ffmpeg/libavformat/matroskaenc.c

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/*
* Matroska file muxer
* Copyright (c) 2007 David Conrad
*
* 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 "riff.h"
#include "xiph.h"
#include "matroska.h"
typedef struct MatroskaMuxContext {
offset_t segment;
offset_t cluster;
uint64_t cluster_pts;
} MatroskaMuxContext;
static void put_ebml_id(ByteIOContext *pb, unsigned int id)
{
if (id >= 0x3fffff)
put_byte(pb, id >> 24);
if (id >= 0x7fff)
put_byte(pb, id >> 16);
if (id >= 0xff)
put_byte(pb, id >> 8);
put_byte(pb, id);
}
// XXX: test this thoroughly and get rid of minbytes hack (currently needed to
// use up all of the space reserved in start_ebml_master)
static void put_ebml_size(ByteIOContext *pb, uint64_t size, int minbytes)
{
int bytes = minbytes;
while (size >> (bytes*7 + 7)) bytes++;
// sizes larger than this are currently undefined in EBML
// XXX: error condition?
if (size > (1ULL<<56)-1) return;
put_byte(pb, (0x80 >> bytes) | (size >> bytes*8));
for (bytes -= 1; bytes >= 0; bytes--)
put_byte(pb, size >> bytes*8);
}
static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
{
int bytes = 1;
while (val >> bytes*8) bytes++;
put_ebml_id(pb, elementid);
put_ebml_size(pb, bytes, 0);
for (bytes -= 1; bytes >= 0; bytes--)
put_byte(pb, val >> bytes*8);
}
//static void put_ebml_sint(ByteIOContext *pb, unsigned int elementid, int64_t val)
static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
{
// XXX: single-precision floats?
put_ebml_id(pb, elementid);
put_ebml_size(pb, 8, 0);
put_be64(pb, av_dbl2int(val));
}
static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
const uint8_t *buf, int size)
{
put_ebml_id(pb, elementid);
put_ebml_size(pb, size, 0);
put_buffer(pb, buf, size);
}
static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
{
put_ebml_binary(pb, elementid, str, strlen(str));
}
static offset_t start_ebml_master(ByteIOContext *pb, unsigned int elementid)
{
put_ebml_id(pb, elementid);
// XXX: this always reserves the maximum needed space to store any size value
// we should be smarter (additional parameter for expected size?)
put_ebml_size(pb, (1ULL<<56)-1, 0); // largest unknown size
return url_ftell(pb);
}
static void end_ebml_master(ByteIOContext *pb, offset_t start)
{
offset_t pos = url_ftell(pb);
url_fseek(pb, start - 8, SEEK_SET);
put_ebml_size(pb, pos - start, 7);
url_fseek(pb, pos, SEEK_SET);
}
static int mkv_write_header(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = &s->pb;
offset_t ebml_header, segment_info, tracks;
int i, j, k;
ebml_header = start_ebml_master(pb, EBML_ID_HEADER);
put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 1);
put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 1);
end_ebml_master(pb, ebml_header);
mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT);
segment_info = start_ebml_master(pb, MATROSKA_ID_INFO);
put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
if (strlen(s->title))
put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
put_ebml_string(pb, MATROSKA_ID_MUXINGAPP, LIBAVFORMAT_IDENT);
// XXX: both are required; something better for writing app?
put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
}
// XXX: segment UID and duration
end_ebml_master(pb, segment_info);
tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS);
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
AVCodecContext *codec = st->codec;
offset_t subinfo, track;
int native_id = 0;
track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i);
// XXX: random number for UID? and can we use the same UID when copying
// from another MKV as the specs recommend?
put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i);
put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
if (st->language[0])
put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
// look for a codec id string specific to mkv to use, if none are found, use AVI codes
for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
if (ff_mkv_codec_tags[j].id == codec->codec_id) {
put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
native_id = 1;
break;
}
}
// XXX: CodecPrivate for vorbis, theora, aac, native mpeg4, ...
if (native_id) {
offset_t codecprivate;
if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
uint8_t *header_start[3];
int header_len[3];
int first_header_size;
if (codec->codec_id == CODEC_ID_VORBIS)
first_header_size = 30;
else
first_header_size = 42;
if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
first_header_size, header_start, header_len) < 0) {
av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
return -1;
}
codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
put_byte(pb, 2); // number packets - 1
for (j = 0; j < 2; j++) {
for (k = 0; k < header_len[j] / 255; k++)
put_byte(pb, 255);
put_byte(pb, header_len[j] % 255);
}
for (j = 0; j < 3; j++)
put_buffer(pb, header_start[j], header_len[j]);
end_ebml_master(pb, codecprivate);
} else {
put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
}
}
switch (codec->codec_type) {
case CODEC_TYPE_VIDEO:
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
if (!native_id) {
offset_t bmp_header;
// if there is no mkv-specific codec id, use VFW mode
if (!codec->codec_tag)
codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
// XXX: codec private isn't a master; is there a better way to re-use put_bmp_header?
bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
put_bmp_header(pb, codec, codec_bmp_tags, 0);
end_ebml_master(pb, bmp_header);
}
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO);
// XXX: interlace flag?
put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
// XXX: display width/height
end_ebml_master(pb, subinfo);
break;
case CODEC_TYPE_AUDIO:
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
// XXX: A_MS/ACM
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO);
put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, codec->sample_rate);
// XXX: output sample freq (for sbr) and bitdepth (for pcm)
end_ebml_master(pb, subinfo);
break;
default:
av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
break;
}
end_ebml_master(pb, track);
// ms precision is the de-facto standard timescale for mkv files
av_set_pts_info(st, 64, 1, 1000);
}
end_ebml_master(pb, tracks);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
mkv->cluster_pts = 0;
return 0;
}
static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = &s->pb;
offset_t block;
// start a new cluster every 5 MB or 5 sec
if (url_ftell(pb) > mkv->cluster + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
end_ebml_master(pb, mkv->cluster);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
mkv->cluster_pts = pkt->pts;
}
block = start_ebml_master(pb, MATROSKA_ID_SIMPLEBLOCK);
put_byte(pb, 0x80 | pkt->stream_index); // this assumes stream_index is less than 127
put_be16(pb, pkt->pts - mkv->cluster_pts);
put_byte(pb, !!(pkt->flags & PKT_FLAG_KEY));
put_buffer(pb, pkt->data, pkt->size);
end_ebml_master(pb, block);
return 0;
}
static int mkv_write_trailer(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = &s->pb;
end_ebml_master(pb, mkv->cluster);
end_ebml_master(pb, mkv->segment);
return 0;
}
AVOutputFormat matroska_muxer = {
"matroska",
"Matroska File Format",
"video/x-matroska",
"mkv",
sizeof(MatroskaMuxContext),
CODEC_ID_MP2,
CODEC_ID_MPEG4,
mkv_write_header,
mkv_write_packet,
mkv_write_trailer,
.codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
};