tag = MKTAG('h','e','v','1');
    else if (track->enc->codec_id == AV_CODEC_ID_AC3)       tag = MKTAG('a','c','-','3');
    else if (track->enc->codec_id == AV_CODEC_ID_DIRAC)     tag = MKTAG('d','r','a','c');
    else if (track->enc->codec_id == AV_CODEC_ID_MOV_TEXT)  tag = MKTAG('t','x','3','g');
    else if (track->enc->codec_id == AV_CODEC_ID_VC1)       tag = MKTAG('v','c','-','1');
    else if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO)  tag = MKTAG('m','p','4','v');
    else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO)  tag = MKTAG('m','p','4','a');

    return tag;
}

static const AVCodecTag codec_ipod_tags[] = {
    { AV_CODEC_ID_H264,     MKTAG('a','v','c','1') },
    { AV_CODEC_ID_MPEG4,    MKTAG('m','p','4','v') },
    { AV_CODEC_ID_AAC,      MKTAG('m','p','4','a') },
    { AV_CODEC_ID_ALAC,     MKTAG('a','l','a','c') },
    { AV_CODEC_ID_AC3,      MKTAG('a','c','-','3') },
    { AV_CODEC_ID_MOV_TEXT, MKTAG('t','x','3','g') },
    { AV_CODEC_ID_MOV_TEXT, MKTAG('t','e','x','t') },
    { AV_CODEC_ID_NONE, 0 },
};

static int ipod_get_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag = track->enc->codec_tag;

    // keep original tag for subs, ipod supports both formats
    if (!(track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE &&
          (tag == MKTAG('t', 'x', '3', 'g') ||
           tag == MKTAG('t', 'e', 'x', 't'))))
        tag = ff_codec_get_tag(codec_ipod_tags, track->enc->codec_id);

    if (!av_match_ext(s->filename, "m4a") && !av_match_ext(s->filename, "m4v"))
        av_log(s, AV_LOG_WARNING, "Warning, extension is not .m4a nor .m4v "
               "Quicktime/Ipod might not play the file\n");

    return tag;
}

static int mov_get_dv_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag;

    if (track->enc->width == 720) { /* SD */
        if (track->enc->height == 480) { /* NTSC */
            if  (track->enc->pix_fmt == AV_PIX_FMT_YUV422P) tag = MKTAG('d','v','5','n');
            else                                            tag = MKTAG('d','v','c',' ');
       }else if (track->enc->pix_fmt == AV_PIX_FMT_YUV422P) tag = MKTAG('d','v','5','p');
        else if (track->enc->pix_fmt == AV_PIX_FMT_YUV420P) tag = MKTAG('d','v','c','p');
        else                                                tag = MKTAG('d','v','p','p');
    } else if (track->enc->height == 720) { /* HD 720 line */
        if  (track->enc->time_base.den == 50)               tag = MKTAG('d','v','h','q');
        else                                                tag = MKTAG('d','v','h','p');
    } else if (track->enc->height == 1080) { /* HD 1080 line */
        if  (track->enc->time_base.den == 25)               tag = MKTAG('d','v','h','5');
        else                                                tag = MKTAG('d','v','h','6');
    } else {
        av_log(s, AV_LOG_ERROR, "unsupported height for dv codec\n");
        return 0;
    }

    return tag;
}

static AVRational find_fps(AVFormatContext *s, AVStream *st)
{
    AVRational rate = {st->codec->time_base.den, st->codec->time_base.num};
    /* if the codec time base makes no sense, try to fallback on stream frame rate */
    if (av_timecode_check_frame_rate(rate) < 0) {
        av_log(s, AV_LOG_DEBUG, "timecode: tbc=%d/%d invalid, fallback on %d/%d\n",
               rate.num, rate.den, st->avg_frame_rate.num, st->avg_frame_rate.den);
        rate = st->avg_frame_rate;
    }

    return rate;
}

static int mov_get_mpeg2_xdcam_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag = track->enc->codec_tag;
    int interlaced = track->enc->field_order > AV_FIELD_PROGRESSIVE;
    AVStream *st = track->st;
    int rate = av_q2d(find_fps(s, st));

    if (!tag)
        tag = MKTAG('m', '2', 'v', '1'); //fallback tag

    if (track->enc->pix_fmt == AV_PIX_FMT_YUV420P) {
        if (track->enc->width == 1280 && track->enc->height == 720) {
            if (!interlaced) {
                if      (rate == 24) tag = MKTAG('x','d','v','4');
                else if (rate == 25) tag = MKTAG('x','d','v','5');
                else if (rate == 30) tag = MKTAG('x','d','v','1');
                else if (rate == 50) tag = MKTAG('x','d','v','a');
                else if (rate == 60) tag = MKTAG('x','d','v','9');
            }
        } else if (track->enc->width == 1440 && track->enc->height == 1080) {
            if (!interlaced) {
                if      (rate == 24) tag = MKTAG('x','d','v','6');
                else if (rate == 25) tag = MKTAG('x','d','v','7');
                else if (rate == 30) tag = MKTAG('x','d','v','8');
            } else {
                if      (rate == 25) tag = MKTAG('x','d','v','3');
                else if (rate == 30) tag = MKTAG('x','d','v','2');
            }
        } else if (track->enc->width == 1920 && track->enc->height == 1080) {
            if (!interlaced) {
                if      (rate == 24) tag = MKTAG('x','d','v','d');
                else if (rate == 25) tag = MKTAG('x','d','v','e');
                else if (rate == 30) tag = MKTAG('x','d','v','f');
            } else {
                if      (rate == 25) tag = MKTAG('x','d','v','c');
                else if (rate == 30) tag = MKTAG('x','d','v','b');
            }
        }
    } else if (track->enc->pix_fmt == AV_PIX_FMT_YUV422P) {
        if (track->enc->width == 1280 && track->enc->height == 720) {
            if (!interlaced) {
                if      (rate == 24) tag = MKTAG('x','d','5','4');
                else if (rate == 25) tag = MKTAG('x','d','5','5');
                else if (rate == 30) tag = MKTAG('x','d','5','1');
                else if (rate == 50) tag = MKTAG('x','d','5','a');
                else if (rate == 60) tag = MKTAG('x','d','5','9');
            }
        } else if (track->enc->width == 1920 && track->enc->height == 1080) {
            if (!interlaced) {
                if      (rate == 24) tag = MKTAG('x','d','5','d');
                else if (rate == 25) tag = MKTAG('x','d','5','e');
                else if (rate == 30) tag = MKTAG('x','d','5','f');
            } else {
                if      (rate == 25) tag = MKTAG('x','d','5','c');
                else if (rate == 30) tag = MKTAG('x','d','5','b');
            }
        }
    }

    return tag;
}

static const struct {
    enum AVPixelFormat pix_fmt;
    uint32_t tag;
    unsigned bps;
} mov_pix_fmt_tags[] = {
    { AV_PIX_FMT_YUYV422, MKTAG('y','u','v','2'),  0 },
    { AV_PIX_FMT_YUYV422, MKTAG('y','u','v','s'),  0 },
    { AV_PIX_FMT_UYVY422, MKTAG('2','v','u','y'),  0 },
    { AV_PIX_FMT_RGB555BE,MKTAG('r','a','w',' '), 16 },
    { AV_PIX_FMT_RGB555LE,MKTAG('L','5','5','5'), 16 },
    { AV_PIX_FMT_RGB565LE,MKTAG('L','5','6','5'), 16 },
    { AV_PIX_FMT_RGB565BE,MKTAG('B','5','6','5'), 16 },
    { AV_PIX_FMT_GRAY16BE,MKTAG('b','1','6','g'), 16 },
    { AV_PIX_FMT_RGB24,   MKTAG('r','a','w',' '), 24 },
    { AV_PIX_FMT_BGR24,   MKTAG('2','4','B','G'), 24 },
    { AV_PIX_FMT_ARGB,    MKTAG('r','a','w',' '), 32 },
    { AV_PIX_FMT_BGRA,    MKTAG('B','G','R','A'), 32 },
    { AV_PIX_FMT_RGBA,    MKTAG('R','G','B','A'), 32 },
    { AV_PIX_FMT_ABGR,    MKTAG('A','B','G','R'), 32 },
    { AV_PIX_FMT_RGB48BE, MKTAG('b','4','8','r'), 48 },
};

static int mov_get_rawvideo_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag = track->enc->codec_tag;
    int i;

    for (i = 0; i < FF_ARRAY_ELEMS(mov_pix_fmt_tags); i++) {
        if (track->enc->pix_fmt == mov_pix_fmt_tags[i].pix_fmt) {
            tag = mov_pix_fmt_tags[i].tag;
            track->enc->bits_per_coded_sample = mov_pix_fmt_tags[i].bps;
            if (track->enc->codec_tag == mov_pix_fmt_tags[i].tag)
                break;
        }
    }

    return tag;
}

static int mov_get_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag = track->enc->codec_tag;

    if (!tag || (track->enc->strict_std_compliance >= FF_COMPLIANCE_NORMAL &&
                 (track->enc->codec_id == AV_CODEC_ID_DVVIDEO ||
                  track->enc->codec_id == AV_CODEC_ID_RAWVIDEO ||
                  track->enc->codec_id == AV_CODEC_ID_H263 ||
                  track->enc->codec_id == AV_CODEC_ID_MPEG2VIDEO ||
                  av_get_bits_per_sample(track->enc->codec_id)))) { // pcm audio
        if (track->enc->codec_id == AV_CODEC_ID_DVVIDEO)
            tag = mov_get_dv_codec_tag(s, track);
        else if (track->enc->codec_id == AV_CODEC_ID_RAWVIDEO)
            tag = mov_get_rawvideo_codec_tag(s, track);
        else if (track->enc->codec_id == AV_CODEC_ID_MPEG2VIDEO)
            tag = mov_get_mpeg2_xdcam_codec_tag(s, track);
        else if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            tag = ff_codec_get_tag(ff_codec_movvideo_tags, track->enc->codec_id);
            if (!tag) { // if no mac fcc found, try with Microsoft tags
                tag = ff_codec_get_tag(ff_codec_bmp_tags, track->enc->codec_id);
                if (tag)
                    av_log(s, AV_LOG_WARNING, "Using MS style video codec tag, "
                           "the file may be unplayable!\n");
            }
        } else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO) {
            tag = ff_codec_get_tag(ff_codec_movaudio_tags, track->enc->codec_id);
            if (!tag) { // if no mac fcc found, try with Microsoft tags
                int ms_tag = ff_codec_get_tag(ff_codec_wav_tags, track->enc->codec_id);
                if (ms_tag) {
                    tag = MKTAG('m', 's', ((ms_tag >> 8) & 0xff), (ms_tag & 0xff));
                    av_log(s, AV_LOG_WARNING, "Using MS style audio codec tag, "
                           "the file may be unplayable!\n");
                }
            }
        } else if (track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE)
            tag = ff_codec_get_tag(ff_codec_movsubtitle_tags, track->enc->codec_id);
    }

    return tag;
}

static const AVCodecTag codec_3gp_tags[] = {
    { AV_CODEC_ID_H263,     MKTAG('s','2','6','3') },
    { AV_CODEC_ID_H264,     MKTAG('a','v','c','1') },
    { AV_CODEC_ID_MPEG4,    MKTAG('m','p','4','v') },
    { AV_CODEC_ID_AAC,      MKTAG('m','p','4','a') },
    { AV_CODEC_ID_AMR_NB,   MKTAG('s','a','m','r') },
    { AV_CODEC_ID_AMR_WB,   MKTAG('s','a','w','b') },
    { AV_CODEC_ID_MOV_TEXT, MKTAG('t','x','3','g') },
    { AV_CODEC_ID_NONE, 0 },
};

static const AVCodecTag codec_f4v_tags[] = { // XXX: add GIF/PNG/JPEG?
    { AV_CODEC_ID_MP3,    MKTAG('.','m','p','3') },
    { AV_CODEC_ID_AAC,    MKTAG('m','p','4','a') },
    { AV_CODEC_ID_H264,   MKTAG('a','v','c','1') },
    { AV_CODEC_ID_VP6A,   MKTAG('V','P','6','A') },
    { AV_CODEC_ID_VP6F,   MKTAG('V','P','6','F') },
    { AV_CODEC_ID_NONE, 0 },
};

static int mov_find_codec_tag(AVFormatContext *s, MOVTrack *track)
{
    int tag;

    if (track->mode == MODE_MP4 || track->mode == MODE_PSP)
        tag = mp4_get_codec_tag(s, track);
    else if (track->mode == MODE_ISM) {
        tag = mp4_get_codec_tag(s, track);
        if (!tag && track->enc->codec_id == AV_CODEC_ID_WMAPRO)
            tag = MKTAG('w', 'm', 'a', ' ');
    } else if (track->mode == MODE_IPOD)
        tag = ipod_get_codec_tag(s, track);
    else if (track->mode & MODE_3GP)
        tag = ff_codec_get_tag(codec_3gp_tags, track->enc->codec_id);
    else if (track->mode == MODE_F4V)
        tag = ff_codec_get_tag(codec_f4v_tags, track->enc->codec_id);
    else
        tag = mov_get_codec_tag(s, track);

    return tag;
}

/** Write uuid atom.
 * Needed to make file play in iPods running newest firmware
 * goes after avcC atom in moov.trak.mdia.minf.stbl.stsd.avc1
 */
static int mov_write_uuid_tag_ipod(AVIOContext *pb)
{
    avio_wb32(pb, 28);
    ffio_wfourcc(pb, "uuid");
    avio_wb32(pb, 0x6b6840f2);
    avio_wb32(pb, 0x5f244fc5);
    avio_wb32(pb, 0xba39a51b);
    avio_wb32(pb, 0xcf0323f3);
    avio_wb32(pb, 0x0);
    return 28;
}

static const uint16_t fiel_data[] = {
    0x0000, 0x0100, 0x0201, 0x0206, 0x0209, 0x020e
};

static int mov_write_fiel_tag(AVIOContext *pb, MOVTrack *track)
{
    unsigned mov_field_order = 0;
    if (track->enc->field_order < FF_ARRAY_ELEMS(fiel_data))
        mov_field_order = fiel_data[track->enc->field_order];
    else
        return 0;
    avio_wb32(pb, 10);
    ffio_wfourcc(pb, "fiel");
    avio_wb16(pb, mov_field_order);
    return 10;
}

static int mov_write_subtitle_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0);    /* size */
    avio_wl32(pb, track->tag); // store it byteswapped
    avio_wb32(pb, 0);    /* Reserved */
    avio_wb16(pb, 0);    /* Reserved */
    avio_wb16(pb, 1);    /* Data-reference index */

    if (track->enc->extradata_size)
        avio_write(pb, track->enc->extradata, track->enc->extradata_size);

    return update_size(pb, pos);
}

static int mov_write_pasp_tag(AVIOContext *pb, MOVTrack *track)
{
    AVRational sar;
    av_reduce(&sar.num, &sar.den, track->enc->sample_aspect_ratio.num,
              track->enc->sample_aspect_ratio.den, INT_MAX);

    avio_wb32(pb, 16);
    ffio_wfourcc(pb, "pasp");
    avio_wb32(pb, sar.num);
    avio_wb32(pb, sar.den);
    return 16;
}

static void find_compressor(char * compressor_name, int len, MOVTrack *track)
{
    int xdcam_res =  (track->enc->width == 1280 && track->enc->height == 720)
                  || (track->enc->width == 1440 && track->enc->height == 1080)
                  || (track->enc->width == 1920 && track->enc->height == 1080);

    if (track->mode == MODE_MOV && track->enc->codec && track->enc->codec->name) {
        av_strlcpy(compressor_name, track->enc->codec->name, 32);
    } else if (track->enc->codec_id == AV_CODEC_ID_MPEG2VIDEO && xdcam_res) {
        int interlaced = track->enc->field_order > AV_FIELD_PROGRESSIVE;
        AVStream *st = track->st;
        int rate = av_q2d(find_fps(NULL, st));
        av_strlcatf(compressor_name, len, "XDCAM");
        if (track->enc->pix_fmt == AV_PIX_FMT_YUV422P) {
            av_strlcatf(compressor_name, len, " HD422");
        } else if(track->enc->width == 1440) {
            av_strlcatf(compressor_name, len, " HD");
        } else
            av_strlcatf(compressor_name, len, " EX");

        av_strlcatf(compressor_name, len, " %d%c", track->enc->height, interlaced ? 'i' : 'p');

        av_strlcatf(compressor_name, len, "%d", rate * (interlaced + 1));
    }
}

static int mov_write_video_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    char compressor_name[32] = { 0 };

    avio_wb32(pb, 0); /* size */
    avio_wl32(pb, track->tag); // store it byteswapped
    avio_wb32(pb, 0); /* Reserved */
    avio_wb16(pb, 0); /* Reserved */
    avio_wb16(pb, 1); /* Data-reference index */

    avio_wb16(pb, 0); /* Codec stream version */
    avio_wb16(pb, 0); /* Codec stream revision (=0) */
    if (track->mode == MODE_MOV) {
        ffio_wfourcc(pb, "FFMP"); /* Vendor */
        if (track->enc->codec_id == AV_CODEC_ID_RAWVIDEO) {
            avio_wb32(pb, 0); /* Temporal Quality */
            avio_wb32(pb, 0x400); /* Spatial Quality = lossless*/
        } else {
            avio_wb32(pb, 0x200); /* Temporal Quality = normal */
            avio_wb32(pb, 0x200); /* Spatial Quality = normal */
        }
    } else {
        avio_wb32(pb, 0); /* Reserved */
        avio_wb32(pb, 0); /* Reserved */
        avio_wb32(pb, 0); /* Reserved */
    }
    avio_wb16(pb, track->enc->width); /* Video width */
    avio_wb16(pb, track->height); /* Video height */
    avio_wb32(pb, 0x00480000); /* Horizontal resolution 72dpi */
    avio_wb32(pb, 0x00480000); /* Vertical resolution 72dpi */
    avio_wb32(pb, 0); /* Data size (= 0) */
    avio_wb16(pb, 1); /* Frame count (= 1) */

