FFmpeg/libavformat/mov.c

/*
 * MOV demuxer
 * Copyright (c) 2001 Fabrice Bellard
 * 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 <limits.h>

//#define DEBUG
//#define MOV_EXPORT_ALL_METADATA

#include "libavutil/intreadwrite.h"
#include "libavutil/intfloat.h"
#include "libavutil/mathematics.h"
#include "libavutil/avstring.h"
#include "libavutil/dict.h"
#include "avformat.h"
#include "internal.h"
#include "avio_internal.h"
#include "riff.h"
#include "isom.h"
#include "libavcodec/get_bits.h"
#include "id3v1.h"
#include "mov_chan.h"

#if CONFIG_ZLIB
#include <zlib.h>
#endif

/*
 * First version by Francois Revol revol@free.fr
 * Seek function by Gael Chardon gael.dev@4now.net
 */

#include "qtpalette.h"


#undef NDEBUG
#include <assert.h>

/* those functions parse an atom */
/* links atom IDs to parse functions */
typedef struct MOVParseTableEntry {
    uint32_t type;
    int (*parse)(MOVContext *ctx, AVIOContext *pb, MOVAtom atom);
} MOVParseTableEntry;

static const MOVParseTableEntry mov_default_parse_table[];

static int mov_metadata_track_or_disc_number(MOVContext *c, AVIOContext *pb,
                                             unsigned len, const char *key)
{
    char buf[16];

    short current, total = 0;
    avio_rb16(pb); // unknown
    current = avio_rb16(pb);
    if (len >= 6)
        total = avio_rb16(pb);
    if (!total)
        snprintf(buf, sizeof(buf), "%d", current);
    else
        snprintf(buf, sizeof(buf), "%d/%d", current, total);
    av_dict_set(&c->fc->metadata, key, buf, 0);

    return 0;
}

static int mov_metadata_int8_bypass_padding(MOVContext *c, AVIOContext *pb,
                                            unsigned len, const char *key)
{
    char buf[16];

    /* bypass padding bytes */
    avio_r8(pb);
    avio_r8(pb);
    avio_r8(pb);

    snprintf(buf, sizeof(buf), "%d", avio_r8(pb));
    av_dict_set(&c->fc->metadata, key, buf, 0);

    return 0;
}

static int mov_metadata_int8_no_padding(MOVContext *c, AVIOContext *pb,
                                        unsigned len, const char *key)
{
    char buf[16];

    snprintf(buf, sizeof(buf), "%d", avio_r8(pb));
    av_dict_set(&c->fc->metadata, key, buf, 0);

    return 0;
}

static int mov_metadata_gnre(MOVContext *c, AVIOContext *pb,
                             unsigned len, const char *key)
{
    short genre;
    char buf[20];

    avio_r8(pb); // unknown

    genre = avio_r8(pb);
    if (genre < 1 || genre > ID3v1_GENRE_MAX)
        return 0;
    snprintf(buf, sizeof(buf), "%s", ff_id3v1_genre_str[genre-1]);
    av_dict_set(&c->fc->metadata, key, buf, 0);

    return 0;
}

static const uint32_t mac_to_unicode[128] = {
    0x00C4,0x00C5,0x00C7,0x00C9,0x00D1,0x00D6,0x00DC,0x00E1,
    0x00E0,0x00E2,0x00E4,0x00E3,0x00E5,0x00E7,0x00E9,0x00E8,
    0x00EA,0x00EB,0x00ED,0x00EC,0x00EE,0x00EF,0x00F1,0x00F3,
    0x00F2,0x00F4,0x00F6,0x00F5,0x00FA,0x00F9,0x00FB,0x00FC,
    0x2020,0x00B0,0x00A2,0x00A3,0x00A7,0x2022,0x00B6,0x00DF,
    0x00AE,0x00A9,0x2122,0x00B4,0x00A8,0x2260,0x00C6,0x00D8,
    0x221E,0x00B1,0x2264,0x2265,0x00A5,0x00B5,0x2202,0x2211,
    0x220F,0x03C0,0x222B,0x00AA,0x00BA,0x03A9,0x00E6,0x00F8,
    0x00BF,0x00A1,0x00AC,0x221A,0x0192,0x2248,0x2206,0x00AB,
    0x00BB,0x2026,0x00A0,0x00C0,0x00C3,0x00D5,0x0152,0x0153,
    0x2013,0x2014,0x201C,0x201D,0x2018,0x2019,0x00F7,0x25CA,
    0x00FF,0x0178,0x2044,0x20AC,0x2039,0x203A,0xFB01,0xFB02,
    0x2021,0x00B7,0x201A,0x201E,0x2030,0x00C2,0x00CA,0x00C1,
    0x00CB,0x00C8,0x00CD,0x00CE,0x00CF,0x00CC,0x00D3,0x00D4,
    0xF8FF,0x00D2,0x00DA,0x00DB,0x00D9,0x0131,0x02C6,0x02DC,
    0x00AF,0x02D8,0x02D9,0x02DA,0x00B8,0x02DD,0x02DB,0x02C7,
};

static int mov_read_mac_string(MOVContext *c, AVIOContext *pb, int len,
                               char *dst, int dstlen)
{
    char *p = dst;
    char *end = dst+dstlen-1;
    int i;

    for (i = 0; i < len; i++) {
        uint8_t t, c = avio_r8(pb);
        if (c < 0x80 && p < end)
            *p++ = c;
        else
            PUT_UTF8(mac_to_unicode[c-0x80], t, if (p < end) *p++ = t;);
    }
    *p = 0;
    return p - dst;
}

static int mov_read_udta_string(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
#ifdef MOV_EXPORT_ALL_METADATA
    char tmp_key[5];
#endif
    char str[1024], key2[16], language[4] = {0};
    const char *key = NULL;
    uint16_t str_size, langcode = 0;
    uint32_t data_type = 0;
    int (*parse)(MOVContext*, AVIOContext*, unsigned, const char*) = NULL;

    switch (atom.type) {
    case MKTAG(0xa9,'n','a','m'): key = "title";     break;
    case MKTAG(0xa9,'a','u','t'):
    case MKTAG(0xa9,'A','R','T'): key = "artist";    break;
    case MKTAG( 'a','A','R','T'): key = "album_artist";    break;
    case MKTAG(0xa9,'w','r','t'): key = "composer";  break;
    case MKTAG( 'c','p','r','t'):
    case MKTAG(0xa9,'c','p','y'): key = "copyright"; break;
    case MKTAG(0xa9,'g','r','p'): key = "grouping"; break;
    case MKTAG(0xa9,'l','y','r'): key = "lyrics"; break;
    case MKTAG(0xa9,'c','m','t'):
    case MKTAG(0xa9,'i','n','f'): key = "comment";   break;
    case MKTAG(0xa9,'a','l','b'): key = "album";     break;
    case MKTAG(0xa9,'d','a','y'): key = "date";      break;
    case MKTAG(0xa9,'g','e','n'): key = "genre";     break;
    case MKTAG( 'g','n','r','e'): key = "genre";
        parse = mov_metadata_gnre; break;
    case MKTAG(0xa9,'t','o','o'):
    case MKTAG(0xa9,'s','w','r'): key = "encoder";   break;
    case MKTAG(0xa9,'e','n','c'): key = "encoder";   break;
    case MKTAG( 'd','e','s','c'): key = "description";break;
    case MKTAG( 'l','d','e','s'): key = "synopsis";  break;
    case MKTAG( 't','v','s','h'): key = "show";      break;
    case MKTAG( 't','v','e','n'): key = "episode_id";break;
    case MKTAG( 't','v','n','n'): key = "network";   break;
    case MKTAG( 't','r','k','n'): key = "track";
        parse = mov_metadata_track_or_disc_number; break;
    case MKTAG( 'd','i','s','k'): key = "disc";
        parse = mov_metadata_track_or_disc_number; break;
    case MKTAG( 't','v','e','s'): key = "episode_sort";
        parse = mov_metadata_int8_bypass_padding; break;
    case MKTAG( 't','v','s','n'): key = "season_number";
        parse = mov_metadata_int8_bypass_padding; break;
    case MKTAG( 's','t','i','k'): key = "media_type";
        parse = mov_metadata_int8_no_padding; break;
    case MKTAG( 'h','d','v','d'): key = "hd_video";
        parse = mov_metadata_int8_no_padding; break;
    case MKTAG( 'p','g','a','p'): key = "gapless_playback";
        parse = mov_metadata_int8_no_padding; break;
    }

    if (c->itunes_metadata && atom.size > 8) {
        int data_size = avio_rb32(pb);
        int tag = avio_rl32(pb);
        if (tag == MKTAG('d','a','t','a')) {
            data_type = avio_rb32(pb); // type
            avio_rb32(pb); // unknown
            str_size = data_size - 16;
            atom.size -= 16;
        } else return 0;
    } else if (atom.size > 4 && key && !c->itunes_metadata) {
        str_size = avio_rb16(pb); // string length
        langcode = avio_rb16(pb);
        ff_mov_lang_to_iso639(langcode, language);
        atom.size -= 4;
    } else
        str_size = atom.size;

#ifdef MOV_EXPORT_ALL_METADATA
    if (!key) {
        snprintf(tmp_key, 5, "%.4s", (char*)&atom.type);
        key = tmp_key;
    }
#endif

    if (!key)
        return 0;
    if (atom.size < 0)
        return -1;

    str_size = FFMIN3(sizeof(str)-1, str_size, atom.size);

    if (parse)
        parse(c, pb, str_size, key);
    else {
        if (data_type == 3 || (data_type == 0 && langcode < 0x800)) { // MAC Encoded
            mov_read_mac_string(c, pb, str_size, str, sizeof(str));
        } else {
            avio_read(pb, str, str_size);
            str[str_size] = 0;
        }
        av_dict_set(&c->fc->metadata, key, str, 0);
        if (*language && strcmp(language, "und")) {
            snprintf(key2, sizeof(key2), "%s-%s", key, language);
            av_dict_set(&c->fc->metadata, key2, str, 0);
        }
    }
    av_dlog(c->fc, "lang \"%3s\" ", language);
    av_dlog(c->fc, "tag \"%s\" value \"%s\" atom \"%.4s\" %d %"PRId64"\n",
            key, str, (char*)&atom.type, str_size, atom.size);

    return 0;
}

static int mov_read_chpl(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    int64_t start;
    int i, nb_chapters, str_len, version;
    char str[256+1];

    if ((atom.size -= 5) < 0)
        return 0;

    version = avio_r8(pb);
    avio_rb24(pb);
    if (version)
        avio_rb32(pb); // ???
    nb_chapters = avio_r8(pb);

    for (i = 0; i < nb_chapters; i++) {
        if (atom.size < 9)
            return 0;

        start = avio_rb64(pb);
        str_len = avio_r8(pb);

        if ((atom.size -= 9+str_len) < 0)
            return 0;

        avio_read(pb, str, str_len);
        str[str_len] = 0;
        avpriv_new_chapter(c->fc, i, (AVRational){1,10000000}, start, AV_NOPTS_VALUE, str);
    }
    return 0;
}

static int mov_read_default(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    int64_t total_size = 0;
    MOVAtom a;
    int i;

    if (atom.size < 0)
        atom.size = INT64_MAX;
    while (total_size + 8 <= atom.size && !url_feof(pb)) {
        int (*parse)(MOVContext*, AVIOContext*, MOVAtom) = NULL;
        a.size = atom.size;
        a.type=0;
        if (atom.size >= 8) {
            a.size = avio_rb32(pb);
            a.type = avio_rl32(pb);
            total_size += 8;
            if (a.size == 1) { /* 64 bit extended size */
                a.size = avio_rb64(pb) - 8;
                total_size += 8;
            }
        }
        av_dlog(c->fc, "type: %08x '%.4s' parent:'%.4s' sz: %"PRId64" %"PRId64" %"PRId64"\n",
                a.type, (char*)&a.type, (char*)&atom.type, a.size, total_size, atom.size);
        if (a.size == 0) {
            a.size = atom.size - total_size + 8;
        }
        a.size -= 8;
        if (a.size < 0)
            break;
        a.size = FFMIN(a.size, atom.size - total_size);

        for (i = 0; mov_default_parse_table[i].type; i++)
            if (mov_default_parse_table[i].type == a.type) {
                parse = mov_default_parse_table[i].parse;
                break;
            }

