FFmpeg/libavformat/riffenc.c

/*
 * RIFF muxing functions
 * Copyright (c) 2000 Fabrice Bellard
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/dict.h"
#include "libavutil/log.h"
#include "libavutil/mathematics.h"
#include "libavcodec/avcodec.h"
#include "libavcodec/bytestream.h"
#include "avformat.h"
#include "avio_internal.h"
#include "riff.h"

int64_t ff_start_tag(AVIOContext *pb, const char *tag)
{
    ffio_wfourcc(pb, tag);
    avio_wl32(pb, 0);
    return avio_tell(pb);
}

void ff_end_tag(AVIOContext *pb, int64_t start)
{
    int64_t pos;

    pos = avio_tell(pb);
    avio_seek(pb, start - 4, SEEK_SET);
    avio_wl32(pb, (uint32_t)(pos - start));
    avio_seek(pb, pos, SEEK_SET);
}

/* WAVEFORMATEX header */
/* returns the size or -1 on error */
int ff_put_wav_header(AVIOContext *pb, AVCodecContext *enc)
{
    int bps, blkalign, bytespersec, frame_size;
    int hdrsize = 18;
    int waveformatextensible;
    uint8_t temp[256];
    uint8_t *riff_extradata       = temp;
    uint8_t *riff_extradata_start = temp;

    if (!enc->codec_tag || enc->codec_tag > 0xffff)
        return -1;

    /* We use the known constant frame size for the codec if known, otherwise
     * fall back on using AVCodecContext.frame_size, which is not as reliable
     * for indicating packet duration. */
    frame_size = av_get_audio_frame_duration(enc, 0);
    if (!frame_size)
        frame_size = enc->frame_size;

    waveformatextensible = (enc->channels > 2 && enc->channel_layout) ||
                           enc->sample_rate > 48000 ||
                           av_get_bits_per_sample(enc->codec_id) > 16;

    if (waveformatextensible)
        avio_wl16(pb, 0xfffe);
    else
        avio_wl16(pb, enc->codec_tag);

    avio_wl16(pb, enc->channels);
    avio_wl32(pb, enc->sample_rate);
    if (enc->codec_id == AV_CODEC_ID_MP2 ||
        enc->codec_id == AV_CODEC_ID_MP3 ||
        enc->codec_id == AV_CODEC_ID_GSM_MS) {
        bps = 0;
    } else {
        if (!(bps = av_get_bits_per_sample(enc->codec_id))) {
            if (enc->bits_per_coded_sample)
                bps = enc->bits_per_coded_sample;
            else
                bps = 16;  // default to 16
        }
    }
    if (bps != enc->bits_per_coded_sample && enc->bits_per_coded_sample) {
        av_log(enc, AV_LOG_WARNING,
               "requested bits_per_coded_sample (%d) "
               "and actually stored (%d) differ\n",
               enc->bits_per_coded_sample, bps);
    }

    if (enc->codec_id == AV_CODEC_ID_MP2 ||
        enc->codec_id == AV_CODEC_ID_MP3) {
        /* This is wrong, but it seems many demuxers do not work if this
         * is set correctly. */
        blkalign = frame_size;
        // blkalign = 144 * enc->bit_rate/enc->sample_rate;
    } else if (enc->codec_id == AV_CODEC_ID_AC3) {
        blkalign = 3840;                /* maximum bytes per frame */
    } else if (enc->block_align != 0) { /* specified by the codec */
        blkalign = enc->block_align;
    } else
        blkalign = bps * enc->channels / av_gcd(8, bps);
    if (enc->codec_id == AV_CODEC_ID_PCM_U8 ||
        enc->codec_id == AV_CODEC_ID_PCM_S24LE ||
        enc->codec_id == AV_CODEC_ID_PCM_S32LE ||
        enc->codec_id == AV_CODEC_ID_PCM_F32LE ||
        enc->codec_id == AV_CODEC_ID_PCM_F64LE ||
        enc->codec_id == AV_CODEC_ID_PCM_S16LE) {
        bytespersec = enc->sample_rate * blkalign;
    } else {
        bytespersec = enc->bit_rate / 8;
    }
    avio_wl32(pb, bytespersec); /* bytes per second */
    avio_wl16(pb, blkalign);    /* block align */
    avio_wl16(pb, bps);         /* bits per sample */
    if (enc->codec_id == AV_CODEC_ID_MP3) {
        hdrsize += 12;
        bytestream_put_le16(&riff_extradata, 1);    /* wID */
        bytestream_put_le32(&riff_extradata, 2);    /* fdwFlags */
        bytestream_put_le16(&riff_extradata, 1152); /* nBlockSize */
        bytestream_put_le16(&riff_extradata, 1);    /* nFramesPerBlock */
        bytestream_put_le16(&riff_extradata, 1393); /* nCodecDelay */
    } else if (enc->codec_id == AV_CODEC_ID_MP2) {
        hdrsize += 22;
        /* fwHeadLayer */
        bytestream_put_le16(&riff_extradata, 2);
        /* dwHeadBitrate */
        bytestream_put_le32(&riff_extradata, enc->bit_rate);
        /* fwHeadMode */
        bytestream_put_le16(&riff_extradata, enc->channels == 2 ? 1 : 8);
        /* fwHeadModeExt */
        bytestream_put_le16(&riff_extradata, 0);
        /* wHeadEmphasis */
        bytestream_put_le16(&riff_extradata, 1);
        /* fwHeadFlags */
        bytestream_put_le16(&riff_extradata, 16);
        /* dwPTSLow */
        bytestream_put_le32(&riff_extradata, 0);
        /* dwPTSHigh */
        bytestream_put_le32(&riff_extradata, 0);
    } else if (enc->codec_id == AV_CODEC_ID_GSM_MS ||
               enc->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV) {
        hdrsize += 2;
        /* wSamplesPerBlock */
        bytestream_put_le16(&riff_extradata, frame_size);
    } else if (enc->extradata_size) {
        riff_extradata_start = enc->extradata;
        riff_extradata       = enc->extradata + enc->extradata_size;
        hdrsize             += enc->extradata_size;
    }
    /* write WAVEFORMATEXTENSIBLE extensions */
    if (waveformatextensible) {
        hdrsize += 22;
        /* 22 is WAVEFORMATEXTENSIBLE size */
        avio_wl16(pb, riff_extradata - riff_extradata_start + 22);
        /* ValidBitsPerSample || SamplesPerBlock || Reserved */
        avio_wl16(pb, bps);
        /* dwChannelMask */
        avio_wl32(pb, enc->channel_layout);
        /* GUID + next 3 */
        avio_wl32(pb, enc->codec_tag);
        avio_wl32(pb, 0x00100000);
        avio_wl32(pb, 0xAA000080);
        avio_wl32(pb, 0x719B3800);
    } else {
        avio_wl16(pb, riff_extradata - riff_extradata_start); /* cbSize */
    }
    avio_write(pb, riff_extradata_start, riff_extradata - riff_extradata_start);
    if (hdrsize & 1) {
        hdrsize++;
        avio_w8(pb, 0);
    }