    /* FIXME not sure, ISO 14496-1 draft where it shall be set to 0 */
    find_compressor(compressor_name, 32, track);
    avio_w8(pb, strlen(compressor_name));
    avio_write(pb, compressor_name, 31);

    if (track->mode == MODE_MOV && track->enc->bits_per_coded_sample)
        avio_wb16(pb, track->enc->bits_per_coded_sample);
    else
        avio_wb16(pb, 0x18); /* Reserved */
    avio_wb16(pb, 0xffff); /* Reserved */
    if (track->tag == MKTAG('m','p','4','v'))
        mov_write_esds_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_H263)
        mov_write_d263_tag(pb);
    else if (track->enc->codec_id == AV_CODEC_ID_AVUI ||
            track->enc->codec_id == AV_CODEC_ID_SVQ3) {
        mov_write_extradata_tag(pb, track);
        avio_wb32(pb, 0);
    } else if (track->enc->codec_id == AV_CODEC_ID_DNXHD)
        mov_write_avid_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_HEVC)
        mov_write_hvcc_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_H264) {
        mov_write_avcc_tag(pb, track);
        if (track->mode == MODE_IPOD)
            mov_write_uuid_tag_ipod(pb);
    } else if (track->enc->codec_id == AV_CODEC_ID_VC1 && track->vos_len > 0)
        mov_write_dvc1_tag(pb, track);
    else if (track->enc->codec_id == AV_CODEC_ID_VP6F ||
             track->enc->codec_id == AV_CODEC_ID_VP6A) {
        /* Don't write any potential extradata here - the cropping
         * is signalled via the normal width/height fields. */
    } else if (track->vos_len > 0)
        mov_write_glbl_tag(pb, track);

    if (track->enc->codec_id != AV_CODEC_ID_H264 &&
        track->enc->codec_id != AV_CODEC_ID_MPEG4 &&
        track->enc->codec_id != AV_CODEC_ID_DNXHD)
        if (track->enc->field_order != AV_FIELD_UNKNOWN)
            mov_write_fiel_tag(pb, track);

    if (track->enc->sample_aspect_ratio.den && track->enc->sample_aspect_ratio.num &&
        track->enc->sample_aspect_ratio.den != track->enc->sample_aspect_ratio.num) {
        mov_write_pasp_tag(pb, track);
    }

    return update_size(pb, pos);
}

static int mov_write_rtp_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "rtp ");
    avio_wb32(pb, 0); /* Reserved */
    avio_wb16(pb, 0); /* Reserved */
    avio_wb16(pb, 1); /* Data-reference index */

    avio_wb16(pb, 1); /* Hint track version */
    avio_wb16(pb, 1); /* Highest compatible version */
    avio_wb32(pb, track->max_packet_size); /* Max packet size */

    avio_wb32(pb, 12); /* size */
    ffio_wfourcc(pb, "tims");
    avio_wb32(pb, track->timescale);

    return update_size(pb, pos);
}

static int mov_write_tmcd_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
#if 1
    int frame_duration = av_rescale(track->timescale, track->enc->time_base.num, track->enc->time_base.den);
    int nb_frames = 1.0/av_q2d(track->enc->time_base) + 0.5;

    if (nb_frames > 255) {
        av_log(NULL, AV_LOG_ERROR, "fps %d is too large\n", nb_frames);
        return AVERROR(EINVAL);
    }

    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "tmcd");               /* Data format */
    avio_wb32(pb, 0);                       /* Reserved */
    avio_wb32(pb, 1);                       /* Data reference index */
    avio_wb32(pb, 0);                       /* Flags */
    avio_wb32(pb, track->timecode_flags);   /* Flags (timecode) */
    avio_wb32(pb, track->timescale);        /* Timescale */
    avio_wb32(pb, frame_duration);          /* Frame duration */
    avio_w8(pb, nb_frames);                 /* Number of frames */
    avio_wb24(pb, 0);                       /* Reserved */
    /* TODO: source reference string */
#else

    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "tmcd");               /* Data format */
    avio_wb32(pb, 0);                       /* Reserved */
    avio_wb32(pb, 1);                       /* Data reference index */
    if (track->enc->extradata_size)
        avio_write(pb, track->enc->extradata, track->enc->extradata_size);
#endif
    return update_size(pb, pos);
}

static int mov_write_stsd_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "stsd");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, 1); /* entry count */
    if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO)
        mov_write_video_tag(pb, track);
    else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
        mov_write_audio_tag(pb, track);
    else if (track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE)
        mov_write_subtitle_tag(pb, track);
    else if (track->enc->codec_tag == MKTAG('r','t','p',' '))
        mov_write_rtp_tag(pb, track);
    else if (track->enc->codec_tag == MKTAG('t','m','c','d'))
        mov_write_tmcd_tag(pb, track);
    return update_size(pb, pos);
}

static int mov_write_ctts_tag(AVIOContext *pb, MOVTrack *track)
{
    MOVStts *ctts_entries;
    uint32_t entries = 0;
    uint32_t atom_size;
    int i;

    ctts_entries = av_malloc((track->entry + 1) * sizeof(*ctts_entries)); /* worst case */
    ctts_entries[0].count = 1;
    ctts_entries[0].duration = track->cluster[0].cts;
    for (i = 1; i < track->entry; i++) {
        if (track->cluster[i].cts == ctts_entries[entries].duration) {
            ctts_entries[entries].count++; /* compress */
        } else {
            entries++;
            ctts_entries[entries].duration = track->cluster[i].cts;
            ctts_entries[entries].count = 1;
        }
    }
    entries++; /* last one */
    atom_size = 16 + (entries * 8);
    avio_wb32(pb, atom_size); /* size */
    ffio_wfourcc(pb, "ctts");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, entries); /* entry count */
    for (i = 0; i < entries; i++) {
        avio_wb32(pb, ctts_entries[i].count);
        avio_wb32(pb, ctts_entries[i].duration);
    }
    av_free(ctts_entries);
    return atom_size;
}

/* Time to sample atom */
static int mov_write_stts_tag(AVIOContext *pb, MOVTrack *track)
{
    MOVStts *stts_entries;
    uint32_t entries = -1;
    uint32_t atom_size;
    int i;

    if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO && !track->audio_vbr) {
        stts_entries = av_malloc(sizeof(*stts_entries)); /* one entry */
        stts_entries[0].count = track->sample_count;
        stts_entries[0].duration = 1;
        entries = 1;
    } else {
        stts_entries = track->entry ?
                       av_malloc(track->entry * sizeof(*stts_entries)) : /* worst case */
                       NULL;
        for (i = 0; i < track->entry; i++) {
            int duration = get_cluster_duration(track, i);
            if (i && duration == stts_entries[entries].duration) {
                stts_entries[entries].count++; /* compress */
            } else {
                entries++;
                stts_entries[entries].duration = duration;
                stts_entries[entries].count = 1;
            }
        }
        entries++; /* last one */
    }
    atom_size = 16 + (entries * 8);
    avio_wb32(pb, atom_size); /* size */
    ffio_wfourcc(pb, "stts");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, entries); /* entry count */
    for (i = 0; i < entries; i++) {
        avio_wb32(pb, stts_entries[i].count);
        avio_wb32(pb, stts_entries[i].duration);
    }
    av_free(stts_entries);
    return atom_size;
}

static int mov_write_dref_tag(AVIOContext *pb)
{
    avio_wb32(pb, 28); /* size */
    ffio_wfourcc(pb, "dref");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, 1); /* entry count */

    avio_wb32(pb, 0xc); /* size */
    //FIXME add the alis and rsrc atom
    ffio_wfourcc(pb, "url ");
    avio_wb32(pb, 1); /* version & flags */

    return 28;
}

static int mov_write_stbl_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "stbl");
    mov_write_stsd_tag(pb, track);
    mov_write_stts_tag(pb, track);
    if ((track->enc->codec_type == AVMEDIA_TYPE_VIDEO ||
         track->enc->codec_tag == MKTAG('r','t','p',' ')) &&
        track->has_keyframes && track->has_keyframes < track->entry)
        mov_write_stss_tag(pb, track, MOV_SYNC_SAMPLE);
    if (track->mode == MODE_MOV && track->flags & MOV_TRACK_STPS)
        mov_write_stss_tag(pb, track, MOV_PARTIAL_SYNC_SAMPLE);
    if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO &&
        track->flags & MOV_TRACK_CTTS)
        mov_write_ctts_tag(pb, track);
    mov_write_stsc_tag(pb, track);
    mov_write_stsz_tag(pb, track);
    mov_write_stco_tag(pb, track);
    return update_size(pb, pos);
}

static int mov_write_dinf_tag(AVIOContext *pb)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "dinf");
    mov_write_dref_tag(pb);
    return update_size(pb, pos);
}

static int mov_write_nmhd_tag(AVIOContext *pb)
{
    avio_wb32(pb, 12);
    ffio_wfourcc(pb, "nmhd");
    avio_wb32(pb, 0);
    return 12;
}

static int mov_write_tcmi_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    const char *font = "Lucida Grande";
    avio_wb32(pb, 0);                   /* size */
    ffio_wfourcc(pb, "tcmi");           /* timecode media information atom */
    avio_wb32(pb, 0);                   /* version & flags */
    avio_wb16(pb, 0);                   /* text font */
    avio_wb16(pb, 0);                   /* text face */
    avio_wb16(pb, 12);                  /* text size */
    avio_wb16(pb, 0);                   /* (unknown, not in the QT specs...) */
    avio_wb16(pb, 0x0000);              /* text color (red) */
    avio_wb16(pb, 0x0000);              /* text color (green) */
    avio_wb16(pb, 0x0000);              /* text color (blue) */
    avio_wb16(pb, 0xffff);              /* background color (red) */
    avio_wb16(pb, 0xffff);              /* background color (green) */
    avio_wb16(pb, 0xffff);              /* background color (blue) */
    avio_w8(pb, strlen(font));          /* font len (part of the pascal string) */
    avio_write(pb, font, strlen(font)); /* font name */
    return update_size(pb, pos);
}

static int mov_write_gmhd_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0);      /* size */
    ffio_wfourcc(pb, "gmhd");
    avio_wb32(pb, 0x18);   /* gmin size */
    ffio_wfourcc(pb, "gmin");/* generic media info */
    avio_wb32(pb, 0);      /* version & flags */
    avio_wb16(pb, 0x40);   /* graphics mode = */
    avio_wb16(pb, 0x8000); /* opColor (r?) */
    avio_wb16(pb, 0x8000); /* opColor (g?) */
    avio_wb16(pb, 0x8000); /* opColor (b?) */
    avio_wb16(pb, 0);      /* balance */
    avio_wb16(pb, 0);      /* reserved */

    /*
     * This special text atom is required for
     * Apple Quicktime chapters. The contents
     * don't appear to be documented, so the
     * bytes are copied verbatim.
     */
    if (track->tag != MKTAG('c','6','0','8')) {
    avio_wb32(pb, 0x2C);   /* size */
    ffio_wfourcc(pb, "text");
    avio_wb16(pb, 0x01);
    avio_wb32(pb, 0x00);
    avio_wb32(pb, 0x00);
    avio_wb32(pb, 0x00);
    avio_wb32(pb, 0x01);
    avio_wb32(pb, 0x00);
    avio_wb32(pb, 0x00);
    avio_wb32(pb, 0x00);
    avio_wb32(pb, 0x00004000);
    avio_wb16(pb, 0x0000);
    }

    if (track->enc->codec_tag == MKTAG('t','m','c','d')) {
        int64_t tmcd_pos = avio_tell(pb);
        avio_wb32(pb, 0); /* size */
        ffio_wfourcc(pb, "tmcd");
        mov_write_tcmi_tag(pb, track);
        update_size(pb, tmcd_pos);
    }
    return update_size(pb, pos);
}

static int mov_write_smhd_tag(AVIOContext *pb)
{
    avio_wb32(pb, 16); /* size */
    ffio_wfourcc(pb, "smhd");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb16(pb, 0); /* reserved (balance, normally = 0) */
    avio_wb16(pb, 0); /* reserved */
    return 16;
}

static int mov_write_vmhd_tag(AVIOContext *pb)
{
    avio_wb32(pb, 0x14); /* size (always 0x14) */
    ffio_wfourcc(pb, "vmhd");
    avio_wb32(pb, 0x01); /* version & flags */
    avio_wb64(pb, 0); /* reserved (graphics mode = copy) */
    return 0x14;
}

static int mov_write_hdlr_tag(AVIOContext *pb, MOVTrack *track)
{
    const char *hdlr, *descr = NULL, *hdlr_type = NULL;
    int64_t pos = avio_tell(pb);

    hdlr      = "dhlr";
    hdlr_type = "url ";
    descr     = "DataHandler";

    if (track) {
        hdlr = (track->mode == MODE_MOV) ? "mhlr" : "\0\0\0\0";
        if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            hdlr_type = "vide";
            descr     = "VideoHandler";
        } else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO) {
            hdlr_type = "soun";
            descr     = "SoundHandler";
        } else if (track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE) {
            if (track->tag == MKTAG('c','6','0','8')) {
                hdlr_type = "clcp";
                descr = "ClosedCaptionHandler";
            } else {
            if (track->tag == MKTAG('t','x','3','g')) hdlr_type = "sbtl";
            else                                      hdlr_type = "text";
            descr = "SubtitleHandler";
            }
        } else if (track->enc->codec_tag == MKTAG('r','t','p',' ')) {
            hdlr_type = "hint";
            descr     = "HintHandler";
        } else if (track->enc->codec_tag == MKTAG('t','m','c','d')) {
            hdlr_type = "tmcd";
            descr = "TimeCodeHandler";
        } else {
            char tag_buf[32];
            av_get_codec_tag_string(tag_buf, sizeof(tag_buf),
                                    track->enc->codec_tag);

            av_log(track->enc, AV_LOG_WARNING,
                   "Unknown hldr_type for %s / 0x%04X, writing dummy values\n",
                   tag_buf, track->enc->codec_tag);
        }
    }

    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "hdlr");
    avio_wb32(pb, 0); /* Version & flags */
    avio_write(pb, hdlr, 4); /* handler */
    ffio_wfourcc(pb, hdlr_type); /* handler type */
    avio_wb32(pb, 0); /* reserved */
    avio_wb32(pb, 0); /* reserved */
    avio_wb32(pb, 0); /* reserved */
    if (!track || track->mode == MODE_MOV)
        avio_w8(pb, strlen(descr)); /* pascal string */
    avio_write(pb, descr, strlen(descr)); /* handler description */
    if (track && track->mode != MODE_MOV)
        avio_w8(pb, 0); /* c string */
    return update_size(pb, pos);
}

static int mov_write_hmhd_tag(AVIOContext *pb)
{
    /* This atom must be present, but leaving the values at zero
     * seems harmless. */
    avio_wb32(pb, 28); /* size */
    ffio_wfourcc(pb, "hmhd");
    avio_wb32(pb, 0); /* version, flags */
    avio_wb16(pb, 0); /* maxPDUsize */
    avio_wb16(pb, 0); /* avgPDUsize */
    avio_wb32(pb, 0); /* maxbitrate */
    avio_wb32(pb, 0); /* avgbitrate */
    avio_wb32(pb, 0); /* reserved */
    return 28;
}

static int mov_write_minf_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "minf");
    if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO)
        mov_write_vmhd_tag(pb);
    else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
        mov_write_smhd_tag(pb);
    else if (track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE) {
        if (track->tag == MKTAG('t','e','x','t') || track->tag == MKTAG('c','6','0','8')) {
            mov_write_gmhd_tag(pb, track);
        } else {
            mov_write_nmhd_tag(pb);
        }
    } else if (track->tag == MKTAG('r','t','p',' ')) {
        mov_write_hmhd_tag(pb);
    } else if (track->tag == MKTAG('t','m','c','d')) {
        mov_write_gmhd_tag(pb, track);
    }
    if (track->mode == MODE_MOV) /* FIXME: Why do it for MODE_MOV only ? */
        mov_write_hdlr_tag(pb, NULL);
    mov_write_dinf_tag(pb);
    mov_write_stbl_tag(pb, track);
    return update_size(pb, pos);
}

static int mov_write_mdhd_tag(AVIOContext *pb, MOVTrack *track)
{
    int version = track->track_duration < INT32_MAX ? 0 : 1;

    if (track->mode == MODE_ISM)
        version = 1;