        // container is user data
        if (!parse && (atom.type == MKTAG('u','d','t','a') ||
                       atom.type == MKTAG('i','l','s','t')))
            parse = mov_read_udta_string;

        if (!parse) { /* skip leaf atoms data */
            avio_skip(pb, a.size);
        } else {
            int64_t start_pos = avio_tell(pb);
            int64_t left;
            int err = parse(c, pb, a);
            if (err < 0)
                return err;
            if (c->found_moov && c->found_mdat &&
                (!pb->seekable || start_pos + a.size == avio_size(pb)))
                return 0;
            left = a.size - avio_tell(pb) + start_pos;
            if (left > 0) /* skip garbage at atom end */
                avio_skip(pb, left);
        }

        total_size += a.size;
    }

    if (total_size < atom.size && atom.size < 0x7ffff)
        avio_skip(pb, atom.size - total_size);

    return 0;
}

static int mov_read_dref(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    int entries, i, j;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_rb32(pb); // version + flags
    entries = avio_rb32(pb);
    if (entries >= UINT_MAX / sizeof(*sc->drefs))
        return -1;
    sc->drefs = av_mallocz(entries * sizeof(*sc->drefs));
    if (!sc->drefs)
        return AVERROR(ENOMEM);
    sc->drefs_count = entries;

    for (i = 0; i < sc->drefs_count; i++) {
        MOVDref *dref = &sc->drefs[i];
        uint32_t size = avio_rb32(pb);
        int64_t next = avio_tell(pb) + size - 4;

        if (size < 12)
            return -1;

        dref->type = avio_rl32(pb);
        avio_rb32(pb); // version + flags
        av_dlog(c->fc, "type %.4s size %d\n", (char*)&dref->type, size);

        if (dref->type == MKTAG('a','l','i','s') && size > 150) {
            /* macintosh alias record */
            uint16_t volume_len, len;
            int16_t type;

            avio_skip(pb, 10);

            volume_len = avio_r8(pb);
            volume_len = FFMIN(volume_len, 27);
            avio_read(pb, dref->volume, 27);
            dref->volume[volume_len] = 0;
            av_log(c->fc, AV_LOG_DEBUG, "volume %s, len %d\n", dref->volume, volume_len);

            avio_skip(pb, 12);

            len = avio_r8(pb);
            len = FFMIN(len, 63);
            avio_read(pb, dref->filename, 63);
            dref->filename[len] = 0;
            av_log(c->fc, AV_LOG_DEBUG, "filename %s, len %d\n", dref->filename, len);

            avio_skip(pb, 16);

            /* read next level up_from_alias/down_to_target */
            dref->nlvl_from = avio_rb16(pb);
            dref->nlvl_to   = avio_rb16(pb);
            av_log(c->fc, AV_LOG_DEBUG, "nlvl from %d, nlvl to %d\n",
                   dref->nlvl_from, dref->nlvl_to);

            avio_skip(pb, 16);

            for (type = 0; type != -1 && avio_tell(pb) < next; ) {
                if(url_feof(pb))
                    return AVERROR_EOF;
                type = avio_rb16(pb);
                len = avio_rb16(pb);
                av_log(c->fc, AV_LOG_DEBUG, "type %d, len %d\n", type, len);
                if (len&1)
                    len += 1;
                if (type == 2) { // absolute path
                    av_free(dref->path);
                    dref->path = av_mallocz(len+1);
                    if (!dref->path)
                        return AVERROR(ENOMEM);
                    avio_read(pb, dref->path, len);
                    if (len > volume_len && !strncmp(dref->path, dref->volume, volume_len)) {
                        len -= volume_len;
                        memmove(dref->path, dref->path+volume_len, len);
                        dref->path[len] = 0;
                    }
                    for (j = 0; j < len; j++)
                        if (dref->path[j] == ':')
                            dref->path[j] = '/';
                    av_log(c->fc, AV_LOG_DEBUG, "path %s\n", dref->path);
                } else if (type == 0) { // directory name
                    av_free(dref->dir);
                    dref->dir = av_malloc(len+1);
                    if (!dref->dir)
                        return AVERROR(ENOMEM);
                    avio_read(pb, dref->dir, len);
                    dref->dir[len] = 0;
                    for (j = 0; j < len; j++)
                        if (dref->dir[j] == ':')
                            dref->dir[j] = '/';
                    av_log(c->fc, AV_LOG_DEBUG, "dir %s\n", dref->dir);
                } else
                    avio_skip(pb, len);
            }
        }
        avio_seek(pb, next, SEEK_SET);
    }
    return 0;
}

static int mov_read_hdlr(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    uint32_t type;
    uint32_t av_unused ctype;
    int title_size;
    char *title_str;

    if (c->fc->nb_streams < 1) // meta before first trak
        return 0;

    st = c->fc->streams[c->fc->nb_streams-1];

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */

    /* component type */
    ctype = avio_rl32(pb);
    type = avio_rl32(pb); /* component subtype */

    av_dlog(c->fc, "ctype= %.4s (0x%08x)\n", (char*)&ctype, ctype);
    av_dlog(c->fc, "stype= %.4s\n", (char*)&type);

    if     (type == MKTAG('v','i','d','e'))
        st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
    else if (type == MKTAG('s','o','u','n'))
        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
    else if (type == MKTAG('m','1','a',' '))
        st->codec->codec_id = CODEC_ID_MP2;
    else if ((type == MKTAG('s','u','b','p')) || (type == MKTAG('c','l','c','p')))
        st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

    avio_rb32(pb); /* component  manufacture */
    avio_rb32(pb); /* component flags */
    avio_rb32(pb); /* component flags mask */

    title_size = atom.size - 24;
    if (title_size > 0) {
        title_str = av_malloc(title_size + 1); /* Add null terminator */
        if (!title_str)
            return AVERROR(ENOMEM);
        avio_read(pb, title_str, title_size);
        title_str[title_size] = 0;
        av_dict_set(&st->metadata, "handler_name", title_str, 0);
        av_freep(&title_str);
    }

    return 0;
}

int ff_mov_read_esds(AVFormatContext *fc, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    int tag;

    if (fc->nb_streams < 1)
        return 0;
    st = fc->streams[fc->nb_streams-1];

    avio_rb32(pb); /* version + flags */
    ff_mp4_read_descr(fc, pb, &tag);
    if (tag == MP4ESDescrTag) {
        ff_mp4_parse_es_descr(pb, NULL);
    } else
        avio_rb16(pb); /* ID */

    ff_mp4_read_descr(fc, pb, &tag);
    if (tag == MP4DecConfigDescrTag)
        ff_mp4_read_dec_config_descr(fc, st, pb);
    return 0;
}

static int mov_read_esds(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    return ff_mov_read_esds(c->fc, pb, atom);
}

static int mov_read_dac3(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    int ac3info, acmod, lfeon, bsmod;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    ac3info = avio_rb24(pb);
    bsmod = (ac3info >> 14) & 0x7;
    acmod = (ac3info >> 11) & 0x7;
    lfeon = (ac3info >> 10) & 0x1;
    st->codec->channels = ((int[]){2,1,2,3,3,4,4,5})[acmod] + lfeon;
    st->codec->audio_service_type = bsmod;
    if (st->codec->channels > 1 && bsmod == 0x7)
        st->codec->audio_service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;

    return 0;
}

static int mov_read_chan(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    uint8_t version;
    uint32_t flags, layout_tag, bitmap, num_descr;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    if (atom.size < 16)
        return 0;

    version = avio_r8(pb);
    flags   = avio_rb24(pb);

    layout_tag = avio_rb32(pb);
    bitmap     = avio_rb32(pb);
    num_descr  = avio_rb32(pb);

    if (atom.size < 16ULL + num_descr * 20ULL)
        return 0;

    av_dlog(c->fc, "chan: size=%" PRId64 " version=%u flags=%u layout=%u bitmap=%u num_descr=%u\n",
            atom.size, version, flags, layout_tag, bitmap, num_descr);

#if 0
    /* TODO: use the channel descriptions if the layout tag is 0 */
    int i;
    for (i = 0; i < num_descr; i++) {
        uint32_t label, cflags;
        float coords[3];
        label     = avio_rb32(pb);          // mChannelLabel
        cflags    = avio_rb32(pb);          // mChannelFlags
        AV_WN32(&coords[0], avio_rl32(pb)); // mCoordinates[0]
        AV_WN32(&coords[1], avio_rl32(pb)); // mCoordinates[1]
        AV_WN32(&coords[2], avio_rl32(pb)); // mCoordinates[2]
    }
#endif

    st->codec->channel_layout = ff_mov_get_channel_layout(layout_tag, bitmap);

    return 0;
}

static int mov_read_wfex(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    ff_get_wav_header(pb, st->codec, atom.size);

    return 0;
}

static int mov_read_pasp(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    const int num = avio_rb32(pb);
    const int den = avio_rb32(pb);
    AVStream *st;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    if ((st->sample_aspect_ratio.den != 1 || st->sample_aspect_ratio.num) && // default
        (den != st->sample_aspect_ratio.den || num != st->sample_aspect_ratio.num)) {
        av_log(c->fc, AV_LOG_WARNING,
               "sample aspect ratio already set to %d:%d, ignoring 'pasp' atom (%d:%d)\n",
               st->sample_aspect_ratio.num, st->sample_aspect_ratio.den,
               num, den);
    } else if (den != 0) {
        st->sample_aspect_ratio.num = num;
        st->sample_aspect_ratio.den = den;
    }
    return 0;
}

/* this atom contains actual media data */
static int mov_read_mdat(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    if (atom.size == 0) /* wrong one (MP4) */
        return 0;
    c->found_mdat=1;
    return 0; /* now go for moov */
}

/* read major brand, minor version and compatible brands and store them as metadata */
static int mov_read_ftyp(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    uint32_t minor_ver;
    int comp_brand_size;
    char minor_ver_str[11]; /* 32 bit integer -> 10 digits + null */
    char* comp_brands_str;
    uint8_t type[5] = {0};

    avio_read(pb, type, 4);
    if (strcmp(type, "qt  "))
        c->isom = 1;
    av_log(c->fc, AV_LOG_DEBUG, "ISO: File Type Major Brand: %.4s\n",(char *)&type);
    av_dict_set(&c->fc->metadata, "major_brand", type, 0);
    minor_ver = avio_rb32(pb); /* minor version */
    snprintf(minor_ver_str, sizeof(minor_ver_str), "%d", minor_ver);
    av_dict_set(&c->fc->metadata, "minor_version", minor_ver_str, 0);

    comp_brand_size = atom.size - 8;
    if (comp_brand_size < 0)
        return -1;
    comp_brands_str = av_malloc(comp_brand_size + 1); /* Add null terminator */
    if (!comp_brands_str)
        return AVERROR(ENOMEM);
    avio_read(pb, comp_brands_str, comp_brand_size);
    comp_brands_str[comp_brand_size] = 0;
    av_dict_set(&c->fc->metadata, "compatible_brands", comp_brands_str, 0);
    av_freep(&comp_brands_str);

    return 0;
}

/* this atom should contain all header atoms */
static int mov_read_moov(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    if (mov_read_default(c, pb, atom) < 0)
        return -1;
    /* we parsed the 'moov' atom, we can terminate the parsing as soon as we find the 'mdat' */
    /* so we don't parse the whole file if over a network */
    c->found_moov=1;
    return 0; /* now go for mdat */
}

static int mov_read_moof(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    c->fragment.moof_offset = avio_tell(pb) - 8;
    av_dlog(c->fc, "moof offset %"PRIx64"\n", c->fragment.moof_offset);
    return mov_read_default(c, pb, atom);
}

static void mov_metadata_creation_time(AVDictionary **metadata, time_t time)
{
    char buffer[32];
    if (time) {
        struct tm *ptm;
        time -= 2082844800;  /* seconds between 1904-01-01 and Epoch */
        ptm = gmtime(&time);
        if (!ptm) return;
        strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", ptm);
        av_dict_set(metadata, "creation_time", buffer, 0);
    }
}

static int mov_read_mdhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    int version;
    char language[4] = {0};
    unsigned lang;
    time_t creation_time;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    version = avio_r8(pb);
    if (version > 1)
        return -1; /* unsupported */

    avio_rb24(pb); /* flags */
    if (version == 1) {
        creation_time = avio_rb64(pb);
        avio_rb64(pb);
    } else {
        creation_time = avio_rb32(pb);
        avio_rb32(pb); /* modification time */
    }
    mov_metadata_creation_time(&st->metadata, creation_time);

    sc->time_scale = avio_rb32(pb);
    st->duration = (version == 1) ? avio_rb64(pb) : avio_rb32(pb); /* duration */

    lang = avio_rb16(pb); /* language */
    if (ff_mov_lang_to_iso639(lang, language))
        av_dict_set(&st->metadata, "language", language, 0);
    avio_rb16(pb); /* quality */

    return 0;
}

static int mov_read_mvhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    time_t creation_time;
    int version = avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */

    if (version == 1) {
        creation_time = avio_rb64(pb);
        avio_rb64(pb);
    } else {
        creation_time = avio_rb32(pb);
        avio_rb32(pb); /* modification time */
    }
    mov_metadata_creation_time(&c->fc->metadata, creation_time);
    c->time_scale = avio_rb32(pb); /* time scale */

    av_dlog(c->fc, "time scale = %i\n", c->time_scale);

    c->duration = (version == 1) ? avio_rb64(pb) : avio_rb32(pb); /* duration */
    avio_rb32(pb); /* preferred scale */

    avio_rb16(pb); /* preferred volume */

    avio_skip(pb, 10); /* reserved */

    avio_skip(pb, 36); /* display matrix */

    avio_rb32(pb); /* preview time */
    avio_rb32(pb); /* preview duration */
    avio_rb32(pb); /* poster time */
    avio_rb32(pb); /* selection time */
    avio_rb32(pb); /* selection duration */
    avio_rb32(pb); /* current time */
    avio_rb32(pb); /* next track ID */

    return 0;
}

static int mov_read_smi(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    if ((uint64_t)atom.size > (1<<30))
        return -1;

