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;
265 int new_entry = seekhead->num_entries;
267 // don't store more elements than we reserved space for
268 if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
271 entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
273 return AVERROR(ENOMEM);
275 entries[new_entry].elementid = elementid;
276 entries[new_entry].segmentpos = filepos - seekhead->segment_offset;
278 seekhead->entries = entries;
279 seekhead->num_entries++;
285 * Write the seek head to the file and free it. If a maximum number of
286 * elements was specified to mkv_start_seekhead(), the seek head will
287 * be written at the location reserved for it. Otherwise, it is written
288 * at the current location in the file.
290 * @return the file offset where the seekhead was written
292 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
294 ebml_master metaseek, seekentry;
298 currentpos = url_ftell(pb);
300 if (seekhead->reserved_size > 0)
301 url_fseek(pb, seekhead->filepos, SEEK_SET);
303 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
304 for (i = 0; i < seekhead->num_entries; i++) {
305 mkv_seekhead_entry *entry = &seekhead->entries[i];
307 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
309 put_ebml_id(pb, MATROSKA_ID_SEEKID);
310 put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
311 put_ebml_id(pb, entry->elementid);
313 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
314 end_ebml_master(pb, seekentry);
316 end_ebml_master(pb, metaseek);
318 if (seekhead->reserved_size > 0) {
319 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
320 put_ebml_void(pb, remaining);
321 url_fseek(pb, currentpos, SEEK_SET);
323 currentpos = seekhead->filepos;
325 av_free(seekhead->entries);
331 static mkv_cues * mkv_start_cues(offset_t segment_offset)
333 mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
337 cues->segment_offset = segment_offset;
341 static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
343 mkv_cuepoint *entries = cues->entries;
344 int new_entry = cues->num_entries;
346 entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
348 return AVERROR(ENOMEM);
350 entries[new_entry].pts = pkt->pts;
351 entries[new_entry].tracknum = pkt->stream_index + 1;
352 entries[new_entry].cluster_pos = cluster_pos - cues->segment_offset;
354 cues->entries = entries;
359 static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
361 ebml_master cues_element;
365 currentpos = url_ftell(pb);
366 cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
368 for (i = 0; i < cues->num_entries; i++) {
369 ebml_master cuepoint, track_positions;
370 mkv_cuepoint *entry = &cues->entries[i];
371 uint64_t pts = entry->pts;
373 cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
374 put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
376 // put all the entries from different tracks that have the exact same
377 // timestamp into the same CuePoint
378 for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
379 track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
380 put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
381 put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
382 end_ebml_master(pb, track_positions);
385 end_ebml_master(pb, cuepoint);
387 end_ebml_master(pb, cues_element);
389 av_free(cues->entries);
394 static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
396 ebml_master codecprivate;
397 uint8_t *header_start[3];
399 int first_header_size;
402 if (codec->codec_id == CODEC_ID_VORBIS)
403 first_header_size = 30;
405 first_header_size = 42;
407 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
408 first_header_size, header_start, header_len) < 0) {
409 av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
413 codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
414 put_byte(pb, 2); // number packets - 1
415 for (j = 0; j < 2; j++) {
416 put_xiph_size(pb, header_len[j]);
418 for (j = 0; j < 3; j++)
419 put_buffer(pb, header_start[j], header_len[j]);
420 end_ebml_master(pb, codecprivate);
425 #define FLAC_STREAMINFO_SIZE 34
427 static int put_flac_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
429 ebml_master codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
431 // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
432 // assume that it's in Matroska's format already
433 if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
434 av_log(codec, AV_LOG_ERROR, "Invalid FLAC extradata\n");
436 } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
437 // only the streaminfo packet
439 put_xiph_size(pb, codec->extradata_size);
440 av_log(codec, AV_LOG_ERROR, "Only one packet\n");
442 put_buffer(pb, codec->extradata, codec->extradata_size);
443 end_ebml_master(pb, codecpriv);
447 static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
449 static const int aac_sample_rates[] = {
450 96000, 88200, 64000, 48000, 44100, 32000,
451 24000, 22050, 16000, 12000, 11025, 8000,
455 if (codec->extradata_size < 2) {
456 av_log(codec, AV_LOG_WARNING, "no AAC extradata, unable to determine samplerate\n");
460 sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