    (version == 1) ? avio_wb32(pb, 44) : avio_wb32(pb, 32); /* size */
    ffio_wfourcc(pb, "mdhd");
    avio_w8(pb, version);
    avio_wb24(pb, 0); /* flags */
    if (version == 1) {
        avio_wb64(pb, track->time);
        avio_wb64(pb, track->time);
    } else {
        avio_wb32(pb, track->time); /* creation time */
        avio_wb32(pb, track->time); /* modification time */
    }
    avio_wb32(pb, track->timescale); /* time scale (sample rate for audio) */
    if (!track->entry)
        (version == 1) ? avio_wb64(pb, UINT64_C(0xffffffffffffffff)) : avio_wb32(pb, 0xffffffff);
    else
        (version == 1) ? avio_wb64(pb, track->track_duration) : avio_wb32(pb, track->track_duration); /* duration */
    avio_wb16(pb, track->language); /* language */
    avio_wb16(pb, 0); /* reserved (quality) */

    if (version != 0 && track->mode == MODE_MOV) {
        av_log(NULL, AV_LOG_ERROR,
               "FATAL error, file duration too long for timebase, this file will not be\n"
               "playable with quicktime. Choose a different timebase or a different\n"
               "container format\n");
    }

    return 32;
}

static int mov_write_mdia_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "mdia");
    mov_write_mdhd_tag(pb, track);
    mov_write_hdlr_tag(pb, track);
    mov_write_minf_tag(pb, track);
    return update_size(pb, pos);
}

/* transformation matrix
     |a  b  u|
     |c  d  v|
     |tx ty w| */
static void write_matrix(AVIOContext *pb, int16_t a, int16_t b, int16_t c,
                         int16_t d, int16_t tx, int16_t ty)
{
    avio_wb32(pb, a << 16);  /* 16.16 format */
    avio_wb32(pb, b << 16);  /* 16.16 format */
    avio_wb32(pb, 0);        /* u in 2.30 format */
    avio_wb32(pb, c << 16);  /* 16.16 format */
    avio_wb32(pb, d << 16);  /* 16.16 format */
    avio_wb32(pb, 0);        /* v in 2.30 format */
    avio_wb32(pb, tx << 16); /* 16.16 format */
    avio_wb32(pb, ty << 16); /* 16.16 format */
    avio_wb32(pb, 1 << 30);  /* w in 2.30 format */
}

static int mov_write_tkhd_tag(AVIOContext *pb, MOVTrack *track, AVStream *st)
{
    int64_t duration = av_rescale_rnd(track->track_duration, MOV_TIMESCALE,
                                      track->timescale, AV_ROUND_UP);
    int version = duration < INT32_MAX ? 0 : 1;
    int rotation = 0;

    if (track->mode == MODE_ISM)
        version = 1;

    (version == 1) ? avio_wb32(pb, 104) : avio_wb32(pb, 92); /* size */
    ffio_wfourcc(pb, "tkhd");
    avio_w8(pb, version);
    avio_wb24(pb, (track->flags & MOV_TRACK_ENABLED) ?
                  MOV_TKHD_FLAG_ENABLED | MOV_TKHD_FLAG_IN_MOVIE :
                  MOV_TKHD_FLAG_IN_MOVIE);
    if (version == 1) {
        avio_wb64(pb, track->time);
        avio_wb64(pb, track->time);
    } else {
        avio_wb32(pb, track->time); /* creation time */
        avio_wb32(pb, track->time); /* modification time */
    }
    avio_wb32(pb, track->track_id); /* track-id */
    avio_wb32(pb, 0); /* reserved */
    if (!track->entry)
        (version == 1) ? avio_wb64(pb, UINT64_C(0xffffffffffffffff)) : avio_wb32(pb, 0xffffffff);
    else
        (version == 1) ? avio_wb64(pb, duration) : avio_wb32(pb, duration);

    avio_wb32(pb, 0); /* reserved */
    avio_wb32(pb, 0); /* reserved */
    avio_wb16(pb, 0); /* layer */
    avio_wb16(pb, st ? st->codec->codec_type : 0); /* alternate group) */
    /* Volume, only for audio */
    if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
        avio_wb16(pb, 0x0100);
    else
        avio_wb16(pb, 0);
    avio_wb16(pb, 0); /* reserved */

    /* Matrix structure */
    if (st && st->metadata) {
        AVDictionaryEntry *rot = av_dict_get(st->metadata, "rotate", NULL, 0);
        rotation = (rot && rot->value) ? atoi(rot->value) : 0;
    }
    if (rotation == 90) {
        write_matrix(pb,  0,  1, -1,  0, track->enc->height, 0);
    } else if (rotation == 180) {
        write_matrix(pb, -1,  0,  0, -1, track->enc->width, track->enc->height);
    } else if (rotation == 270) {
        write_matrix(pb,  0, -1,  1,  0, 0, track->enc->width);
    } else {
        write_matrix(pb,  1,  0,  0,  1, 0, 0);
    }
    /* Track width and height, for visual only */
    if (st && (track->enc->codec_type == AVMEDIA_TYPE_VIDEO ||
               track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE)) {
        if (track->mode == MODE_MOV) {
            avio_wb32(pb, track->enc->width << 16);
            avio_wb32(pb, track->height << 16);
        } else {
            double sample_aspect_ratio = av_q2d(st->sample_aspect_ratio);
            if (!sample_aspect_ratio || track->height != track->enc->height)
                sample_aspect_ratio = 1;
            avio_wb32(pb, sample_aspect_ratio * track->enc->width * 0x10000);
            avio_wb32(pb, track->height * 0x10000);
        }
    } else {
        avio_wb32(pb, 0);
        avio_wb32(pb, 0);
    }
    return 0x5c;
}

static int mov_write_tapt_tag(AVIOContext *pb, MOVTrack *track)
{
    int32_t width = av_rescale(track->enc->sample_aspect_ratio.num, track->enc->width,
                               track->enc->sample_aspect_ratio.den);

    int64_t pos = avio_tell(pb);

    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "tapt");

    avio_wb32(pb, 20);
    ffio_wfourcc(pb, "clef");
    avio_wb32(pb, 0);
    avio_wb32(pb, width << 16);
    avio_wb32(pb, track->enc->height << 16);

    avio_wb32(pb, 20);
    ffio_wfourcc(pb, "prof");
    avio_wb32(pb, 0);
    avio_wb32(pb, width << 16);
    avio_wb32(pb, track->enc->height << 16);

    avio_wb32(pb, 20);
    ffio_wfourcc(pb, "enof");
    avio_wb32(pb, 0);
    avio_wb32(pb, track->enc->width << 16);
    avio_wb32(pb, track->enc->height << 16);

    return update_size(pb, pos);
}

// This box seems important for the psp playback ... without it the movie seems to hang
static int mov_write_edts_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t duration = av_rescale_rnd(track->track_duration, MOV_TIMESCALE,
                                      track->timescale, AV_ROUND_UP);
    int version = duration < INT32_MAX ? 0 : 1;
    int entry_size, entry_count, size;
    int64_t delay, start_ct = track->cluster[0].cts;
    delay = av_rescale_rnd(track->cluster[0].dts + start_ct, MOV_TIMESCALE,
                           track->timescale, AV_ROUND_DOWN);
    version |= delay < INT32_MAX ? 0 : 1;

    entry_size = (version == 1) ? 20 : 12;
    entry_count = 1 + (delay > 0);
    size = 24 + entry_count * entry_size;

    /* write the atom data */
    avio_wb32(pb, size);
    ffio_wfourcc(pb, "edts");
    avio_wb32(pb, size - 8);
    ffio_wfourcc(pb, "elst");
    avio_w8(pb, version);
    avio_wb24(pb, 0); /* flags */

    avio_wb32(pb, entry_count);
    if (delay > 0) { /* add an empty edit to delay presentation */
        if (version == 1) {
            avio_wb64(pb, delay);
            avio_wb64(pb, -1);
        } else {
            avio_wb32(pb, delay);
            avio_wb32(pb, -1);
        }
        avio_wb32(pb, 0x00010000);
    } else {
        av_assert0(av_rescale_rnd(track->cluster[0].dts, MOV_TIMESCALE, track->timescale, AV_ROUND_DOWN) <= 0);
        start_ct  = -FFMIN(track->cluster[0].dts, 0); //FFMIN needed due to rounding
        duration += delay;
    }

    /* duration */
    if (version == 1) {
        avio_wb64(pb, duration);
        avio_wb64(pb, start_ct);
    } else {
        avio_wb32(pb, duration);
        avio_wb32(pb, start_ct);
    }
    avio_wb32(pb, 0x00010000);
    return size;
}

static int mov_write_tref_tag(AVIOContext *pb, MOVTrack *track)
{
    avio_wb32(pb, 20);   // size
    ffio_wfourcc(pb, "tref");
    avio_wb32(pb, 12);   // size (subatom)
    avio_wl32(pb, track->tref_tag);
    avio_wb32(pb, track->tref_id);
    return 20;
}

// goes at the end of each track!  ... Critical for PSP playback ("Incompatible data" without it)
static int mov_write_uuid_tag_psp(AVIOContext *pb, MOVTrack *mov)
{
    avio_wb32(pb, 0x34); /* size ... reports as 28 in mp4box! */
    ffio_wfourcc(pb, "uuid");
    ffio_wfourcc(pb, "USMT");
    avio_wb32(pb, 0x21d24fce);
    avio_wb32(pb, 0xbb88695c);
    avio_wb32(pb, 0xfac9c740);
    avio_wb32(pb, 0x1c);     // another size here!
    ffio_wfourcc(pb, "MTDT");
    avio_wb32(pb, 0x00010012);
    avio_wb32(pb, 0x0a);
    avio_wb32(pb, 0x55c40000);
    avio_wb32(pb, 0x1);
    avio_wb32(pb, 0x0);
    return 0x34;
}

static int mov_write_udta_sdp(AVIOContext *pb, MOVTrack *track)
{
    AVFormatContext *ctx = track->rtp_ctx;
    char buf[1000] = "";
    int len;

    ff_sdp_write_media(buf, sizeof(buf), ctx->streams[0], track->src_track,
                       NULL, NULL, 0, 0, ctx);
    av_strlcatf(buf, sizeof(buf), "a=control:streamid=%d\r\n", track->track_id);
    len = strlen(buf);

    avio_wb32(pb, len + 24);
    ffio_wfourcc(pb, "udta");
    avio_wb32(pb, len + 16);
    ffio_wfourcc(pb, "hnti");
    avio_wb32(pb, len + 8);
    ffio_wfourcc(pb, "sdp ");
    avio_write(pb, buf, len);
    return len + 24;
}

static int mov_write_trak_tag(AVIOContext *pb, MOVMuxContext *mov,
                              MOVTrack *track, AVStream *st)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "trak");
    mov_write_tkhd_tag(pb, track, st);
    if (supports_edts(mov))
        mov_write_edts_tag(pb, track);  // PSP Movies and several other cases require edts box
    if (track->tref_tag)
        mov_write_tref_tag(pb, track);
    mov_write_mdia_tag(pb, track);
    if (track->mode == MODE_PSP)
        mov_write_uuid_tag_psp(pb, track); // PSP Movies require this uuid box
    if (track->tag == MKTAG('r','t','p',' '))
        mov_write_udta_sdp(pb, track);
    if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO && track->mode == MODE_MOV) {
        double sample_aspect_ratio = av_q2d(st->sample_aspect_ratio);
        if (st->sample_aspect_ratio.num && 1.0 != sample_aspect_ratio)
            mov_write_tapt_tag(pb, track);
    }
    return update_size(pb, pos);
}

static int mov_write_iods_tag(AVIOContext *pb, MOVMuxContext *mov)
{
    int i, has_audio = 0, has_video = 0;
    int64_t pos = avio_tell(pb);
    int audio_profile = mov->iods_audio_profile;
    int video_profile = mov->iods_video_profile;
    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].entry > 0) {
            has_audio |= mov->tracks[i].enc->codec_type == AVMEDIA_TYPE_AUDIO;
            has_video |= mov->tracks[i].enc->codec_type == AVMEDIA_TYPE_VIDEO;
        }
    }
    if (audio_profile < 0)
        audio_profile = 0xFF - has_audio;
    if (video_profile < 0)
        video_profile = 0xFF - has_video;
    avio_wb32(pb, 0x0); /* size */
    ffio_wfourcc(pb, "iods");
    avio_wb32(pb, 0);    /* version & flags */
    put_descr(pb, 0x10, 7);
    avio_wb16(pb, 0x004f);
    avio_w8(pb, 0xff);
    avio_w8(pb, 0xff);
    avio_w8(pb, audio_profile);
    avio_w8(pb, video_profile);
    avio_w8(pb, 0xff);
    return update_size(pb, pos);
}

static int mov_write_trex_tag(AVIOContext *pb, MOVTrack *track)
{
    avio_wb32(pb, 0x20); /* size */
    ffio_wfourcc(pb, "trex");
    avio_wb32(pb, 0);   /* version & flags */
    avio_wb32(pb, track->track_id); /* track ID */
    avio_wb32(pb, 1);   /* default sample description index */
    avio_wb32(pb, 0);   /* default sample duration */
    avio_wb32(pb, 0);   /* default sample size */
    avio_wb32(pb, 0);   /* default sample flags */
    return 0;
}

static int mov_write_mvex_tag(AVIOContext *pb, MOVMuxContext *mov)
{
    int64_t pos = avio_tell(pb);
    int i;
    avio_wb32(pb, 0x0); /* size */
    ffio_wfourcc(pb, "mvex");
    for (i = 0; i < mov->nb_streams; i++)
        mov_write_trex_tag(pb, &mov->tracks[i]);
    return update_size(pb, pos);
}

static int mov_write_mvhd_tag(AVIOContext *pb, MOVMuxContext *mov)
{
    int max_track_id = 1, i;
    int64_t max_track_len_temp, max_track_len = 0;
    int version;

    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].entry > 0 && mov->tracks[i].timescale) {
            max_track_len_temp = av_rescale_rnd(mov->tracks[i].track_duration,
                                                MOV_TIMESCALE,
                                                mov->tracks[i].timescale,
                                                AV_ROUND_UP);
            if (max_track_len < max_track_len_temp)
                max_track_len = max_track_len_temp;
            if (max_track_id < mov->tracks[i].track_id)
                max_track_id = mov->tracks[i].track_id;
        }
    }

    version = max_track_len < UINT32_MAX ? 0 : 1;
    (version == 1) ? avio_wb32(pb, 120) : avio_wb32(pb, 108); /* size */
    ffio_wfourcc(pb, "mvhd");
    avio_w8(pb, version);
    avio_wb24(pb, 0); /* flags */
    if (version == 1) {
        avio_wb64(pb, mov->time);
        avio_wb64(pb, mov->time);
    } else {
        avio_wb32(pb, mov->time); /* creation time */
        avio_wb32(pb, mov->time); /* modification time */
    }
    avio_wb32(pb, MOV_TIMESCALE);
    (version == 1) ? avio_wb64(pb, max_track_len) : avio_wb32(pb, max_track_len); /* duration of longest track */

    avio_wb32(pb, 0x00010000); /* reserved (preferred rate) 1.0 = normal */
    avio_wb16(pb, 0x0100); /* reserved (preferred volume) 1.0 = normal */
    avio_wb16(pb, 0); /* reserved */
    avio_wb32(pb, 0); /* reserved */
    avio_wb32(pb, 0); /* reserved */

    /* Matrix structure */
    write_matrix(pb, 1, 0, 0, 1, 0, 0);

    avio_wb32(pb, 0); /* reserved (preview time) */
    avio_wb32(pb, 0); /* reserved (preview duration) */
    avio_wb32(pb, 0); /* reserved (poster time) */
    avio_wb32(pb, 0); /* reserved (selection time) */
    avio_wb32(pb, 0); /* reserved (selection duration) */
    avio_wb32(pb, 0); /* reserved (current time) */
    avio_wb32(pb, max_track_id + 1); /* Next track id */
    return 0x6c;
}

static int mov_write_itunes_hdlr_tag(AVIOContext *pb, MOVMuxContext *mov,
                                     AVFormatContext *s)
{
    avio_wb32(pb, 33); /* size */
    ffio_wfourcc(pb, "hdlr");
    avio_wb32(pb, 0);
    avio_wb32(pb, 0);
    ffio_wfourcc(pb, "mdir");
    ffio_wfourcc(pb, "appl");
    avio_wb32(pb, 0);
    avio_wb32(pb, 0);
    avio_w8(pb, 0);
    return 33;
}

/* helper function to write a data tag with the specified string as data */
static int mov_write_string_data_tag(AVIOContext *pb, const char *data, int lang, int long_style)
{
    if (long_style) {
        int size = 16 + strlen(data);
        avio_wb32(pb, size); /* size */
        ffio_wfourcc(pb, "data");
        avio_wb32(pb, 1);
        avio_wb32(pb, 0);
        avio_write(pb, data, strlen(data));
        return size;
    } else {
        if (!lang)
            lang = ff_mov_iso639_to_lang("und", 1);
        avio_wb16(pb, strlen(data)); /* string length */
        avio_wb16(pb, lang);
        avio_write(pb, data, strlen(data));
        return strlen(data) + 4;
    }
}

static int mov_write_string_tag(AVIOContext *pb, const char *name,
                                const char *value, int lang, int long_style)
{
    int size = 0;
    if (value && value[0]) {
        int64_t pos = avio_tell(pb);
        avio_wb32(pb, 0); /* size */
        ffio_wfourcc(pb, name);
        mov_write_string_data_tag(pb, value, lang, long_style);
        size = update_size(pb, pos);
    }
    return size;
}

static int mov_write_string_metadata(AVFormatContext *s, AVIOContext *pb,
                                     const char *name, const char *tag,
                                     int long_style)
{
    int l, lang = 0, len, len2;
    AVDictionaryEntry *t, *t2 = NULL;
    char tag2[16];

    if (!(t = av_dict_get(s->metadata, tag, NULL, 0)))
        return 0;

    len = strlen(t->key);
    snprintf(tag2, sizeof(tag2), "%s-", tag);
    while ((t2 = av_dict_get(s->metadata, tag2, t2, AV_DICT_IGNORE_SUFFIX))) {
        len2 = strlen(t2->key);
        if (len2 == len + 4 && !strcmp(t->value, t2->value)
            && (l = ff_mov_iso639_to_lang(&t2->key[len2 - 3], 1)) >= 0) {
            lang = l;
            break;
        }
    }
    return mov_write_string_tag(pb, name, t->value, lang, long_style);
}

