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ffmpeg/libavformat/oggenc.c

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/*
* Ogg muxer
* Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>
*
* 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 "avformat.h"
#include "crc.h"
#include "xiph.h"
#include "bytestream.h"
typedef struct {
int64_t duration;
unsigned page_counter;
uint8_t *header[3];
int header_len[3];
/** for theora granule */
int kfgshift;
int64_t last_kf_pts;
int vrev;
} OGGStreamContext;
static void ogg_update_checksum(AVFormatContext *s, offset_t crc_offset)
{
offset_t pos = url_ftell(&s->pb);
uint32_t checksum = get_checksum(&s->pb);
url_fseek(&s->pb, crc_offset, SEEK_SET);
put_be32(&s->pb, checksum);
url_fseek(&s->pb, pos, SEEK_SET);
}
static int ogg_write_page(AVFormatContext *s, const uint8_t *data, int size,
int64_t granule, int stream_index, int flags)
{
OGGStreamContext *oggstream = s->streams[stream_index]->priv_data;
offset_t crc_offset;
int page_segments, i;
size = FFMIN(size, 255*255);
page_segments = FFMIN((size/255)+!!size, 255);
init_checksum(&s->pb, ff_crc04C11DB7_update, 0);
put_tag(&s->pb, "OggS");
put_byte(&s->pb, 0);
put_byte(&s->pb, flags);
put_le64(&s->pb, granule);
put_le32(&s->pb, stream_index);
put_le32(&s->pb, oggstream->page_counter++);
crc_offset = url_ftell(&s->pb);
put_le32(&s->pb, 0); // crc
put_byte(&s->pb, page_segments);
for (i = 0; i < page_segments-1; i++)
put_byte(&s->pb, 255);
if (size) {
put_byte(&s->pb, size - (page_segments-1)*255);
put_buffer(&s->pb, data, size);
}
ogg_update_checksum(s, crc_offset);
put_flush_packet(&s->pb);
return size;
}
static int ogg_build_flac_headers(const uint8_t *extradata, int extradata_size,
OGGStreamContext *oggstream, int bitexact)
{
const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
uint8_t *p;
if (extradata_size != 34)
return -1;
oggstream->header_len[0] = 79;
oggstream->header[0] = av_mallocz(79); // per ogg flac specs
p = oggstream->header[0];
bytestream_put_byte(&p, 0x7F);
bytestream_put_buffer(&p, "FLAC", 4);
bytestream_put_byte(&p, 1); // major version
bytestream_put_byte(&p, 0); // minor version
bytestream_put_be16(&p, 1); // headers packets without this one
bytestream_put_buffer(&p, "fLaC", 4);
bytestream_put_byte(&p, 0x00); // streaminfo
bytestream_put_be24(&p, 34);
bytestream_put_buffer(&p, extradata, 34);
oggstream->header_len[1] = 1+3+4+strlen(vendor)+4;
oggstream->header[1] = av_mallocz(oggstream->header_len[1]);
p = oggstream->header[1];
bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment
bytestream_put_be24(&p, oggstream->header_len[1] - 4);
bytestream_put_le32(&p, strlen(vendor));
bytestream_put_buffer(&p, vendor, strlen(vendor));
bytestream_put_le32(&p, 0); // user comment list length
return 0;
}
static int ogg_write_header(AVFormatContext *s)
{
OGGStreamContext *oggstream;
int i, j;
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
if (st->codec->codec_type == CODEC_TYPE_AUDIO)
av_set_pts_info(st, 64, 1, st->codec->sample_rate);
else if (st->codec->codec_type == CODEC_TYPE_VIDEO)
av_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);
if (st->codec->codec_id != CODEC_ID_VORBIS &&
st->codec->codec_id != CODEC_ID_THEORA &&
st->codec->codec_id != CODEC_ID_FLAC) {
av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
return -1;
}
if (!st->codec->extradata || !st->codec->extradata_size) {
av_log(s, AV_LOG_ERROR, "No extradata present\n");
return -1;
}
oggstream = av_mallocz(sizeof(*oggstream));
st->priv_data = oggstream;
if (st->codec->codec_id == CODEC_ID_FLAC) {
if (ogg_build_flac_headers(st->codec->extradata, st->codec->extradata_size,
oggstream, st->codec->flags & CODEC_FLAG_BITEXACT) < 0) {
av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
av_freep(&st->priv_data);
}
} else {
if (ff_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
st->codec->codec_id == CODEC_ID_VORBIS ? 30 : 42,
oggstream->header, oggstream->header_len) < 0) {
av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
av_freep(&st->priv_data);
return -1;
}
if (st->codec->codec_id == CODEC_ID_THEORA) {
/** KFGSHIFT is the width of the less significant section of the granule position
The less significant section is the frame count since the last keyframe */
oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
oggstream->vrev = oggstream->header[0][9];
av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",
oggstream->kfgshift, oggstream->vrev);
}
}
}
for (i = 0; i < 3; i++) {
for (j = 0; j < s->nb_streams; j++) {
AVStream *st = s->streams[j];
OGGStreamContext *oggstream = st->priv_data;
if (oggstream && oggstream->header_len[i]) {
ogg_write_page(s, oggstream->header[i], oggstream->header_len[i],
0, st->index, i ? 0 : 2); // bos
}
}
}
return 0;
}
static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
{
AVStream *st = s->streams[pkt->stream_index];
OGGStreamContext *oggstream = st->priv_data;
uint8_t *ptr = pkt->data;
int ret, size = pkt->size;
int64_t granule;
if (st->codec->codec_id == CODEC_ID_THEORA) {
int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
int pframe_count;
if (pkt->flags & PKT_FLAG_KEY)
oggstream->last_kf_pts = pts;
pframe_count = pts - oggstream->last_kf_pts;
// prevent frame count from overflow if key frame flag is not set
if (pframe_count >= (1<<oggstream->kfgshift)) {
oggstream->last_kf_pts += pframe_count;
pframe_count = 0;
}
granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
} else
granule = pkt->pts + pkt->duration;
oggstream->duration = granule;
do {
ret = ogg_write_page(s, ptr, size, granule, pkt->stream_index, ptr != pkt->data);
ptr += ret; size -= ret;
} while (size > 0 || ret == 255*255); // need to output a last nil page
return 0;
}
static int ogg_write_trailer(AVFormatContext *s)
{
int i;
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
OGGStreamContext *oggstream = st->priv_data;
ogg_write_page(s, NULL, 0, oggstream->duration, i, 4); // eos
if (st->codec->codec_id == CODEC_ID_FLAC) {
av_free(oggstream->header[0]);
av_free(oggstream->header[1]);
}
av_freep(&st->priv_data);
}
return 0;
}
AVOutputFormat ogg_muxer = {
"ogg",
"Ogg format",
"application/ogg",
"ogg",
0,
CODEC_ID_FLAC,
CODEC_ID_THEORA,
ogg_write_header,
ogg_write_packet,
ogg_write_trailer,
};
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