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
77 * offset, 4 bytes for target EBML ID */
78 #define MAX_SEEKENTRY_SIZE 21
80 /** per-cuepoint-track - 3 1-byte EBML IDs, 3 1-byte EBML sizes, 2
82 #define MAX_CUETRACKPOS_SIZE 22
84 /** per-cuepoint - 2 1-byte EBML IDs, 2 1-byte EBML sizes, 8-byte uint max */
85 #define MAX_CUEPOINT_SIZE(num_tracks) 12 + MAX_CUETRACKPOS_SIZE*num_tracks
88 static int ebml_id_size(unsigned int id)
90 return (av_log2(id+1)-1)/7+1;
93 static void put_ebml_id(ByteIOContext *pb, unsigned int id)
95 int i = ebml_id_size(id);
97 put_byte(pb, id >> (i*8));
101 * Write an EBML size meaning "unknown size"
103 * @param bytes The number of bytes the size should occupy. Maximum of 8.
105 static void put_ebml_size_unknown(ByteIOContext *pb, int bytes)
108 put_byte(pb, 0x1ff >> bytes);
114 * Calculate how many bytes are needed to represent a given size in EBML.
116 static int ebml_size_bytes(uint64_t size)
119 while ((size+1) >> bytes*7) bytes++;
124 * Write a size in EBML variable length format.
126 * @param bytes The number of bytes that need to be used to write the size.
127 * If zero, any number of bytes can be used.
129 static void put_ebml_size(ByteIOContext *pb, uint64_t size, int bytes)
131 int i, needed_bytes = ebml_size_bytes(size);
133 // sizes larger than this are currently undefined in EBML
134 // so write "unknown" size
135 if (size >= (1ULL<<56)-1) {
136 put_ebml_size_unknown(pb, 1);
141 // don't care how many bytes are used, so use the min
142 bytes = needed_bytes;
143 // the bytes needed to write the given size would exceed the bytes
144 // that we need to use, so write unknown size. This shouldn't happen.
145 assert(bytes >= needed_bytes);
147 size |= 1ULL << bytes*7;
148 for (i = bytes - 1; i >= 0; i--)
149 put_byte(pb, size >> i*8);
152 static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
155 while (val >> bytes*8) bytes++;
157 put_ebml_id(pb, elementid);
158 put_ebml_size(pb, bytes, 0);
159 for (i = bytes - 1; i >= 0; i--)
160 put_byte(pb, val >> i*8);
163 static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
165 put_ebml_id(pb, elementid);
166 put_ebml_size(pb, 8, 0);
167 put_be64(pb, av_dbl2int(val));
170 static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
171 const uint8_t *buf, int size)
173 put_ebml_id(pb, elementid);
174 put_ebml_size(pb, size, 0);
175 put_buffer(pb, buf, size);
178 static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
180 put_ebml_binary(pb, elementid, str, strlen(str));
184 * Writes a void element of a given size. Useful for reserving space in
185 * the file to be written to later.
187 * @param size The number of bytes to reserve, which must be at least 2.
189 static void put_ebml_void(ByteIOContext *pb, uint64_t size)
191 offset_t currentpos = url_ftell(pb);
195 put_ebml_id(pb, EBML_ID_VOID);
196 // we need to subtract the length needed to store the size from the
197 // size we need to reserve so 2 cases, we use 8 bytes to store the
198 // size if possible, 1 byte otherwise
200 put_ebml_size(pb, size-1, 0);
202 put_ebml_size(pb, size-9, 8);
203 url_fseek(pb, currentpos + size, SEEK_SET);
206 static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
208 int bytes = expectedsize ? ebml_size_bytes(expectedsize) : 8;
209 put_ebml_id(pb, elementid);
210 put_ebml_size_unknown(pb, bytes);
211 return (ebml_master){ url_ftell(pb), bytes };
214 static void end_ebml_master(ByteIOContext *pb, ebml_master master)
216 offset_t pos = url_ftell(pb);
218 url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
219 put_ebml_size(pb, pos - master.pos, master.sizebytes);
220 url_fseek(pb, pos, SEEK_SET);
223 static void put_xiph_size(ByteIOContext *pb, int size)
226 for (i = 0; i < size / 255; i++)
228 put_byte(pb, size % 255);
232 * Initialize a mkv_seekhead element to be ready to index level 1 Matroska
233 * elements. If a maximum number of elements is specified, enough space
234 * will be reserved at the current file location to write a seek head of
237 * @param segment_offset The absolute offset to the position in the file
238 * where the segment begins
239 * @param numelements the maximum number of elements that will be indexed
240 * by this seek head, 0 if unlimited.
