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
27 typedef struct mkv_seekhead_entry {
28 unsigned int elementid;
32 typedef struct mkv_seekhead {
34 offset_t segment_offset; ///< the file offset to the beginning of the segment
35 int reserved_size; ///< -1 if appending to file
37 mkv_seekhead_entry *entries;
44 offset_t cluster_pos; ///< file offset of the cluster containing the block
48 offset_t segment_offset;
49 mkv_cuepoint *entries;
53 typedef struct MatroskaMuxContext {
55 offset_t segment_offset;
57 offset_t cluster_pos; ///< file offset of the current cluster
59 offset_t duration_offset;
61 mkv_seekhead *main_seekhead;
62 mkv_seekhead *cluster_seekhead;
66 static void put_ebml_id(ByteIOContext *pb, unsigned int id)
69 put_byte(pb, id >> 24);
71 put_byte(pb, id >> 16);
73 put_byte(pb, id >> 8);
77 static int ebml_id_size(unsigned int id)
79 return (av_log2(id+1)-1)/7+1;
82 // XXX: test this thoroughly and get rid of minbytes hack (currently needed to
83 // use up all of the space reserved in start_ebml_master)
84 static void put_ebml_size(ByteIOContext *pb, uint64_t size, int minbytes)
88 // sizes larger than this are currently undefined in EBML
89 // so write "unknown" size
90 size = FFMIN(size, (1ULL<<56)-1);
92 while (size >> (bytes*7 + 7)) bytes++;
94 put_byte(pb, (0x80 >> bytes) | (size >> bytes*8));
95 for (bytes -= 1; bytes >= 0; bytes--)
96 put_byte(pb, size >> bytes*8);
99 static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
102 while (val >> bytes*8) bytes++;
104 put_ebml_id(pb, elementid);
105 put_ebml_size(pb, bytes, 0);
106 for (bytes -= 1; bytes >= 0; bytes--)
107 put_byte(pb, val >> bytes*8);
110 static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
112 put_ebml_id(pb, elementid);
113 put_ebml_size(pb, 8, 0);
114 put_be64(pb, av_dbl2int(val));
117 static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
118 const uint8_t *buf, int size)
120 put_ebml_id(pb, elementid);
121 put_ebml_size(pb, size, 0);
122 put_buffer(pb, buf, size);
125 static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
127 put_ebml_binary(pb, elementid, str, strlen(str));
130 // avtime is POSIX time, microseconds
131 static void put_ebml_date(ByteIOContext *pb, unsigned int elementid, int64_t avtime)
133 // midnight Jan 1, 1970 in UNIX epoch, microseconds
134 const int64_t ebmlDateStart = 978307200ULL * 1000000;
135 int64_t ebmlTime = (avtime - ebmlDateStart) * 1000;
137 put_ebml_id(pb, elementid);
138 put_ebml_size(pb, 8, 0);
139 put_be64(pb, ebmlTime);
142 // this reserves exactly the amount of space specified by size, which must be at least 2
143 static void put_ebml_void(ByteIOContext *pb, uint64_t size)
145 offset_t currentpos = url_ftell(pb);
150 put_ebml_id(pb, EBML_ID_VOID);
151 // we need to subtract the length needed to store the size from the size we need to reserve
152 // so 2 cases, we use 8 bytes to store the size if possible, 1 byte otherwise
154 put_ebml_size(pb, size-1, 0);
156 put_ebml_size(pb, size-9, 7);
157 url_fseek(pb, currentpos + size, SEEK_SET);
160 static offset_t start_ebml_master(ByteIOContext *pb, unsigned int elementid)
162 put_ebml_id(pb, elementid);
163 // XXX: this always reserves the maximum needed space to store any size value
164 // we should be smarter (additional parameter for expected size?)
