3 * Copyright (c) 2007 David Conrad
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 typedef struct ebml_master {
29 offset_t pos; ///< absolute offset in the file where the master's elements start
30 int sizebytes; ///< how many bytes were reserved for the size
33 typedef struct mkv_seekhead_entry {
34 unsigned int elementid;
38 typedef struct mkv_seekhead {
40 offset_t segment_offset; ///< the file offset to the beginning of the segment
41 int reserved_size; ///< -1 if appending to file
43 mkv_seekhead_entry *entries;
50 offset_t cluster_pos; ///< file offset of the cluster containing the block
54 offset_t segment_offset;
55 mkv_cuepoint *entries;
59 typedef struct MatroskaMuxContext {
61 offset_t segment_offset;
64 offset_t cluster_pos; ///< file offset of the current cluster
66 offset_t duration_offset;
68 mkv_seekhead *main_seekhead;
69 mkv_seekhead *cluster_seekhead;
72 struct AVMD5 *md5_ctx;
76 // 2 bytes * 3 for EBML IDs, 3 1-byte EBML lengths, 8 bytes for 64 bit offset, 4 bytes for target EBML ID
77 #define MAX_SEEKENTRY_SIZE 21
79 // per-cuepoint-track - 3 1-byte EBML IDs, 3 1-byte EBML sizes, 2 8-byte uint max
80 #define MAX_CUETRACKPOS_SIZE 22
82 // per-cuepoint - 2 1-byte EBML IDs, 2 1-byte EBML sizes, 8-byte uint max
83 #define MAX_CUEPOINT_SIZE(num_tracks) 12 + MAX_CUETRACKPOS_SIZE*num_tracks
86 static int ebml_id_size(unsigned int id)
88 return (av_log2(id+1)-1)/7+1;
91 static void put_ebml_id(ByteIOContext *pb, unsigned int id)
93 int i = ebml_id_size(id);
95 put_byte(pb, id >> (i*8));
99 * Write an EBML size meaning "unknown size"
101 * @param bytes The number of bytes the size should occupy. Maximum of 8.
103 static void put_ebml_size_unknown(ByteIOContext *pb, int bytes)
108 bytes = FFMIN(bytes, 8);
109 for (i = 0; i < bytes*7 + 1; i++)
111 for (i = bytes-1; i >= 0; i--)
112 put_byte(pb, value >> i*8);
116 * Calculate how many bytes are needed to represent a given size in EBML
118 static int ebml_size_bytes(uint64_t size)
121 while ((size+1) >> bytes*7) bytes++;
126 * Write a size in EBML variable length format.
128 * @param bytes The number of bytes that need to be used to write the size.
129 * If zero, any number of bytes can be used.
131 static void put_ebml_size(ByteIOContext *pb, uint64_t size, int bytes)
133 int i, needed_bytes = ebml_size_bytes(size);
135 // sizes larger than this are currently undefined in EBML
136 // so write "unknown" size
137 if (size >= (1ULL<<56)-1) {
138 put_ebml_size_unknown(pb, 1);
143 // don't care how many bytes are used, so use the min
144 bytes = needed_bytes;
145 else if (needed_bytes > bytes) {
146 // the bytes needed to write the given size would exceed the bytes
147 // that we need to use, so write unknown size. This shouldn't happen.
148 av_log(NULL, AV_LOG_WARNING, "Size of %" PRIu64 " needs %d bytes but only %d bytes reserved\n",
149 size, needed_bytes, bytes);
150 put_ebml_size_unknown(pb, bytes);
154 size |= 1ULL << bytes*7;
155 for (i = bytes - 1; i >= 0; i--)
156 put_byte(pb, size >> i*8);
159 static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
162 while (val >> bytes*8) bytes++;
164 put_ebml_id(pb, elementid);
165 put_ebml_size(pb, bytes, 0);
166 for (i = bytes - 1; i >= 0; i--)
167 put_byte(pb, val >> i*8);
170 static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
172 put_ebml_id(pb, elementid);
173 put_ebml_size(pb, 8, 0);
174 put_be64(pb, av_dbl2int(val));
177 static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
178 const uint8_t *buf, int size)
180 put_ebml_id(pb, elementid);
181 put_ebml_size(pb, size, 0);
182 put_buffer(pb, buf, size);
185 static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
187 put_ebml_binary(pb, elementid, str, strlen(str));
191 * Writes a void element of a given size. Useful for reserving space in the file to be
194 * @param size The number of bytes to reserve, which must be at least 2.