    // currently SVQ3 decoder expect full STSD header - so let's fake it
    // this should be fixed and just SMI header should be passed
    av_free(st->codec->extradata);
    st->codec->extradata = av_mallocz(atom.size + 0x5a + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!st->codec->extradata)
        return AVERROR(ENOMEM);
    st->codec->extradata_size = 0x5a + atom.size;
    memcpy(st->codec->extradata, "SVQ3", 4); // fake
    avio_read(pb, st->codec->extradata + 0x5a, atom.size);
    av_dlog(c->fc, "Reading SMI %"PRId64"  %s\n", atom.size, st->codec->extradata + 0x5a);
    return 0;
}

static int mov_read_enda(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    int little_endian;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    little_endian = avio_rb16(pb) & 0xFF;
    av_dlog(c->fc, "enda %d\n", little_endian);
    if (little_endian == 1) {
        switch (st->codec->codec_id) {
        case CODEC_ID_PCM_S24BE:
            st->codec->codec_id = CODEC_ID_PCM_S24LE;
            break;
        case CODEC_ID_PCM_S32BE:
            st->codec->codec_id = CODEC_ID_PCM_S32LE;
            break;
        case CODEC_ID_PCM_F32BE:
            st->codec->codec_id = CODEC_ID_PCM_F32LE;
            break;
        case CODEC_ID_PCM_F64BE:
            st->codec->codec_id = CODEC_ID_PCM_F64LE;
            break;
        default:
            break;
        }
    }
    return 0;
}

static int mov_read_fiel(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    unsigned mov_field_order;
    enum AVFieldOrder decoded_field_order = AV_FIELD_UNKNOWN;

    if (c->fc->nb_streams < 1) // will happen with jp2 files
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    if (atom.size < 2)
        return AVERROR_INVALIDDATA;
    mov_field_order = avio_rb16(pb);
    if ((mov_field_order & 0xFF00) == 0x0100)
        decoded_field_order = AV_FIELD_PROGRESSIVE;
    else if ((mov_field_order & 0xFF00) == 0x0200) {
        switch (mov_field_order & 0xFF) {
        case 0x01: decoded_field_order = AV_FIELD_TT;
                   break;
        case 0x06: decoded_field_order = AV_FIELD_BB;
                   break;
        case 0x09: decoded_field_order = AV_FIELD_TB;
                   break;
        case 0x0E: decoded_field_order = AV_FIELD_BT;
                   break;
        }
    }
    if (decoded_field_order == AV_FIELD_UNKNOWN && mov_field_order) {
        av_log(NULL, AV_LOG_ERROR, "Unknown MOV field order 0x%04x\n", mov_field_order);
    }
    st->codec->field_order = decoded_field_order;

    return 0;
}

/* FIXME modify qdm2/svq3/h264 decoders to take full atom as extradata */
static int mov_read_extradata(MOVContext *c, AVIOContext *pb, MOVAtom atom,
                              enum CodecID codec_id)
{
    AVStream *st;
    uint64_t size;
    uint8_t *buf;

    if (c->fc->nb_streams < 1) // will happen with jp2 files
        return 0;
    st= c->fc->streams[c->fc->nb_streams-1];

    if (st->codec->codec_id != codec_id)
        return 0; /* unexpected codec_id - don't mess with extradata */

    size= (uint64_t)st->codec->extradata_size + atom.size + 8 + FF_INPUT_BUFFER_PADDING_SIZE;
    if (size > INT_MAX || (uint64_t)atom.size > INT_MAX)
        return -1;
    buf= av_realloc(st->codec->extradata, size);
    if (!buf)
        return -1;
    st->codec->extradata= buf;
    buf+= st->codec->extradata_size;
    st->codec->extradata_size= size - FF_INPUT_BUFFER_PADDING_SIZE;
    AV_WB32(       buf    , atom.size + 8);
    AV_WL32(       buf + 4, atom.type);
    avio_read(pb, buf + 8, atom.size);
    return 0;
}

/* wrapper functions for reading ALAC/AVS/MJPEG/MJPEG2000 extradata atoms only for those codecs */
static int mov_read_alac(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    return mov_read_extradata(c, pb, atom, CODEC_ID_ALAC);
}

static int mov_read_avss(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    return mov_read_extradata(c, pb, atom, CODEC_ID_AVS);
}

static int mov_read_jp2h(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    return mov_read_extradata(c, pb, atom, CODEC_ID_JPEG2000);
}

static int mov_read_wave(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    if ((uint64_t)atom.size > (1<<30))
        return -1;

    if (st->codec->codec_id == CODEC_ID_QDM2 || st->codec->codec_id == CODEC_ID_QDMC) {
        // pass all frma atom to codec, needed at least for QDMC and QDM2
        av_free(st->codec->extradata);
        st->codec->extradata = av_mallocz(atom.size + FF_INPUT_BUFFER_PADDING_SIZE);
        if (!st->codec->extradata)
            return AVERROR(ENOMEM);
        st->codec->extradata_size = atom.size;
        avio_read(pb, st->codec->extradata, atom.size);
    } else if (atom.size > 8) { /* to read frma, esds atoms */
        if (mov_read_default(c, pb, atom) < 0)
            return -1;
    } else
        avio_skip(pb, atom.size);
    return 0;
}

/**
 * This function reads atom content and puts data in extradata without tag
 * nor size unlike mov_read_extradata.
 */
static int mov_read_glbl(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    if ((uint64_t)atom.size > (1<<30))
        return -1;

    if (atom.size >= 10) {
        // Broken files created by legacy versions of Libav and FFmpeg will
        // wrap a whole fiel atom inside of a glbl atom.
        unsigned size = avio_rb32(pb);
        unsigned type = avio_rl32(pb);
        avio_seek(pb, -8, SEEK_CUR);
        if (type == MKTAG('f','i','e','l') && size == atom.size)
            return mov_read_default(c, pb, atom);
    }
    av_free(st->codec->extradata);
    st->codec->extradata = av_mallocz(atom.size + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!st->codec->extradata)
        return AVERROR(ENOMEM);
    st->codec->extradata_size = atom.size;
    avio_read(pb, st->codec->extradata, atom.size);
    return 0;
}

/**
 * An strf atom is a BITMAPINFOHEADER struct. This struct is 40 bytes itself,
 * but can have extradata appended at the end after the 40 bytes belonging
 * to the struct.
 */
static int mov_read_strf(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;

    if (c->fc->nb_streams < 1)
        return 0;
    if (atom.size <= 40)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];

    if ((uint64_t)atom.size > (1<<30))
        return -1;

    av_free(st->codec->extradata);
    st->codec->extradata = av_mallocz(atom.size - 40 + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!st->codec->extradata)
        return AVERROR(ENOMEM);
    st->codec->extradata_size = atom.size - 40;
    avio_skip(pb, 40);
    avio_read(pb, st->codec->extradata, atom.size - 40);
    return 0;
}

static int mov_read_stco(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */

    entries = avio_rb32(pb);

    if (!entries)
        return 0;
    if (entries >= UINT_MAX/sizeof(int64_t))
        return -1;

    sc->chunk_offsets = av_malloc(entries * sizeof(int64_t));
    if (!sc->chunk_offsets)
        return AVERROR(ENOMEM);
    sc->chunk_count = entries;

    if      (atom.type == MKTAG('s','t','c','o'))
        for (i=0; i<entries; i++)
            sc->chunk_offsets[i] = avio_rb32(pb);
    else if (atom.type == MKTAG('c','o','6','4'))
        for (i=0; i<entries; i++)
            sc->chunk_offsets[i] = avio_rb64(pb);
    else
        return -1;

    return 0;
}

/**
 * Compute codec id for 'lpcm' tag.
 * See CoreAudioTypes and AudioStreamBasicDescription at Apple.
 */
enum CodecID ff_mov_get_lpcm_codec_id(int bps, int flags)
{
    if (flags & 1) { // floating point
        if (flags & 2) { // big endian
            if      (bps == 32) return CODEC_ID_PCM_F32BE;
            else if (bps == 64) return CODEC_ID_PCM_F64BE;
        } else {
            if      (bps == 32) return CODEC_ID_PCM_F32LE;
            else if (bps == 64) return CODEC_ID_PCM_F64LE;
        }
    } else {
        if (flags & 2) {
            if      (bps == 8)
                // signed integer
                if (flags & 4)  return CODEC_ID_PCM_S8;
                else            return CODEC_ID_PCM_U8;
            else if (bps == 16) return CODEC_ID_PCM_S16BE;
            else if (bps == 24) return CODEC_ID_PCM_S24BE;
            else if (bps == 32) return CODEC_ID_PCM_S32BE;
        } else {
            if      (bps == 8)
                if (flags & 4)  return CODEC_ID_PCM_S8;
                else            return CODEC_ID_PCM_U8;
            else if (bps == 16) return CODEC_ID_PCM_S16LE;
            else if (bps == 24) return CODEC_ID_PCM_S24LE;
            else if (bps == 32) return CODEC_ID_PCM_S32LE;
        }
    }
    return CODEC_ID_NONE;
}

int ff_mov_read_stsd_entries(MOVContext *c, AVIOContext *pb, int entries)
{
    AVStream *st;
    MOVStreamContext *sc;
    int j, pseudo_stream_id;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    for (pseudo_stream_id=0; pseudo_stream_id<entries; pseudo_stream_id++) {
        //Parsing Sample description table
        enum CodecID id;
        int dref_id = 1;
        MOVAtom a = { AV_RL32("stsd") };
        int64_t start_pos = avio_tell(pb);
        int size = avio_rb32(pb); /* size */
        uint32_t format = avio_rl32(pb); /* data format */

        if (size >= 16) {
            avio_rb32(pb); /* reserved */
            avio_rb16(pb); /* reserved */
            dref_id = avio_rb16(pb);
        }else if (size <= 0){
            av_log(c->fc, AV_LOG_ERROR, "invalid size %d in stsd\n", size);
            return -1;
        }

        if (st->codec->codec_tag &&
            st->codec->codec_tag != format &&
            (c->fc->video_codec_id ? ff_codec_get_id(codec_movvideo_tags, format) != c->fc->video_codec_id
                                   : st->codec->codec_tag != MKTAG('j','p','e','g'))
           ){
            /* Multiple fourcc, we skip JPEG. This is not correct, we should
             * export it as a separate AVStream but this needs a few changes
             * in the MOV demuxer, patch welcome. */
        multiple_stsd:
            av_log(c->fc, AV_LOG_WARNING, "multiple fourcc not supported\n");
            avio_skip(pb, size - (avio_tell(pb) - start_pos));
            continue;
        }
        /* we cannot demux concatenated h264 streams because of different extradata */
        if (st->codec->codec_tag && st->codec->codec_tag == AV_RL32("avc1"))
            goto multiple_stsd;
        sc->pseudo_stream_id = st->codec->codec_tag ? -1 : pseudo_stream_id;
        sc->dref_id= dref_id;