242 static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_offset, int numelements)
244 mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
245 if (new_seekhead == NULL)
248 new_seekhead->segment_offset = segment_offset;
250 if (numelements > 0) {
251 new_seekhead->filepos = url_ftell(pb);
252 // 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID
253 // and size, and 3 bytes to guarantee that an EBML void element
254 // will fit afterwards
255 new_seekhead->reserved_size = numelements * MAX_SEEKENTRY_SIZE + 13;
256 new_seekhead->max_entries = numelements;
257 put_ebml_void(pb, new_seekhead->reserved_size);
262 static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
264 mkv_seekhead_entry *entries = seekhead->entries;
266 // don't store more elements than we reserved space for
267 if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
270 entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
272 return AVERROR(ENOMEM);
274 entries[seekhead->num_entries ].elementid = elementid;
275 entries[seekhead->num_entries++].segmentpos = filepos - seekhead->segment_offset;
277 seekhead->entries = entries;
283 * Write the seek head to the file and free it. If a maximum number of
284 * elements was specified to mkv_start_seekhead(), the seek head will
285 * be written at the location reserved for it. Otherwise, it is written
286 * at the current location in the file.
288 * @return the file offset where the seekhead was written
290 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
292 ebml_master metaseek, seekentry;
296 currentpos = url_ftell(pb);
298 if (seekhead->reserved_size > 0)
299 url_fseek(pb, seekhead->filepos, SEEK_SET);
301 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
302 for (i = 0; i < seekhead->num_entries; i++) {
303 mkv_seekhead_entry *entry = &seekhead->entries[i];
305 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
307 put_ebml_id(pb, MATROSKA_ID_SEEKID);
308 put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
309 put_ebml_id(pb, entry->elementid);
311 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
312 end_ebml_master(pb, seekentry);
314 end_ebml_master(pb, metaseek);
316 if (seekhead->reserved_size > 0) {
317 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
318 put_ebml_void(pb, remaining);
319 url_fseek(pb, currentpos, SEEK_SET);
321 currentpos = seekhead->filepos;
323 av_free(seekhead->entries);
329 static mkv_cues * mkv_start_cues(offset_t segment_offset)
331 mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
335 cues->segment_offset = segment_offset;
339 static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
341 mkv_cuepoint *entries = cues->entries;
343 entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
345 return AVERROR(ENOMEM);
347 entries[cues->num_entries ].pts = pkt->pts;
348 entries[cues->num_entries ].tracknum = pkt->stream_index + 1;
349 entries[cues->num_entries++].cluster_pos = cluster_pos - cues->segment_offset;
351 cues->entries = entries;
355 static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
357 ebml_master cues_element;
361 currentpos = url_ftell(pb);
362 cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
364 for (i = 0; i < cues->num_entries; i++) {
365 ebml_master cuepoint, track_positions;
366 mkv_cuepoint *entry = &cues->entries[i];
367 uint64_t pts = entry->pts;
369 cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
370 put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
372 // put all the entries from different tracks that have the exact same
373 // timestamp into the same CuePoint
374 for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
375 track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
376 put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
377 put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
378 end_ebml_master(pb, track_positions);
381 end_ebml_master(pb, cuepoint);
383 end_ebml_master(pb, cues_element);
385 av_free(cues->entries);
390 static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
392 ebml_master codecprivate;
393 uint8_t *header_start[3];
395 int first_header_size;
398 if (codec->codec_id == CODEC_ID_VORBIS)
399 first_header_size = 30;
401 first_header_size = 42;
403 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
404 first_header_size, header_start, header_len) < 0) {
405 av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
409 codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
410 put_byte(pb, 2); // number packets - 1
411 for (j = 0; j < 2; j++) {
412 put_xiph_size(pb, header_len[j]);
414 for (j = 0; j < 3; j++)
415 put_buffer(pb, header_start[j], header_len[j]);
416 end_ebml_master(pb, codecprivate);
421 #define FLAC_STREAMINFO_SIZE 34
423 static int put_flac_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
425 ebml_master codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
427 // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
428 // assume that it's in Matroska's format already
429 if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
430 av_log(codec, AV_LOG_ERROR, "Invalid FLAC extradata\n");
432 } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
433 // only the streaminfo packet
435 put_xiph_size(pb, codec->extradata_size);
436 av_log(codec, AV_LOG_ERROR, "Only one packet\n");
