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)
110 bytes = FFMIN(bytes, 8);
111 for (i = 0; i < bytes*7 + 1; i++)
113 for (i = bytes-1; i >= 0; i--)
114 put_byte(pb, value >> i*8);
118 * Calculate how many bytes are needed to represent a given size in EBML.
120 static int ebml_size_bytes(uint64_t size)
123 while ((size+1) >> bytes*7) bytes++;
128 * Write a size in EBML variable length format.
130 * @param bytes The number of bytes that need to be used to write the size.
131 * If zero, any number of bytes can be used.
133 static void put_ebml_size(ByteIOContext *pb, uint64_t size, int bytes)
135 int i, needed_bytes = ebml_size_bytes(size);
137 // sizes larger than this are currently undefined in EBML
138 // so write "unknown" size
139 if (size >= (1ULL<<56)-1) {
140 put_ebml_size_unknown(pb, 1);
145 // don't care how many bytes are used, so use the min
146 bytes = needed_bytes;
147 else if (needed_bytes > bytes) {
148 // the bytes needed to write the given size would exceed the bytes
149 // that we need to use, so write unknown size. This shouldn't happen.
150 av_log(NULL, AV_LOG_WARNING, "Size of %" PRIu64 " needs %d bytes but only %d bytes reserved\n",
151 size, needed_bytes, bytes);
152 put_ebml_size_unknown(pb, bytes);
156 size |= 1ULL << bytes*7;
157 for (i = bytes - 1; i >= 0; i--)
158 put_byte(pb, size >> i*8);
161 static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
164 while (val >> bytes*8) bytes++;
166 put_ebml_id(pb, elementid);
167 put_ebml_size(pb, bytes, 0);
168 for (i = bytes - 1; i >= 0; i--)
169 put_byte(pb, val >> i*8);
172 static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
174 put_ebml_id(pb, elementid);
175 put_ebml_size(pb, 8, 0);
176 put_be64(pb, av_dbl2int(val));
179 static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
180 const uint8_t *buf, int size)
182 put_ebml_id(pb, elementid);
183 put_ebml_size(pb, size, 0);
184 put_buffer(pb, buf, size);
187 static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
189 put_ebml_binary(pb, elementid, str, strlen(str));
193 * Writes a void element of a given size. Useful for reserving space in
194 * the file to be written to later.
196 * @param size The number of bytes to reserve, which must be at least 2.
198 static void put_ebml_void(ByteIOContext *pb, uint64_t size)
200 offset_t currentpos = url_ftell(pb);
205 put_ebml_id(pb, EBML_ID_VOID);
206 // we need to subtract the length needed to store the size from the
207 // size we need to reserve so 2 cases, we use 8 bytes to store the
208 // size if possible, 1 byte otherwise
210 put_ebml_size(pb, size-1, 0);
212 put_ebml_size(pb, size-9, 8);
213 url_fseek(pb, currentpos + size, SEEK_SET);
216 static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
218 int bytes = expectedsize ? ebml_size_bytes(expectedsize) : 8;
219 put_ebml_id(pb, elementid);
220 put_ebml_size_unknown(pb, bytes);
221 return (ebml_master){ url_ftell(pb), bytes };
224 static void end_ebml_master(ByteIOContext *pb, ebml_master master)
226 offset_t pos = url_ftell(pb);
228 url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
229 put_ebml_size(pb, pos - master.pos, master.sizebytes);
230 url_fseek(pb, pos, SEEK_SET);
233 static void put_xiph_size(ByteIOContext *pb, int size)
236 for (i = 0; i < size / 255; i++)
238 put_byte(pb, size % 255);
242 * Initialize a mkv_seekhead element to be ready to index level 1 Matroska
243 * elements. If a maximum number of elements is specified, enough space
244 * will be reserved at the current file location to write a seek head of
247 * @param segment_offset The absolute offset to the position in the file
248 * where the segment begins
249 * @param numelements the maximum number of elements that will be indexed
250 * by this seek head, 0 if unlimited.