    return hdrsize;
}

/* BITMAPINFOHEADER header */
void ff_put_bmp_header(AVIOContext *pb, AVCodecContext *enc,
                       const AVCodecTag *tags, int for_asf)
{
    /* size */
    avio_wl32(pb, 40 + enc->extradata_size);
    avio_wl32(pb, enc->width);
    //We always store RGB TopDown
    avio_wl32(pb, enc->codec_tag ? enc->height : -enc->height);
    /* planes */
    avio_wl16(pb, 1);
    /* depth */
    avio_wl16(pb, enc->bits_per_coded_sample ? enc->bits_per_coded_sample : 24);
    /* compression type */
    avio_wl32(pb, enc->codec_tag);
    avio_wl32(pb, enc->width * enc->height * 3);
    avio_wl32(pb, 0);
    avio_wl32(pb, 0);
    avio_wl32(pb, 0);
    avio_wl32(pb, 0);

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

    if (!for_asf && enc->extradata_size & 1)
        avio_w8(pb, 0);
}

void ff_parse_specific_params(AVCodecContext *stream, int *au_rate,
                              int *au_ssize, int *au_scale)
{
    int gcd;
    int audio_frame_size;

    /* We use the known constant frame size for the codec if known, otherwise
     * fall back on using AVCodecContext.frame_size, which is not as reliable
     * for indicating packet duration. */
    audio_frame_size = av_get_audio_frame_duration(stream, 0);
    if (!audio_frame_size)
        audio_frame_size = stream->frame_size;

    *au_ssize = stream->block_align;
    if (audio_frame_size && stream->sample_rate) {
        *au_scale = audio_frame_size;
        *au_rate  = stream->sample_rate;
    } else if (stream->codec_type == AVMEDIA_TYPE_VIDEO ||
               stream->codec_type == AVMEDIA_TYPE_DATA ||
               stream->codec_type == AVMEDIA_TYPE_SUBTITLE) {
        *au_scale = stream->time_base.num;
        *au_rate  = stream->time_base.den;
    } else {
        *au_scale = stream->block_align ? stream->block_align * 8 : 8;
        *au_rate  = stream->bit_rate ? stream->bit_rate :
                    8 * stream->sample_rate;
    }
    gcd        = av_gcd(*au_scale, *au_rate);
    *au_scale /= gcd;
    *au_rate  /= gcd;
}

void ff_riff_write_info_tag(AVIOContext *pb, const char *tag, const char *str)
{
    int len = strlen(str);
    if (len > 0) {
        len++;
        ffio_wfourcc(pb, tag);
        avio_wl32(pb, len);
        avio_put_str(pb, str);
        if (len & 1)
            avio_w8(pb, 0);
    }
}

static const char riff_tags[][5] = {
    "IARL", "IART", "ICMS", "ICMT", "ICOP", "ICRD", "ICRP", "IDIM", "IDPI",
    "IENG", "IGNR", "IKEY", "ILGT", "ILNG", "IMED", "INAM", "IPLT", "IPRD",
    "IPRT", "ISBJ", "ISFT", "ISHP", "ISRC", "ISRF", "ITCH",
    { 0 }
};

static int riff_has_valid_tags(AVFormatContext *s)
{
    int i;

    for (i = 0; *riff_tags[i]; i++)
        if (av_dict_get(s->metadata, riff_tags[i], NULL, AV_DICT_MATCH_CASE))
            return 1;

    return 0;
}

void ff_riff_write_info(AVFormatContext *s)
{
    AVIOContext *pb = s->pb;
    int i;
    int64_t list_pos;
    AVDictionaryEntry *t = NULL;

    ff_metadata_conv(&s->metadata, ff_riff_info_conv, NULL);

    /* writing empty LIST is not nice and may cause problems */
    if (!riff_has_valid_tags(s))
        return;

    list_pos = ff_start_tag(pb, "LIST");
    ffio_wfourcc(pb, "INFO");
    for (i = 0; *riff_tags[i]; i++)
        if ((t = av_dict_get(s->metadata, riff_tags[i],
                             NULL, AV_DICT_MATCH_CASE)))
            ff_riff_write_info_tag(s->pb, t->key, t->value);
    ff_end_tag(pb, list_pos);
}