462 av_log(codec, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
465 *sample_rate = aac_sample_rates[sri];
467 // if sbr, get output sample rate as well
468 if (codec->extradata_size == 5) {
469 sri = (codec->extradata[4] >> 3) & 0xF;
471 av_log(codec, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
474 *output_sample_rate = aac_sample_rates[sri];
478 static int mkv_write_tracks(AVFormatContext *s)
480 MatroskaMuxContext *mkv = s->priv_data;
481 ByteIOContext *pb = &s->pb;
485 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb));
486 if (ret < 0) return ret;
488 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
489 for (i = 0; i < s->nb_streams; i++) {
490 AVStream *st = s->streams[i];
491 AVCodecContext *codec = st->codec;
492 ebml_master subinfo, track;
494 int bit_depth = av_get_bits_per_sample(codec->codec_id);
495 int sample_rate = codec->sample_rate;
496 int output_sample_rate = 0;
499 bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
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,
515 // if none are found, use AVI codes
516 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
517 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
518 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
525 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
526 ret = put_xiph_codecpriv(pb, codec);
527 if (ret < 0) return ret;
528 } else if (codec->codec_id == CODEC_ID_FLAC) {
529 ret = put_flac_codecpriv(pb, codec);
530 if (ret < 0) return ret;
531 } else if (codec->extradata_size) {
532 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
536 switch (codec->codec_type) {
537 case CODEC_TYPE_VIDEO:
538 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
541 ebml_master bmp_header;
542 // if there is no mkv-specific codec id, use VFW mode
543 if (!codec->codec_tag)
544 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
546 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
547 bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
548 put_bmp_header(pb, codec, codec_bmp_tags, 0);
549 end_ebml_master(pb, bmp_header);
551 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
552 // XXX: interlace flag?
553 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
554 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
555 if (codec->sample_aspect_ratio.num) {
556 AVRational dar = av_mul_q(codec->sample_aspect_ratio, (AVRational){codec->width, codec->height});
557 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , dar.num);
558 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, dar.den);
560 end_ebml_master(pb, subinfo);
563 case CODEC_TYPE_AUDIO:
564 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
567 ebml_master wav_header;
568 // no mkv-specific ID, use ACM mode
569 codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
570 if (!codec->codec_tag) {
571 av_log(s, AV_LOG_ERROR, "no codec id found for stream %d", i);
575 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
576 wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
577 put_wav_header(pb, codec);
578 end_ebml_master(pb, wav_header);
580 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
581 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
582 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
583 if (output_sample_rate)
584 put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
586 put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
587 end_ebml_master(pb, subinfo);
590 case CODEC_TYPE_SUBTITLE:
591 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
594 av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.");
597 end_ebml_master(pb, track);
599 // ms precision is the de-facto standard timescale for mkv files
600 av_set_pts_info(st, 64, 1, 1000);
602 end_ebml_master(pb, tracks);
606 static int mkv_write_header(AVFormatContext *s)
608 MatroskaMuxContext *mkv = s->priv_data;
609 ByteIOContext *pb = &s->pb;
610 ebml_master ebml_header, segment_info;
613 mkv->md5_ctx = av_mallocz(av_md5_size);
614 av_md5_init(mkv->md5_ctx);
616 ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
617 put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
618 put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
619 put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
620 put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
621 put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
622 put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
623 put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
624 end_ebml_master(pb, ebml_header);
626 mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
627 mkv->segment_offset = url_ftell(pb);
629 // we write 2 seek heads - one at the end of the file to point to each
630 // cluster, and one at the beginning to point to all other level one
631 // elements (including the seek head at the end of the file), which
632 // isn't more than 10 elements if we only write one of each other
633 // currently defined level 1 element
634 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
635 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
