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 #include "libavutil/md5.h"
28 #include "libavcodec/xiph.h"
29 #include "libavcodec/mpeg4audio.h"
31 typedef struct ebml_master {
32 offset_t pos; ///< absolute offset in the file where the master's elements start
33 int sizebytes; ///< how many bytes were reserved for the size
36 typedef struct mkv_seekhead_entry {
37 unsigned int elementid;
41 typedef struct mkv_seekhead {
43 offset_t segment_offset; ///< the file offset to the beginning of the segment
44 int reserved_size; ///< -1 if appending to file
46 mkv_seekhead_entry *entries;
53 offset_t cluster_pos; ///< file offset of the cluster containing the block
57 offset_t segment_offset;
58 mkv_cuepoint *entries;
62 typedef struct MatroskaMuxContext {
64 offset_t segment_offset;
67 offset_t cluster_pos; ///< file offset of the current cluster
69 offset_t duration_offset;
71 mkv_seekhead *main_seekhead;
72 mkv_seekhead *cluster_seekhead;
75 struct AVMD5 *md5_ctx;
79 /** 2 bytes * 3 for EBML IDs, 3 1-byte EBML lengths, 8 bytes for 64 bit
80 * offset, 4 bytes for target EBML ID */
81 #define MAX_SEEKENTRY_SIZE 21
83 /** per-cuepoint-track - 3 1-byte EBML IDs, 3 1-byte EBML sizes, 2
85 #define MAX_CUETRACKPOS_SIZE 22
87 /** per-cuepoint - 2 1-byte EBML IDs, 2 1-byte EBML sizes, 8-byte uint max */
88 #define MAX_CUEPOINT_SIZE(num_tracks) 12 + MAX_CUETRACKPOS_SIZE*num_tracks
91 static int ebml_id_size(unsigned int id)
93 return (av_log2(id+1)-1)/7+1;
96 static void put_ebml_id(ByteIOContext *pb, unsigned int id)
98 int i = ebml_id_size(id);
100 put_byte(pb, id >> (i*8));
104 * Write an EBML size meaning "unknown size".
106 * @param bytes The number of bytes the size should occupy (maximum: 8).
108 static void put_ebml_size_unknown(ByteIOContext *pb, int bytes)
111 put_byte(pb, 0x1ff >> bytes);
117 * Calculate how many bytes are needed to represent a given number in EBML.
119 static int ebml_num_size(uint64_t num)
122 while ((num+1) >> bytes*7) bytes++;
127 * Write a number in EBML variable length format.
129 * @param bytes The number of bytes that need to be used to write the number.
130 * If zero, any number of bytes can be used.
132 static void put_ebml_num(ByteIOContext *pb, uint64_t num, int bytes)
134 int i, needed_bytes = ebml_num_size(num);
136 // sizes larger than this are currently undefined in EBML
137 assert(num < (1ULL<<56)-1);
140 // don't care how many bytes are used, so use the min
141 bytes = needed_bytes;
142 // the bytes needed to write the given size would exceed the bytes
143 // that we need to use, so write unknown size. This shouldn't happen.
144 assert(bytes >= needed_bytes);
146 num |= 1ULL << bytes*7;
147 for (i = bytes - 1; i >= 0; i--)
148 put_byte(pb, num >> i*8);
151 static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
155 while (tmp>>=8) bytes++;
157 put_ebml_id(pb, elementid);
158 put_ebml_num(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_num(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_num(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_num(pb, size-1, 0);
202 put_ebml_num(pb, size-9, 8);
203 while(url_ftell(pb) < currentpos + size)
207 static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
209 int bytes = expectedsize ? ebml_num_size(expectedsize) : 8;
210 put_ebml_id(pb, elementid);
211 put_ebml_size_unknown(pb, bytes);
212 return (ebml_master){ url_ftell(pb), bytes };
215 static void end_ebml_master(ByteIOContext *pb, ebml_master master)
217 offset_t pos = url_ftell(pb);
219 // leave the unknown size for masters when streaming
220 if (url_is_streamed(pb))
223 url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
224 put_ebml_num(pb, pos - master.pos, master.sizebytes);
225 url_fseek(pb, pos, SEEK_SET);
228 static void put_xiph_size(ByteIOContext *pb, int size)
231 for (i = 0; i < size / 255; i++)
233 put_byte(pb, size % 255);
237 * Initialize a mkv_seekhead element to be ready to index level 1 Matroska
238 * elements. If a maximum number of elements is specified, enough space
239 * will be reserved at the current file location to write a seek head of
242 * @param segment_offset The absolute offset to the position in the file
243 * where the segment begins.
