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Beginning of mkv muxer, only EBML head is written correctly

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Originally committed as revision 10294 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
David Conrad 2007-09-05 00:22:37 +00:00
parent 5be3a81871
commit 67143c0f69
1 changed files with 179 additions and 0 deletions
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179
libavformat/matroskaenc.c Normal file
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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 "matroska.h"
typedef struct MatroskaMuxContext {
offset_t segment;
} 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*8 + 7-bytes) > 0) 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_binary(ByteIOContext *pb, unsigned int elementid,
uint8_t *buf, int size)
{
put_ebml_id(pb, elementid);
put_ebml_size(pb, size, 0);
put_buffer(pb, buf, size);
}
// XXX: should we do any special checking for valid strings for these 2 functions?
static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, char *str)
{
put_ebml_binary(pb, elementid, str, strlen(str));
}
static void put_ebml_utf8(ByteIOContext *pb, unsigned int elementid, 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;
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_utf8(pb, MATROSKA_ID_TITLE, s->title);
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
put_ebml_utf8(pb, MATROSKA_ID_MUXINGAPP, LIBAVFORMAT_IDENT);
// XXX: both are required; something better for writing app?
put_ebml_utf8(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];
offset_t track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
end_ebml_master(pb, track);
}
end_ebml_master(pb, tracks);
put_be64(pb, 0xdeadbeef);
return 0;
}
static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
{
ByteIOContext *pb = &s->pb;
put_buffer(pb, pkt->data, pkt->size);
return 0;
}
static int mkv_write_trailer(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = &s->pb;
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},
};