196 static void put_ebml_void(ByteIOContext *pb, uint64_t size)
198 offset_t currentpos = url_ftell(pb);
203 put_ebml_id(pb, EBML_ID_VOID);
204 // we need to subtract the length needed to store the size from the size we need to reserve
205 // so 2 cases, we use 8 bytes to store the size if possible, 1 byte otherwise
207 put_ebml_size(pb, size-1, 0);
209 put_ebml_size(pb, size-9, 8);
210 url_fseek(pb, currentpos + size, SEEK_SET);
213 static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
215 int bytes = expectedsize ? ebml_size_bytes(expectedsize) : 8;
216 put_ebml_id(pb, elementid);
217 put_ebml_size_unknown(pb, bytes);
218 return (ebml_master){ url_ftell(pb), bytes };
221 static void end_ebml_master(ByteIOContext *pb, ebml_master master)
223 offset_t pos = url_ftell(pb);
225 url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
226 put_ebml_size(pb, pos - master.pos, master.sizebytes);
227 url_fseek(pb, pos, SEEK_SET);
230 static void put_xiph_size(ByteIOContext *pb, int size)
233 for (i = 0; i < size / 255; i++)
235 put_byte(pb, size % 255);
239 * Initialize a mkv_seekhead element to be ready to index level 1 Matroska elements.
240 * If a maximum number of elements is specified, enough space will be reserved at
241 * the current file location to write a seek head of that size.
243 * @param segment_offset The absolute offset to the position in the file where the segment begins
244 * @param numelements the maximum number of elements that will be indexed by this
245 * seek head, 0 if unlimited.
247 static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_offset, int numelements)
249 mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
250 if (new_seekhead == NULL)
253 new_seekhead->segment_offset = segment_offset;
255 if (numelements > 0) {
256 new_seekhead->filepos = url_ftell(pb);
257 // 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID and size,
258 // and 3 bytes to guarantee that an EBML void element will fit afterwards
259 new_seekhead->reserved_size = numelements * MAX_SEEKENTRY_SIZE + 13;
260 new_seekhead->max_entries = numelements;
261 put_ebml_void(pb, new_seekhead->reserved_size);
266 static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
268 mkv_seekhead_entry *entries = seekhead->entries;
269 int new_entry = seekhead->num_entries;
271 // don't store more elements than we reserved space for
272 if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
275 entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
279 entries[new_entry].elementid = elementid;
280 entries[new_entry].segmentpos = filepos - seekhead->segment_offset;
282 seekhead->entries = entries;
283 seekhead->num_entries++;
289 * Write the seek head to the file and free it. If a maximum number of elements was
290 * specified to mkv_start_seekhead(), the seek head will be written at the location
291 * reserved for it. Otherwise, it is written at the current location in the file.
293 * @return the file offset where the seekhead was written
295 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
297 ebml_master metaseek, seekentry;
301 currentpos = url_ftell(pb);
303 if (seekhead->reserved_size > 0)
304 url_fseek(pb, seekhead->filepos, SEEK_SET);
306 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
307 for (i = 0; i < seekhead->num_entries; i++) {
308 mkv_seekhead_entry *entry = &seekhead->entries[i];
310 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
312 put_ebml_id(pb, MATROSKA_ID_SEEKID);
313 put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
314 put_ebml_id(pb, entry->elementid);
316 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
317 end_ebml_master(pb, seekentry);
319 end_ebml_master(pb, metaseek);
321 if (seekhead->reserved_size > 0) {
322 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
323 put_ebml_void(pb, remaining);
324 url_fseek(pb, currentpos, SEEK_SET);
326 currentpos = seekhead->filepos;
328 av_free(seekhead->entries);
334 static mkv_cues * mkv_start_cues(offset_t segment_offset)
336 mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
340 cues->segment_offset = segment_offset;
344 static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
346 mkv_cuepoint *entries = cues->entries;
347 int new_entry = cues->num_entries;
349 entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
353 entries[new_entry].pts = pkt->pts;
354 entries[new_entry].tracknum = pkt->stream_index + 1;
355 entries[new_entry].cluster_pos = cluster_pos - cues->segment_offset;
357 cues->entries = entries;
362 static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
364 ebml_master cues_element;
368 currentpos = url_ftell(pb);
369 cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
371 for (i = 0; i < cues->num_entries; i++) {
372 ebml_master cuepoint, track_positions;
373 mkv_cuepoint *entry = &cues->entries[i];
374 uint64_t pts = entry->pts;
376 cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