/* iTunes bpm number */
static int mov_write_tmpo_tag(AVIOContext *pb, AVFormatContext *s)
{
    AVDictionaryEntry *t = av_dict_get(s->metadata, "tmpo", NULL, 0);
    int size = 0, tmpo = t ? atoi(t->value) : 0;
    if (tmpo) {
        size = 26;
        avio_wb32(pb, size);
        ffio_wfourcc(pb, "tmpo");
        avio_wb32(pb, size-8); /* size */
        ffio_wfourcc(pb, "data");
        avio_wb32(pb, 0x15);  //type specifier
        avio_wb32(pb, 0);
        avio_wb16(pb, tmpo);        // data
    }
    return size;
}

/* iTunes track or disc number */
static int mov_write_trkn_tag(AVIOContext *pb, MOVMuxContext *mov,
                              AVFormatContext *s, int disc)
{
    AVDictionaryEntry *t = av_dict_get(s->metadata,
                                       disc ? "disc" : "track",
                                       NULL, 0);
    int size = 0, track = t ? atoi(t->value) : 0;
    if (track) {
        int tracks = 0;
        char *slash = strchr(t->value, '/');
        if (slash)
            tracks = atoi(slash + 1);
        avio_wb32(pb, 32); /* size */
        ffio_wfourcc(pb, disc ? "disk" : "trkn");
        avio_wb32(pb, 24); /* size */
        ffio_wfourcc(pb, "data");
        avio_wb32(pb, 0);        // 8 bytes empty
        avio_wb32(pb, 0);
        avio_wb16(pb, 0);        // empty
        avio_wb16(pb, track);    // track / disc number
        avio_wb16(pb, tracks);   // total track / disc number
        avio_wb16(pb, 0);        // empty
        size = 32;
    }
    return size;
}

static int mov_write_int8_metadata(AVFormatContext *s, AVIOContext *pb,
                                   const char *name, const char *tag,
                                   int len)
{
    AVDictionaryEntry *t = NULL;
    uint8_t num;
    int size = 24 + len;

    if (len != 1 && len != 4)
        return -1;

    if (!(t = av_dict_get(s->metadata, tag, NULL, 0)))
        return 0;
    num = atoi(t->value);

    avio_wb32(pb, size);
    ffio_wfourcc(pb, name);
    avio_wb32(pb, size - 8);
    ffio_wfourcc(pb, "data");
    avio_wb32(pb, 0x15);
    avio_wb32(pb, 0);
    if (len==4) avio_wb32(pb, num);
    else        avio_w8 (pb, num);

    return size;
}

/* iTunes meta data list */
static int mov_write_ilst_tag(AVIOContext *pb, MOVMuxContext *mov,
                              AVFormatContext *s)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "ilst");
    mov_write_string_metadata(s, pb, "\251nam", "title"    , 1);
    mov_write_string_metadata(s, pb, "\251ART", "artist"   , 1);
    mov_write_string_metadata(s, pb, "aART", "album_artist", 1);
    mov_write_string_metadata(s, pb, "\251wrt", "composer" , 1);
    mov_write_string_metadata(s, pb, "\251alb", "album"    , 1);
    mov_write_string_metadata(s, pb, "\251day", "date"     , 1);
    if (!mov_write_string_metadata(s, pb, "\251too", "encoding_tool", 1))
        mov_write_string_tag(pb, "\251too", LIBAVFORMAT_IDENT, 0, 1);
    mov_write_string_metadata(s, pb, "\251cmt", "comment"  , 1);
    mov_write_string_metadata(s, pb, "\251gen", "genre"    , 1);
    mov_write_string_metadata(s, pb, "\251cpy", "copyright", 1);
    mov_write_string_metadata(s, pb, "\251grp", "grouping" , 1);
    mov_write_string_metadata(s, pb, "\251lyr", "lyrics"   , 1);
    mov_write_string_metadata(s, pb, "desc",    "description",1);
    mov_write_string_metadata(s, pb, "ldes",    "synopsis" , 1);
    mov_write_string_metadata(s, pb, "tvsh",    "show"     , 1);
    mov_write_string_metadata(s, pb, "tven",    "episode_id",1);
    mov_write_string_metadata(s, pb, "tvnn",    "network"  , 1);
    mov_write_int8_metadata  (s, pb, "tves",    "episode_sort",4);
    mov_write_int8_metadata  (s, pb, "tvsn",    "season_number",4);
    mov_write_int8_metadata  (s, pb, "stik",    "media_type",1);
    mov_write_int8_metadata  (s, pb, "hdvd",    "hd_video",  1);
    mov_write_int8_metadata  (s, pb, "pgap",    "gapless_playback",1);
    mov_write_trkn_tag(pb, mov, s, 0); // track number
    mov_write_trkn_tag(pb, mov, s, 1); // disc number
    mov_write_tmpo_tag(pb, s);
    return update_size(pb, pos);
}

/* iTunes meta data tag */
static int mov_write_meta_tag(AVIOContext *pb, MOVMuxContext *mov,
                              AVFormatContext *s)
{
    int size = 0;
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "meta");
    avio_wb32(pb, 0);
    mov_write_itunes_hdlr_tag(pb, mov, s);
    mov_write_ilst_tag(pb, mov, s);
    size = update_size(pb, pos);
    return size;
}

static int utf8len(const uint8_t *b)
{
    int len = 0;
    int val;
    while (*b) {
        GET_UTF8(val, *b++, return -1;)
        len++;
    }
    return len;
}

static int ascii_to_wc(AVIOContext *pb, const uint8_t *b)
{
    int val;
    while (*b) {
        GET_UTF8(val, *b++, return -1;)
        avio_wb16(pb, val);
    }
    avio_wb16(pb, 0x00);
    return 0;
}

static uint16_t language_code(const char *str)
{
    return (((str[0] - 0x60) & 0x1F) << 10) +
           (((str[1] - 0x60) & 0x1F) <<  5) +
           (( str[2] - 0x60) & 0x1F);
}

static int mov_write_3gp_udta_tag(AVIOContext *pb, AVFormatContext *s,
                                  const char *tag, const char *str)
{
    int64_t pos = avio_tell(pb);
    AVDictionaryEntry *t = av_dict_get(s->metadata, str, NULL, 0);
    if (!t || !utf8len(t->value))
        return 0;
    avio_wb32(pb, 0);   /* size */
    ffio_wfourcc(pb, tag); /* type */
    avio_wb32(pb, 0);   /* version + flags */
    if (!strcmp(tag, "yrrc"))
        avio_wb16(pb, atoi(t->value));
    else {
        avio_wb16(pb, language_code("eng")); /* language */
        avio_write(pb, t->value, strlen(t->value) + 1); /* UTF8 string value */
        if (!strcmp(tag, "albm") &&
            (t = av_dict_get(s->metadata, "track", NULL, 0)))
            avio_w8(pb, atoi(t->value));
    }
    return update_size(pb, pos);
}

static int mov_write_chpl_tag(AVIOContext *pb, AVFormatContext *s)
{
    int64_t pos = avio_tell(pb);
    int i, nb_chapters = FFMIN(s->nb_chapters, 255);

    avio_wb32(pb, 0);            // size
    ffio_wfourcc(pb, "chpl");
    avio_wb32(pb, 0x01000000);   // version + flags
    avio_wb32(pb, 0);            // unknown
    avio_w8(pb, nb_chapters);

    for (i = 0; i < nb_chapters; i++) {
        AVChapter *c = s->chapters[i];
        AVDictionaryEntry *t;
        avio_wb64(pb, av_rescale_q(c->start, c->time_base, (AVRational){1,10000000}));

        if ((t = av_dict_get(c->metadata, "title", NULL, 0))) {
            int len = FFMIN(strlen(t->value), 255);
            avio_w8(pb, len);
            avio_write(pb, t->value, len);
        } else
            avio_w8(pb, 0);
    }
    return update_size(pb, pos);
}

static int mov_write_udta_tag(AVIOContext *pb, MOVMuxContext *mov,
                              AVFormatContext *s)
{
    AVIOContext *pb_buf;
    int i, ret, size;
    uint8_t *buf;

    for (i = 0; i < s->nb_streams; i++)
        if (mov->tracks[i].enc->flags & CODEC_FLAG_BITEXACT) {
            return 0;
        }

    ret = avio_open_dyn_buf(&pb_buf);
    if (ret < 0)
        return ret;

    if (mov->mode & MODE_3GP) {
        mov_write_3gp_udta_tag(pb_buf, s, "perf", "artist");
        mov_write_3gp_udta_tag(pb_buf, s, "titl", "title");
        mov_write_3gp_udta_tag(pb_buf, s, "auth", "author");
        mov_write_3gp_udta_tag(pb_buf, s, "gnre", "genre");
        mov_write_3gp_udta_tag(pb_buf, s, "dscp", "comment");
        mov_write_3gp_udta_tag(pb_buf, s, "albm", "album");
        mov_write_3gp_udta_tag(pb_buf, s, "cprt", "copyright");
        mov_write_3gp_udta_tag(pb_buf, s, "yrrc", "date");
    } else if (mov->mode == MODE_MOV) { // the title field breaks gtkpod with mp4 and my suspicion is that stuff is not valid in mp4
        mov_write_string_metadata(s, pb_buf, "\251ART", "artist",      0);
        mov_write_string_metadata(s, pb_buf, "\251nam", "title",       0);
        mov_write_string_metadata(s, pb_buf, "\251aut", "author",      0);
        mov_write_string_metadata(s, pb_buf, "\251alb", "album",       0);
        mov_write_string_metadata(s, pb_buf, "\251day", "date",        0);
        mov_write_string_metadata(s, pb_buf, "\251swr", "encoder",     0);
        // currently ignored by mov.c
        mov_write_string_metadata(s, pb_buf, "\251des", "comment",     0);
        // add support for libquicktime, this atom is also actually read by mov.c
        mov_write_string_metadata(s, pb_buf, "\251cmt", "comment",     0);
        mov_write_string_metadata(s, pb_buf, "\251gen", "genre",       0);
        mov_write_string_metadata(s, pb_buf, "\251cpy", "copyright",   0);
    } else {
        /* iTunes meta data */
        mov_write_meta_tag(pb_buf, mov, s);
    }

    if (s->nb_chapters)
        mov_write_chpl_tag(pb_buf, s);

    if ((size = avio_close_dyn_buf(pb_buf, &buf)) > 0) {
        avio_wb32(pb, size + 8);
        ffio_wfourcc(pb, "udta");
        avio_write(pb, buf, size);
    }
    av_free(buf);

    return 0;
}

static void mov_write_psp_udta_tag(AVIOContext *pb,
                                   const char *str, const char *lang, int type)
{
    int len = utf8len(str) + 1;
    if (len <= 0)
        return;
    avio_wb16(pb, len * 2 + 10);        /* size */
    avio_wb32(pb, type);                /* type */
    avio_wb16(pb, language_code(lang)); /* language */
    avio_wb16(pb, 0x01);                /* ? */
    ascii_to_wc(pb, str);
}

static int mov_write_uuidusmt_tag(AVIOContext *pb, AVFormatContext *s)
{
    AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL, 0);
    int64_t pos, pos2;

    if (title) {
        pos = avio_tell(pb);
        avio_wb32(pb, 0); /* size placeholder*/
        ffio_wfourcc(pb, "uuid");
        ffio_wfourcc(pb, "USMT");
        avio_wb32(pb, 0x21d24fce); /* 96 bit UUID */
        avio_wb32(pb, 0xbb88695c);
        avio_wb32(pb, 0xfac9c740);

        pos2 = avio_tell(pb);
        avio_wb32(pb, 0); /* size placeholder*/
        ffio_wfourcc(pb, "MTDT");
        avio_wb16(pb, 4);

        // ?
        avio_wb16(pb, 0x0C);                 /* size */
        avio_wb32(pb, 0x0B);                 /* type */
        avio_wb16(pb, language_code("und")); /* language */
        avio_wb16(pb, 0x0);                  /* ? */
        avio_wb16(pb, 0x021C);               /* data */

        mov_write_psp_udta_tag(pb, LIBAVCODEC_IDENT,      "eng", 0x04);
        mov_write_psp_udta_tag(pb, title->value,          "eng", 0x01);
        mov_write_psp_udta_tag(pb, "2006/04/01 11:11:11", "und", 0x03);

        update_size(pb, pos2);
        return update_size(pb, pos);
    }

    return 0;
}

static void build_chunks(MOVTrack *trk)
{
    int i;
    MOVIentry *chunk = &trk->cluster[0];
    uint64_t chunkSize = chunk->size;
    chunk->chunkNum = 1;
    if (trk->chunkCount)
        return;
    trk->chunkCount = 1;
    for (i = 1; i<trk->entry; i++){
        if (chunk->pos + chunkSize == trk->cluster[i].pos &&
            chunkSize + trk->cluster[i].size < (1<<20)){
            chunkSize             += trk->cluster[i].size;
            chunk->samples_in_chunk += trk->cluster[i].entries;
        } else {
            trk->cluster[i].chunkNum = chunk->chunkNum+1;
            chunk=&trk->cluster[i];
            chunkSize = chunk->size;
            trk->chunkCount++;
        }
    }
}

static int mov_write_moov_tag(AVIOContext *pb, MOVMuxContext *mov,
                              AVFormatContext *s)
{
    int i;
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size placeholder*/
    ffio_wfourcc(pb, "moov");

    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].entry <= 0 && !(mov->flags & FF_MOV_FLAG_FRAGMENT))
            continue;

        mov->tracks[i].time     = mov->time;
        mov->tracks[i].track_id = i + 1;

        if (mov->tracks[i].entry)
            build_chunks(&mov->tracks[i]);
    }

    if (mov->chapter_track)
        for (i = 0; i < s->nb_streams; i++) {
            mov->tracks[i].tref_tag = MKTAG('c','h','a','p');
            mov->tracks[i].tref_id  = mov->tracks[mov->chapter_track].track_id;
        }
    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].tag == MKTAG('r','t','p',' ')) {
            mov->tracks[i].tref_tag = MKTAG('h','i','n','t');
            mov->tracks[i].tref_id =
                mov->tracks[mov->tracks[i].src_track].track_id;
        }
    }
    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].tag == MKTAG('t','m','c','d')) {
            int src_trk = mov->tracks[i].src_track;
            mov->tracks[src_trk].tref_tag = mov->tracks[i].tag;
            mov->tracks[src_trk].tref_id  = mov->tracks[i].track_id;
            //src_trk may have a different timescale than the tmcd track
            mov->tracks[i].track_duration = av_rescale(mov->tracks[src_trk].track_duration,
                                                       mov->tracks[i].timescale,
                                                       mov->tracks[src_trk].timescale);
        }
    }

    mov_write_mvhd_tag(pb, mov);
    if (mov->mode != MODE_MOV && !mov->iods_skip)
        mov_write_iods_tag(pb, mov);
    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].entry > 0 || mov->flags & FF_MOV_FLAG_FRAGMENT) {
            mov_write_trak_tag(pb, mov, &(mov->tracks[i]), i < s->nb_streams ? s->streams[i] : NULL);
        }
    }
    if (mov->flags & FF_MOV_FLAG_FRAGMENT)
        mov_write_mvex_tag(pb, mov); /* QuickTime requires trak to precede this */

    if (mov->mode == MODE_PSP)
        mov_write_uuidusmt_tag(pb, s);
    else
        mov_write_udta_tag(pb, mov, s);

    return update_size(pb, pos);
}

static void param_write_int(AVIOContext *pb, const char *name, int value)
{
    avio_printf(pb, "<param name=\"%s\" value=\"%d\" valuetype=\"data\"/>\n", name, value);
}

static void param_write_string(AVIOContext *pb, const char *name, const char *value)
{
    avio_printf(pb, "<param name=\"%s\" value=\"%s\" valuetype=\"data\"/>\n", name, value);
}

static void param_write_hex(AVIOContext *pb, const char *name, const uint8_t *value, int len)
{
    char buf[150];
    len = FFMIN(sizeof(buf) / 2 - 1, len);
    ff_data_to_hex(buf, value, len, 0);
    buf[2 * len] = '\0';
    avio_printf(pb, "<param name=\"%s\" value=\"%s\" valuetype=\"data\"/>\n", name, buf);
}

static int mov_write_isml_manifest(AVIOContext *pb, MOVMuxContext *mov)
{
    int64_t pos = avio_tell(pb);
    int i;
    static const uint8_t uuid[] = {
        0xa5, 0xd4, 0x0b, 0x30, 0xe8, 0x14, 0x11, 0xdd,
        0xba, 0x2f, 0x08, 0x00, 0x20, 0x0c, 0x9a, 0x66
    };

    avio_wb32(pb, 0);
    ffio_wfourcc(pb, "uuid");
    avio_write(pb, uuid, sizeof(uuid));
    avio_wb32(pb, 0);