438 put_buffer(pb, codec->extradata, codec->extradata_size);
439 end_ebml_master(pb, codecpriv);
443 static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
445 static const int aac_sample_rates[] = {
446 96000, 88200, 64000, 48000, 44100, 32000,
447 24000, 22050, 16000, 12000, 11025, 8000,
451 if (codec->extradata_size < 2) {
452 av_log(codec, AV_LOG_WARNING, "no AAC extradata, unable to determine samplerate\n");
456 sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
458 av_log(codec, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
461 *sample_rate = aac_sample_rates[sri];
463 // if sbr, get output sample rate as well
464 if (codec->extradata_size == 5) {
465 sri = (codec->extradata[4] >> 3) & 0xF;
467 av_log(codec, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
470 *output_sample_rate = aac_sample_rates[sri];
474 static int mkv_write_tracks(AVFormatContext *s)
476 MatroskaMuxContext *mkv = s->priv_data;
477 ByteIOContext *pb = &s->pb;
481 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb));
482 if (ret < 0) return ret;
484 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
485 for (i = 0; i < s->nb_streams; i++) {
486 AVStream *st = s->streams[i];
487 AVCodecContext *codec = st->codec;
488 ebml_master subinfo, track;
490 int bit_depth = av_get_bits_per_sample(codec->codec_id);
491 int sample_rate = codec->sample_rate;
492 int output_sample_rate = 0;
495 bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
497 if (codec->codec_id == CODEC_ID_AAC)
498 get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
500 track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
501 put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
502 put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
503 put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
506 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
508 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, "und");
510 // look for a codec id string specific to mkv to use,
511 // if none are found, use AVI codes
512 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
513 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
514 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
521 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
522 ret = put_xiph_codecpriv(pb, codec);
523 if (ret < 0) return ret;
524 } else if (codec->codec_id == CODEC_ID_FLAC) {
525 ret = put_flac_codecpriv(pb, codec);
526 if (ret < 0) return ret;
527 } else if (codec->extradata_size) {
528 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
532 switch (codec->codec_type) {
533 case CODEC_TYPE_VIDEO:
534 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
537 ebml_master bmp_header;
538 // if there is no mkv-specific codec id, use VFW mode
539 if (!codec->codec_tag)
540 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
542 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
543 bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
544 put_bmp_header(pb, codec, codec_bmp_tags, 0);
545 end_ebml_master(pb, bmp_header);
547 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
548 // XXX: interlace flag?
549 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
550 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
551 if (codec->sample_aspect_ratio.num) {
552 AVRational dar = av_mul_q(codec->sample_aspect_ratio,
553 (AVRational){codec->width, codec->height});
554 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , dar.num);
555 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, dar.den);
557 end_ebml_master(pb, subinfo);
560 case CODEC_TYPE_AUDIO:
561 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
564 ebml_master wav_header;
565 // no mkv-specific ID, use ACM mode
566 codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
567 if (!codec->codec_tag) {
568 av_log(s, AV_LOG_ERROR, "no codec id found for stream %d", i);
572 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
573 wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
574 put_wav_header(pb, codec);
575 end_ebml_master(pb, wav_header);
577 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
578 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
579 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
580 if (output_sample_rate)
581 put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
583 put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
584 end_ebml_master(pb, subinfo);
587 case CODEC_TYPE_SUBTITLE:
588 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
591 av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.");
594 end_ebml_master(pb, track);
596 // ms precision is the de-facto standard timescale for mkv files
597 av_set_pts_info(st, 64, 1, 1000);
599 end_ebml_master(pb, tracks);
603 static int mkv_write_header(AVFormatContext *s)
605 MatroskaMuxContext *mkv = s->priv_data;
606 ByteIOContext *pb = &s->pb;
607 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
627 // cluster, and one at the beginning to point to all other level one
628 // elements (including the seek head at the end of the file), which
629 // isn't more than 10 elements if we only write one of each other
630 // currently defined level 1 element
631 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