        st->codec->codec_tag = format;
        id = ff_codec_get_id(codec_movaudio_tags, format);
        if (id<=0 && ((format&0xFFFF) == 'm'+('s'<<8) || (format&0xFFFF) == 'T'+('S'<<8)))
            id = ff_codec_get_id(ff_codec_wav_tags, av_bswap32(format)&0xFFFF);

        if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO && id > 0) {
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        } else if (st->codec->codec_type != AVMEDIA_TYPE_AUDIO && /* do not overwrite codec type */
                   format && format != MKTAG('m','p','4','s')) { /* skip old asf mpeg4 tag */
            id = ff_codec_get_id(codec_movvideo_tags, format);
            if (id <= 0)
                id = ff_codec_get_id(ff_codec_bmp_tags, format);
            if (id > 0)
                st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
            else if (st->codec->codec_type == AVMEDIA_TYPE_DATA){
                id = ff_codec_get_id(ff_codec_movsubtitle_tags, format);
                if (id > 0)
                    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
            }
        }

        av_dlog(c->fc, "size=%d 4CC= %c%c%c%c codec_type=%d\n", size,
                (format >> 0) & 0xff, (format >> 8) & 0xff, (format >> 16) & 0xff,
                (format >> 24) & 0xff, st->codec->codec_type);

        if (st->codec->codec_type==AVMEDIA_TYPE_VIDEO) {
            unsigned int color_depth, len;
            int color_greyscale;

            st->codec->codec_id = id;
            avio_rb16(pb); /* version */
            avio_rb16(pb); /* revision level */
            avio_rb32(pb); /* vendor */
            avio_rb32(pb); /* temporal quality */
            avio_rb32(pb); /* spatial quality */

            st->codec->width = avio_rb16(pb); /* width */
            st->codec->height = avio_rb16(pb); /* height */

            avio_rb32(pb); /* horiz resolution */
            avio_rb32(pb); /* vert resolution */
            avio_rb32(pb); /* data size, always 0 */
            avio_rb16(pb); /* frames per samples */

            len = avio_r8(pb); /* codec name, pascal string */
            if (len > 31)
                len = 31;
            mov_read_mac_string(c, pb, len, st->codec->codec_name, 32);
            if (len < 31)
                avio_skip(pb, 31 - len);
            /* codec_tag YV12 triggers an UV swap in rawdec.c */
            if (!memcmp(st->codec->codec_name, "Planar Y'CbCr 8-bit 4:2:0", 25))
                st->codec->codec_tag=MKTAG('I', '4', '2', '0');

            st->codec->bits_per_coded_sample = avio_rb16(pb); /* depth */
            st->codec->color_table_id = avio_rb16(pb); /* colortable id */
            av_dlog(c->fc, "depth %d, ctab id %d\n",
                   st->codec->bits_per_coded_sample, st->codec->color_table_id);
            /* figure out the palette situation */
            color_depth = st->codec->bits_per_coded_sample & 0x1F;
            color_greyscale = st->codec->bits_per_coded_sample & 0x20;

            /* if the depth is 2, 4, or 8 bpp, file is palettized */
            if ((color_depth == 2) || (color_depth == 4) ||
                (color_depth == 8)) {
                /* for palette traversal */
                unsigned int color_start, color_count, color_end;
                unsigned char a, r, g, b;

                if (color_greyscale) {
                    int color_index, color_dec;
                    /* compute the greyscale palette */
                    st->codec->bits_per_coded_sample = color_depth;
                    color_count = 1 << color_depth;
                    color_index = 255;
                    color_dec = 256 / (color_count - 1);
                    for (j = 0; j < color_count; j++) {
                        if (id == CODEC_ID_CINEPAK){
                            r = g = b = color_count - 1 - color_index;
                        }else
                        r = g = b = color_index;
                        sc->palette[j] =
                            (0xFFU << 24) | (r << 16) | (g << 8) | (b);
                        color_index -= color_dec;
                        if (color_index < 0)
                            color_index = 0;
                    }
                } else if (st->codec->color_table_id) {
                    const uint8_t *color_table;
                    /* if flag bit 3 is set, use the default palette */
                    color_count = 1 << color_depth;
                    if (color_depth == 2)
                        color_table = ff_qt_default_palette_4;
                    else if (color_depth == 4)
                        color_table = ff_qt_default_palette_16;
                    else
                        color_table = ff_qt_default_palette_256;

                    for (j = 0; j < color_count; j++) {
                        r = color_table[j * 3 + 0];
                        g = color_table[j * 3 + 1];
                        b = color_table[j * 3 + 2];
                        sc->palette[j] =
                            (0xFFU << 24) | (r << 16) | (g << 8) | (b);
                    }
                } else {
                    /* load the palette from the file */
                    color_start = avio_rb32(pb);
                    color_count = avio_rb16(pb);
                    color_end = avio_rb16(pb);
                    if ((color_start <= 255) &&
                        (color_end <= 255)) {
                        for (j = color_start; j <= color_end; j++) {
                            /* each A, R, G, or B component is 16 bits;
                             * only use the top 8 bits */
                            a = avio_r8(pb);
                            avio_r8(pb);
                            r = avio_r8(pb);
                            avio_r8(pb);
                            g = avio_r8(pb);
                            avio_r8(pb);
                            b = avio_r8(pb);
                            avio_r8(pb);
                            sc->palette[j] =
                                (a << 24 ) | (r << 16) | (g << 8) | (b);
                        }
                    }
                }
                sc->has_palette = 1;
            }
        } else if (st->codec->codec_type==AVMEDIA_TYPE_AUDIO) {
            int bits_per_sample, flags;
            uint16_t version = avio_rb16(pb);

            st->codec->codec_id = id;
            avio_rb16(pb); /* revision level */
            avio_rb32(pb); /* vendor */

            st->codec->channels = avio_rb16(pb);             /* channel count */
            av_dlog(c->fc, "audio channels %d\n", st->codec->channels);
            st->codec->bits_per_coded_sample = avio_rb16(pb);      /* sample size */

            sc->audio_cid = avio_rb16(pb);
            avio_rb16(pb); /* packet size = 0 */

            st->codec->sample_rate = ((avio_rb32(pb) >> 16));

            //Read QT version 1 fields. In version 0 these do not exist.
            av_dlog(c->fc, "version =%d, isom =%d\n",version,c->isom);
            if (!c->isom) {
                if (version==1) {
                    sc->samples_per_frame = avio_rb32(pb);
                    avio_rb32(pb); /* bytes per packet */
                    sc->bytes_per_frame = avio_rb32(pb);
                    avio_rb32(pb); /* bytes per sample */
                } else if (version==2) {
                    avio_rb32(pb); /* sizeof struct only */
                    st->codec->sample_rate = av_int2double(avio_rb64(pb)); /* float 64 */
                    st->codec->channels = avio_rb32(pb);
                    avio_rb32(pb); /* always 0x7F000000 */
                    st->codec->bits_per_coded_sample = avio_rb32(pb); /* bits per channel if sound is uncompressed */
                    flags = avio_rb32(pb); /* lpcm format specific flag */
                    sc->bytes_per_frame = avio_rb32(pb); /* bytes per audio packet if constant */
                    sc->samples_per_frame = avio_rb32(pb); /* lpcm frames per audio packet if constant */
                    if (format == MKTAG('l','p','c','m'))
                        st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, flags);
                }
            }

            switch (st->codec->codec_id) {
            case CODEC_ID_PCM_S8:
            case CODEC_ID_PCM_U8:
                if (st->codec->bits_per_coded_sample == 16)
                    st->codec->codec_id = CODEC_ID_PCM_S16BE;
                break;
            case CODEC_ID_PCM_S16LE:
            case CODEC_ID_PCM_S16BE:
                if (st->codec->bits_per_coded_sample == 8)
                    st->codec->codec_id = CODEC_ID_PCM_S8;
                else if (st->codec->bits_per_coded_sample == 24)
                    st->codec->codec_id =
                        st->codec->codec_id == CODEC_ID_PCM_S16BE ?
                        CODEC_ID_PCM_S24BE : CODEC_ID_PCM_S24LE;
                break;
            /* set values for old format before stsd version 1 appeared */
            case CODEC_ID_MACE3:
                sc->samples_per_frame = 6;
                sc->bytes_per_frame = 2*st->codec->channels;
                break;
            case CODEC_ID_MACE6:
                sc->samples_per_frame = 6;
                sc->bytes_per_frame = 1*st->codec->channels;
                break;
            case CODEC_ID_ADPCM_IMA_QT:
                sc->samples_per_frame = 64;
                sc->bytes_per_frame = 34*st->codec->channels;
                break;
            case CODEC_ID_GSM:
                sc->samples_per_frame = 160;
                sc->bytes_per_frame = 33;
                break;
            default:
                break;
            }

            bits_per_sample = av_get_bits_per_sample(st->codec->codec_id);
            if (bits_per_sample) {
                st->codec->bits_per_coded_sample = bits_per_sample;
                sc->sample_size = (bits_per_sample >> 3) * st->codec->channels;
            }
        } else if (st->codec->codec_type==AVMEDIA_TYPE_SUBTITLE){
            // ttxt stsd contains display flags, justification, background
            // color, fonts, and default styles, so fake an atom to read it
            MOVAtom fake_atom = { .size = size - (avio_tell(pb) - start_pos) };
            if (format != AV_RL32("mp4s")) // mp4s contains a regular esds atom
                mov_read_glbl(c, pb, fake_atom);
            st->codec->codec_id= id;
            st->codec->width = sc->width;
            st->codec->height = sc->height;
        } else {
            if (st->codec->codec_tag == MKTAG('t','m','c','d')) {
                int val;
                avio_rb32(pb);       /* reserved */
                val = avio_rb32(pb); /* flags */
                if (val & 1)
                    st->codec->flags2 |= CODEC_FLAG2_DROP_FRAME_TIMECODE;
                avio_rb32(pb); /* time scale */
                avio_rb32(pb); /* frame duration */
                st->codec->time_base.den = avio_r8(pb); /* number of frame */
                st->codec->time_base.num = 1;
            }
            /* other codec type, just skip (rtp, mp4s, ...) */
            avio_skip(pb, size - (avio_tell(pb) - start_pos));
        }
        /* this will read extra atoms at the end (wave, alac, damr, avcC, SMI ...) */
        a.size = size - (avio_tell(pb) - start_pos);
        if (a.size > 8) {
            if (mov_read_default(c, pb, a) < 0)
                return -1;
        } else if (a.size > 0)
            avio_skip(pb, a.size);
    }

    if (st->codec->codec_type==AVMEDIA_TYPE_AUDIO && st->codec->sample_rate==0 && sc->time_scale>1)
        st->codec->sample_rate= sc->time_scale;