252 static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_offset, int numelements)
254 mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
255 if (new_seekhead == NULL)
258 new_seekhead->segment_offset = segment_offset;
260 if (numelements > 0) {
261 new_seekhead->filepos = url_ftell(pb);
262 // 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID
263 // and size, and 3 bytes to guarantee that an EBML void element
264 // will fit afterwards
265 new_seekhead->reserved_size = numelements * MAX_SEEKENTRY_SIZE + 13;
266 new_seekhead->max_entries = numelements;
267 put_ebml_void(pb, new_seekhead->reserved_size);
272 static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
274 mkv_seekhead_entry *entries = seekhead->entries;
275 int new_entry = seekhead->num_entries;
277 // don't store more elements than we reserved space for
278 if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
281 entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
285 entries[new_entry].elementid = elementid;
286 entries[new_entry].segmentpos = filepos - seekhead->segment_offset;
288 seekhead->entries = entries;
289 seekhead->num_entries++;
295 * Write the seek head to the file and free it. If a maximum number of
296 * elements was specified to mkv_start_seekhead(), the seek head will
297 * be written at the location reserved for it. Otherwise, it is written
298 * at the current location in the file.
300 * @return the file offset where the seekhead was written
302 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
304 ebml_master metaseek, seekentry;
308 currentpos = url_ftell(pb);
310 if (seekhead->reserved_size > 0)
311 url_fseek(pb, seekhead->filepos, SEEK_SET);
313 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
314 for (i = 0; i < seekhead->num_entries; i++) {
315 mkv_seekhead_entry *entry = &seekhead->entries[i];
317 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
319 put_ebml_id(pb, MATROSKA_ID_SEEKID);
320 put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
321 put_ebml_id(pb, entry->elementid);
323 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
324 end_ebml_master(pb, seekentry);
326 end_ebml_master(pb, metaseek);
328 if (seekhead->reserved_size > 0) {
329 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
330 put_ebml_void(pb, remaining);
331 url_fseek(pb, currentpos, SEEK_SET);
333 currentpos = seekhead->filepos;
335 av_free(seekhead->entries);
341 static mkv_cues * mkv_start_cues(offset_t segment_offset)
343 mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
347 cues->segment_offset = segment_offset;
351 static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
353 mkv_cuepoint *entries = cues->entries;
354 int new_entry = cues->num_entries;
356 entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
360 entries[new_entry].pts = pkt->pts;
361 entries[new_entry].tracknum = pkt->stream_index + 1;
362 entries[new_entry].cluster_pos = cluster_pos - cues->segment_offset;
364 cues->entries = entries;
369 static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
371 ebml_master cues_element;
375 currentpos = url_ftell(pb);
376 cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
378 for (i = 0; i < cues->num_entries; i++) {
379 ebml_master cuepoint, track_positions;
380 mkv_cuepoint *entry = &cues->entries[i];
381 uint64_t pts = entry->pts;
383 cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
384 put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
386 // put all the entries from different tracks that have the exact same
387 // timestamp into the same CuePoint
388 for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
389 track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
390 put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
391 put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
392 end_ebml_master(pb, track_positions);
395 end_ebml_master(pb, cuepoint);
397 end_ebml_master(pb, cues_element);
399 av_free(cues->entries);
404 static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
406 ebml_master codecprivate;
407 uint8_t *header_start[3];
409 int first_header_size;
412 if (codec->codec_id == CODEC_ID_VORBIS)
413 first_header_size = 30;
415 first_header_size = 42;
417 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
418 first_header_size, header_start, header_len) < 0) {
419 av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
423 codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
424 put_byte(pb, 2); // number packets - 1
425 for (j = 0; j < 2; j++) {
426 put_xiph_size(pb, header_len[j]);
428 for (j = 0; j < 3; j++)
429 put_buffer(pb, header_start[j], header_len[j]);
430 end_ebml_master(pb, codecprivate);
435 #define FLAC_STREAMINFO_SIZE 34
437 static int put_flac_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
439 ebml_master codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
441 // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
442 // assume that it's in Matroska's format already
443 if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
444 av_log(codec, AV_LOG_ERROR, "Invalid FLAC extradata\n");
446 } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
447 // only the streaminfo packet
449 put_xiph_size(pb, codec->extradata_size);
450 av_log(codec, AV_LOG_ERROR, "Only one packet\n");
452 put_buffer(pb, codec->extradata, codec->extradata_size);