377 put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
379 // put all the entries from different tracks that have the exact same
380 // timestamp into the same CuePoint
381 for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
382 track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
383 put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
384 put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
385 end_ebml_master(pb, track_positions);
388 end_ebml_master(pb, cuepoint);
390 end_ebml_master(pb, cues_element);
392 av_free(cues->entries);
397 static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
399 ebml_master codecprivate;
400 uint8_t *header_start[3];
402 int first_header_size;
405 if (codec->codec_id == CODEC_ID_VORBIS)
406 first_header_size = 30;
408 first_header_size = 42;
410 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
411 first_header_size, header_start, header_len) < 0) {
412 av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
416 codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
417 put_byte(pb, 2); // number packets - 1
418 for (j = 0; j < 2; j++) {
419 put_xiph_size(pb, header_len[j]);
421 for (j = 0; j < 3; j++)
422 put_buffer(pb, header_start[j], header_len[j]);
423 end_ebml_master(pb, codecprivate);
428 #define FLAC_STREAMINFO_SIZE 34
430 static int put_flac_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
432 ebml_master codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
434 // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
435 // assume that it's in Matroska's format already
436 if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
437 av_log(codec, AV_LOG_ERROR, "Invalid FLAC extradata\n");
439 } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
440 // only the streaminfo packet
442 put_xiph_size(pb, codec->extradata_size);
443 av_log(codec, AV_LOG_ERROR, "Only one packet\n");
445 put_buffer(pb, codec->extradata, codec->extradata_size);
446 end_ebml_master(pb, codecpriv);
450 static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
452 static const int aac_sample_rates[] = {
453 96000, 88200, 64000, 48000, 44100, 32000,
454 24000, 22050, 16000, 12000, 11025, 8000,
458 if (codec->extradata_size < 2) {
459 av_log(codec, AV_LOG_WARNING, "no aac extradata, unable to determine sample rate\n");
463 sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
465 av_log(codec, AV_LOG_WARNING, "aac samplerate index out of bounds\n");
468 *sample_rate = aac_sample_rates[sri];
470 // if sbr, get output sample rate as well
471 if (codec->extradata_size == 5) {
472 sri = (codec->extradata[4] >> 3) & 0xF;
474 av_log(codec, AV_LOG_WARNING, "aac output samplerate index out of bounds\n");
477 *output_sample_rate = aac_sample_rates[sri];
481 static int mkv_write_tracks(AVFormatContext *s)
483 MatroskaMuxContext *mkv = s->priv_data;
484 ByteIOContext *pb = &s->pb;
488 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb)) < 0)
491 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
492 for (i = 0; i < s->nb_streams; i++) {
493 AVStream *st = s->streams[i];
494 AVCodecContext *codec = st->codec;
495 ebml_master subinfo, track;
497 int bit_depth = av_get_bits_per_sample(codec->codec_id);
498 int sample_rate = codec->sample_rate;
499 int output_sample_rate = 0;
501 if (codec->codec_id == CODEC_ID_AAC)
502 get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
504 track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
505 put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
506 put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
507 put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
510 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
512 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, "und");
514 // look for a codec id string specific to mkv to use, if none are found, use AVI codes
515 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
516 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
517 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
524 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
525 if (put_xiph_codecpriv(pb, codec) < 0)
527 } else if (codec->codec_id == CODEC_ID_FLAC) {
528 if (put_flac_codecpriv(pb, codec) < 0)
530 } else if (codec->extradata_size) {
531 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
535 switch (codec->codec_type) {
536 case CODEC_TYPE_VIDEO:
537 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
540 ebml_master bmp_header;
541 // if there is no mkv-specific codec id, use VFW mode
542 if (!codec->codec_tag)
543 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
545 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
546 bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
547 put_bmp_header(pb, codec, codec_bmp_tags, 0);
548 end_ebml_master(pb, bmp_header);
550 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
551 // XXX: interlace flag?