244 * @param numelements The maximum number of elements that will be indexed
245 * by this 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
258 // and size, and 3 bytes to guarantee that an EBML void element
259 // will fit afterwards
260 new_seekhead->reserved_size = numelements * MAX_SEEKENTRY_SIZE + 13;
261 new_seekhead->max_entries = numelements;
262 put_ebml_void(pb, new_seekhead->reserved_size);
267 static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
269 mkv_seekhead_entry *entries = seekhead->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));
277 return AVERROR(ENOMEM);
279 entries[seekhead->num_entries ].elementid = elementid;
280 entries[seekhead->num_entries++].segmentpos = filepos - seekhead->segment_offset;
282 seekhead->entries = entries;
287 * Write the seek head to the file and free it. If a maximum number of
288 * elements was specified to mkv_start_seekhead(), the seek head will
289 * be written at the location reserved for it. Otherwise, it is written
290 * at the current location in the file.
292 * @return The file offset where the seekhead was written.
294 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
296 ebml_master metaseek, seekentry;
300 currentpos = url_ftell(pb);
302 if (seekhead->reserved_size > 0)
303 url_fseek(pb, seekhead->filepos, SEEK_SET);
305 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
306 for (i = 0; i < seekhead->num_entries; i++) {
307 mkv_seekhead_entry *entry = &seekhead->entries[i];
309 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
311 put_ebml_id(pb, MATROSKA_ID_SEEKID);
312 put_ebml_num(pb, ebml_id_size(entry->elementid), 0);
313 put_ebml_id(pb, entry->elementid);
315 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
316 end_ebml_master(pb, seekentry);
318 end_ebml_master(pb, metaseek);
320 if (seekhead->reserved_size > 0) {
321 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
322 put_ebml_void(pb, remaining);
323 url_fseek(pb, currentpos, SEEK_SET);
325 currentpos = seekhead->filepos;
327 av_free(seekhead->entries);
333 static mkv_cues * mkv_start_cues(offset_t segment_offset)
335 mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
339 cues->segment_offset = segment_offset;
343 static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
345 mkv_cuepoint *entries = cues->entries;
347 entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
349 return AVERROR(ENOMEM);
351 entries[cues->num_entries ].pts = pkt->pts;
352 entries[cues->num_entries ].tracknum = pkt->stream_index + 1;
353 entries[cues->num_entries++].cluster_pos = cluster_pos - cues->segment_offset;
355 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(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec)
396 uint8_t *header_start[3];
398 int first_header_size;
401 if (codec->codec_id == CODEC_ID_VORBIS)
402 first_header_size = 30;
404 first_header_size = 42;
406 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
407 first_header_size, header_start, header_len) < 0) {
408 av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
412 put_byte(pb, 2); // number packets - 1
413 for (j = 0; j < 2; j++) {
414 put_xiph_size(pb, header_len[j]);
416 for (j = 0; j < 3; j++)
417 put_buffer(pb, header_start[j], header_len[j]);
422 #define FLAC_STREAMINFO_SIZE 34
424 static int put_flac_codecpriv(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec)
426 // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
427 // assume that it's in Matroska's format already
428 if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
429 av_log(s, AV_LOG_ERROR, "Invalid FLAC extradata\n");
431 } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
432 // only the streaminfo packet
433 put_buffer(pb, "fLaC", 4);
435 put_be24(pb, FLAC_STREAMINFO_SIZE);
436 } else if(memcmp("fLaC", codec->extradata, 4)) {
437 av_log(s, AV_LOG_ERROR, "Invalid FLAC extradata\n");
440 put_buffer(pb, codec->extradata, codec->extradata_size);
444 static void get_aac_sample_rates(AVFormatContext *s, AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
448 if (codec->extradata_size < 2) {
449 av_log(s, AV_LOG_WARNING, "No AAC extradata, unable to determine samplerate.\n");
453 sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
455 av_log(s, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
458 *sample_rate = ff_mpeg4audio_sample_rates[sri];
460 // if sbr, get output sample rate as well
461 if (codec->extradata_size == 5) {
462 sri = (codec->extradata[4] >> 3) & 0xF;
464 av_log(s, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
467 *output_sample_rate = ff_mpeg4audio_sample_rates[sri];
471 static int mkv_write_codecprivate(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec, int native_id, int qt_id)
473 ByteIOContext *dyn_cp;
475 int ret, codecpriv_size;
477 ret = url_open_dyn_buf(&dyn_cp);
482 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA)
483 ret = put_xiph_codecpriv(s, dyn_cp, codec);
484 else if (codec->codec_id == CODEC_ID_FLAC)
485 ret = put_flac_codecpriv(s, dyn_cp, codec);
486 else if (codec->codec_id == CODEC_ID_H264)
487 ret = ff_isom_write_avcc(dyn_cp, codec->extradata, codec->extradata_size);
488 else if (codec->extradata_size)
489 put_buffer(dyn_cp, codec->extradata, codec->extradata_size);
490 } else if (codec->codec_type == CODEC_TYPE_VIDEO) {
492 if (!codec->codec_tag)
493 codec->codec_tag = codec_get_tag(codec_movvideo_tags, codec->codec_id);
494 if (codec->extradata_size)
495 put_buffer(dyn_cp, codec->extradata, codec->extradata_size);