453 end_ebml_master(pb, codecpriv);
457 static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
459 static const int aac_sample_rates[] = {
460 96000, 88200, 64000, 48000, 44100, 32000,
461 24000, 22050, 16000, 12000, 11025, 8000,
465 if (codec->extradata_size < 2) {
466 av_log(codec, AV_LOG_WARNING, "no AAC extradata, unable to determine samplerate\n");
470 sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
472 av_log(codec, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
475 *sample_rate = aac_sample_rates[sri];
477 // if sbr, get output sample rate as well
478 if (codec->extradata_size == 5) {
479 sri = (codec->extradata[4] >> 3) & 0xF;
481 av_log(codec, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
484 *output_sample_rate = aac_sample_rates[sri];
488 static int mkv_write_tracks(AVFormatContext *s)
490 MatroskaMuxContext *mkv = s->priv_data;
491 ByteIOContext *pb = &s->pb;
495 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb)) < 0)
498 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
499 for (i = 0; i < s->nb_streams; i++) {
500 AVStream *st = s->streams[i];
501 AVCodecContext *codec = st->codec;
502 ebml_master subinfo, track;
504 int bit_depth = av_get_bits_per_sample(codec->codec_id);
505 int sample_rate = codec->sample_rate;
506 int output_sample_rate = 0;
509 bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
511 if (codec->codec_id == CODEC_ID_AAC)
512 get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
514 track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
515 put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
516 put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
517 put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
520 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
522 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, "und");
524 // look for a codec id string specific to mkv to use,
525 // if none are found, use AVI codes
526 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
527 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
528 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
535 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
536 if (put_xiph_codecpriv(pb, codec) < 0)
538 } else if (codec->codec_id == CODEC_ID_FLAC) {
539 if (put_flac_codecpriv(pb, codec) < 0)
541 } else if (codec->extradata_size) {
542 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
546 switch (codec->codec_type) {
547 case CODEC_TYPE_VIDEO:
548 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
551 ebml_master bmp_header;
552 // if there is no mkv-specific codec id, use VFW mode
553 if (!codec->codec_tag)
554 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
556 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
557 bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
558 put_bmp_header(pb, codec, codec_bmp_tags, 0);
559 end_ebml_master(pb, bmp_header);
561 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
562 // XXX: interlace flag?
563 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
564 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
565 if (codec->sample_aspect_ratio.num) {
566 AVRational dar = av_mul_q(codec->sample_aspect_ratio, (AVRational){codec->width, codec->height});
567 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , dar.num);
568 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, dar.den);
570 end_ebml_master(pb, subinfo);
573 case CODEC_TYPE_AUDIO:
574 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
577 ebml_master wav_header;
578 // no mkv-specific ID, use ACM mode
579 codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
580 if (!codec->codec_tag) {
581 av_log(s, AV_LOG_ERROR, "no codec id found for stream %d", i);
585 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
586 wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
587 put_wav_header(pb, codec);
588 end_ebml_master(pb, wav_header);
590 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
591 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
592 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
593 if (output_sample_rate)
594 put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
596 put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
597 end_ebml_master(pb, subinfo);
600 case CODEC_TYPE_SUBTITLE:
601 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
604 av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
607 end_ebml_master(pb, track);
609 // ms precision is the de-facto standard timescale for mkv files
610 av_set_pts_info(st, 64, 1, 1000);
612 end_ebml_master(pb, tracks);
616 static int mkv_write_header(AVFormatContext *s)
618 MatroskaMuxContext *mkv = s->priv_data;
619 ByteIOContext *pb = &s->pb;
620 ebml_master ebml_header, segment_info;
622 mkv->md5_ctx = av_mallocz(av_md5_size);
623 av_md5_init(mkv->md5_ctx);
625 ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
626 put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
627 put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
628 put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
629 put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
630 put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
631 put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
632 put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
633 end_ebml_master(pb, ebml_header);
