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179 lines
5.4 KiB
179 lines
5.4 KiB
/* |
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* Matroska file muxer |
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* Copyright (c) 2007 David Conrad |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "avformat.h" |
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#include "riff.h" |
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#include "matroska.h" |
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typedef struct MatroskaMuxContext { |
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offset_t segment; |
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} MatroskaMuxContext; |
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static void put_ebml_id(ByteIOContext *pb, unsigned int id) |
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{ |
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if (id >= 0x3fffff) |
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put_byte(pb, id >> 24); |
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if (id >= 0x7fff) |
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put_byte(pb, id >> 16); |
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if (id >= 0xff) |
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put_byte(pb, id >> 8); |
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put_byte(pb, id); |
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} |
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// XXX: test this thoroughly and get rid of minbytes hack (currently needed to |
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// use up all of the space reserved in start_ebml_master) |
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static void put_ebml_size(ByteIOContext *pb, uint64_t size, int minbytes) |
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{ |
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int bytes = minbytes; |
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while (size >> (bytes*7 + 7)) bytes++; |
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// sizes larger than this are currently undefined in EBML |
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// XXX: error condition? |
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if (size > (1ULL<<56)-1) return; |
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put_byte(pb, (0x80 >> bytes) | (size >> bytes*8)); |
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for (bytes -= 1; bytes >= 0; bytes--) |
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put_byte(pb, size >> bytes*8); |
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} |
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static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val) |
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{ |
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int bytes = 1; |
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while (val >> bytes*8) bytes++; |
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put_ebml_id(pb, elementid); |
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put_ebml_size(pb, bytes, 0); |
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for (bytes -= 1; bytes >= 0; bytes--) |
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put_byte(pb, val >> bytes*8); |
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} |
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//static void put_ebml_sint(ByteIOContext *pb, unsigned int elementid, int64_t val) |
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static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid, |
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uint8_t *buf, int size) |
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{ |
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put_ebml_id(pb, elementid); |
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put_ebml_size(pb, size, 0); |
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put_buffer(pb, buf, size); |
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} |
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// XXX: should we do any special checking for valid strings for these 2 functions? |
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static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, char *str) |
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{ |
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put_ebml_binary(pb, elementid, str, strlen(str)); |
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} |
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static void put_ebml_utf8(ByteIOContext *pb, unsigned int elementid, char *str) |
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{ |
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put_ebml_binary(pb, elementid, str, strlen(str)); |
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} |
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static offset_t start_ebml_master(ByteIOContext *pb, unsigned int elementid) |
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{ |
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put_ebml_id(pb, elementid); |
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// XXX: this always reserves the maximum needed space to store any size value |
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// we should be smarter (additional parameter for expected size?) |
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put_ebml_size(pb, (1ULL<<56)-1, 0); // largest unknown size |
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return url_ftell(pb); |
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} |
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static void end_ebml_master(ByteIOContext *pb, offset_t start) |
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{ |
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offset_t pos = url_ftell(pb); |
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url_fseek(pb, start - 8, SEEK_SET); |
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put_ebml_size(pb, pos - start, 7); |
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url_fseek(pb, pos, SEEK_SET); |
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} |
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static int mkv_write_header(AVFormatContext *s) |
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{ |
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MatroskaMuxContext *mkv = s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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offset_t ebml_header, segment_info, tracks; |
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int i; |
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ebml_header = start_ebml_master(pb, EBML_ID_HEADER); |
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put_ebml_uint(pb, EBML_ID_EBMLVERSION, 1); |
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put_ebml_uint(pb, EBML_ID_EBMLREADVERSION, 1); |
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put_ebml_uint(pb, EBML_ID_EBMLMAXIDLENGTH, 4); |
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put_ebml_uint(pb, EBML_ID_EBMLMAXSIZELENGTH, 8); |
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put_ebml_string(pb, EBML_ID_DOCTYPE, "matroska"); |
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put_ebml_uint(pb, EBML_ID_DOCTYPEVERSION, 1); |
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put_ebml_uint(pb, EBML_ID_DOCTYPEREADVERSION, 1); |
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end_ebml_master(pb, ebml_header); |
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mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT); |
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segment_info = start_ebml_master(pb, MATROSKA_ID_INFO); |
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put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000); |
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if (strlen(s->title)) |
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put_ebml_utf8(pb, MATROSKA_ID_TITLE, s->title); |
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if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) { |
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put_ebml_utf8(pb, MATROSKA_ID_MUXINGAPP, LIBAVFORMAT_IDENT); |
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// XXX: both are required; something better for writing app? |
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put_ebml_utf8(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT); |
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} |
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// XXX: segment UID and duration |
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end_ebml_master(pb, segment_info); |
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tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS); |
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for (i = 0; i < s->nb_streams; i++) { |
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AVStream *st = s->streams[i]; |
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offset_t track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY); |
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end_ebml_master(pb, track); |
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} |
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end_ebml_master(pb, tracks); |
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put_be64(pb, 0xdeadbeef); |
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return 0; |
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} |
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static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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ByteIOContext *pb = &s->pb; |
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put_buffer(pb, pkt->data, pkt->size); |
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return 0; |
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} |
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static int mkv_write_trailer(AVFormatContext *s) |
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{ |
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MatroskaMuxContext *mkv = s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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end_ebml_master(pb, mkv->segment); |
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return 0; |
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} |
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AVOutputFormat matroska_muxer = { |
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"matroska", |
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"Matroska File Format", |
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"video/x-matroska", |
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"mkv", |
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sizeof(MatroskaMuxContext), |
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CODEC_ID_MP2, |
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CODEC_ID_MPEG4, |
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mkv_write_header, |
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mkv_write_packet, |
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mkv_write_trailer, |
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.codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0}, |
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};
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