497 if (!codec->codec_tag)
498 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
499 if (!codec->codec_tag) {
500 av_log(s, AV_LOG_ERROR, "No bmp codec ID found.");
504 put_bmp_header(dyn_cp, codec, codec_bmp_tags, 0);
507 } else if (codec->codec_type == CODEC_TYPE_AUDIO) {
508 if (!codec->codec_tag)
509 codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
510 if (!codec->codec_tag) {
511 av_log(s, AV_LOG_ERROR, "No wav codec ID found.");
515 put_wav_header(dyn_cp, codec);
518 codecpriv_size = url_close_dyn_buf(dyn_cp, &codecpriv);
520 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codecpriv, codecpriv_size);
525 static int mkv_write_tracks(AVFormatContext *s)
527 MatroskaMuxContext *mkv = s->priv_data;
528 ByteIOContext *pb = s->pb;
532 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb));
533 if (ret < 0) return ret;
535 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
536 for (i = 0; i < s->nb_streams; i++) {
537 AVStream *st = s->streams[i];
538 AVCodecContext *codec = st->codec;
539 ebml_master subinfo, track;
542 int bit_depth = av_get_bits_per_sample(codec->codec_id);
543 int sample_rate = codec->sample_rate;
544 int output_sample_rate = 0;
547 bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
549 if (codec->codec_id == CODEC_ID_AAC)
550 get_aac_sample_rates(s, codec, &sample_rate, &output_sample_rate);
552 track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
553 put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
554 put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
555 put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
558 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
560 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, "und");
562 put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGDEFAULT, !!(st->disposition & AV_DISPOSITION_DEFAULT));
564 // look for a codec ID string specific to mkv to use,
565 // if none are found, use AVI codes
566 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
567 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
568 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
574 switch (codec->codec_type) {
575 case CODEC_TYPE_VIDEO:
576 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
579 codec_get_tag(codec_movvideo_tags, codec->codec_id) &&
580 (!codec_get_tag(codec_bmp_tags, codec->codec_id)
581 || codec->codec_id == CODEC_ID_SVQ1
582 || codec->codec_id == CODEC_ID_SVQ3
583 || codec->codec_id == CODEC_ID_CINEPAK))
587 put_ebml_string(pb, MATROSKA_ID_CODECID, "V_QUICKTIME");
589 // if there is no mkv-specific codec ID, use VFW mode
590 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
592 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
593 // XXX: interlace flag?
594 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
595 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
596 if (codec->sample_aspect_ratio.num) {
597 AVRational dar = av_mul_q(codec->sample_aspect_ratio,
598 (AVRational){codec->width, codec->height});
599 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , dar.num);
600 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, dar.den);
602 end_ebml_master(pb, subinfo);
605 case CODEC_TYPE_AUDIO:
606 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
609 // no mkv-specific ID, use ACM mode
610 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
612 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
613 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
614 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
615 if (output_sample_rate)
616 put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
618 put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
619 end_ebml_master(pb, subinfo);
622 case CODEC_TYPE_SUBTITLE:
623 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
626 av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.");
629 ret = mkv_write_codecprivate(s, pb, codec, native_id, qt_id);
630 if (ret < 0) return ret;
632 end_ebml_master(pb, track);
634 // ms precision is the de-facto standard timescale for mkv files
635 av_set_pts_info(st, 64, 1, 1000);
637 end_ebml_master(pb, tracks);
641 static int mkv_write_header(AVFormatContext *s)
643 MatroskaMuxContext *mkv = s->priv_data;
644 ByteIOContext *pb = s->pb;
645 ebml_master ebml_header, segment_info;
648 mkv->md5_ctx = av_mallocz(av_md5_size);
649 av_md5_init(mkv->md5_ctx);
651 ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
652 put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
653 put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
654 put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
655 put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
656 put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
657 put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
658 put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
659 end_ebml_master(pb, ebml_header);
661 mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
662 mkv->segment_offset = url_ftell(pb);
664 // we write 2 seek heads - one at the end of the file to point to each
665 // cluster, and one at the beginning to point to all other level one
666 // elements (including the seek head at the end of the file), which
667 // isn't more than 10 elements if we only write one of each other
668 // currently defined level 1 element
669 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
670 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
671 if (mkv->main_seekhead == NULL || mkv->cluster_seekhead == NULL)