636 if (mkv->main_seekhead == NULL || mkv->cluster_seekhead == NULL)
637 return AVERROR(ENOMEM);
639 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb));
640 if (ret < 0) return ret;
642 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
643 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
644 if (strlen(s->title))
645 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
646 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
647 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
648 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
650 // reserve space to write the segment UID later
651 mkv->segment_uid = url_ftell(pb);
652 put_ebml_void(pb, 19);
655 // reserve space for the duration
657 mkv->duration_offset = url_ftell(pb);
658 put_ebml_void(pb, 11); // assumes double-precision float to be written
659 end_ebml_master(pb, segment_info);
661 ret = mkv_write_tracks(s);
662 if (ret < 0) return ret;
664 ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
665 if (ret < 0) return ret;
667 mkv->cluster_pos = url_ftell(pb);
668 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
669 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
670 mkv->cluster_pts = 0;
672 mkv->cues = mkv_start_cues(mkv->segment_offset);
673 if (mkv->cues == NULL)
674 return AVERROR(ENOMEM);
679 static int mkv_block_size(AVPacket *pkt)
681 int size = 4; // track num + timecode + flags
682 return size + pkt->size;
685 static int mkv_blockgroup_size(AVPacket *pkt)
687 int size = mkv_block_size(pkt);
688 size += ebml_size_bytes(size);
689 size += 2; // EBML ID for block and block duration
690 size += 8; // max size of block duration
691 size += ebml_size_bytes(size);
692 size += 1; // blockgroup EBML ID
696 static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
698 MatroskaMuxContext *mkv = s->priv_data;
699 ByteIOContext *pb = &s->pb;
701 av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
702 url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
703 put_ebml_id(pb, blockid);
704 put_ebml_size(pb, mkv_block_size(pkt), 0);
705 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
706 put_be16(pb, pkt->pts - mkv->cluster_pts);
708 put_buffer(pb, pkt->data, pkt->size);
711 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
713 MatroskaMuxContext *mkv = s->priv_data;
714 ByteIOContext *pb = &s->pb;
715 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
716 int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
719 // start a new cluster every 5 MB or 5 sec
720 if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
721 av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64 " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
722 end_ebml_master(pb, mkv->cluster);
724 ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
725 if (ret < 0) return ret;
727 mkv->cluster_pos = url_ftell(pb);
728 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
729 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
730 mkv->cluster_pts = pkt->pts;
731 av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
734 if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
735 mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
737 ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
738 mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
739 put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
740 end_ebml_master(pb, blockgroup);
743 if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
744 ret = mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos);
745 if (ret < 0) return ret;
748 mkv->duration = pkt->pts + pkt->duration;
752 static int mkv_write_trailer(AVFormatContext *s)
754 MatroskaMuxContext *mkv = s->priv_data;
755 ByteIOContext *pb = &s->pb;
756 offset_t currentpos, second_seekhead, cuespos;
759 end_ebml_master(pb, mkv->cluster);
761 cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
762 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
764 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
765 if (ret < 0) return ret;
766 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
767 if (ret < 0) return ret;
768 mkv_write_seekhead(pb, mkv->main_seekhead);
770 // update the duration
771 av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
772 currentpos = url_ftell(pb);
773 url_fseek(pb, mkv->duration_offset, SEEK_SET);
774 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
776 // write the md5sum of some frames as the segment UID
777 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
778 uint8_t segment_uid[16];
779 av_md5_final(mkv->md5_ctx, segment_uid);
780 url_fseek(pb, mkv->segment_uid, SEEK_SET);
781 put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
783 url_fseek(pb, currentpos, SEEK_SET);
785 end_ebml_master(pb, mkv->segment);
786 av_free(mkv->md5_ctx);
790 AVOutputFormat matroska_muxer = {
792 "Matroska File Format",
795 sizeof(MatroskaMuxContext),
801 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
802 .subtitle_codec = CODEC_ID_TEXT,
805 AVOutputFormat matroska_audio_muxer = {
807 "Matroska File Format",
810 sizeof(MatroskaMuxContext),
816 .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},