165 put_ebml_size(pb, (1ULL<<56)-1, 0); // largest unknown size
166 return url_ftell(pb);
169 static void end_ebml_master(ByteIOContext *pb, offset_t start)
171 offset_t pos = url_ftell(pb);
173 url_fseek(pb, start - 8, SEEK_SET);
174 put_ebml_size(pb, pos - start, 7);
175 url_fseek(pb, pos, SEEK_SET);
178 // initializes a mkv_seekhead element to be ready to index level 1 matroska elements
179 // if numelements is greater than 0, it reserves enough space for that many elements
180 // at the current file position and writes the seekhead there, otherwise the seekhead
181 // will be appended to the file when end_mkv_seekhead() is called
182 static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_offset, int numelements)
184 mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
185 if (new_seekhead == NULL)
188 new_seekhead->segment_offset = segment_offset;
190 if (numelements > 0) {
191 new_seekhead->filepos = url_ftell(pb);
192 // 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID and size,
193 // and 3 bytes to guarantee that an EBML void element will fit afterwards
194 // XXX: 28 bytes right now because begin_ebml_master() reserves more than necessary
195 new_seekhead->reserved_size = numelements * 28 + 13;
196 new_seekhead->max_entries = numelements;
197 put_ebml_void(pb, new_seekhead->reserved_size);
202 static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
204 mkv_seekhead_entry *entries = seekhead->entries;
205 int new_entry = seekhead->num_entries;
207 // don't store more elements than we reserved space for
208 if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
211 entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
215 entries[new_entry].elementid = elementid;
216 entries[new_entry].segmentpos = filepos - seekhead->segment_offset;
218 seekhead->entries = entries;
219 seekhead->num_entries++;
224 // returns the file offset where the seekhead was written and frees the seekhead
225 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
227 offset_t metaseek, seekentry, currentpos;
230 currentpos = url_ftell(pb);
232 if (seekhead->reserved_size > 0)
233 url_fseek(pb, seekhead->filepos, SEEK_SET);
235 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD);
236 for (i = 0; i < seekhead->num_entries; i++) {
237 mkv_seekhead_entry *entry = &seekhead->entries[i];
239 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY);
241 put_ebml_id(pb, MATROSKA_ID_SEEKID);
242 put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
243 put_ebml_id(pb, entry->elementid);
245 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
246 end_ebml_master(pb, seekentry);
248 end_ebml_master(pb, metaseek);
250 if (seekhead->reserved_size > 0) {
251 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
252 put_ebml_void(pb, remaining);
253 url_fseek(pb, currentpos, SEEK_SET);
255 currentpos = seekhead->filepos;
257 av_free(seekhead->entries);
263 static mkv_cues * mkv_start_cues(offset_t segment_offset)
265 mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
269 cues->segment_offset = segment_offset;
273 static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
275 mkv_cuepoint *entries = cues->entries;
276 int new_entry = cues->num_entries;
278 entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
282 entries[new_entry].pts = pkt->pts;
283 entries[new_entry].tracknum = pkt->stream_index + 1;
284 entries[new_entry].cluster_pos = cluster_pos - cues->segment_offset;
286 cues->entries = entries;
291 static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues)
293 offset_t currentpos, cues_element;
296 currentpos = url_ftell(pb);
297 cues_element = start_ebml_master(pb, MATROSKA_ID_CUES);
299 for (i = 0; i < cues->num_entries; i++) {
300 offset_t cuepoint, track_positions;
301 mkv_cuepoint *entry = &cues->entries[i];
302 uint64_t pts = entry->pts;
304 cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY);
305 put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
307 // put all the entries from different tracks that have the exact same
308 // timestamp into the same CuePoint
309 for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
310 track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION);
311 put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
312 put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
313 end_ebml_master(pb, track_positions);
316 end_ebml_master(pb, cuepoint);
318 end_ebml_master(pb, cues_element);
320 av_free(cues->entries);
325 static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
327 offset_t codecprivate;
328 uint8_t *header_start[3];
330 int first_header_size;
333 if (codec->codec_id == CODEC_ID_VORBIS)
334 first_header_size = 30;
336 first_header_size = 42;
338 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
339 first_header_size, header_start, header_len) < 0) {
340 av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
344 codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
345 put_byte(pb, 2); // number packets - 1
346 for (j = 0; j < 2; j++) {
347 for (k = 0; k < header_len[j] / 255; k++)
349 put_byte(pb, header_len[j] % 255);
351 for (j = 0; j < 3; j++)
352 put_buffer(pb, header_start[j], header_len[j]);
353 end_ebml_master(pb, codecprivate);
358 static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
360 static const int aac_sample_rates[] = {
361 96000, 88200, 64000, 48000, 44100, 32000,
362 24000, 22050, 16000, 12000, 11025, 8000,
366 if (codec->extradata_size < 2) {
367 av_log(codec, AV_LOG_WARNING, "no aac extradata, unable to determine sample rate\n");
371 sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
373 av_log(codec, AV_LOG_WARNING, "aac samplerate index out of bounds\n");
376 *sample_rate = aac_sample_rates[sri];
378 // if sbr, get output sample rate as well
379 if (codec->extradata_size == 5) {
380 sri = (codec->extradata[4] >> 3) & 0xF;
382 av_log(codec, AV_LOG_WARNING, "aac output samplerate index out of bounds\n");
385 *output_sample_rate = aac_sample_rates[sri];
389 static int mkv_write_tracks(AVFormatContext *s)
391 MatroskaMuxContext *mkv = s->priv_data;
392 ByteIOContext *pb = &s->pb;
396 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb)) < 0)
399 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS);
400 for (i = 0; i < s->nb_streams; i++) {
401 AVStream *st = s->streams[i];
402 AVCodecContext *codec = st->codec;
403 offset_t subinfo, track;
405 int bit_depth = av_get_bits_per_sample(codec->codec_id);
406 int sample_rate = codec->sample_rate;
407 int output_sample_rate = 0;
409 if (codec->codec_id == CODEC_ID_AAC)
410 get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
412 track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
413 put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
414 put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
415 put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
418 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
420 // look for a codec id string specific to mkv to use, if none are found, use AVI codes
421 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
422 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
423 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
429 // XXX: CodecPrivate for vorbis, theora, aac, native mpeg4, ...