672 return AVERROR(ENOMEM);
674 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb));
675 if (ret < 0) return ret;
677 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
678 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
679 if (strlen(s->title))
680 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
681 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
682 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
683 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
685 // reserve space to write the segment UID later
686 mkv->segment_uid = url_ftell(pb);
687 put_ebml_void(pb, 19);
690 // reserve space for the duration
692 mkv->duration_offset = url_ftell(pb);
693 put_ebml_void(pb, 11); // assumes double-precision float to be written
694 end_ebml_master(pb, segment_info);
696 ret = mkv_write_tracks(s);
697 if (ret < 0) return ret;
699 ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
700 if (ret < 0) return ret;
702 mkv->cluster_pos = url_ftell(pb);
703 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
704 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
705 mkv->cluster_pts = 0;
707 mkv->cues = mkv_start_cues(mkv->segment_offset);
708 if (mkv->cues == NULL)
709 return AVERROR(ENOMEM);
714 static int mkv_block_size(AVPacket *pkt)
716 int size = 4; // track num + timecode + flags
717 return size + pkt->size;
720 static int mkv_blockgroup_size(AVPacket *pkt)
722 int size = mkv_block_size(pkt);
723 size += ebml_num_size(size);
724 size += 2; // EBML ID for block and block duration
725 size += 8; // max size of block duration
726 size += ebml_num_size(size);
727 size += 1; // blockgroup EBML ID
731 static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
733 MatroskaMuxContext *mkv = s->priv_data;
734 ByteIOContext *pb = s->pb;
736 av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, "
737 "pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
738 url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
739 put_ebml_id(pb, blockid);
740 put_ebml_num(pb, mkv_block_size(pkt), 0);
741 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
742 put_be16(pb, pkt->pts - mkv->cluster_pts);
744 put_buffer(pb, pkt->data, pkt->size);
747 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
749 MatroskaMuxContext *mkv = s->priv_data;
750 ByteIOContext *pb = s->pb;
751 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
752 int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
755 // start a new cluster every 5 MB or 5 sec
756 if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
757 av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64
758 " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
759 end_ebml_master(pb, mkv->cluster);
761 ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
762 if (ret < 0) return ret;
764 mkv->cluster_pos = url_ftell(pb);
765 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
766 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
767 mkv->cluster_pts = pkt->pts;
768 av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
771 if (codec->codec_id == CODEC_ID_H264 &&
772 codec->extradata_size > 0 && AV_RB32(codec->extradata) == 0x00000001) {
773 /* from x264 or from bytestream h264 */
774 /* nal reformating needed */
775 int ret = ff_avc_parse_nal_units(pkt->data, &pkt->data, &pkt->size);
781 if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
782 mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
784 ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
785 mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
786 put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
787 end_ebml_master(pb, blockgroup);
790 if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
791 ret = mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos);
792 if (ret < 0) return ret;
795 mkv->duration = FFMAX(mkv->duration, pkt->pts + pkt->duration);
799 static int mkv_write_trailer(AVFormatContext *s)
801 MatroskaMuxContext *mkv = s->priv_data;
802 ByteIOContext *pb = s->pb;
803 offset_t currentpos, second_seekhead, cuespos;
806 end_ebml_master(pb, mkv->cluster);
808 if (!url_is_streamed(pb)) {
809 cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
810 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
812 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
813 if (ret < 0) return ret;
814 ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
815 if (ret < 0) return ret;
816 mkv_write_seekhead(pb, mkv->main_seekhead);
818 // update the duration
819 av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
820 currentpos = url_ftell(pb);
821 url_fseek(pb, mkv->duration_offset, SEEK_SET);
822 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
824 // write the md5sum of some frames as the segment UID
825 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
826 uint8_t segment_uid[16];
827 av_md5_final(mkv->md5_ctx, segment_uid);
828 url_fseek(pb, mkv->segment_uid, SEEK_SET);
829 put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
831 url_fseek(pb, currentpos, SEEK_SET);
834 end_ebml_master(pb, mkv->segment);
835 av_free(mkv->md5_ctx);
839 AVOutputFormat matroska_muxer = {
841 NULL_IF_CONFIG_SMALL("Matroska file format"),
844 sizeof(MatroskaMuxContext),
850 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
851 .subtitle_codec = CODEC_ID_TEXT,
854 AVOutputFormat matroska_audio_muxer = {
856 NULL_IF_CONFIG_SMALL("Matroska file format"),
859 sizeof(MatroskaMuxContext),
865 .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},