    /* special codec parameters handling */
    switch (st->codec->codec_id) {
#if CONFIG_DV_DEMUXER
    case CODEC_ID_DVAUDIO:
        c->dv_fctx = avformat_alloc_context();
        c->dv_demux = avpriv_dv_init_demux(c->dv_fctx);
        if (!c->dv_demux) {
            av_log(c->fc, AV_LOG_ERROR, "dv demux context init error\n");
            return -1;
        }
        sc->dv_audio_container = 1;
        st->codec->codec_id = CODEC_ID_PCM_S16LE;
        break;
#endif
    /* no ifdef since parameters are always those */
    case CODEC_ID_QCELP:
        // force sample rate for qcelp when not stored in mov
        if (st->codec->codec_tag != MKTAG('Q','c','l','p'))
            st->codec->sample_rate = 8000;
        st->codec->frame_size= 160;
        st->codec->channels= 1; /* really needed */
        break;
    case CODEC_ID_AMR_NB:
        st->codec->channels= 1; /* really needed */
        /* force sample rate for amr, stsd in 3gp does not store sample rate */
        st->codec->sample_rate = 8000;
        /* force frame_size, too, samples_per_frame isn't always set properly */
        st->codec->frame_size  = 160;
        break;
    case CODEC_ID_AMR_WB:
        st->codec->channels    = 1;
        st->codec->sample_rate = 16000;
        st->codec->frame_size  = 320;
        break;
    case CODEC_ID_MP2:
    case CODEC_ID_MP3:
        st->codec->codec_type = AVMEDIA_TYPE_AUDIO; /* force type after stsd for m1a hdlr */
        st->need_parsing = AVSTREAM_PARSE_FULL;
        break;
    case CODEC_ID_GSM:
    case CODEC_ID_ADPCM_MS:
    case CODEC_ID_ADPCM_IMA_WAV:
        st->codec->frame_size = sc->samples_per_frame;
        st->codec->block_align = sc->bytes_per_frame;
        break;
    case CODEC_ID_ALAC:
        if (st->codec->extradata_size == 36) {
            st->codec->frame_size = AV_RB32(st->codec->extradata+12);
            st->codec->channels   = AV_RB8 (st->codec->extradata+21);
            st->codec->sample_rate = AV_RB32(st->codec->extradata+32);
        }
        break;
    case CODEC_ID_AC3:
        st->need_parsing = AVSTREAM_PARSE_FULL;
        break;
    case CODEC_ID_MPEG1VIDEO:
        st->need_parsing = AVSTREAM_PARSE_FULL;
        break;
    default:
        break;
    }

    return 0;
}

static int mov_read_stsd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    int entries;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    entries = avio_rb32(pb);

    return ff_mov_read_stsd_entries(c, pb, entries);
}

static int mov_read_stsc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */

    entries = avio_rb32(pb);

    av_dlog(c->fc, "track[%i].stsc.entries = %i\n", c->fc->nb_streams-1, entries);

    if (!entries)
        return 0;
    if (entries >= UINT_MAX / sizeof(*sc->stsc_data))
        return -1;
    sc->stsc_data = av_malloc(entries * sizeof(*sc->stsc_data));
    if (!sc->stsc_data)
        return AVERROR(ENOMEM);
    sc->stsc_count = entries;

    for (i=0; i<entries; i++) {
        sc->stsc_data[i].first = avio_rb32(pb);
        sc->stsc_data[i].count = avio_rb32(pb);
        sc->stsc_data[i].id = avio_rb32(pb);
    }
    return 0;
}

static int mov_read_stps(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned i, entries;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_rb32(pb); // version + flags

    entries = avio_rb32(pb);
    if (entries >= UINT_MAX / sizeof(*sc->stps_data))
        return -1;
    sc->stps_data = av_malloc(entries * sizeof(*sc->stps_data));
    if (!sc->stps_data)
        return AVERROR(ENOMEM);
    sc->stps_count = entries;

    for (i = 0; i < entries; i++) {
        sc->stps_data[i] = avio_rb32(pb);
        //av_dlog(c->fc, "stps %d\n", sc->stps_data[i]);
    }

    return 0;
}

static int mov_read_stss(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */

    entries = avio_rb32(pb);

    av_dlog(c->fc, "keyframe_count = %d\n", entries);

    if (entries >= UINT_MAX / sizeof(int))
        return -1;
    sc->keyframes = av_malloc(entries * sizeof(int));
    if (!sc->keyframes)
        return AVERROR(ENOMEM);
    sc->keyframe_count = entries;

    for (i=0; i<entries; i++) {
        sc->keyframes[i] = avio_rb32(pb);
        //av_dlog(c->fc, "keyframes[]=%d\n", sc->keyframes[i]);
    }
    return 0;
}

static int mov_read_stsz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries, sample_size, field_size, num_bytes;
    GetBitContext gb;
    unsigned char* buf;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */

    if (atom.type == MKTAG('s','t','s','z')) {
        sample_size = avio_rb32(pb);
        if (!sc->sample_size) /* do not overwrite value computed in stsd */
            sc->sample_size = sample_size;
        field_size = 32;
    } else {
        sample_size = 0;
        avio_rb24(pb); /* reserved */
        field_size = avio_r8(pb);
    }
    entries = avio_rb32(pb);

    av_dlog(c->fc, "sample_size = %d sample_count = %d\n", sc->sample_size, entries);

    sc->sample_count = entries;
    if (sample_size)
        return 0;

    if (field_size != 4 && field_size != 8 && field_size != 16 && field_size != 32) {
        av_log(c->fc, AV_LOG_ERROR, "Invalid sample field size %d\n", field_size);
        return -1;
    }

    if (!entries)
        return 0;
    if (entries >= UINT_MAX / sizeof(int) || entries >= (UINT_MAX - 4) / field_size)
        return -1;
    sc->sample_sizes = av_malloc(entries * sizeof(int));
    if (!sc->sample_sizes)
        return AVERROR(ENOMEM);

    num_bytes = (entries*field_size+4)>>3;

    buf = av_malloc(num_bytes+FF_INPUT_BUFFER_PADDING_SIZE);
    if (!buf) {
        av_freep(&sc->sample_sizes);
        return AVERROR(ENOMEM);
    }

    if (avio_read(pb, buf, num_bytes) < num_bytes) {
        av_freep(&sc->sample_sizes);
        av_free(buf);
        return -1;
    }

    init_get_bits(&gb, buf, 8*num_bytes);

    for (i=0; i<entries; i++)
        sc->sample_sizes[i] = get_bits_long(&gb, field_size);

    av_free(buf);
    return 0;
}

static int mov_read_stts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries;
    int64_t duration=0;
    int64_t total_sample_count=0;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    entries = avio_rb32(pb);

    av_dlog(c->fc, "track[%i].stts.entries = %i\n",
            c->fc->nb_streams-1, entries);

    if (entries >= UINT_MAX / sizeof(*sc->stts_data))
        return -1;

    sc->stts_data = av_malloc(entries * sizeof(*sc->stts_data));
    if (!sc->stts_data)
        return AVERROR(ENOMEM);

    sc->stts_count = entries;

    for (i=0; i<entries; i++) {
        int sample_duration;
        int sample_count;

        sample_count=avio_rb32(pb);
        sample_duration = avio_rb32(pb);
        /* sample_duration < 0 is invalid based on the spec */
        if (sample_duration < 0) {
            av_log(c->fc, AV_LOG_ERROR, "Invalid SampleDelta in STTS %d\n", sample_duration);
            sample_duration = 1;
        }
        sc->stts_data[i].count= sample_count;
        sc->stts_data[i].duration= sample_duration;

        av_dlog(c->fc, "sample_count=%d, sample_duration=%d\n",
                sample_count, sample_duration);

        duration+=(int64_t)sample_duration*sample_count;
        total_sample_count+=sample_count;
    }

    st->nb_frames= total_sample_count;
    if (duration)
        st->duration= duration;
    return 0;
}

static int mov_read_ctts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    unsigned int i, entries;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    entries = avio_rb32(pb);

    av_dlog(c->fc, "track[%i].ctts.entries = %i\n", c->fc->nb_streams-1, entries);

    if (!entries)
        return 0;
    if (entries >= UINT_MAX / sizeof(*sc->ctts_data))
        return -1;
    sc->ctts_data = av_malloc(entries * sizeof(*sc->ctts_data));
    if (!sc->ctts_data)
        return AVERROR(ENOMEM);
    sc->ctts_count = entries;

    for (i=0; i<entries; i++) {
        int count    =avio_rb32(pb);
        int duration =avio_rb32(pb);

        sc->ctts_data[i].count   = count;
        sc->ctts_data[i].duration= duration;
        if (duration < 0 && i+2<entries)
            sc->dts_shift = FFMAX(sc->dts_shift, -duration);
    }

    av_dlog(c->fc, "dts shift %d\n", sc->dts_shift);

    return 0;
}

static void mov_build_index(MOVContext *mov, AVStream *st)
{
    MOVStreamContext *sc = st->priv_data;
    int64_t current_offset;
    int64_t current_dts = 0;
    unsigned int stts_index = 0;
    unsigned int stsc_index = 0;
    unsigned int stss_index = 0;
    unsigned int stps_index = 0;
    unsigned int i, j;
    uint64_t stream_size = 0;

    /* adjust first dts according to edit list */
    if ((sc->empty_duration || sc->start_time) && mov->time_scale > 0) {
        if (sc->empty_duration)
            sc->empty_duration = av_rescale(sc->empty_duration, sc->time_scale, mov->time_scale);
        sc->time_offset = sc->start_time - sc->empty_duration;
        current_dts = -sc->time_offset;
        if (sc->ctts_data && sc->stts_data &&
            sc->ctts_data[0].duration / FFMAX(sc->stts_data[0].duration, 1) > 16) {
            /* more than 16 frames delay, dts are likely wrong
               this happens with files created by iMovie */
            sc->wrong_dts = 1;
            st->codec->has_b_frames = 1;
        }
    }

    /* only use old uncompressed audio chunk demuxing when stts specifies it */
    if (!(st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
          sc->stts_count == 1 && sc->stts_data[0].duration == 1)) {
        unsigned int current_sample = 0;
        unsigned int stts_sample = 0;
        unsigned int sample_size;
        unsigned int distance = 0;
        int key_off = sc->keyframes && sc->keyframes[0] == 1;

        current_dts -= sc->dts_shift;

        if (!sc->sample_count)
            return;
        if (sc->sample_count >= UINT_MAX / sizeof(*st->index_entries))
            return;
        st->index_entries = av_malloc(sc->sample_count*sizeof(*st->index_entries));
        if (!st->index_entries)
            return;
        st->index_entries_allocated_size = sc->sample_count*sizeof(*st->index_entries);

        for (i = 0; i < sc->chunk_count; i++) {
            current_offset = sc->chunk_offsets[i];
            while (stsc_index + 1 < sc->stsc_count &&
                i + 1 == sc->stsc_data[stsc_index + 1].first)
                stsc_index++;
            for (j = 0; j < sc->stsc_data[stsc_index].count; j++) {
                int keyframe = 0;
                if (current_sample >= sc->sample_count) {
                    av_log(mov->fc, AV_LOG_ERROR, "wrong sample count\n");
                    return;
                }

                if (!sc->keyframe_count || current_sample+key_off == sc->keyframes[stss_index]) {
                    keyframe = 1;
                    if (stss_index + 1 < sc->keyframe_count)
                        stss_index++;
                } else if (sc->stps_count && current_sample+key_off == sc->stps_data[stps_index]) {
                    keyframe = 1;
                    if (stps_index + 1 < sc->stps_count)
                        stps_index++;
                }
                if (keyframe)
                    distance = 0;
                sample_size = sc->sample_size > 0 ? sc->sample_size : sc->sample_sizes[current_sample];
                if (sc->pseudo_stream_id == -1 ||
                   sc->stsc_data[stsc_index].id - 1 == sc->pseudo_stream_id) {
                    AVIndexEntry *e = &st->index_entries[st->nb_index_entries++];
                    e->pos = current_offset;
                    e->timestamp = current_dts;
                    e->size = sample_size;
                    e->min_distance = distance;
                    e->flags = keyframe ? AVINDEX_KEYFRAME : 0;
                    av_dlog(mov->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", dts %"PRId64", "
                            "size %d, distance %d, keyframe %d\n", st->index, current_sample,
                            current_offset, current_dts, sample_size, distance, keyframe);
                }

                current_offset += sample_size;
                stream_size += sample_size;
                current_dts += sc->stts_data[stts_index].duration;
                distance++;
                stts_sample++;
                current_sample++;
                if (stts_index + 1 < sc->stts_count && stts_sample == sc->stts_data[stts_index].count) {
                    stts_sample = 0;
                    stts_index++;
                }
            }
        }
        if (st->duration > 0)
            st->codec->bit_rate = stream_size*8*sc->time_scale/st->duration;
    } else {
        unsigned chunk_samples, total = 0;

        // compute total chunk count
        for (i = 0; i < sc->stsc_count; i++) {
            unsigned count, chunk_count;

            chunk_samples = sc->stsc_data[i].count;
            if (i != sc->stsc_count - 1 &&
                sc->samples_per_frame && chunk_samples % sc->samples_per_frame) {
                av_log(mov->fc, AV_LOG_ERROR, "error unaligned chunk\n");
                return;
            }

            if (sc->samples_per_frame >= 160) { // gsm
                count = chunk_samples / sc->samples_per_frame;
            } else if (sc->samples_per_frame > 1) {
                unsigned samples = (1024/sc->samples_per_frame)*sc->samples_per_frame;
                count = (chunk_samples+samples-1) / samples;
            } else {
                count = (chunk_samples+1023) / 1024;
            }

            if (i < sc->stsc_count - 1)
                chunk_count = sc->stsc_data[i+1].first - sc->stsc_data[i].first;
            else
                chunk_count = sc->chunk_count - (sc->stsc_data[i].first - 1);
            total += chunk_count * count;
        }

        av_dlog(mov->fc, "chunk count %d\n", total);
        if (total >= UINT_MAX / sizeof(*st->index_entries))
            return;
        st->index_entries = av_malloc(total*sizeof(*st->index_entries));
        if (!st->index_entries)
            return;
        st->index_entries_allocated_size = total*sizeof(*st->index_entries);