    avio_printf(pb, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
    avio_printf(pb, "<smil xmlns=\"http://www.w3.org/2001/SMIL20/Language\">\n");
    avio_printf(pb, "<head>\n");
    avio_printf(pb, "<meta name=\"creator\" content=\"%s\" />\n",
                    LIBAVFORMAT_IDENT);
    avio_printf(pb, "</head>\n");
    avio_printf(pb, "<body>\n");
    avio_printf(pb, "<switch>\n");
    for (i = 0; i < mov->nb_streams; i++) {
        MOVTrack *track = &mov->tracks[i];
        const char *type;
        /* track->track_id is initialized in write_moov, and thus isn't known
         * here yet */
        int track_id = i + 1;

        if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            type = "video";
        } else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO) {
            type = "audio";
        } else {
            continue;
        }
        avio_printf(pb, "<%s systemBitrate=\"%d\">\n", type,
                                                       track->enc->bit_rate);
        param_write_int(pb, "systemBitrate", track->enc->bit_rate);
        param_write_int(pb, "trackID", track_id);
        if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            if (track->enc->codec_id == AV_CODEC_ID_H264) {
                uint8_t *ptr;
                int size = track->enc->extradata_size;
                if (!ff_avc_write_annexb_extradata(track->enc->extradata, &ptr,
                                                   &size)) {
                    param_write_hex(pb, "CodecPrivateData",
                                    ptr ? ptr : track->enc->extradata,
                                    size);
                    av_free(ptr);
                }
                param_write_string(pb, "FourCC", "H264");
            } else if (track->enc->codec_id == AV_CODEC_ID_VC1) {
                param_write_string(pb, "FourCC", "WVC1");
                param_write_hex(pb, "CodecPrivateData", track->enc->extradata,
                                track->enc->extradata_size);
            }
            param_write_int(pb, "MaxWidth", track->enc->width);
            param_write_int(pb, "MaxHeight", track->enc->height);
            param_write_int(pb, "DisplayWidth", track->enc->width);
            param_write_int(pb, "DisplayHeight", track->enc->height);
        } else {
            if (track->enc->codec_id == AV_CODEC_ID_AAC) {
                param_write_string(pb, "FourCC", "AACL");
            } else if (track->enc->codec_id == AV_CODEC_ID_WMAPRO) {
                param_write_string(pb, "FourCC", "WMAP");
            }
            param_write_hex(pb, "CodecPrivateData", track->enc->extradata,
                            track->enc->extradata_size);
            param_write_int(pb, "AudioTag", ff_codec_get_tag(ff_codec_wav_tags,
                                                             track->enc->codec_id));
            param_write_int(pb, "Channels", track->enc->channels);
            param_write_int(pb, "SamplingRate", track->enc->sample_rate);
            param_write_int(pb, "BitsPerSample", 16);
            param_write_int(pb, "PacketSize", track->enc->block_align ?
                                              track->enc->block_align : 4);
        }
        avio_printf(pb, "</%s>\n", type);
    }
    avio_printf(pb, "</switch>\n");
    avio_printf(pb, "</body>\n");
    avio_printf(pb, "</smil>\n");

    return update_size(pb, pos);
}

static int mov_write_mfhd_tag(AVIOContext *pb, MOVMuxContext *mov)
{
    avio_wb32(pb, 16);
    ffio_wfourcc(pb, "mfhd");
    avio_wb32(pb, 0);
    avio_wb32(pb, mov->fragments);
    return 0;
}

static int mov_write_tfhd_tag(AVIOContext *pb, MOVMuxContext *mov,
                              MOVTrack *track, int64_t moof_offset)
{
    int64_t pos = avio_tell(pb);
    uint32_t flags = MOV_TFHD_DEFAULT_SIZE | MOV_TFHD_DEFAULT_DURATION |
                     MOV_TFHD_BASE_DATA_OFFSET;
    if (!track->entry) {
        flags |= MOV_TFHD_DURATION_IS_EMPTY;
    } else {
        flags |= MOV_TFHD_DEFAULT_FLAGS;
    }
    if (mov->flags & FF_MOV_FLAG_OMIT_TFHD_OFFSET)
        flags &= ~MOV_TFHD_BASE_DATA_OFFSET;

    /* Don't set a default sample size, the silverlight player refuses
     * to play files with that set. Don't set a default sample duration,
     * WMP freaks out if it is set. Don't set a base data offset, PIFF
     * file format says it MUST NOT be set. */
    if (track->mode == MODE_ISM)
        flags &= ~(MOV_TFHD_DEFAULT_SIZE | MOV_TFHD_DEFAULT_DURATION |
                   MOV_TFHD_BASE_DATA_OFFSET);

    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "tfhd");
    avio_w8(pb, 0); /* version */
    avio_wb24(pb, flags);

    avio_wb32(pb, track->track_id); /* track-id */
    if (flags & MOV_TFHD_BASE_DATA_OFFSET)
        avio_wb64(pb, moof_offset);
    if (flags & MOV_TFHD_DEFAULT_DURATION) {
        track->default_duration = get_cluster_duration(track, 0);
        avio_wb32(pb, track->default_duration);
    }
    if (flags & MOV_TFHD_DEFAULT_SIZE) {
        track->default_size = track->entry ? track->cluster[0].size : 1;
        avio_wb32(pb, track->default_size);
    } else
        track->default_size = -1;

    if (flags & MOV_TFHD_DEFAULT_FLAGS) {
        track->default_sample_flags =
            track->enc->codec_type == AVMEDIA_TYPE_VIDEO ?
            (MOV_FRAG_SAMPLE_FLAG_DEPENDS_YES | MOV_FRAG_SAMPLE_FLAG_IS_NON_SYNC) :
            MOV_FRAG_SAMPLE_FLAG_DEPENDS_NO;
        avio_wb32(pb, track->default_sample_flags);
    }

    return update_size(pb, pos);
}

static uint32_t get_sample_flags(MOVTrack *track, MOVIentry *entry)
{
    return entry->flags & MOV_SYNC_SAMPLE ? MOV_FRAG_SAMPLE_FLAG_DEPENDS_NO :
           (MOV_FRAG_SAMPLE_FLAG_DEPENDS_YES | MOV_FRAG_SAMPLE_FLAG_IS_NON_SYNC);
}

static int mov_write_trun_tag(AVIOContext *pb, MOVMuxContext *mov,
                              MOVTrack *track, int moof_size)
{
    int64_t pos = avio_tell(pb);
    uint32_t flags = MOV_TRUN_DATA_OFFSET;
    int i;

    for (i = 0; i < track->entry; i++) {
        if (get_cluster_duration(track, i) != track->default_duration)
            flags |= MOV_TRUN_SAMPLE_DURATION;
        if (track->cluster[i].size != track->default_size)
            flags |= MOV_TRUN_SAMPLE_SIZE;
        if (i > 0 && get_sample_flags(track, &track->cluster[i]) != track->default_sample_flags)
            flags |= MOV_TRUN_SAMPLE_FLAGS;
    }
    if (!(flags & MOV_TRUN_SAMPLE_FLAGS))
        flags |= MOV_TRUN_FIRST_SAMPLE_FLAGS;
    if (track->flags & MOV_TRACK_CTTS)
        flags |= MOV_TRUN_SAMPLE_CTS;

    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "trun");
    avio_w8(pb, 0); /* version */
    avio_wb24(pb, flags);

    avio_wb32(pb, track->entry); /* sample count */
    if (mov->flags & FF_MOV_FLAG_OMIT_TFHD_OFFSET &&
        !(mov->flags & FF_MOV_FLAG_SEPARATE_MOOF) &&
        track->track_id != 1)
        avio_wb32(pb, 0); /* Later tracks follow immediately after the previous one */
    else
        avio_wb32(pb, moof_size + 8 + track->data_offset +
                      track->cluster[0].pos); /* data offset */
    if (flags & MOV_TRUN_FIRST_SAMPLE_FLAGS)
        avio_wb32(pb, get_sample_flags(track, &track->cluster[0]));

    for (i = 0; i < track->entry; i++) {
        if (flags & MOV_TRUN_SAMPLE_DURATION)
            avio_wb32(pb, get_cluster_duration(track, i));
        if (flags & MOV_TRUN_SAMPLE_SIZE)
            avio_wb32(pb, track->cluster[i].size);
        if (flags & MOV_TRUN_SAMPLE_FLAGS)
            avio_wb32(pb, get_sample_flags(track, &track->cluster[i]));
        if (flags & MOV_TRUN_SAMPLE_CTS)
            avio_wb32(pb, track->cluster[i].cts);
    }

    return update_size(pb, pos);
}

static int mov_write_tfxd_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    static const uint8_t uuid[] = {
        0x6d, 0x1d, 0x9b, 0x05, 0x42, 0xd5, 0x44, 0xe6,
        0x80, 0xe2, 0x14, 0x1d, 0xaf, 0xf7, 0x57, 0xb2
    };

    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "uuid");
    avio_write(pb, uuid, sizeof(uuid));
    avio_w8(pb, 1);
    avio_wb24(pb, 0);
    avio_wb64(pb, track->frag_start);
    avio_wb64(pb, track->start_dts + track->track_duration -
                  track->cluster[0].dts);

    return update_size(pb, pos);
}

static int mov_write_tfrf_tag(AVIOContext *pb, MOVMuxContext *mov,
                              MOVTrack *track, int entry)
{
    int n = track->nb_frag_info - 1 - entry, i;
    int size = 8 + 16 + 4 + 1 + 16*n;
    static const uint8_t uuid[] = {
        0xd4, 0x80, 0x7e, 0xf2, 0xca, 0x39, 0x46, 0x95,
        0x8e, 0x54, 0x26, 0xcb, 0x9e, 0x46, 0xa7, 0x9f
    };

    if (entry < 0)
        return 0;

    avio_seek(pb, track->frag_info[entry].tfrf_offset, SEEK_SET);
    avio_wb32(pb, size);
    ffio_wfourcc(pb, "uuid");
    avio_write(pb, uuid, sizeof(uuid));
    avio_w8(pb, 1);
    avio_wb24(pb, 0);
    avio_w8(pb, n);
    for (i = 0; i < n; i++) {
        int index = entry + 1 + i;
        avio_wb64(pb, track->frag_info[index].time);
        avio_wb64(pb, track->frag_info[index].duration);
    }
    if (n < mov->ism_lookahead) {
        int free_size = 16 * (mov->ism_lookahead - n);
        avio_wb32(pb, free_size);
        ffio_wfourcc(pb, "free");
        ffio_fill(pb, 0, free_size - 8);
    }

    return 0;
}

static int mov_write_tfrf_tags(AVIOContext *pb, MOVMuxContext *mov,
                               MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    int i;
    for (i = 0; i < mov->ism_lookahead; i++) {
        /* Update the tfrf tag for the last ism_lookahead fragments,
         * nb_frag_info - 1 is the next fragment to be written. */
        mov_write_tfrf_tag(pb, mov, track, track->nb_frag_info - 2 - i);
    }
    avio_seek(pb, pos, SEEK_SET);
    return 0;
}

static int mov_write_traf_tag(AVIOContext *pb, MOVMuxContext *mov,
                              MOVTrack *track, int64_t moof_offset,
                              int moof_size)
{
    int64_t pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "traf");

    mov_write_tfhd_tag(pb, mov, track, moof_offset);
    mov_write_trun_tag(pb, mov, track, moof_size);
    if (mov->mode == MODE_ISM) {
        mov_write_tfxd_tag(pb, track);

        if (mov->ism_lookahead) {
            int i, size = 16 + 4 + 1 + 16 * mov->ism_lookahead;

            track->tfrf_offset = avio_tell(pb);
            avio_wb32(pb, 8 + size);
            ffio_wfourcc(pb, "free");
            for (i = 0; i < size; i++)
                avio_w8(pb, 0);
        }
    }

    return update_size(pb, pos);
}

static int mov_write_moof_tag_internal(AVIOContext *pb, MOVMuxContext *mov,
                                       int tracks, int moof_size)
{
    int64_t pos = avio_tell(pb);
    int i;

    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "moof");

    mov_write_mfhd_tag(pb, mov);
    for (i = 0; i < mov->nb_streams; i++) {
        MOVTrack *track = &mov->tracks[i];
        if (tracks >= 0 && i != tracks)
            continue;
        if (!track->entry)
            continue;
        mov_write_traf_tag(pb, mov, track, pos, moof_size);
    }

    return update_size(pb, pos);
}

static int mov_write_moof_tag(AVIOContext *pb, MOVMuxContext *mov, int tracks)
{
    AVIOContext *avio_buf;
    int ret, moof_size;

    if ((ret = ffio_open_null_buf(&avio_buf)) < 0)
        return ret;
    mov_write_moof_tag_internal(avio_buf, mov, tracks, 0);
    moof_size = ffio_close_null_buf(avio_buf);
    return mov_write_moof_tag_internal(pb, mov, tracks, moof_size);
}

static int mov_write_tfra_tag(AVIOContext *pb, MOVTrack *track)
{
    int64_t pos = avio_tell(pb);
    int i;

    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "tfra");
    avio_w8(pb, 1); /* version */
    avio_wb24(pb, 0);

    avio_wb32(pb, track->track_id);
    avio_wb32(pb, 0); /* length of traf/trun/sample num */
    avio_wb32(pb, track->nb_frag_info);
    for (i = 0; i < track->nb_frag_info; i++) {
        avio_wb64(pb, track->frag_info[i].time);
        avio_wb64(pb, track->frag_info[i].offset);
        avio_w8(pb, 1); /* traf number */
        avio_w8(pb, 1); /* trun number */
        avio_w8(pb, 1); /* sample number */
    }

    return update_size(pb, pos);
}

static int mov_write_mfra_tag(AVIOContext *pb, MOVMuxContext *mov)
{
    int64_t pos = avio_tell(pb);
    int i;

    avio_wb32(pb, 0); /* size placeholder */
    ffio_wfourcc(pb, "mfra");
    /* An empty mfra atom is enough to indicate to the publishing point that
     * the stream has ended. */
    if (mov->flags & FF_MOV_FLAG_ISML)
        return update_size(pb, pos);

    for (i = 0; i < mov->nb_streams; i++) {
        MOVTrack *track = &mov->tracks[i];
        if (track->nb_frag_info)
            mov_write_tfra_tag(pb, track);
    }

    avio_wb32(pb, 16);
    ffio_wfourcc(pb, "mfro");
    avio_wb32(pb, 0); /* version + flags */
    avio_wb32(pb, avio_tell(pb) + 4 - pos);

    return update_size(pb, pos);
}

static int mov_write_mdat_tag(AVIOContext *pb, MOVMuxContext *mov)
{
    avio_wb32(pb, 8);    // placeholder for extended size field (64 bit)
    ffio_wfourcc(pb, mov->mode == MODE_MOV ? "wide" : "free");

    mov->mdat_pos = avio_tell(pb);
    avio_wb32(pb, 0); /* size placeholder*/
    ffio_wfourcc(pb, "mdat");
    return 0;
}

/* TODO: This needs to be more general */
static int mov_write_ftyp_tag(AVIOContext *pb, AVFormatContext *s)
{
    MOVMuxContext *mov = s->priv_data;
    int64_t pos = avio_tell(pb);
    int has_h264 = 0, has_video = 0;
    int minor = 0x200;
    int i;