431 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
432 if (put_xiph_codecpriv(pb, codec) < 0)
434 } else if (codec->extradata_size) {
435 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
439 switch (codec->codec_type) {
440 case CODEC_TYPE_VIDEO:
441 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
445 // if there is no mkv-specific codec id, use VFW mode
446 if (!codec->codec_tag)
447 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
449 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
450 bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
451 put_bmp_header(pb, codec, codec_bmp_tags, 0);
452 end_ebml_master(pb, bmp_header);
454 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO);
455 // XXX: interlace flag?
456 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
457 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
458 // XXX: display width/height
459 end_ebml_master(pb, subinfo);
462 case CODEC_TYPE_AUDIO:
463 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
467 // no mkv-specific ID, use ACM mode
468 codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
469 if (!codec->codec_tag) {
470 av_log(s, AV_LOG_ERROR, "no codec id found for stream %d", i);
474 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
475 wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
476 put_wav_header(pb, codec);
477 end_ebml_master(pb, wav_header);
479 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO);
480 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
481 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
482 if (output_sample_rate)
483 put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
485 put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
486 end_ebml_master(pb, subinfo);
489 case CODEC_TYPE_SUBTITLE:
490 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
493 av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
496 end_ebml_master(pb, track);
498 // ms precision is the de-facto standard timescale for mkv files
499 av_set_pts_info(st, 64, 1, 1000);
501 end_ebml_master(pb, tracks);
505 static int mkv_write_header(AVFormatContext *s)
507 MatroskaMuxContext *mkv = s->priv_data;
508 ByteIOContext *pb = &s->pb;
509 offset_t ebml_header, segment_info;
511 ebml_header = start_ebml_master(pb, EBML_ID_HEADER);
512 put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
513 put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
514 put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
515 put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
516 put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
517 put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
518 put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
519 end_ebml_master(pb, ebml_header);
521 mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT);
522 mkv->segment_offset = url_ftell(pb);
524 // we write 2 seek heads - one at the end of the file to point to each cluster, and
525 // one at the beginning to point to all other level one elements (including the seek
526 // head at the end of the file), which isn't more than 10 elements if we only write one
527 // of each other currently defined level 1 element
528 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
529 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
531 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb)) < 0)
534 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO);
535 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
536 if (strlen(s->title))
537 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
538 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
539 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
540 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
541 put_ebml_date (pb, MATROSKA_ID_DATEUTC , av_gettime() );
544 // reserve space for the duration
546 mkv->duration_offset = url_ftell(pb);
547 put_ebml_void(pb, 11); // assumes double-precision float to be written
548 end_ebml_master(pb, segment_info);
550 if (mkv_write_tracks(s) < 0)
553 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
556 mkv->cluster_pos = url_ftell(pb);
557 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
558 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
559 mkv->cluster_pts = 0;
561 mkv->cues = mkv_start_cues(mkv->segment_offset);
562 if (mkv->cues == NULL)
568 static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
570 MatroskaMuxContext *mkv = s->priv_data;
571 ByteIOContext *pb = &s->pb;
573 put_ebml_id(pb, blockid);
574 put_ebml_size(pb, pkt->size + 4, 0);
575 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
576 put_be16(pb, pkt->pts - mkv->cluster_pts);
578 put_buffer(pb, pkt->data, pkt->size);
581 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
583 MatroskaMuxContext *mkv = s->priv_data;
584 ByteIOContext *pb = &s->pb;
585 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
586 int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
588 // start a new cluster every 5 MB or 5 sec
589 if (url_ftell(pb) > mkv->cluster + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
590 end_ebml_master(pb, mkv->cluster);
592 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
595 mkv->cluster_pos = url_ftell(pb);
596 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
597 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
598 mkv->cluster_pts = pkt->pts;
601 if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
602 mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
604 offset_t blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP);
605 mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
606 put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
607 end_ebml_master(pb, blockgroup);
610 if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
611 if (mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos) < 0)
615 mkv->duration = pkt->pts + pkt->duration;
619 static int mkv_write_trailer(AVFormatContext *s)
621 MatroskaMuxContext *mkv = s->priv_data;
622 ByteIOContext *pb = &s->pb;
623 offset_t currentpos, second_seekhead, cuespos;
625 end_ebml_master(pb, mkv->cluster);
627 cuespos = mkv_write_cues(pb, mkv->cues);
628 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
630 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
631 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
632 mkv_write_seekhead(pb, mkv->main_seekhead);
634 // update the duration
635 currentpos = url_ftell(pb);
636 url_fseek(pb, mkv->duration_offset, SEEK_SET);
637 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
638 url_fseek(pb, currentpos, SEEK_SET);
640 end_ebml_master(pb, mkv->segment);
644 AVOutputFormat matroska_muxer = {
646 "Matroska File Format",
649 sizeof(MatroskaMuxContext),
655 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},