        // populate index
        for (i = 0; i < sc->chunk_count; i++) {
            current_offset = sc->chunk_offsets[i];
            if (stsc_index + 1 < sc->stsc_count &&
                i + 1 == sc->stsc_data[stsc_index + 1].first)
                stsc_index++;
            chunk_samples = sc->stsc_data[stsc_index].count;

            while (chunk_samples > 0) {
                AVIndexEntry *e;
                unsigned size, samples;

                if (sc->samples_per_frame >= 160) { // gsm
                    samples = sc->samples_per_frame;
                    size = sc->bytes_per_frame;
                } else {
                    if (sc->samples_per_frame > 1) {
                        samples = FFMIN((1024 / sc->samples_per_frame)*
                                        sc->samples_per_frame, chunk_samples);
                        size = (samples / sc->samples_per_frame) * sc->bytes_per_frame;
                    } else {
                        samples = FFMIN(1024, chunk_samples);
                        size = samples * sc->sample_size;
                    }
                }

                if (st->nb_index_entries >= total) {
                    av_log(mov->fc, AV_LOG_ERROR, "wrong chunk count %d\n", total);
                    return;
                }
                e = &st->index_entries[st->nb_index_entries++];
                e->pos = current_offset;
                e->timestamp = current_dts;
                e->size = size;
                e->min_distance = 0;
                e->flags = AVINDEX_KEYFRAME;
                av_dlog(mov->fc, "AVIndex stream %d, chunk %d, offset %"PRIx64", dts %"PRId64", "
                        "size %d, duration %d\n", st->index, i, current_offset, current_dts,
                        size, samples);

                current_offset += size;
                current_dts += samples;
                chunk_samples -= samples;
            }
        }
    }
}

static int mov_open_dref(AVIOContext **pb, const char *src, MOVDref *ref,
                         AVIOInterruptCB *int_cb)
{
    /* try relative path, we do not try the absolute because it can leak information about our
       system to an attacker */
    if (ref->nlvl_to > 0 && ref->nlvl_from > 0) {
        char filename[1024];
        const char *src_path;
        int i, l;

        /* find a source dir */
        src_path = strrchr(src, '/');
        if (src_path)
            src_path++;
        else
            src_path = src;

        /* find a next level down to target */
        for (i = 0, l = strlen(ref->path) - 1; l >= 0; l--)
            if (ref->path[l] == '/') {
                if (i == ref->nlvl_to - 1)
                    break;
                else
                    i++;
            }

        /* compose filename if next level down to target was found */
        if (i == ref->nlvl_to - 1 && src_path - src  < sizeof(filename)) {
            memcpy(filename, src, src_path - src);
            filename[src_path - src] = 0;

            for (i = 1; i < ref->nlvl_from; i++)
                av_strlcat(filename, "../", 1024);

            av_strlcat(filename, ref->path + l + 1, 1024);

            if (!avio_open2(pb, filename, AVIO_FLAG_READ, int_cb, NULL))
                return 0;
        }
    }

    return AVERROR(ENOENT);
}

static int mov_read_trak(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    int ret;

    st = avformat_new_stream(c->fc, NULL);
    if (!st) return AVERROR(ENOMEM);
    st->id = c->fc->nb_streams;
    sc = av_mallocz(sizeof(MOVStreamContext));
    if (!sc) return AVERROR(ENOMEM);

    st->priv_data = sc;
    st->codec->codec_type = AVMEDIA_TYPE_DATA;
    sc->ffindex = st->index;

    if ((ret = mov_read_default(c, pb, atom)) < 0)
        return ret;

    /* sanity checks */
    if (sc->chunk_count && (!sc->stts_count || !sc->stsc_count ||
                            (!sc->sample_size && !sc->sample_count))) {
        av_log(c->fc, AV_LOG_ERROR, "stream %d, missing mandatory atoms, broken header\n",
               st->index);
        return 0;
    }

    if (sc->time_scale <= 0) {
        av_log(c->fc, AV_LOG_WARNING, "stream %d, timescale not set\n", st->index);
        sc->time_scale = c->time_scale;
        if (sc->time_scale <= 0)
            sc->time_scale = 1;
    }

    avpriv_set_pts_info(st, 64, 1, sc->time_scale);

    if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
        !st->codec->frame_size && sc->stts_count == 1) {
        st->codec->frame_size = av_rescale(sc->stts_data[0].duration,
                                           st->codec->sample_rate, sc->time_scale);
        av_dlog(c->fc, "frame size %d\n", st->codec->frame_size);
    }

    mov_build_index(c, st);

    if (sc->dref_id-1 < sc->drefs_count && sc->drefs[sc->dref_id-1].path) {
        MOVDref *dref = &sc->drefs[sc->dref_id - 1];
        if (mov_open_dref(&sc->pb, c->fc->filename, dref, &c->fc->interrupt_callback) < 0)
            av_log(c->fc, AV_LOG_ERROR,
                   "stream %d, error opening alias: path='%s', dir='%s', "
                   "filename='%s', volume='%s', nlvl_from=%d, nlvl_to=%d\n",
                   st->index, dref->path, dref->dir, dref->filename,
                   dref->volume, dref->nlvl_from, dref->nlvl_to);
    } else
        sc->pb = c->fc->pb;

    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
        if (!st->sample_aspect_ratio.num &&
            (st->codec->width != sc->width || st->codec->height != sc->height)) {
            st->sample_aspect_ratio = av_d2q(((double)st->codec->height * sc->width) /
                                             ((double)st->codec->width * sc->height), INT_MAX);
        }

        av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
                  sc->time_scale*st->nb_frames, st->duration, INT_MAX);

        if (sc->stts_count == 1 || (sc->stts_count == 2 && sc->stts_data[1].count == 1))
            av_reduce(&st->r_frame_rate.num, &st->r_frame_rate.den,
                      sc->time_scale, sc->stts_data[0].duration, INT_MAX);
    }

    switch (st->codec->codec_id) {
#if CONFIG_H261_DECODER
    case CODEC_ID_H261:
#endif
#if CONFIG_H263_DECODER
    case CODEC_ID_H263:
#endif
#if CONFIG_H264_DECODER
    case CODEC_ID_H264:
#endif
#if CONFIG_MPEG4_DECODER
    case CODEC_ID_MPEG4:
#endif
        st->codec->width = 0; /* let decoder init width/height */
        st->codec->height= 0;
        break;
    }

    /* Do not need those anymore. */
    av_freep(&sc->chunk_offsets);
    av_freep(&sc->stsc_data);
    av_freep(&sc->sample_sizes);
    av_freep(&sc->keyframes);
    av_freep(&sc->stts_data);
    av_freep(&sc->stps_data);

    return 0;
}

static int mov_read_ilst(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    int ret;
    c->itunes_metadata = 1;
    ret = mov_read_default(c, pb, atom);
    c->itunes_metadata = 0;
    return ret;
}

static int mov_read_meta(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    while (atom.size > 8) {
        uint32_t tag = avio_rl32(pb);
        atom.size -= 4;
        if (tag == MKTAG('h','d','l','r')) {
            avio_seek(pb, -8, SEEK_CUR);
            atom.size += 8;
            return mov_read_default(c, pb, atom);
        }
    }
    return 0;
}

static int mov_read_tkhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    int i;
    int width;
    int height;
    int64_t disp_transform[2];
    int display_matrix[3][2];
    AVStream *st;
    MOVStreamContext *sc;
    int version;

    if (c->fc->nb_streams < 1)
        return 0;
    st = c->fc->streams[c->fc->nb_streams-1];
    sc = st->priv_data;

    version = avio_r8(pb);
    avio_rb24(pb); /* flags */
    /*
    MOV_TRACK_ENABLED 0x0001
    MOV_TRACK_IN_MOVIE 0x0002
    MOV_TRACK_IN_PREVIEW 0x0004
    MOV_TRACK_IN_POSTER 0x0008
    */

    if (version == 1) {
        avio_rb64(pb);
        avio_rb64(pb);
    } else {
        avio_rb32(pb); /* creation time */
        avio_rb32(pb); /* modification time */
    }
    st->id = (int)avio_rb32(pb); /* track id (NOT 0 !)*/
    avio_rb32(pb); /* reserved */

    /* highlevel (considering edits) duration in movie timebase */
    (version == 1) ? avio_rb64(pb) : avio_rb32(pb);
    avio_rb32(pb); /* reserved */
    avio_rb32(pb); /* reserved */

    avio_rb16(pb); /* layer */
    avio_rb16(pb); /* alternate group */
    avio_rb16(pb); /* volume */
    avio_rb16(pb); /* reserved */

    //read in the display matrix (outlined in ISO 14496-12, Section 6.2.2)
    // they're kept in fixed point format through all calculations
    // ignore u,v,z b/c we don't need the scale factor to calc aspect ratio
    for (i = 0; i < 3; i++) {
        display_matrix[i][0] = avio_rb32(pb);   // 16.16 fixed point
        display_matrix[i][1] = avio_rb32(pb);   // 16.16 fixed point
        avio_rb32(pb);           // 2.30 fixed point (not used)
    }

    width = avio_rb32(pb);       // 16.16 fixed point track width
    height = avio_rb32(pb);      // 16.16 fixed point track height
    sc->width = width >> 16;
    sc->height = height >> 16;

    if (display_matrix[0][0] == -65536 && display_matrix[1][1] == -65536) {
         av_dict_set(&st->metadata, "rotate", "180", 0);
    }

    // transform the display width/height according to the matrix
    // skip this if the display matrix is the default identity matrix
    // or if it is rotating the picture, ex iPhone 3GS
    // to keep the same scale, use [width height 1<<16]
    if (width && height &&
        ((display_matrix[0][0] != 65536  ||
          display_matrix[1][1] != 65536) &&
         !display_matrix[0][1] &&
         !display_matrix[1][0] &&
         !display_matrix[2][0] && !display_matrix[2][1])) {
        for (i = 0; i < 2; i++)
            disp_transform[i] =
                (int64_t)  width  * display_matrix[0][i] +
                (int64_t)  height * display_matrix[1][i] +
                ((int64_t) display_matrix[2][i] << 16);

        //sample aspect ratio is new width/height divided by old width/height
        st->sample_aspect_ratio = av_d2q(
            ((double) disp_transform[0] * height) /
            ((double) disp_transform[1] * width), INT_MAX);
    }
    return 0;
}

static int mov_read_tfhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    MOVFragment *frag = &c->fragment;
    MOVTrackExt *trex = NULL;
    int flags, track_id, i;

    avio_r8(pb); /* version */
    flags = avio_rb24(pb);

    track_id = avio_rb32(pb);
    if (!track_id)
        return -1;
    frag->track_id = track_id;
    for (i = 0; i < c->trex_count; i++)
        if (c->trex_data[i].track_id == frag->track_id) {
            trex = &c->trex_data[i];
            break;
        }
    if (!trex) {
        av_log(c->fc, AV_LOG_ERROR, "could not find corresponding trex\n");
        return -1;
    }

    if (flags & 0x01) frag->base_data_offset = avio_rb64(pb);
    else              frag->base_data_offset = frag->moof_offset;
    if (flags & 0x02) frag->stsd_id          = avio_rb32(pb);
    else              frag->stsd_id          = trex->stsd_id;

    frag->duration = flags & 0x08 ? avio_rb32(pb) : trex->duration;
    frag->size     = flags & 0x10 ? avio_rb32(pb) : trex->size;
    frag->flags    = flags & 0x20 ? avio_rb32(pb) : trex->flags;
    av_dlog(c->fc, "frag flags 0x%x\n", frag->flags);
    return 0;
}

static int mov_read_chap(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    c->chapter_track = avio_rb32(pb);
    return 0;
}

static int mov_read_trex(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    MOVTrackExt *trex;

    if ((uint64_t)c->trex_count+1 >= UINT_MAX / sizeof(*c->trex_data))
        return -1;
    trex = av_realloc(c->trex_data, (c->trex_count+1)*sizeof(*c->trex_data));
    if (!trex)
        return AVERROR(ENOMEM);
    c->trex_data = trex;
    trex = &c->trex_data[c->trex_count++];
    avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    trex->track_id = avio_rb32(pb);
    trex->stsd_id  = avio_rb32(pb);
    trex->duration = avio_rb32(pb);
    trex->size     = avio_rb32(pb);
    trex->flags    = avio_rb32(pb);
    return 0;
}

static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    MOVFragment *frag = &c->fragment;
    AVStream *st = NULL;
    MOVStreamContext *sc;
    MOVStts *ctts_data;
    uint64_t offset;
    int64_t dts;
    int data_offset = 0;
    unsigned entries, first_sample_flags = frag->flags;
    int flags, distance, i;

    for (i = 0; i < c->fc->nb_streams; i++) {
        if (c->fc->streams[i]->id == frag->track_id) {
            st = c->fc->streams[i];
            break;
        }
    }
    if (!st) {
        av_log(c->fc, AV_LOG_ERROR, "could not find corresponding track id %d\n", frag->track_id);
        return -1;
    }
    sc = st->priv_data;
    if (sc->pseudo_stream_id+1 != frag->stsd_id)
        return 0;
    avio_r8(pb); /* version */
    flags = avio_rb24(pb);
    entries = avio_rb32(pb);
    av_dlog(c->fc, "flags 0x%x entries %d\n", flags, entries);