635 mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
636 mkv->segment_offset = url_ftell(pb);
638 // we write 2 seek heads - one at the end of the file to point to each
639 // cluster, and one at the beginning to point to all other level one
640 // elements (including the seek head at the end of the file), which
641 // isn't more than 10 elements if we only write one of each other
642 // currently defined level 1 element
643 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
644 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
646 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb)) < 0)
649 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
650 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
651 if (strlen(s->title))
652 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
653 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
654 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
655 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
657 // reserve space to write the segment UID later
658 mkv->segment_uid = url_ftell(pb);
659 put_ebml_void(pb, 19);
662 // reserve space for the duration
664 mkv->duration_offset = url_ftell(pb);
665 put_ebml_void(pb, 11); // assumes double-precision float to be written
666 end_ebml_master(pb, segment_info);
668 if (mkv_write_tracks(s) < 0)
671 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
674 mkv->cluster_pos = url_ftell(pb);
675 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
676 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
677 mkv->cluster_pts = 0;
679 mkv->cues = mkv_start_cues(mkv->segment_offset);
680 if (mkv->cues == NULL)
686 static int mkv_block_size(AVPacket *pkt)
688 int size = 4; // track num + timecode + flags
689 return size + pkt->size;
692 static int mkv_blockgroup_size(AVPacket *pkt)
694 int size = mkv_block_size(pkt);
695 size += ebml_size_bytes(size);
696 size += 2; // EBML ID for block and block duration
697 size += 8; // max size of block duration
698 size += ebml_size_bytes(size);
699 size += 1; // blockgroup EBML ID
703 static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
705 MatroskaMuxContext *mkv = s->priv_data;
706 ByteIOContext *pb = &s->pb;
708 av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
709 url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
710 put_ebml_id(pb, blockid);
711 put_ebml_size(pb, mkv_block_size(pkt), 0);
712 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
713 put_be16(pb, pkt->pts - mkv->cluster_pts);
715 put_buffer(pb, pkt->data, pkt->size);
718 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
720 MatroskaMuxContext *mkv = s->priv_data;
721 ByteIOContext *pb = &s->pb;
722 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
723 int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
725 // start a new cluster every 5 MB or 5 sec
726 if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
727 av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64 " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
728 end_ebml_master(pb, mkv->cluster);
730 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
733 mkv->cluster_pos = url_ftell(pb);
734 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
735 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
736 mkv->cluster_pts = pkt->pts;
737 av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
740 if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
741 mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
743 ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
744 mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
745 put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
746 end_ebml_master(pb, blockgroup);
749 if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
750 if (mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos) < 0)
754 mkv->duration = pkt->pts + pkt->duration;
758 static int mkv_write_trailer(AVFormatContext *s)
760 MatroskaMuxContext *mkv = s->priv_data;
761 ByteIOContext *pb = &s->pb;
762 offset_t currentpos, second_seekhead, cuespos;
764 end_ebml_master(pb, mkv->cluster);
766 cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
767 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
769 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
770 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
771 mkv_write_seekhead(pb, mkv->main_seekhead);
773 // update the duration
774 av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
775 currentpos = url_ftell(pb);
776 url_fseek(pb, mkv->duration_offset, SEEK_SET);
777 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
779 // write the md5sum of some frames as the segment UID
780 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
781 uint8_t segment_uid[16];
782 av_md5_final(mkv->md5_ctx, segment_uid);
783 url_fseek(pb, mkv->segment_uid, SEEK_SET);
784 put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
786 url_fseek(pb, currentpos, SEEK_SET);
788 end_ebml_master(pb, mkv->segment);
789 av_free(mkv->md5_ctx);
793 AVOutputFormat matroska_muxer = {
795 "Matroska File Format",
798 sizeof(MatroskaMuxContext),
804 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
805 .subtitle_codec = CODEC_ID_TEXT,
808 AVOutputFormat matroska_audio_muxer = {
810 "Matroska File Format",
813 sizeof(MatroskaMuxContext),
819 .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},