552 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
553 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
554 if (codec->sample_aspect_ratio.num) {
555 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , codec->sample_aspect_ratio.num);
556 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, codec->sample_aspect_ratio.den);
558 end_ebml_master(pb, subinfo);
561 case CODEC_TYPE_AUDIO:
562 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
565 ebml_master wav_header;
566 // no mkv-specific ID, use ACM mode
567 codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
568 if (!codec->codec_tag) {
569 av_log(s, AV_LOG_ERROR, "no codec id found for stream %d", i);
573 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
574 wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
575 put_wav_header(pb, codec);
576 end_ebml_master(pb, wav_header);
578 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
579 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
580 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
581 if (output_sample_rate)
582 put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
584 put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
585 end_ebml_master(pb, subinfo);
588 case CODEC_TYPE_SUBTITLE:
589 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
592 av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
595 end_ebml_master(pb, track);
597 // ms precision is the de-facto standard timescale for mkv files
598 av_set_pts_info(st, 64, 1, 1000);
600 end_ebml_master(pb, tracks);
604 static int mkv_write_header(AVFormatContext *s)
606 MatroskaMuxContext *mkv = s->priv_data;
607 ByteIOContext *pb = &s->pb;
608 ebml_master ebml_header, segment_info;
610 mkv->md5_ctx = av_mallocz(av_md5_size);
611 av_md5_init(mkv->md5_ctx);
613 ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
614 put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
615 put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
616 put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
617 put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
618 put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
619 put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
620 put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
621 end_ebml_master(pb, ebml_header);
623 mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
624 mkv->segment_offset = url_ftell(pb);
626 // we write 2 seek heads - one at the end of the file to point to each cluster, and
627 // one at the beginning to point to all other level one elements (including the seek
628 // head at the end of the file), which isn't more than 10 elements if we only write one
629 // of each other currently defined level 1 element
630 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
631 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
633 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb)) < 0)
636 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
637 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
638 if (strlen(s->title))
639 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
640 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
641 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
642 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
644 // reserve space to write the segment UID later
645 mkv->segment_uid = url_ftell(pb);
646 put_ebml_void(pb, 19);
649 // reserve space for the duration
651 mkv->duration_offset = url_ftell(pb);
652 put_ebml_void(pb, 11); // assumes double-precision float to be written
653 end_ebml_master(pb, segment_info);
655 if (mkv_write_tracks(s) < 0)
658 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
661 mkv->cluster_pos = url_ftell(pb);
662 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
663 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
664 mkv->cluster_pts = 0;
666 mkv->cues = mkv_start_cues(mkv->segment_offset);
667 if (mkv->cues == NULL)
673 static int mkv_block_size(AVPacket *pkt)
675 int size = 4; // track num + timecode + flags
676 return size + pkt->size;
679 static int mkv_blockgroup_size(AVPacket *pkt)
681 int size = mkv_block_size(pkt);
682 size += ebml_size_bytes(size);
683 size += 2; // EBML ID for block and block duration
684 size += 8; // max size of block duration
685 size += ebml_size_bytes(size);
686 size += 1; // blockgroup EBML ID
690 static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
692 MatroskaMuxContext *mkv = s->priv_data;
693 ByteIOContext *pb = &s->pb;
695 av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
696 url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
697 put_ebml_id(pb, blockid);
698 put_ebml_size(pb, mkv_block_size(pkt), 0);
699 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
700 put_be16(pb, pkt->pts - mkv->cluster_pts);
702 put_buffer(pb, pkt->data, pkt->size);
705 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
707 MatroskaMuxContext *mkv = s->priv_data;
708 ByteIOContext *pb = &s->pb;
709 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
710 int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
712 // start a new cluster every 5 MB or 5 sec
713 if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
714 av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64 " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
715 end_ebml_master(pb, mkv->cluster);
717 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
720 mkv->cluster_pos = url_ftell(pb);
721 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
722 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
723 mkv->cluster_pts = pkt->pts;
724 av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
727 if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
728 mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
730 ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
731 mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
732 put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
733 end_ebml_master(pb, blockgroup);
736 if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
737 if (mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos) < 0)
741 mkv->duration = pkt->pts + pkt->duration;
745 static int mkv_write_trailer(AVFormatContext *s)
747 MatroskaMuxContext *mkv = s->priv_data;
748 ByteIOContext *pb = &s->pb;
749 offset_t currentpos, second_seekhead, cuespos;
751 end_ebml_master(pb, mkv->cluster);
753 cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
754 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
756 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
757 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
758 mkv_write_seekhead(pb, mkv->main_seekhead);
760 // update the duration
761 av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
762 currentpos = url_ftell(pb);
763 url_fseek(pb, mkv->duration_offset, SEEK_SET);
764 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
766 // write the md5sum of some frames as the segment UID
767 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
768 uint8_t segment_uid[16];
769 av_md5_final(mkv->md5_ctx, segment_uid);
770 url_fseek(pb, mkv->segment_uid, SEEK_SET);
771 put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
773 url_fseek(pb, currentpos, SEEK_SET);
775 end_ebml_master(pb, mkv->segment);
776 av_free(mkv->md5_ctx);
780 AVOutputFormat matroska_muxer = {
782 "Matroska File Format",
785 sizeof(MatroskaMuxContext),
791 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
792 .subtitle_codec = CODEC_ID_TEXT,
795 AVOutputFormat matroska_audio_muxer = {
797 "Matroska File Format",
800 sizeof(MatroskaMuxContext),
806 .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},