    /* Always assume the presence of composition time offsets.
     * Without this assumption, for instance, we cannot deal with a track in fragmented movies that meet the following.
     *  1) in the initial movie, there are no samples.
     *  2) in the first movie fragment, there is only one sample without composition time offset.
     *  3) in the subsequent movie fragments, there are samples with composition time offset. */
    if (!sc->ctts_count && sc->sample_count)
    {
        /* Complement ctts table if moov atom doesn't have ctts atom. */
        ctts_data = av_malloc(sizeof(*sc->ctts_data));
        if (!ctts_data)
            return AVERROR(ENOMEM);
        sc->ctts_data = ctts_data;
        sc->ctts_data[sc->ctts_count].count = sc->sample_count;
        sc->ctts_data[sc->ctts_count].duration = 0;
        sc->ctts_count++;
    }
    if ((uint64_t)entries+sc->ctts_count >= UINT_MAX/sizeof(*sc->ctts_data))
        return -1;
    ctts_data = av_realloc(sc->ctts_data,
                           (entries+sc->ctts_count)*sizeof(*sc->ctts_data));
    if (!ctts_data)
        return AVERROR(ENOMEM);
    sc->ctts_data = ctts_data;

    if (flags & 0x001) data_offset        = avio_rb32(pb);
    if (flags & 0x004) first_sample_flags = avio_rb32(pb);
    dts = st->duration - sc->time_offset;
    offset = frag->base_data_offset + data_offset;
    distance = 0;
    av_dlog(c->fc, "first sample flags 0x%x\n", first_sample_flags);
    for (i = 0; i < entries; i++) {
        unsigned sample_size = frag->size;
        int sample_flags = i ? frag->flags : first_sample_flags;
        unsigned sample_duration = frag->duration;
        int keyframe;

        if (flags & 0x100) sample_duration = avio_rb32(pb);
        if (flags & 0x200) sample_size     = avio_rb32(pb);
        if (flags & 0x400) sample_flags    = avio_rb32(pb);
        sc->ctts_data[sc->ctts_count].count = 1;
        sc->ctts_data[sc->ctts_count].duration = (flags & 0x800) ? avio_rb32(pb) : 0;
        sc->ctts_count++;
        if ((keyframe = st->codec->codec_type == AVMEDIA_TYPE_AUDIO ||
             (flags & 0x004 && !i && !sample_flags) || sample_flags & 0x2000000))
            distance = 0;
        av_add_index_entry(st, offset, dts, sample_size, distance,
                           keyframe ? AVINDEX_KEYFRAME : 0);
        av_dlog(c->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", dts %"PRId64", "
                "size %d, distance %d, keyframe %d\n", st->index, sc->sample_count+i,
                offset, dts, sample_size, distance, keyframe);
        distance++;
        dts += sample_duration;
        offset += sample_size;
    }
    frag->moof_offset = offset;
    st->duration = dts + sc->time_offset;
    return 0;
}

/* this atom should be null (from specs), but some buggy files put the 'moov' atom inside it... */
/* like the files created with Adobe Premiere 5.0, for samples see */
/* http://graphics.tudelft.nl/~wouter/publications/soundtests/ */
static int mov_read_wide(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    int err;

    if (atom.size < 8)
        return 0; /* continue */
    if (avio_rb32(pb) != 0) { /* 0 sized mdat atom... use the 'wide' atom size */
        avio_skip(pb, atom.size - 4);
        return 0;
    }
    atom.type = avio_rl32(pb);
    atom.size -= 8;
    if (atom.type != MKTAG('m','d','a','t')) {
        avio_skip(pb, atom.size);
        return 0;
    }
    err = mov_read_mdat(c, pb, atom);
    return err;
}

static int mov_read_cmov(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
#if CONFIG_ZLIB
    AVIOContext ctx;
    uint8_t *cmov_data;
    uint8_t *moov_data; /* uncompressed data */
    long cmov_len, moov_len;
    int ret = -1;

    avio_rb32(pb); /* dcom atom */
    if (avio_rl32(pb) != MKTAG('d','c','o','m'))
        return -1;
    if (avio_rl32(pb) != MKTAG('z','l','i','b')) {
        av_log(c->fc, AV_LOG_ERROR, "unknown compression for cmov atom !");
        return -1;
    }
    avio_rb32(pb); /* cmvd atom */
    if (avio_rl32(pb) != MKTAG('c','m','v','d'))
        return -1;
    moov_len = avio_rb32(pb); /* uncompressed size */
    cmov_len = atom.size - 6 * 4;

    cmov_data = av_malloc(cmov_len);
    if (!cmov_data)
        return AVERROR(ENOMEM);
    moov_data = av_malloc(moov_len);
    if (!moov_data) {
        av_free(cmov_data);
        return AVERROR(ENOMEM);
    }
    avio_read(pb, cmov_data, cmov_len);
    if (uncompress (moov_data, (uLongf *) &moov_len, (const Bytef *)cmov_data, cmov_len) != Z_OK)
        goto free_and_return;
    if (ffio_init_context(&ctx, moov_data, moov_len, 0, NULL, NULL, NULL, NULL) != 0)
        goto free_and_return;
    atom.type = MKTAG('m','o','o','v');
    atom.size = moov_len;
    ret = mov_read_default(c, &ctx, atom);
free_and_return:
    av_free(moov_data);
    av_free(cmov_data);
    return ret;
#else
    av_log(c->fc, AV_LOG_ERROR, "this file requires zlib support compiled in\n");
    return -1;
#endif
}

/* edit list atom */
static int mov_read_elst(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    MOVStreamContext *sc;
    int i, edit_count, version, edit_start_index = 0;

    if (c->fc->nb_streams < 1)
        return 0;
    sc = c->fc->streams[c->fc->nb_streams-1]->priv_data;

    version = avio_r8(pb); /* version */
    avio_rb24(pb); /* flags */
    edit_count = avio_rb32(pb); /* entries */

    if ((uint64_t)edit_count*12+8 > atom.size)
        return -1;

    for (i=0; i<edit_count; i++){
        int64_t time;
        int64_t duration;
        if (version == 1) {
            duration = avio_rb64(pb);
            time     = avio_rb64(pb);
        } else {
            duration = avio_rb32(pb); /* segment duration */
            time     = (int32_t)avio_rb32(pb); /* media time */
        }
        avio_rb32(pb); /* Media rate */
        if (i == 0 && time == -1) {
            sc->empty_duration = duration;
            edit_start_index = 1;
        } else if (i == edit_start_index && time >= 0)
            sc->start_time = time;
    }

    if (edit_count > 1)
        av_log(c->fc, AV_LOG_WARNING, "multiple edit list entries, "
               "a/v desync might occur, patch welcome\n");

    av_dlog(c->fc, "track[%i].edit_count = %i\n", c->fc->nb_streams-1, edit_count);
    return 0;
}

static int mov_read_chan2(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    if (atom.size < 16)
        return 0;
    avio_skip(pb, 4);
    ff_mov_read_chan(c->fc, atom.size - 4, c->fc->streams[0]->codec);
    return 0;
}

static const MOVParseTableEntry mov_default_parse_table[] = {
{ MKTAG('a','v','s','s'), mov_read_avss },
{ MKTAG('c','h','p','l'), mov_read_chpl },
{ MKTAG('c','o','6','4'), mov_read_stco },
{ MKTAG('c','t','t','s'), mov_read_ctts }, /* composition time to sample */
{ MKTAG('d','i','n','f'), mov_read_default },
{ MKTAG('d','r','e','f'), mov_read_dref },
{ MKTAG('e','d','t','s'), mov_read_default },
{ MKTAG('e','l','s','t'), mov_read_elst },
{ MKTAG('e','n','d','a'), mov_read_enda },
{ MKTAG('f','i','e','l'), mov_read_fiel },
{ MKTAG('f','t','y','p'), mov_read_ftyp },
{ MKTAG('g','l','b','l'), mov_read_glbl },
{ MKTAG('h','d','l','r'), mov_read_hdlr },
{ MKTAG('i','l','s','t'), mov_read_ilst },
{ MKTAG('j','p','2','h'), mov_read_jp2h },
{ MKTAG('m','d','a','t'), mov_read_mdat },
{ MKTAG('m','d','h','d'), mov_read_mdhd },
{ MKTAG('m','d','i','a'), mov_read_default },
{ MKTAG('m','e','t','a'), mov_read_meta },
{ MKTAG('m','i','n','f'), mov_read_default },
{ MKTAG('m','o','o','f'), mov_read_moof },
{ MKTAG('m','o','o','v'), mov_read_moov },
{ MKTAG('m','v','e','x'), mov_read_default },
{ MKTAG('m','v','h','d'), mov_read_mvhd },
{ MKTAG('S','M','I',' '), mov_read_smi }, /* Sorenson extension ??? */
{ MKTAG('a','l','a','c'), mov_read_alac }, /* alac specific atom */
{ MKTAG('a','v','c','C'), mov_read_glbl },
{ MKTAG('p','a','s','p'), mov_read_pasp },
{ MKTAG('s','t','b','l'), mov_read_default },
{ MKTAG('s','t','c','o'), mov_read_stco },
{ MKTAG('s','t','p','s'), mov_read_stps },
{ MKTAG('s','t','r','f'), mov_read_strf },
{ MKTAG('s','t','s','c'), mov_read_stsc },
{ MKTAG('s','t','s','d'), mov_read_stsd }, /* sample description */
{ MKTAG('s','t','s','s'), mov_read_stss }, /* sync sample */
{ MKTAG('s','t','s','z'), mov_read_stsz }, /* sample size */
{ MKTAG('s','t','t','s'), mov_read_stts },
{ MKTAG('s','t','z','2'), mov_read_stsz }, /* compact sample size */
{ MKTAG('t','k','h','d'), mov_read_tkhd }, /* track header */
{ MKTAG('t','f','h','d'), mov_read_tfhd }, /* track fragment header */
{ MKTAG('t','r','a','k'), mov_read_trak },
{ MKTAG('t','r','a','f'), mov_read_default },
{ MKTAG('t','r','e','f'), mov_read_default },
{ MKTAG('c','h','a','p'), mov_read_chap },
{ MKTAG('t','r','e','x'), mov_read_trex },
{ MKTAG('t','r','u','n'), mov_read_trun },
{ MKTAG('u','d','t','a'), mov_read_default },
{ MKTAG('w','a','v','e'), mov_read_wave },
{ MKTAG('e','s','d','s'), mov_read_esds },
{ MKTAG('d','a','c','3'), mov_read_dac3 }, /* AC-3 info */
{ MKTAG('w','i','d','e'), mov_read_wide }, /* place holder */
{ MKTAG('w','f','e','x'), mov_read_wfex },
{ MKTAG('c','m','o','v'), mov_read_cmov },
{ MKTAG('c','h','a','n'), mov_read_chan }, /* channel layout */
{ 0, NULL }
};

static int mov_probe(AVProbeData *p)
{
    unsigned int offset;
    uint32_t tag;
    int score = 0;

