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mirror of https://git.videolan.org/git/ffmpeg.git synced 2024-08-03 09:49:58 +02:00
ffmpeg/libavformat/riffenc.c
Anton Khirnov 9200514ad8 lavf: replace AVStream.codec with AVStream.codecpar
Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.

In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.

There are multiple important problems with this approach:
    - the fields in AVCodecContext are in general one of
        * stream parameters
        * codec options
        * codec state
      However, it's not clear which ones are which. It is consequently
      unclear which fields are a demuxer allowed to set or a muxer allowed to
      read. This leads to erratic behaviour depending on whether decoding or
      encoding is being performed or not (and whether it uses the AVStream
      embedded codec context).
    - various synchronization issues arising from the fact that the same
      context is used by several different APIs (muxers/demuxers,
      parsers, bitstream filters and encoders/decoders) simultaneously, with
      there being no clear rules for who can modify what and the different
      processes being typically delayed with respect to each other.
    - avformat_find_stream_info() making it necessary to support opening
      and closing a single codec context multiple times, thus
      complicating the semantics of freeing various allocated objects in the
      codec context.

Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.
2016-02-23 17:01:58 +01:00

289 lines
9.5 KiB
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(AVFormatContext *s, AVIOContext *pb,
AVCodecParameters *par)
{
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 (!par->codec_tag || par->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_duration2(par, par->block_align);
waveformatextensible = (par->channels > 2 && par->channel_layout) ||
par->sample_rate > 48000 ||
av_get_bits_per_sample(par->codec_id) > 16;
if (waveformatextensible)
avio_wl16(pb, 0xfffe);
else
avio_wl16(pb, par->codec_tag);
avio_wl16(pb, par->channels);
avio_wl32(pb, par->sample_rate);
if (par->codec_id == AV_CODEC_ID_MP2 ||
par->codec_id == AV_CODEC_ID_MP3 ||
par->codec_id == AV_CODEC_ID_GSM_MS) {
bps = 0;
} else {
if (!(bps = av_get_bits_per_sample(par->codec_id))) {
if (par->bits_per_coded_sample)
bps = par->bits_per_coded_sample;
else
bps = 16; // default to 16
}
}
if (bps != par->bits_per_coded_sample && par->bits_per_coded_sample) {
av_log(s, AV_LOG_WARNING,
"requested bits_per_coded_sample (%d) "
"and actually stored (%d) differ\n",
par->bits_per_coded_sample, bps);
}
if (par->codec_id == AV_CODEC_ID_MP2) {
blkalign = frame_size;
} else if (par->codec_id == AV_CODEC_ID_MP3) {
blkalign = 576 * (par->sample_rate <= 24000 ? 1 : 2);
} else if (par->codec_id == AV_CODEC_ID_AC3) {
blkalign = 3840; /* maximum bytes per frame */
} else if (par->block_align != 0) { /* specified by the codec */
blkalign = par->block_align;
} else
blkalign = bps * par->channels / av_gcd(8, bps);
if (par->codec_id == AV_CODEC_ID_PCM_U8 ||
par->codec_id == AV_CODEC_ID_PCM_S24LE ||
par->codec_id == AV_CODEC_ID_PCM_S32LE ||
par->codec_id == AV_CODEC_ID_PCM_F32LE ||
par->codec_id == AV_CODEC_ID_PCM_F64LE ||
par->codec_id == AV_CODEC_ID_PCM_S16LE) {
bytespersec = par->sample_rate * blkalign;
} else {
bytespersec = par->bit_rate / 8;
}
avio_wl32(pb, bytespersec); /* bytes per second */
avio_wl16(pb, blkalign); /* block align */
avio_wl16(pb, bps); /* bits per sample */
if (par->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 (par->codec_id == AV_CODEC_ID_MP2) {
hdrsize += 22;
/* fwHeadLayer */
bytestream_put_le16(&riff_extradata, 2);
/* dwHeadBitrate */
bytestream_put_le32(&riff_extradata, par->bit_rate);
/* fwHeadMode */
bytestream_put_le16(&riff_extradata, par->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 (par->codec_id == AV_CODEC_ID_GSM_MS ||
par->codec_id == AV_CODEC_ID_ADPCM_IMA_WAV) {
hdrsize += 2;
/* wSamplesPerBlock */
bytestream_put_le16(&riff_extradata, frame_size);
} else if (par->extradata_size) {
riff_extradata_start = par->extradata;
riff_extradata = par->extradata + par->extradata_size;
hdrsize += par->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, par->channel_layout);
/* GUID + next 3 */
avio_wl32(pb, par->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, AVCodecParameters *par,
const AVCodecTag *tags, int for_asf)
{
/* size */
avio_wl32(pb, 40 + par->extradata_size);
avio_wl32(pb, par->width);
//We always store RGB TopDown
avio_wl32(pb, par->codec_tag ? par->height : -par->height);
/* planes */
avio_wl16(pb, 1);
/* depth */
avio_wl16(pb, par->bits_per_coded_sample ? par->bits_per_coded_sample : 24);
/* compression type */
avio_wl32(pb, par->codec_tag);
avio_wl32(pb, par->width * par->height * 3);
avio_wl32(pb, 0);
avio_wl32(pb, 0);
avio_wl32(pb, 0);
avio_wl32(pb, 0);
avio_write(pb, par->extradata, par->extradata_size);
if (!for_asf && par->extradata_size & 1)
avio_w8(pb, 0);
}
void ff_parse_specific_params(AVStream *st, int *au_rate,
int *au_ssize, int *au_scale)
{
AVCodecParameters *par = st->codecpar;
int gcd;
int audio_frame_size;
audio_frame_size = av_get_audio_frame_duration2(par, 0);
*au_ssize = par->block_align;
if (audio_frame_size && par->sample_rate) {
*au_scale = audio_frame_size;
*au_rate = par->sample_rate;
} else if (par->codec_type == AVMEDIA_TYPE_VIDEO ||
par->codec_type == AVMEDIA_TYPE_DATA ||
par->codec_type == AVMEDIA_TYPE_SUBTITLE) {
*au_scale = st->time_base.num;
*au_rate = st->time_base.den;
} else {
*au_scale = par->block_align ? par->block_align * 8 : 8;
*au_rate = par->bit_rate ? par->bit_rate :
8 * par->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", "ITRK", "ISBJ", "ISFT", "ISHP", "ISMP", "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);
}