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];
        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
            has_video = 1;
        if (st->codec->codec_id == AV_CODEC_ID_H264)
            has_h264 = 1;
    }

    avio_wb32(pb, 0); /* size */
    ffio_wfourcc(pb, "ftyp");

    if (mov->mode == MODE_3GP) {
        ffio_wfourcc(pb, has_h264 ? "3gp6"  : "3gp4");
        minor =     has_h264 ?   0x100 :   0x200;
    } else if (mov->mode & MODE_3G2) {
        ffio_wfourcc(pb, has_h264 ? "3g2b"  : "3g2a");
        minor =     has_h264 ? 0x20000 : 0x10000;
    } else if (mov->mode == MODE_PSP)
        ffio_wfourcc(pb, "MSNV");
    else if (mov->mode == MODE_MP4)
        ffio_wfourcc(pb, "isom");
    else if (mov->mode == MODE_IPOD)
        ffio_wfourcc(pb, has_video ? "M4V ":"M4A ");
    else if (mov->mode == MODE_ISM)
        ffio_wfourcc(pb, "isml");
    else if (mov->mode == MODE_F4V)
        ffio_wfourcc(pb, "f4v ");
    else
        ffio_wfourcc(pb, "qt  ");

    avio_wb32(pb, minor);

    if (mov->mode == MODE_MOV)
        ffio_wfourcc(pb, "qt  ");
    else if (mov->mode == MODE_ISM) {
        ffio_wfourcc(pb, "piff");
        ffio_wfourcc(pb, "iso2");
    } else {
        ffio_wfourcc(pb, "isom");
        ffio_wfourcc(pb, "iso2");
        if (has_h264)
            ffio_wfourcc(pb, "avc1");
    }

    if (mov->mode == MODE_3GP)
        ffio_wfourcc(pb, has_h264 ? "3gp6":"3gp4");
    else if (mov->mode & MODE_3G2)
        ffio_wfourcc(pb, has_h264 ? "3g2b":"3g2a");
    else if (mov->mode == MODE_PSP)
        ffio_wfourcc(pb, "MSNV");
    else if (mov->mode == MODE_MP4)
        ffio_wfourcc(pb, "mp41");
    return update_size(pb, pos);
}

static void mov_write_uuidprof_tag(AVIOContext *pb, AVFormatContext *s)
{
    AVCodecContext *video_codec = s->streams[0]->codec;
    AVCodecContext *audio_codec = s->streams[1]->codec;
    int audio_rate = audio_codec->sample_rate;
    int frame_rate = ((video_codec->time_base.den) * (0x10000)) / (video_codec->time_base.num);
    int audio_kbitrate = audio_codec->bit_rate / 1000;
    int video_kbitrate = FFMIN(video_codec->bit_rate / 1000, 800 - audio_kbitrate);

    avio_wb32(pb, 0x94); /* size */
    ffio_wfourcc(pb, "uuid");
    ffio_wfourcc(pb, "PROF");

    avio_wb32(pb, 0x21d24fce); /* 96 bit UUID */
    avio_wb32(pb, 0xbb88695c);
    avio_wb32(pb, 0xfac9c740);

    avio_wb32(pb, 0x0);  /* ? */
    avio_wb32(pb, 0x3);  /* 3 sections ? */

    avio_wb32(pb, 0x14); /* size */
    ffio_wfourcc(pb, "FPRF");
    avio_wb32(pb, 0x0);  /* ? */
    avio_wb32(pb, 0x0);  /* ? */
    avio_wb32(pb, 0x0);  /* ? */

    avio_wb32(pb, 0x2c);  /* size */
    ffio_wfourcc(pb, "APRF"); /* audio */
    avio_wb32(pb, 0x0);
    avio_wb32(pb, 0x2);   /* TrackID */
    ffio_wfourcc(pb, "mp4a");
    avio_wb32(pb, 0x20f);
    avio_wb32(pb, 0x0);
    avio_wb32(pb, audio_kbitrate);
    avio_wb32(pb, audio_kbitrate);
    avio_wb32(pb, audio_rate);
    avio_wb32(pb, audio_codec->channels);

    avio_wb32(pb, 0x34);  /* size */
    ffio_wfourcc(pb, "VPRF");   /* video */
    avio_wb32(pb, 0x0);
    avio_wb32(pb, 0x1);    /* TrackID */
    if (video_codec->codec_id == AV_CODEC_ID_H264) {
        ffio_wfourcc(pb, "avc1");
        avio_wb16(pb, 0x014D);
        avio_wb16(pb, 0x0015);
    } else {
        ffio_wfourcc(pb, "mp4v");
        avio_wb16(pb, 0x0000);
        avio_wb16(pb, 0x0103);
    }
    avio_wb32(pb, 0x0);
    avio_wb32(pb, video_kbitrate);
    avio_wb32(pb, video_kbitrate);
    avio_wb32(pb, frame_rate);
    avio_wb32(pb, frame_rate);
    avio_wb16(pb, video_codec->width);
    avio_wb16(pb, video_codec->height);
    avio_wb32(pb, 0x010001); /* ? */
}

static int mov_parse_mpeg2_frame(AVPacket *pkt, uint32_t *flags)
{
    uint32_t c = -1;
    int i, closed_gop = 0;

    for (i = 0; i < pkt->size - 4; i++) {
        c = (c << 8) + pkt->data[i];
        if (c == 0x1b8) { // gop
            closed_gop = pkt->data[i + 4] >> 6 & 0x01;
        } else if (c == 0x100) { // pic
            int temp_ref = (pkt->data[i + 1] << 2) | (pkt->data[i + 2] >> 6);
            if (!temp_ref || closed_gop) // I picture is not reordered
                *flags = MOV_SYNC_SAMPLE;
            else
                *flags = MOV_PARTIAL_SYNC_SAMPLE;
            break;
        }
    }
    return 0;
}

static void mov_parse_vc1_frame(AVPacket *pkt, MOVTrack *trk, int fragment)
{
    const uint8_t *start, *next, *end = pkt->data + pkt->size;
    int seq = 0, entry = 0;
    int key = pkt->flags & AV_PKT_FLAG_KEY;
    start = find_next_marker(pkt->data, end);
    for (next = start; next < end; start = next) {
        next = find_next_marker(start + 4, end);
        switch (AV_RB32(start)) {
        case VC1_CODE_SEQHDR:
            seq = 1;
            break;
        case VC1_CODE_ENTRYPOINT:
            entry = 1;
            break;
        case VC1_CODE_SLICE:
            trk->vc1_info.slices = 1;
            break;
        }
    }
    if (!trk->entry && !fragment) {
        /* First packet in first fragment */
        trk->vc1_info.first_packet_seq   = seq;
        trk->vc1_info.first_packet_entry = entry;
    } else if ((seq && !trk->vc1_info.packet_seq) ||
               (entry && !trk->vc1_info.packet_entry)) {
        int i;
        for (i = 0; i < trk->entry; i++)
            trk->cluster[i].flags &= ~MOV_SYNC_SAMPLE;
        trk->has_keyframes = 0;
        if (seq)
            trk->vc1_info.packet_seq = 1;
        if (entry)
            trk->vc1_info.packet_entry = 1;
        if (!fragment) {
            /* First fragment */
            if ((!seq   || trk->vc1_info.first_packet_seq) &&
                (!entry || trk->vc1_info.first_packet_entry)) {
                /* First packet had the same headers as this one, readd the
                 * sync sample flag. */
                trk->cluster[0].flags |= MOV_SYNC_SAMPLE;
                trk->has_keyframes = 1;
            }
        }
    }
    if (trk->vc1_info.packet_seq && trk->vc1_info.packet_entry)
        key = seq && entry;
    else if (trk->vc1_info.packet_seq)
        key = seq;
    else if (trk->vc1_info.packet_entry)
        key = entry;
    if (key) {
        trk->cluster[trk->entry].flags |= MOV_SYNC_SAMPLE;
        trk->has_keyframes++;
    }
}

static int mov_flush_fragment(AVFormatContext *s)
{
    MOVMuxContext *mov = s->priv_data;
    int i, first_track = -1;
    int64_t mdat_size = 0;

    if (!(mov->flags & FF_MOV_FLAG_FRAGMENT))
        return 0;

    if (!(mov->flags & FF_MOV_FLAG_EMPTY_MOOV) && mov->fragments == 0) {
        int64_t pos = avio_tell(s->pb);
        uint8_t *buf;
        int buf_size, moov_size;

        for (i = 0; i < mov->nb_streams; i++)
            if (!mov->tracks[i].entry)
                break;
        /* Don't write the initial moov unless all tracks have data */
        if (i < mov->nb_streams)
            return 0;

        moov_size = get_moov_size(s);
        for (i = 0; i < mov->nb_streams; i++)
            mov->tracks[i].data_offset = pos + moov_size + 8;

        mov_write_moov_tag(s->pb, mov, s);

        buf_size = avio_close_dyn_buf(mov->mdat_buf, &buf);
        mov->mdat_buf = NULL;
        avio_wb32(s->pb, buf_size + 8);
        ffio_wfourcc(s->pb, "mdat");
        avio_write(s->pb, buf, buf_size);
        av_free(buf);

        mov->fragments++;
        mov->mdat_size = 0;
        for (i = 0; i < mov->nb_streams; i++) {
            if (mov->tracks[i].entry)
                mov->tracks[i].frag_start += mov->tracks[i].start_dts +
                                             mov->tracks[i].track_duration -
                                             mov->tracks[i].cluster[0].dts;
            mov->tracks[i].entry = 0;
        }
        avio_flush(s->pb);
        return 0;
    }

    for (i = 0; i < mov->nb_streams; i++) {
        MOVTrack *track = &mov->tracks[i];
        if (mov->flags & FF_MOV_FLAG_SEPARATE_MOOF)
            track->data_offset = 0;
        else
            track->data_offset = mdat_size;
        if (!track->mdat_buf)
            continue;
        mdat_size += avio_tell(track->mdat_buf);
        if (first_track < 0)
            first_track = i;
    }

    if (!mdat_size)
        return 0;

    for (i = 0; i < mov->nb_streams; i++) {
        MOVTrack *track = &mov->tracks[i];
        int buf_size, write_moof = 1, moof_tracks = -1;
        uint8_t *buf;
        int64_t duration = 0;

        if (track->entry)
            duration = track->start_dts + track->track_duration -
                       track->cluster[0].dts;
        if (mov->flags & FF_MOV_FLAG_SEPARATE_MOOF) {
            if (!track->mdat_buf)
                continue;
            mdat_size = avio_tell(track->mdat_buf);
            moof_tracks = i;
        } else {
            write_moof = i == first_track;
        }

        if (write_moof) {
            MOVFragmentInfo *info;
            avio_flush(s->pb);
            track->nb_frag_info++;
            if (track->nb_frag_info >= track->frag_info_capacity) {
                unsigned new_capacity = track->nb_frag_info + MOV_FRAG_INFO_ALLOC_INCREMENT;
                if (av_reallocp_array(&track->frag_info,
                                      new_capacity,
                                      sizeof(*track->frag_info)))
                    return AVERROR(ENOMEM);
                track->frag_info_capacity = new_capacity;
            }
            info = &track->frag_info[track->nb_frag_info - 1];
            info->offset   = avio_tell(s->pb);
            info->time     = mov->tracks[i].frag_start;
            info->duration = duration;
            mov_write_tfrf_tags(s->pb, mov, track);

            mov_write_moof_tag(s->pb, mov, moof_tracks);
            info->tfrf_offset = track->tfrf_offset;
            mov->fragments++;

            avio_wb32(s->pb, mdat_size + 8);
            ffio_wfourcc(s->pb, "mdat");
        }

        if (track->entry)
            track->frag_start += duration;
        track->entry = 0;
        if (!track->mdat_buf)
            continue;
        buf_size = avio_close_dyn_buf(track->mdat_buf, &buf);
        track->mdat_buf = NULL;

        avio_write(s->pb, buf, buf_size);
        av_free(buf);
    }

    mov->mdat_size = 0;

    avio_flush(s->pb);
    return 0;
}

int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
{
    MOVMuxContext *mov = s->priv_data;
    AVIOContext *pb = s->pb;
    MOVTrack *trk = &mov->tracks[pkt->stream_index];
    AVCodecContext *enc = trk->enc;
    unsigned int samples_in_chunk = 0;
    int size = pkt->size;
    uint8_t *reformatted_data = NULL;

    if (trk->entry) {
        int64_t duration = pkt->dts - trk->cluster[trk->entry - 1].dts;
        if (duration < 0 || duration > INT_MAX) {
            av_log(s, AV_LOG_ERROR, "Application provided duration: %"PRId64" / timestamp: %"PRId64" is out of range for mov/mp4 format\n",
                duration, pkt->dts
            );

            pkt->dts = trk->cluster[trk->entry - 1].dts + 1;
            pkt->pts = AV_NOPTS_VALUE;
        }
    }
    if (mov->flags & FF_MOV_FLAG_FRAGMENT) {
        int ret;
        if (mov->fragments > 0) {
            if (!trk->mdat_buf) {
                if ((ret = avio_open_dyn_buf(&trk->mdat_buf)) < 0)
                    return ret;
            }
            pb = trk->mdat_buf;
        } else {
            if (!mov->mdat_buf) {
                if ((ret = avio_open_dyn_buf(&mov->mdat_buf)) < 0)
                    return ret;
            }
            pb = mov->mdat_buf;
        }
    }

    if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
        /* We must find out how many AMR blocks there are in one packet */
        static uint16_t packed_size[16] =
            {13, 14, 16, 18, 20, 21, 27, 32, 6, 0, 0, 0, 0, 0, 0, 1};
        int len = 0;

        while (len < size && samples_in_chunk < 100) {
            len += packed_size[(pkt->data[len] >> 3) & 0x0F];
            samples_in_chunk++;
        }
        if (samples_in_chunk > 1) {
            av_log(s, AV_LOG_ERROR, "fatal error, input is not a single packet, implement a AVParser for it\n");
            return -1;
        }
    } else if (enc->codec_id == AV_CODEC_ID_ADPCM_MS ||
               enc->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV) {
        samples_in_chunk = enc->frame_size;
    } else if (trk->sample_size)
        samples_in_chunk = size / trk->sample_size;
    else
        samples_in_chunk = 1;

    /* copy extradata if it exists */
    if (trk->vos_len == 0 && enc->extradata_size > 0) {
        trk->vos_len  = enc->extradata_size;
        trk->vos_data = av_malloc(trk->vos_len);
        memcpy(trk->vos_data, enc->extradata, trk->vos_len);
    }

    if (enc->codec_id == AV_CODEC_ID_AAC && pkt->size > 2 &&
        (AV_RB16(pkt->data) & 0xfff0) == 0xfff0) {
        if (!s->streams[pkt->stream_index]->nb_frames) {
            av_log(s, AV_LOG_ERROR, "Malformed AAC bitstream detected: "
                   "use audio bitstream filter 'aac_adtstoasc' to fix it "
                   "('-bsf:a aac_adtstoasc' option with ffmpeg)\n");
            return -1;
        }
        av_log(s, AV_LOG_WARNING, "aac bitstream error\n");
    }
    if (enc->codec_id == AV_CODEC_ID_H264 && trk->vos_len > 0 && *(uint8_t *)trk->vos_data != 1) {
        /* from x264 or from bytestream h264 */
        /* nal reformating needed */
        if (trk->hint_track >= 0 && trk->hint_track < mov->nb_streams) {
            ff_avc_parse_nal_units_buf(pkt->data, &reformatted_data,
                                       &size);
            avio_write(pb, reformatted_data, size);
        } else {
            size = ff_avc_parse_nal_units(pb, pkt->data, pkt->size);
        }
    } else if (enc->codec_id == AV_CODEC_ID_HEVC && trk->vos_len > 6 &&
               (AV_RB24(trk->vos_data) == 1 || AV_RB32(trk->vos_data) == 1)) {
        /* extradata is Annex B, assume the bitstream is too and convert it */
        if (trk->hint_track >= 0 && trk->hint_track < mov->nb_streams) {
            ff_hevc_annexb2mp4_buf(pkt->data, &reformatted_data, &size, 0, NULL);
            avio_write(pb, reformatted_data, size);
        } else {
            size = ff_hevc_annexb2mp4(pb, pkt->data, pkt->size, 0, NULL);
        }
    } else {
        avio_write(pb, pkt->data, size);
    }

    if ((enc->codec_id == AV_CODEC_ID_DNXHD ||
         enc->codec_id == AV_CODEC_ID_AC3) && !trk->vos_len) {
        /* copy frame to create needed atoms */
        trk->vos_len  = size;
        trk->vos_data = av_malloc(size);
        if (!trk->vos_data)
            return AVERROR(ENOMEM);
        memcpy(trk->vos_data, pkt->data, size);
    }

    if (trk->entry >= trk->cluster_capacity) {
        unsigned new_capacity = 2 * (trk->entry + MOV_INDEX_CLUSTER_SIZE);
        if (av_reallocp_array(&trk->cluster, new_capacity,
                              sizeof(*trk->cluster)))
            return AVERROR(ENOMEM);
        trk->cluster_capacity = new_capacity;
    }

    trk->cluster[trk->entry].pos              = avio_tell(pb) - size;
    trk->cluster[trk->entry].samples_in_chunk = samples_in_chunk;
    trk->cluster[trk->entry].chunkNum         = 0;
    trk->cluster[trk->entry].size             = size;
    trk->cluster[trk->entry].entries          = samples_in_chunk;
    trk->cluster[trk->entry].dts              = pkt->dts;
    if (!trk->entry && trk->start_dts != AV_NOPTS_VALUE) {
        /* First packet of a new fragment. We already wrote the duration
         * of the last packet of the previous fragment based on track_duration,
         * which might not exactly match our dts. Therefore adjust the dts
         * of this packet to be what the previous packets duration implies. */
        trk->cluster[trk->entry].dts = trk->start_dts + trk->track_duration;
    }
    if (!trk->entry && trk->start_dts == AV_NOPTS_VALUE && !supports_edts(mov)) {
        trk->cluster[trk->entry].dts = trk->start_dts = 0;
    }
    if (trk->start_dts == AV_NOPTS_VALUE)
        trk->start_dts = pkt->dts;
    trk->track_duration = pkt->dts - trk->start_dts + pkt->duration;
    trk->last_sample_is_subtitle_end = 0;

    if (pkt->pts == AV_NOPTS_VALUE) {
        av_log(s, AV_LOG_WARNING, "pts has no value\n");
        pkt->pts = pkt->dts;
    }
    if (pkt->dts != pkt->pts)
        trk->flags |= MOV_TRACK_CTTS;
    trk->cluster[trk->entry].cts   = pkt->pts - pkt->dts;
    trk->cluster[trk->entry].flags = 0;
    if (enc->codec_id == AV_CODEC_ID_VC1) {
        mov_parse_vc1_frame(pkt, trk, mov->fragments);
    } else if (pkt->flags & AV_PKT_FLAG_KEY) {
        if (mov->mode == MODE_MOV && enc->codec_id == AV_CODEC_ID_MPEG2VIDEO &&
            trk->entry > 0) { // force sync sample for the first key frame
            mov_parse_mpeg2_frame(pkt, &trk->cluster[trk->entry].flags);
            if (trk->cluster[trk->entry].flags & MOV_PARTIAL_SYNC_SAMPLE)
                trk->flags |= MOV_TRACK_STPS;
        } else {
            trk->cluster[trk->entry].flags = MOV_SYNC_SAMPLE;
        }
        if (trk->cluster[trk->entry].flags & MOV_SYNC_SAMPLE)
            trk->has_keyframes++;
    }
    trk->entry++;
    trk->sample_count += samples_in_chunk;
    mov->mdat_size    += size;

    if (trk->hint_track >= 0 && trk->hint_track < mov->nb_streams)
        ff_mov_add_hinted_packet(s, pkt, trk->hint_track, trk->entry,
                                 reformatted_data, size);
    av_free(reformatted_data);
    return 0;
}