    /* check file header */
    offset = 0;
    for (;;) {
        /* ignore invalid offset */
        if ((offset + 8) > (unsigned int)p->buf_size)
            return score;
        tag = AV_RL32(p->buf + offset + 4);
        switch(tag) {
        /* check for obvious tags */
        case MKTAG('j','P',' ',' '): /* jpeg 2000 signature */
        case MKTAG('m','o','o','v'):
        case MKTAG('m','d','a','t'):
        case MKTAG('p','n','o','t'): /* detect movs with preview pics like ew.mov and april.mov */
        case MKTAG('u','d','t','a'): /* Packet Video PVAuthor adds this and a lot of more junk */
        case MKTAG('f','t','y','p'):
            return AVPROBE_SCORE_MAX;
        /* those are more common words, so rate then a bit less */
        case MKTAG('e','d','i','w'): /* xdcam files have reverted first tags */
        case MKTAG('w','i','d','e'):
        case MKTAG('f','r','e','e'):
        case MKTAG('j','u','n','k'):
        case MKTAG('p','i','c','t'):
            return AVPROBE_SCORE_MAX - 5;
        case MKTAG(0x82,0x82,0x7f,0x7d):
        case MKTAG('s','k','i','p'):
        case MKTAG('u','u','i','d'):
        case MKTAG('p','r','f','l'):
            offset = AV_RB32(p->buf+offset) + offset;
            /* if we only find those cause probedata is too small at least rate them */
            score = AVPROBE_SCORE_MAX - 50;
            break;
        default:
            /* unrecognized tag */
            return score;
        }
    }
}

// must be done after parsing all trak because there's no order requirement
static void mov_read_chapters(AVFormatContext *s)
{
    MOVContext *mov = s->priv_data;
    AVStream *st = NULL;
    MOVStreamContext *sc;
    int64_t cur_pos;
    int i;

    for (i = 0; i < s->nb_streams; i++)
        if (s->streams[i]->id == mov->chapter_track) {
            st = s->streams[i];
            break;
        }
    if (!st) {
        av_log(s, AV_LOG_ERROR, "Referenced QT chapter track not found\n");
        return;
    }

    st->discard = AVDISCARD_ALL;
    sc = st->priv_data;
    cur_pos = avio_tell(sc->pb);

    for (i = 0; i < st->nb_index_entries; i++) {
        AVIndexEntry *sample = &st->index_entries[i];
        int64_t end = i+1 < st->nb_index_entries ? st->index_entries[i+1].timestamp : st->duration;
        uint8_t *title;
        uint16_t ch;
        int len, title_len;

        if (avio_seek(sc->pb, sample->pos, SEEK_SET) != sample->pos) {
            av_log(s, AV_LOG_ERROR, "Chapter %d not found in file\n", i);
            goto finish;
        }

        // the first two bytes are the length of the title
        len = avio_rb16(sc->pb);
        if (len > sample->size-2)
            continue;
        title_len = 2*len + 1;
        if (!(title = av_mallocz(title_len)))
            goto finish;

        // The samples could theoretically be in any encoding if there's an encd
        // atom following, but in practice are only utf-8 or utf-16, distinguished
        // instead by the presence of a BOM
        if (!len) {
            title[0] = 0;
        } else {
            ch = avio_rb16(sc->pb);
            if (ch == 0xfeff)
                avio_get_str16be(sc->pb, len, title, title_len);
            else if (ch == 0xfffe)
                avio_get_str16le(sc->pb, len, title, title_len);
            else {
                AV_WB16(title, ch);
                if (len == 1 || len == 2)
                    title[len] = 0;
                else
                    get_strz(sc->pb, title + 2, len - 1);
            }
        }

        avpriv_new_chapter(s, i, st->time_base, sample->timestamp, end, title);
        av_freep(&title);
    }
finish:
    avio_seek(sc->pb, cur_pos, SEEK_SET);
}

static int mov_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    MOVContext *mov = s->priv_data;
    AVIOContext *pb = s->pb;
    int err;
    MOVAtom atom = { AV_RL32("root") };

    mov->fc = s;
    /* .mov and .mp4 aren't streamable anyway (only progressive download if moov is before mdat) */
    if (pb->seekable)
        atom.size = avio_size(pb);
    else
        atom.size = INT64_MAX;

    /* check MOV header */
    if ((err = mov_read_default(mov, pb, atom)) < 0) {
        av_log(s, AV_LOG_ERROR, "error reading header: %d\n", err);
        return err;
    }
    if (!mov->found_moov) {
        av_log(s, AV_LOG_ERROR, "moov atom not found\n");
        return -1;
    }
    av_dlog(mov->fc, "on_parse_exit_offset=%"PRId64"\n", avio_tell(pb));

    if (pb->seekable && mov->chapter_track > 0)
        mov_read_chapters(s);

    return 0;
}

static AVIndexEntry *mov_find_next_sample(AVFormatContext *s, AVStream **st)
{
    AVIndexEntry *sample = NULL;
    int64_t best_dts = INT64_MAX;
    int i;
    for (i = 0; i < s->nb_streams; i++) {
        AVStream *avst = s->streams[i];
        MOVStreamContext *msc = avst->priv_data;
        if (msc->pb && msc->current_sample < avst->nb_index_entries) {
            AVIndexEntry *current_sample = &avst->index_entries[msc->current_sample];
            int64_t dts = av_rescale(current_sample->timestamp, AV_TIME_BASE, msc->time_scale);
            av_dlog(s, "stream %d, sample %d, dts %"PRId64"\n", i, msc->current_sample, dts);
            if (!sample || (!s->pb->seekable && current_sample->pos < sample->pos) ||
                (s->pb->seekable &&
                 ((msc->pb != s->pb && dts < best_dts) || (msc->pb == s->pb &&
                 ((FFABS(best_dts - dts) <= AV_TIME_BASE && current_sample->pos < sample->pos) ||
                  (FFABS(best_dts - dts) > AV_TIME_BASE && dts < best_dts)))))) {
                sample = current_sample;
                best_dts = dts;
                *st = avst;
            }
        }
    }
    return sample;
}

static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    MOVContext *mov = s->priv_data;
    MOVStreamContext *sc;
    AVIndexEntry *sample;
    AVStream *st = NULL;
    int ret;
 retry:
    sample = mov_find_next_sample(s, &st);
    if (!sample) {
        mov->found_mdat = 0;
        if (s->pb->seekable||
            mov_read_default(mov, s->pb, (MOVAtom){ AV_RL32("root"), INT64_MAX }) < 0 ||
            url_feof(s->pb))
            return AVERROR_EOF;
        av_dlog(s, "read fragments, offset 0x%"PRIx64"\n", avio_tell(s->pb));
        goto retry;
    }
    sc = st->priv_data;
    /* must be done just before reading, to avoid infinite loop on sample */
    sc->current_sample++;

    if (st->discard != AVDISCARD_ALL) {
        if (avio_seek(sc->pb, sample->pos, SEEK_SET) != sample->pos) {
            av_log(mov->fc, AV_LOG_ERROR, "stream %d, offset 0x%"PRIx64": partial file\n",
                   sc->ffindex, sample->pos);
            return -1;
        }
        ret = av_get_packet(sc->pb, pkt, sample->size);
        if (ret < 0)
            return ret;
        if (sc->has_palette) {
            uint8_t *pal;

            pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
            if (!pal) {
                av_log(mov->fc, AV_LOG_ERROR, "Cannot append palette to packet\n");
            } else {
                memcpy(pal, sc->palette, AVPALETTE_SIZE);
                sc->has_palette = 0;
            }
        }
#if CONFIG_DV_DEMUXER
        if (mov->dv_demux && sc->dv_audio_container) {
            avpriv_dv_produce_packet(mov->dv_demux, pkt, pkt->data, pkt->size, pkt->pos);
            av_free(pkt->data);
            pkt->size = 0;
            ret = avpriv_dv_get_packet(mov->dv_demux, pkt);
            if (ret < 0)
                return ret;
        }
#endif
    }

    pkt->stream_index = sc->ffindex;
    pkt->dts = sample->timestamp;
    if (sc->ctts_data) {
        pkt->pts = pkt->dts + sc->dts_shift + sc->ctts_data[sc->ctts_index].duration;
        /* update ctts context */
        sc->ctts_sample++;
        if (sc->ctts_index < sc->ctts_count &&
            sc->ctts_data[sc->ctts_index].count == sc->ctts_sample) {
            sc->ctts_index++;
            sc->ctts_sample = 0;
        }
        if (sc->wrong_dts)
            pkt->dts = AV_NOPTS_VALUE;
    } else {
        int64_t next_dts = (sc->current_sample < st->nb_index_entries) ?
            st->index_entries[sc->current_sample].timestamp : st->duration;
        pkt->duration = next_dts - pkt->dts;
        pkt->pts = pkt->dts;
    }
    if (st->discard == AVDISCARD_ALL)
        goto retry;
    pkt->flags |= sample->flags & AVINDEX_KEYFRAME ? AV_PKT_FLAG_KEY : 0;
    pkt->pos = sample->pos;
    av_dlog(s, "stream %d, pts %"PRId64", dts %"PRId64", pos 0x%"PRIx64", duration %d\n",
            pkt->stream_index, pkt->pts, pkt->dts, pkt->pos, pkt->duration);
    return 0;
}

static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp, int flags)
{
    MOVStreamContext *sc = st->priv_data;
    int sample, time_sample;
    int i;

    sample = av_index_search_timestamp(st, timestamp, flags);
    av_dlog(s, "stream %d, timestamp %"PRId64", sample %d\n", st->index, timestamp, sample);
    if (sample < 0 && st->nb_index_entries && timestamp < st->index_entries[0].timestamp)
        sample = 0;
    if (sample < 0) /* not sure what to do */
        return -1;
    sc->current_sample = sample;
    av_dlog(s, "stream %d, found sample %d\n", st->index, sc->current_sample);
    /* adjust ctts index */
    if (sc->ctts_data) {
        time_sample = 0;
        for (i = 0; i < sc->ctts_count; i++) {
            int next = time_sample + sc->ctts_data[i].count;
            if (next > sc->current_sample) {
                sc->ctts_index = i;
                sc->ctts_sample = sc->current_sample - time_sample;
                break;
            }
            time_sample = next;
        }
    }
    return sample;
}

static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t sample_time, int flags)
{
    AVStream *st;
    int64_t seek_timestamp, timestamp;
    int sample;
    int i;

    if (stream_index >= s->nb_streams)
        return -1;
    if (sample_time < 0)
        sample_time = 0;

    st = s->streams[stream_index];
    sample = mov_seek_stream(s, st, sample_time, flags);
    if (sample < 0)
        return -1;

    /* adjust seek timestamp to found sample timestamp */
    seek_timestamp = st->index_entries[sample].timestamp;

    for (i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        if (stream_index == i)
            continue;

        timestamp = av_rescale_q(seek_timestamp, s->streams[stream_index]->time_base, st->time_base);
        mov_seek_stream(s, st, timestamp, flags);
    }
    return 0;
}

static int mov_read_close(AVFormatContext *s)
{
    MOVContext *mov = s->priv_data;
    int i, j;

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

        av_freep(&sc->ctts_data);
        for (j = 0; j < sc->drefs_count; j++) {
            av_freep(&sc->drefs[j].path);
            av_freep(&sc->drefs[j].dir);
        }
        av_freep(&sc->drefs);
        if (sc->pb && sc->pb != s->pb)
            avio_close(sc->pb);
    }

    if (mov->dv_demux) {
        for (i = 0; i < mov->dv_fctx->nb_streams; i++) {
            av_freep(&mov->dv_fctx->streams[i]->codec);
            av_freep(&mov->dv_fctx->streams[i]);
        }
        av_freep(&mov->dv_fctx);
        av_freep(&mov->dv_demux);
    }

    av_freep(&mov->trex_data);

    return 0;
}

AVInputFormat ff_mov_demuxer = {
    .name           = "mov,mp4,m4a,3gp,3g2,mj2",
    .long_name      = NULL_IF_CONFIG_SMALL("QuickTime/MPEG-4/Motion JPEG 2000 format"),
    .priv_data_size = sizeof(MOVContext),
    .read_probe     = mov_probe,
    .read_header    = mov_read_header,
    .read_packet    = mov_read_packet,
    .read_close     = mov_read_close,
    .read_seek      = mov_read_seek,
};