632 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
633 if (mkv->main_seekhead == NULL || mkv->cluster_seekhead == NULL)
634 return AVERROR(ENOMEM);
636 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb));
637 if (ret < 0) return ret;
639 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
640 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
641 if (strlen(s->title))
642 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
643 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
644 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
645 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
647 // reserve space to write the segment UID later
648 mkv->segment_uid = url_ftell(pb);
649 put_ebml_void(pb, 19);
652 // reserve space for the duration
654 mkv->duration_offset = url_ftell(pb);
655 put_ebml_void(pb, 11); // assumes double-precision float to be written
656 end_ebml_master(pb, segment_info);
658 ret = mkv_write_tracks(s);
659 if (ret < 0) return ret;
661 ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
662 if (ret < 0) return ret;
664 mkv->cluster_pos = url_ftell(pb);
665 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
666 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
667 mkv->cluster_pts = 0;
669 mkv->cues = mkv_start_cues(mkv->segment_offset);
670 if (mkv->cues == NULL)
671 return AVERROR(ENOMEM);
676 static int mkv_block_size(AVPacket *pkt)
678 int size = 4; // track num + timecode + flags
679 return size + pkt->size;
682 static int mkv_blockgroup_size(AVPacket *pkt)
684 int size = mkv_block_size(pkt);
685 size += ebml_size_bytes(size);
686 size += 2; // EBML ID for block and block duration
687 size += 8; // max size of block duration
688 size += ebml_size_bytes(size);
689 size += 1; // blockgroup EBML ID
693 static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
695 MatroskaMuxContext *mkv = s->priv_data;
696 ByteIOContext *pb = &s->pb;
698 av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, "
699 "pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
700 url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
701 put_ebml_id(pb, blockid);
702 put_ebml_size(pb, mkv_block_size(pkt), 0);
703 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
704 put_be16(pb, pkt->pts - mkv->cluster_pts);
706 put_buffer(pb, pkt->data, pkt->size);
709 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
711 MatroskaMuxContext *mkv = s->priv_data;
712 ByteIOContext *pb = &s->pb;
713 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
714 int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
717 // start a new cluster every 5 MB or 5 sec
718 if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
719 av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64
720 " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
721 end_ebml_master(pb, mkv->cluster);
723 ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
724 if (ret < 0) return ret;
726 mkv->cluster_pos = url_ftell(pb);
727 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
728 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
729 mkv->cluster_pts = pkt->pts;
730 av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
733 if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
734 mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
736 ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
737 mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
738 put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
739 end_ebml_master(pb, blockgroup);
742 if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
743 ret = mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos);
744 if (ret < 0) return ret;
747 mkv->duration = FFMAX(mkv->duration, pkt->pts + pkt->duration);
751 static int mkv_write_trailer(AVFormatContext *s)
753 MatroskaMuxContext *mkv = s->priv_data;
754 ByteIOContext *pb = &s->pb;
755 offset_t currentpos, second_seekhead, cuespos;
758 end_ebml_master(pb, mkv->cluster);
760 cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
761 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
763 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
764 if (ret < 0) return ret;
765 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
766 if (ret < 0) return ret;
767 mkv_write_seekhead(pb, mkv->main_seekhead);
769 // update the duration
770 av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
771 currentpos = url_ftell(pb);
772 url_fseek(pb, mkv->duration_offset, SEEK_SET);
773 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
775 // write the md5sum of some frames as the segment UID
776 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
777 uint8_t segment_uid[16];
778 av_md5_final(mkv->md5_ctx, segment_uid);
779 url_fseek(pb, mkv->segment_uid, SEEK_SET);
780 put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
782 url_fseek(pb, currentpos, SEEK_SET);
784 end_ebml_master(pb, mkv->segment);
785 av_free(mkv->md5_ctx);
789 AVOutputFormat matroska_muxer = {
791 "Matroska File Format",
794 sizeof(MatroskaMuxContext),
800 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
801 .subtitle_codec = CODEC_ID_TEXT,
804 AVOutputFormat matroska_audio_muxer = {
806 "Matroska File Format",
809 sizeof(MatroskaMuxContext),
815 .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},