static int mov_write_single_packet(AVFormatContext *s, AVPacket *pkt)
{
        MOVMuxContext *mov = s->priv_data;
        MOVTrack *trk = &mov->tracks[pkt->stream_index];
        AVCodecContext *enc = trk->enc;
        int64_t frag_duration = 0;
        int size = pkt->size;

        if (!pkt->size)
            return 0;             /* Discard 0 sized packets */

        if (trk->entry && pkt->stream_index < s->nb_streams)
            frag_duration = av_rescale_q(pkt->dts - trk->cluster[0].dts,
                                         s->streams[pkt->stream_index]->time_base,
                                         AV_TIME_BASE_Q);
        if ((mov->max_fragment_duration &&
             frag_duration >= mov->max_fragment_duration) ||
             (mov->max_fragment_size && mov->mdat_size + size >= mov->max_fragment_size) ||
             (mov->flags & FF_MOV_FLAG_FRAG_KEYFRAME &&
              enc->codec_type == AVMEDIA_TYPE_VIDEO &&
              trk->entry && pkt->flags & AV_PKT_FLAG_KEY)) {
            if (frag_duration >= mov->min_fragment_duration)
                mov_flush_fragment(s);
        }

        return ff_mov_write_packet(s, pkt);
}

static int mov_write_subtitle_end_packet(AVFormatContext *s,
                                         int stream_index,
                                         int64_t dts) {
    AVPacket end;
    uint8_t data[2] = {0};
    int ret;

    av_init_packet(&end);
    end.size = sizeof(data);
    end.data = data;
    end.pts = dts;
    end.dts = dts;
    end.duration = 0;
    end.stream_index = stream_index;

    ret = mov_write_single_packet(s, &end);
    av_free_packet(&end);

    return ret;
}

static int mov_write_packet(AVFormatContext *s, AVPacket *pkt)
{
    if (!pkt) {
        mov_flush_fragment(s);
        return 1;
    } else {
        int i;
        MOVMuxContext *mov = s->priv_data;

        if (!pkt->size) return 0; /* Discard 0 sized packets */

        /*
         * Subtitles require special handling.
         *
         * 1) For full complaince, every track must have a sample at
         * dts == 0, which is rarely true for subtitles. So, as soon
         * as we see any packet with dts > 0, write an empty subtitle
         * at dts == 0 for any subtitle track with no samples in it.
         *
         * 2) For each subtitle track, check if the current packet's
         * dts is past the duration of the last subtitle sample. If
         * so, we now need to write an end sample for that subtitle.
         *
         * This must be done conditionally to allow for subtitles that
         * immediately replace each other, in which case an end sample
         * is not needed, and is, in fact, actively harmful.
         *
         * 3) See mov_write_trailer for how the final end sample is
         * handled.
         */
        for (i = 0; i < mov->nb_streams; i++) {
            MOVTrack *trk = &mov->tracks[i];
            int ret;

            if (trk->enc->codec_id == AV_CODEC_ID_MOV_TEXT &&
                trk->track_duration < pkt->dts &&
                (trk->entry == 0 || !trk->last_sample_is_subtitle_end)) {
                ret = mov_write_subtitle_end_packet(s, i, trk->track_duration);
                if (ret < 0) return ret;
                trk->last_sample_is_subtitle_end = 1;
            }
        }

        return mov_write_single_packet(s, pkt);
    }
}

// QuickTime chapters involve an additional text track with the chapter names
// as samples, and a tref pointing from the other tracks to the chapter one.
static int mov_create_chapter_track(AVFormatContext *s, int tracknum)
{
    AVIOContext *pb;

    MOVMuxContext *mov = s->priv_data;
    MOVTrack *track = &mov->tracks[tracknum];
    AVPacket pkt = { .stream_index = tracknum, .flags = AV_PKT_FLAG_KEY };
    int i, len;

    track->mode = mov->mode;
    track->tag = MKTAG('t','e','x','t');
    track->timescale = MOV_TIMESCALE;
    track->enc = avcodec_alloc_context3(NULL);
    if (!track->enc)
        return AVERROR(ENOMEM);
    track->enc->codec_type = AVMEDIA_TYPE_SUBTITLE;
#if 0
    // These properties are required to make QT recognize the chapter track
    uint8_t chapter_properties[43] = { 0, 0, 0, 0, 0, 0, 0, 1, };
    if (ff_alloc_extradata(track->enc, sizeof(chapter_properties)))
        return AVERROR(ENOMEM);
    memcpy(track->enc->extradata, chapter_properties, sizeof(chapter_properties));
#else
    if (avio_open_dyn_buf(&pb) >= 0) {
        int size;
        uint8_t *buf;

        /* Stub header (usually for Quicktime chapter track) */
        // TextSampleEntry
        avio_wb32(pb, 0x01); // displayFlags
        avio_w8(pb, 0x00);   // horizontal justification
        avio_w8(pb, 0x00);   // vertical justification
        avio_w8(pb, 0x00);   // bgColourRed
        avio_w8(pb, 0x00);   // bgColourGreen
        avio_w8(pb, 0x00);   // bgColourBlue
        avio_w8(pb, 0x00);   // bgColourAlpha
        // BoxRecord
        avio_wb16(pb, 0x00); // defTextBoxTop
        avio_wb16(pb, 0x00); // defTextBoxLeft
        avio_wb16(pb, 0x00); // defTextBoxBottom
        avio_wb16(pb, 0x00); // defTextBoxRight
        // StyleRecord
        avio_wb16(pb, 0x00); // startChar
        avio_wb16(pb, 0x00); // endChar
        avio_wb16(pb, 0x01); // fontID
        avio_w8(pb, 0x00);   // fontStyleFlags
        avio_w8(pb, 0x00);   // fontSize
        avio_w8(pb, 0x00);   // fgColourRed
        avio_w8(pb, 0x00);   // fgColourGreen
        avio_w8(pb, 0x00);   // fgColourBlue
        avio_w8(pb, 0x00);   // fgColourAlpha
        // FontTableBox
        avio_wb32(pb, 0x0D); // box size
        ffio_wfourcc(pb, "ftab"); // box atom name
        avio_wb16(pb, 0x01); // entry count
        // FontRecord
        avio_wb16(pb, 0x01); // font ID
        avio_w8(pb, 0x00);   // font name length

        if ((size = avio_close_dyn_buf(pb, &buf)) > 0) {
            track->enc->extradata = buf;
            track->enc->extradata_size = size;
        } else {
            av_freep(&buf);
        }
    }
#endif

    for (i = 0; i < s->nb_chapters; i++) {
        AVChapter *c = s->chapters[i];
        AVDictionaryEntry *t;

        int64_t end = av_rescale_q(c->end, c->time_base, (AVRational){1,MOV_TIMESCALE});
        pkt.pts = pkt.dts = av_rescale_q(c->start, c->time_base, (AVRational){1,MOV_TIMESCALE});
        pkt.duration = end - pkt.dts;

        if ((t = av_dict_get(c->metadata, "title", NULL, 0))) {
            len      = strlen(t->value);
            pkt.size = len + 2;
            pkt.data = av_malloc(pkt.size);
            if (!pkt.data)
                return AVERROR(ENOMEM);
            AV_WB16(pkt.data, len);
            memcpy(pkt.data + 2, t->value, len);
            ff_mov_write_packet(s, &pkt);
            av_freep(&pkt.data);
        }
    }

    return 0;
}

static int mov_create_timecode_track(AVFormatContext *s, int index, int src_index, const char *tcstr)
{
    int ret;
    MOVMuxContext *mov  = s->priv_data;
    MOVTrack *track     = &mov->tracks[index];
    AVStream *src_st    = s->streams[src_index];
    AVTimecode tc;
    AVPacket pkt    = {.stream_index = index, .flags = AV_PKT_FLAG_KEY, .size = 4};
    AVRational rate = find_fps(s, src_st);

    /* compute the frame number */
    ret = av_timecode_init_from_string(&tc, rate, tcstr, s);
    if (ret < 0)
        return ret;

    /* tmcd track based on video stream */
    track->mode      = mov->mode;
    track->tag       = MKTAG('t','m','c','d');
    track->src_track = src_index;
    track->timescale = mov->tracks[src_index].timescale;
    if (tc.flags & AV_TIMECODE_FLAG_DROPFRAME)
        track->timecode_flags |= MOV_TIMECODE_FLAG_DROPFRAME;

    /* encode context: tmcd data stream */
    track->enc = avcodec_alloc_context3(NULL);
    track->enc->codec_type = AVMEDIA_TYPE_DATA;
    track->enc->codec_tag  = track->tag;
    track->enc->time_base  = av_inv_q(rate);

    /* the tmcd track just contains one packet with the frame number */
    pkt.data = av_malloc(pkt.size);
    AV_WB32(pkt.data, tc.start);
    ret = ff_mov_write_packet(s, &pkt);
    av_free(pkt.data);
    return ret;
}

/*
 * st->disposition controls the "enabled" flag in the tkhd tag.
 * QuickTime will not play a track if it is not enabled.  So make sure
 * that one track of each type (audio, video, subtitle) is enabled.
 *
 * Subtitles are special.  For audio and video, setting "enabled" also
 * makes the track "default" (i.e. it is rendered when played). For
 * subtitles, an "enabled" subtitle is not rendered by default, but
 * if no subtitle is enabled, the subtitle menu in QuickTime will be
 * empty!
 */
static void enable_tracks(AVFormatContext *s)
{
    MOVMuxContext *mov = s->priv_data;
    int i;
    uint8_t enabled[AVMEDIA_TYPE_NB];
    int first[AVMEDIA_TYPE_NB];

    for (i = 0; i < AVMEDIA_TYPE_NB; i++) {
        enabled[i] = 0;
        first[i] = -1;
    }

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];

        if (st->codec->codec_type <= AVMEDIA_TYPE_UNKNOWN ||
            st->codec->codec_type >= AVMEDIA_TYPE_NB)
            continue;

        if (first[st->codec->codec_type] < 0)
            first[st->codec->codec_type] = i;
        if (st->disposition & AV_DISPOSITION_DEFAULT) {
            mov->tracks[i].flags |= MOV_TRACK_ENABLED;
            enabled[st->codec->codec_type] = 1;
        }
    }

    for (i = 0; i < AVMEDIA_TYPE_NB; i++) {
        switch (i) {
        case AVMEDIA_TYPE_VIDEO:
        case AVMEDIA_TYPE_AUDIO:
        case AVMEDIA_TYPE_SUBTITLE:
            if (!enabled[i] && first[i] >= 0)
                mov->tracks[first[i]].flags |= MOV_TRACK_ENABLED;
            break;
        }
    }
}

static void mov_free(AVFormatContext *s)
{
    MOVMuxContext *mov = s->priv_data;
    int i;

    if (mov->chapter_track) {
        if (mov->tracks[mov->chapter_track].enc)
            av_freep(&mov->tracks[mov->chapter_track].enc->extradata);
        av_freep(&mov->tracks[mov->chapter_track].enc);
    }

    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->tracks[i].tag == MKTAG('r','t','p',' '))
            ff_mov_close_hinting(&mov->tracks[i]);
        else if (mov->tracks[i].tag == MKTAG('t','m','c','d') && mov->nb_meta_tmcd)
            av_freep(&mov->tracks[i].enc);
        av_freep(&mov->tracks[i].cluster);
        av_freep(&mov->tracks[i].frag_info);

        if (mov->tracks[i].vos_len)
            av_freep(&mov->tracks[i].vos_data);
    }

    av_freep(&mov->tracks);
}

static int mov_write_header(AVFormatContext *s)
{
    AVIOContext *pb = s->pb;
    MOVMuxContext *mov = s->priv_data;
    AVDictionaryEntry *t, *global_tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
    int i, ret, hint_track = 0, tmcd_track = 0;

    /* Default mode == MP4 */
    mov->mode = MODE_MP4;

    if (s->oformat != NULL) {
        if (!strcmp("3gp", s->oformat->name)) mov->mode = MODE_3GP;
        else if (!strcmp("3g2", s->oformat->name)) mov->mode = MODE_3GP|MODE_3G2;
        else if (!strcmp("mov", s->oformat->name)) mov->mode = MODE_MOV;
        else if (!strcmp("psp", s->oformat->name)) mov->mode = MODE_PSP;
        else if (!strcmp("ipod",s->oformat->name)) mov->mode = MODE_IPOD;
        else if (!strcmp("ismv",s->oformat->name)) mov->mode = MODE_ISM;
        else if (!strcmp("f4v", s->oformat->name)) mov->mode = MODE_F4V;
    }

    /* Set the FRAGMENT flag if any of the fragmentation methods are
     * enabled. */
    if (mov->max_fragment_duration || mov->max_fragment_size ||
        mov->flags & (FF_MOV_FLAG_EMPTY_MOOV |
                      FF_MOV_FLAG_FRAG_KEYFRAME |
                      FF_MOV_FLAG_FRAG_CUSTOM))
        mov->flags |= FF_MOV_FLAG_FRAGMENT;

    /* Set other implicit flags immediately */
    if (mov->mode == MODE_ISM)
        mov->flags |= FF_MOV_FLAG_EMPTY_MOOV | FF_MOV_FLAG_SEPARATE_MOOF |
                      FF_MOV_FLAG_FRAGMENT;

    /* faststart: moov at the beginning of the file, if supported */
    if (mov->flags & FF_MOV_FLAG_FASTSTART) {
        if ((mov->flags & FF_MOV_FLAG_FRAGMENT) ||
            (s->flags & AVFMT_FLAG_CUSTOM_IO)) {
            av_log(s, AV_LOG_WARNING, "The faststart flag is incompatible "
                   "with fragmentation and custom IO, disabling faststart\n");
            mov->flags &= ~FF_MOV_FLAG_FASTSTART;
        } else
            mov->reserved_moov_size = -1;
    }

    if (!supports_edts(mov) && s->avoid_negative_ts < 0) {
        s->avoid_negative_ts = 2;
    }

    /* Non-seekable output is ok if using fragmentation. If ism_lookahead
     * is enabled, we don't support non-seekable output at all. */
    if (!s->pb->seekable &&
        (!(mov->flags & FF_MOV_FLAG_FRAGMENT) || mov->ism_lookahead)) {
        av_log(s, AV_LOG_ERROR, "muxer does not support non seekable output\n");
        return AVERROR(EINVAL);
    }

    mov_write_ftyp_tag(pb,s);
    if (mov->mode == MODE_PSP) {
        int video_streams_nb = 0, audio_streams_nb = 0, other_streams_nb = 0;
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
                video_streams_nb++;
            else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
                audio_streams_nb++;
            else
                other_streams_nb++;
            }

        if (video_streams_nb != 1 || audio_streams_nb != 1 || other_streams_nb) {
            av_log(s, AV_LOG_ERROR, "PSP mode need one video and one audio stream\n");
            return AVERROR(EINVAL);
        }
        mov_write_uuidprof_tag(pb, s);
    }

    mov->nb_streams = s->nb_streams;
    if (mov->mode & (MODE_MP4|MODE_MOV|MODE_IPOD) && s->nb_chapters)
        mov->chapter_track = mov->nb_streams++;

    if (mov->flags & FF_MOV_FLAG_RTP_HINT) {
        /* Add hint tracks for each audio and video stream */
        hint_track = mov->nb_streams;
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO ||
                st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
                mov->nb_streams++;
            }
        }
    }

    if (mov->mode == MODE_MOV) {
        tmcd_track = mov->nb_streams;

        /* +1 tmcd track for each video stream with a timecode */
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
                (global_tcr || av_dict_get(st->metadata, "timecode", NULL, 0)))
                mov->nb_meta_tmcd++;
        }

        /* check if there is already a tmcd track to remux */
        if (mov->nb_meta_tmcd) {
            for (i = 0; i < s->nb_streams; i++) {
                AVStream *st = s->streams[i];
                if (st->codec->codec_tag == MKTAG('t','m','c','d')) {
                    av_log(s, AV_LOG_WARNING, "You requested a copy of the original timecode track "
                           "so timecode metadata are now ignored\n");
                    mov->nb_meta_tmcd = 0;
                }
            }
        }

        mov->nb_streams += mov->nb_meta_tmcd;
    }

    // Reserve an extra stream for chapters for the case where chapters
    // are written in the trailer
    mov->tracks = av_mallocz((mov->nb_streams + 1) * sizeof(*mov->tracks));
    if (!mov->tracks)
        return AVERROR(ENOMEM);

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st= s->streams[i];
        MOVTrack *track= &mov->tracks[i];
        AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,0);

        track->enc = st->codec;
        track->st = st;
        track->language = ff_mov_iso639_to_lang(lang?lang->value:"und", mov->mode!=MODE_MOV);
        if (track->language < 0)
            track->language = 0;
        track->mode = mov->mode;
        track->tag  = mov_find_codec_tag(s, track);
        if (!track->tag) {
            av_log(s, AV_LOG_ERROR, "Could not find tag for codec %s in stream #%d, "
                   "codec not currently supported in container\n",
                   avcodec_get_name(st->codec->codec_id), i);
            ret = AVERROR(EINVAL);
            goto error;
        }
        /* If hinting of this track is enabled by a later hint track,
         * this is updated. */
        track->hint_track = -1;
        track->start_dts  = AV_NOPTS_VALUE;
        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
            if (track->tag == MKTAG('m','x','3','p') || track->tag == MKTAG('m','x','3','n') ||
                track->tag == MKTAG('m','x','4','p') || track->tag == MKTAG('m','x','4','n') ||
                track->tag == MKTAG('m','x','5','p') || track->tag == MKTAG('m','x','5','n')) {
                if (st->codec->width != 720 || (st->codec->height != 608 && st->codec->height != 512)) {
                    av_log(s, AV_LOG_ERROR, "D-10/IMX must use 720x608 or 720x512 video resolution\n");
                    ret = AVERROR(EINVAL);
                    goto error;
                }
                track->height = track->tag >> 24 == 'n' ? 486 : 576;
            }
            if (mov->video_track_timescale) {
                track->timescale = mov->video_track_timescale;
            } else {
                track->timescale = st->codec->time_base.den;
                while(track->timescale < 10000)
                    track->timescale *= 2;
            }
            if (track->mode == MODE_MOV && track->timescale > 100000)
                av_log(s, AV_LOG_WARNING,
                       "WARNING codec timebase is very high. If duration is too long,\n"
                       "file may not be playable by quicktime. Specify a shorter timebase\n"
                       "or choose different container.\n");
        } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
            track->timescale = st->codec->sample_rate;
            if (!st->codec->frame_size && !av_get_bits_per_sample(st->codec->codec_id)) {
                av_log(s, AV_LOG_WARNING, "track %d: codec frame size is not set\n", i);
                track->audio_vbr = 1;
            }else if (st->codec->codec_id == AV_CODEC_ID_ADPCM_MS ||
                     st->codec->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV ||
                     st->codec->codec_id == AV_CODEC_ID_ILBC){
                if (!st->codec->block_align) {
                    av_log(s, AV_LOG_ERROR, "track %d: codec block align is not set for adpcm\n", i);
                    ret = AVERROR(EINVAL);
                    goto error;
                }
                track->sample_size = st->codec->block_align;
            }else if (st->codec->frame_size > 1){ /* assume compressed audio */
                track->audio_vbr = 1;
            }else{
                track->sample_size = (av_get_bits_per_sample(st->codec->codec_id) >> 3) * st->codec->channels;
            }
            if (st->codec->codec_id == AV_CODEC_ID_ILBC ||
                st->codec->codec_id == AV_CODEC_ID_ADPCM_IMA_QT) {
                track->audio_vbr = 1;
            }
            if (track->mode != MODE_MOV &&
                track->enc->codec_id == AV_CODEC_ID_MP3 && track->timescale < 16000) {
                av_log(s, AV_LOG_ERROR, "track %d: muxing mp3 at %dhz is not supported\n",
                       i, track->enc->sample_rate);
                ret = AVERROR(EINVAL);
                goto error;
            }
        } else if (st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
            track->timescale = st->codec->time_base.den;
        } else if (st->codec->codec_type == AVMEDIA_TYPE_DATA) {
            track->timescale = st->codec->time_base.den;
        } else {
            track->timescale = MOV_TIMESCALE;
        }
        if (!track->height)
            track->height = st->codec->height;
        /* The ism specific timescale isn't mandatory, but is assumed by
         * some tools, such as mp4split. */
        if (mov->mode == MODE_ISM)
            track->timescale = 10000000;

        avpriv_set_pts_info(st, 64, 1, track->timescale);

        /* copy extradata if it exists */
        if (st->codec->extradata_size) {
            track->vos_len  = st->codec->extradata_size;
            track->vos_data = av_malloc(track->vos_len);
            memcpy(track->vos_data, st->codec->extradata, track->vos_len);
        }
    }

    enable_tracks(s);


    if (mov->reserved_moov_size){
        mov->reserved_moov_pos= avio_tell(pb);
        if (mov->reserved_moov_size > 0)
            avio_skip(pb, mov->reserved_moov_size);
    }

    if (mov->flags & FF_MOV_FLAG_FRAGMENT) {
        /* If no fragmentation options have been set, set a default. */
        if (!(mov->flags & (FF_MOV_FLAG_FRAG_KEYFRAME |
                            FF_MOV_FLAG_FRAG_CUSTOM)) &&
            !mov->max_fragment_duration && !mov->max_fragment_size)
            mov->flags |= FF_MOV_FLAG_FRAG_KEYFRAME;
    } else {
        if (mov->flags & FF_MOV_FLAG_FASTSTART)
            mov->reserved_moov_pos = avio_tell(pb);
        mov_write_mdat_tag(pb, mov);
    }

    if (t = av_dict_get(s->metadata, "creation_time", NULL, 0))
        mov->time = ff_iso8601_to_unix_time(t->value);
    if (mov->time)
        mov->time += 0x7C25B080; // 1970 based -> 1904 based

    if (mov->chapter_track)
        if ((ret = mov_create_chapter_track(s, mov->chapter_track)) < 0)
            goto error;

    if (mov->flags & FF_MOV_FLAG_RTP_HINT) {
        /* Initialize the hint tracks for each audio and video stream */
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO ||
                st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
                if ((ret = ff_mov_init_hinting(s, hint_track, i)) < 0)
                    goto error;
                hint_track++;
            }
        }
    }

    if (mov->nb_meta_tmcd) {
        /* Initialize the tmcd tracks */
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            t = global_tcr;

            if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
                if (!t)
                    t = av_dict_get(st->metadata, "timecode", NULL, 0);
                if (!t)
                    continue;
                if ((ret = mov_create_timecode_track(s, tmcd_track, i, t->value)) < 0)
                    goto error;
                tmcd_track++;
            }
        }
    }

    avio_flush(pb);

    if (mov->flags & FF_MOV_FLAG_ISML)
        mov_write_isml_manifest(pb, mov);

    if (mov->flags & FF_MOV_FLAG_EMPTY_MOOV) {
        mov_write_moov_tag(pb, mov, s);
        mov->fragments++;
    }

    return 0;
 error:
    mov_free(s);
    return ret;
}

static int get_moov_size(AVFormatContext *s)
{
    int ret;
    AVIOContext *moov_buf;
    MOVMuxContext *mov = s->priv_data;

    if ((ret = ffio_open_null_buf(&moov_buf)) < 0)
        return ret;
    mov_write_moov_tag(moov_buf, mov, s);
    return ffio_close_null_buf(moov_buf);
}

/*
 * This function gets the moov size if moved to the top of the file: the chunk
 * offset table can switch between stco (32-bit entries) to co64 (64-bit
 * entries) when the moov is moved to the beginning, so the size of the moov
 * would change. It also updates the chunk offset tables.
 */
static int compute_moov_size(AVFormatContext *s)
{
    int i, moov_size, moov_size2;
    MOVMuxContext *mov = s->priv_data;

    moov_size = get_moov_size(s);
    if (moov_size < 0)
        return moov_size;

    for (i = 0; i < mov->nb_streams; i++)
        mov->tracks[i].data_offset += moov_size;

    moov_size2 = get_moov_size(s);
    if (moov_size2 < 0)
        return moov_size2;

    /* if the size changed, we just switched from stco to co64 and need to
     * update the offsets */
    if (moov_size2 != moov_size)
        for (i = 0; i < mov->nb_streams; i++)
            mov->tracks[i].data_offset += moov_size2 - moov_size;

    return moov_size2;
}

static int shift_data(AVFormatContext *s)
{
    int ret = 0, moov_size;
    MOVMuxContext *mov = s->priv_data;
    int64_t pos, pos_end = avio_tell(s->pb);
    uint8_t *buf, *read_buf[2];
    int read_buf_id = 0;
    int read_size[2];
    AVIOContext *read_pb;

    moov_size = compute_moov_size(s);
    if (moov_size < 0)
        return moov_size;

    buf = av_malloc(moov_size * 2);
    if (!buf)
        return AVERROR(ENOMEM);
    read_buf[0] = buf;
    read_buf[1] = buf + moov_size;

    /* Shift the data: the AVIO context of the output can only be used for
     * writing, so we re-open the same output, but for reading. It also avoids
     * a read/seek/write/seek back and forth. */
    avio_flush(s->pb);
    ret = avio_open(&read_pb, s->filename, AVIO_FLAG_READ);
    if (ret < 0) {
        av_log(s, AV_LOG_ERROR, "Unable to re-open %s output file for "
               "the second pass (faststart)\n", s->filename);
        goto end;
    }

    /* mark the end of the shift to up to the last data we wrote, and get ready
     * for writing */
    pos_end = avio_tell(s->pb);
    avio_seek(s->pb, mov->reserved_moov_pos + moov_size, SEEK_SET);

    /* start reading at where the new moov will be placed */
    avio_seek(read_pb, mov->reserved_moov_pos, SEEK_SET);
    pos = avio_tell(read_pb);

#define READ_BLOCK do {                                                             \
    read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], moov_size);  \
    read_buf_id ^= 1;                                                               \
} while (0)

    /* shift data by chunk of at most moov_size */
    READ_BLOCK;
    do {
        int n;
        READ_BLOCK;
        n = read_size[read_buf_id];
        if (n <= 0)
            break;
        avio_write(s->pb, read_buf[read_buf_id], n);
        pos += n;
    } while (pos < pos_end);
    avio_close(read_pb);

end:
    av_free(buf);
    return ret;
}

static int mov_write_trailer(AVFormatContext *s)
{
    MOVMuxContext *mov = s->priv_data;
    AVIOContext *pb = s->pb;
    int res = 0;
    int i;
    int64_t moov_pos;

    /*
     * Before actually writing the trailer, make sure that there are no
     * dangling subtitles, that need a terminating sample.
     */
    for (i = 0; i < mov->nb_streams; i++) {
        MOVTrack *trk = &mov->tracks[i];
        if (trk->enc->codec_id == AV_CODEC_ID_MOV_TEXT &&
            !trk->last_sample_is_subtitle_end) {
            mov_write_subtitle_end_packet(s, i, trk->track_duration);
            trk->last_sample_is_subtitle_end = 1;
        }
    }

    // If there were no chapters when the header was written, but there
    // are chapters now, write them in the trailer.  This only works
    // when we are not doing fragments.
    if (!mov->chapter_track && !(mov->flags & FF_MOV_FLAG_FRAGMENT)) {
        if (mov->mode & (MODE_MP4|MODE_MOV|MODE_IPOD) && s->nb_chapters) {
            mov->chapter_track = mov->nb_streams++;
            if ((res = mov_create_chapter_track(s, mov->chapter_track)) < 0)
                goto error;
        }
    }

    if (!(mov->flags & FF_MOV_FLAG_FRAGMENT)) {
        moov_pos = avio_tell(pb);

        /* Write size of mdat tag */
        if (mov->mdat_size + 8 <= UINT32_MAX) {
            avio_seek(pb, mov->mdat_pos, SEEK_SET);
            avio_wb32(pb, mov->mdat_size + 8);
        } else {
            /* overwrite 'wide' placeholder atom */
            avio_seek(pb, mov->mdat_pos - 8, SEEK_SET);
            /* special value: real atom size will be 64 bit value after
             * tag field */
            avio_wb32(pb, 1);
            ffio_wfourcc(pb, "mdat");
            avio_wb64(pb, mov->mdat_size + 16);
        }
        avio_seek(pb, mov->reserved_moov_size > 0 ? mov->reserved_moov_pos : moov_pos, SEEK_SET);

        if (mov->flags & FF_MOV_FLAG_FASTSTART) {
            av_log(s, AV_LOG_INFO, "Starting second pass: moving the moov atom to the beginning of the file\n");
            res = shift_data(s);
            if (res == 0) {
                avio_seek(s->pb, mov->reserved_moov_pos, SEEK_SET);
                mov_write_moov_tag(pb, mov, s);
            }
        } else if (mov->reserved_moov_size > 0) {
            int64_t size;
            mov_write_moov_tag(pb, mov, s);
            size = mov->reserved_moov_size - (avio_tell(pb) - mov->reserved_moov_pos);
            if (size < 8){
                av_log(s, AV_LOG_ERROR, "reserved_moov_size is too small, needed %"PRId64" additional\n", 8-size);
                return -1;
            }
            avio_wb32(pb, size);
            ffio_wfourcc(pb, "free");
            for (i = 0; i < size; i++)
                avio_w8(pb, 0);
            avio_seek(pb, moov_pos, SEEK_SET);
        } else {
            mov_write_moov_tag(pb, mov, s);
        }
    } else {
        mov_flush_fragment(s);
        mov_write_mfra_tag(pb, mov);
    }

    for (i = 0; i < mov->nb_streams; i++) {
        if (mov->flags & FF_MOV_FLAG_FRAGMENT &&
            mov->tracks[i].vc1_info.struct_offset && s->pb->seekable) {
            int64_t off = avio_tell(pb);
            uint8_t buf[7];
            if (mov_write_dvc1_structs(&mov->tracks[i], buf) >= 0) {
                avio_seek(pb, mov->tracks[i].vc1_info.struct_offset, SEEK_SET);
                avio_write(pb, buf, 7);
                avio_seek(pb, off, SEEK_SET);
            }
        }
    }

error:
    mov_free(s);

    return res;
}

#if CONFIG_MOV_MUXER
MOV_CLASS(mov)
AVOutputFormat ff_mov_muxer = {
    .name              = "mov",
    .long_name         = NULL_IF_CONFIG_SMALL("QuickTime / MOV"),
    .extensions        = "mov",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AAC,
    .video_codec       = CONFIG_LIBX264_ENCODER ?
                         AV_CODEC_ID_H264 : AV_CODEC_ID_MPEG4,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){
        ff_codec_movvideo_tags, ff_codec_movaudio_tags, 0
    },
    .priv_class        = &mov_muxer_class,
};
#endif
#if CONFIG_TGP_MUXER
MOV_CLASS(tgp)
AVOutputFormat ff_tgp_muxer = {
    .name              = "3gp",
    .long_name         = NULL_IF_CONFIG_SMALL("3GP (3GPP file format)"),
    .extensions        = "3gp",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AMR_NB,
    .video_codec       = AV_CODEC_ID_H263,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){ codec_3gp_tags, 0 },
    .priv_class        = &tgp_muxer_class,
};
#endif
#if CONFIG_MP4_MUXER
MOV_CLASS(mp4)
AVOutputFormat ff_mp4_muxer = {
    .name              = "mp4",
    .long_name         = NULL_IF_CONFIG_SMALL("MP4 (MPEG-4 Part 14)"),
    .mime_type         = "application/mp4",
    .extensions        = "mp4",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AAC,
    .video_codec       = CONFIG_LIBX264_ENCODER ?
                         AV_CODEC_ID_H264 : AV_CODEC_ID_MPEG4,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){ ff_mp4_obj_type, 0 },
    .priv_class        = &mp4_muxer_class,
};
#endif
#if CONFIG_PSP_MUXER
MOV_CLASS(psp)
AVOutputFormat ff_psp_muxer = {
    .name              = "psp",
    .long_name         = NULL_IF_CONFIG_SMALL("PSP MP4 (MPEG-4 Part 14)"),
    .extensions        = "mp4,psp",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AAC,
    .video_codec       = CONFIG_LIBX264_ENCODER ?
                         AV_CODEC_ID_H264 : AV_CODEC_ID_MPEG4,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){ ff_mp4_obj_type, 0 },
    .priv_class        = &psp_muxer_class,
};
#endif
#if CONFIG_TG2_MUXER
MOV_CLASS(tg2)
AVOutputFormat ff_tg2_muxer = {
    .name              = "3g2",
    .long_name         = NULL_IF_CONFIG_SMALL("3GP2 (3GPP2 file format)"),
    .extensions        = "3g2",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AMR_NB,
    .video_codec       = AV_CODEC_ID_H263,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){ codec_3gp_tags, 0 },
    .priv_class        = &tg2_muxer_class,
};
#endif
#if CONFIG_IPOD_MUXER
MOV_CLASS(ipod)
AVOutputFormat ff_ipod_muxer = {
    .name              = "ipod",
    .long_name         = NULL_IF_CONFIG_SMALL("iPod H.264 MP4 (MPEG-4 Part 14)"),
    .mime_type         = "application/mp4",
    .extensions        = "m4v,m4a",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AAC,
    .video_codec       = AV_CODEC_ID_H264,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){ codec_ipod_tags, 0 },
    .priv_class        = &ipod_muxer_class,
};
#endif
#if CONFIG_ISMV_MUXER
MOV_CLASS(ismv)
AVOutputFormat ff_ismv_muxer = {
    .name              = "ismv",
    .long_name         = NULL_IF_CONFIG_SMALL("ISMV/ISMA (Smooth Streaming)"),
    .mime_type         = "application/mp4",
    .extensions        = "ismv,isma",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AAC,
    .video_codec       = AV_CODEC_ID_H264,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
    .codec_tag         = (const AVCodecTag* const []){ ff_mp4_obj_type, 0 },
    .priv_class        = &ismv_muxer_class,
};
#endif
#if CONFIG_F4V_MUXER
MOV_CLASS(f4v)
AVOutputFormat ff_f4v_muxer = {
    .name              = "f4v",
    .long_name         = NULL_IF_CONFIG_SMALL("F4V Adobe Flash Video"),
    .mime_type         = "application/f4v",
    .extensions        = "f4v",
    .priv_data_size    = sizeof(MOVMuxContext),
    .audio_codec       = AV_CODEC_ID_AAC,
    .video_codec       = AV_CODEC_ID_H264,
    .write_header      = mov_write_header,
    .write_packet      = mov_write_packet,
    .write_trailer     = mov_write_trailer,
    .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH,
    .codec_tag         = (const AVCodecTag* const []){ codec_f4v_tags, 0 },
    .priv_class        = &f4v_muxer_class,
};
#endif