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;
41 typedef struct MatroskaMuxContext {
43 offset_t segment_offset;
46 offset_t duration_offset;
48 mkv_seekhead *main_seekhead;
49 mkv_seekhead *cluster_seekhead;
52 static void put_ebml_id(ByteIOContext *pb, unsigned int id)
55 put_byte(pb, id >> 24);
57 put_byte(pb, id >> 16);
59 put_byte(pb, id >> 8);
63 static int ebml_id_size(unsigned int id)
74 // XXX: test this thoroughly and get rid of minbytes hack (currently needed to
75 // use up all of the space reserved in start_ebml_master)
76 static void put_ebml_size(ByteIOContext *pb, uint64_t size, int minbytes)
80 // sizes larger than this are currently undefined in EBML
81 // so write "unknown" size
82 size = FFMIN(size, (1ULL<<56)-1);
84 while (size >> (bytes*7 + 7)) bytes++;
86 put_byte(pb, (0x80 >> bytes) | (size >> bytes*8));
87 for (bytes -= 1; bytes >= 0; bytes--)
88 put_byte(pb, size >> bytes*8);
91 static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
94 while (val >> bytes*8) bytes++;
96 put_ebml_id(pb, elementid);
97 put_ebml_size(pb, bytes, 0);
98 for (bytes -= 1; bytes >= 0; bytes--)
99 put_byte(pb, val >> bytes*8);
102 static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
104 // XXX: single-precision floats?
105 put_ebml_id(pb, elementid);
106 put_ebml_size(pb, 8, 0);
107 put_be64(pb, av_dbl2int(val));
110 static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
111 const uint8_t *buf, int size)
113 put_ebml_id(pb, elementid);
114 put_ebml_size(pb, size, 0);
115 put_buffer(pb, buf, size);
118 static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
120 put_ebml_binary(pb, elementid, str, strlen(str));
123 // this reserves exactly the amount of space specified by size, which must be at least 2
124 static void put_ebml_void(ByteIOContext *pb, uint64_t size)
126 offset_t currentpos = url_ftell(pb);
131 put_ebml_id(pb, EBML_ID_VOID);
132 // we need to subtract the length needed to store the size from the size we need to reserve
133 // so 2 cases, we use 8 bytes to store the size if possible, 1 byte otherwise
135 put_ebml_size(pb, size-1, 0);
137 put_ebml_size(pb, size-9, 7);
138 url_fseek(pb, currentpos + size, SEEK_SET);
141 static offset_t start_ebml_master(ByteIOContext *pb, unsigned int elementid)
143 put_ebml_id(pb, elementid);
144 // XXX: this always reserves the maximum needed space to store any size value
145 // we should be smarter (additional parameter for expected size?)
146 put_ebml_size(pb, (1ULL<<56)-1, 0); // largest unknown size
147 return url_ftell(pb);
150 static void end_ebml_master(ByteIOContext *pb, offset_t start)
152 offset_t pos = url_ftell(pb);
154 url_fseek(pb, start - 8, SEEK_SET);
155 put_ebml_size(pb, pos - start, 7);
156 url_fseek(pb, pos, SEEK_SET);
159 // initializes a mkv_seekhead element to be ready to index level 1 matroska elements
160 // if numelements is greater than 0, it reserves enough space for that many elements
161 // at the current file position and writes the seekhead there, otherwise the seekhead
162 // will be appended to the file when end_mkv_seekhead() is called
163 static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_offset, int numelements)
165 mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
166 if (new_seekhead == NULL)
169 new_seekhead->segment_offset = segment_offset;
171 if (numelements > 0) {
172 new_seekhead->filepos = url_ftell(pb);
173 // 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID and size,
174 // and 3 bytes to guarantee that an EBML void element will fit afterwards
175 // XXX: 28 bytes right now because begin_ebml_master() reserves more than necessary
176 new_seekhead->reserved_size = numelements * 28 + 13;
177 new_seekhead->max_entries = numelements;
178 put_ebml_void(pb, new_seekhead->reserved_size);
183 static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
185 mkv_seekhead_entry *entries = seekhead->entries;
186 int new_entry = seekhead->num_entries;
188 // don't store more elements than we reserved space for
189 if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
192 entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
196 entries[new_entry].elementid = elementid;
197 entries[new_entry].segmentpos = filepos - seekhead->segment_offset;
199 seekhead->entries = entries;
200 seekhead->num_entries++;
205 // returns the file offset where the seekhead was written and frees the seekhead
206 static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
208 offset_t metaseek, seekentry, currentpos;
211 currentpos = url_ftell(pb);
213 if (seekhead->reserved_size > 0)
214 url_fseek(pb, seekhead->filepos, SEEK_SET);
216 metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD);
217 for (i = 0; i < seekhead->num_entries; i++) {
218 mkv_seekhead_entry *entry = &seekhead->entries[i];
220 seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY);
222 put_ebml_id(pb, MATROSKA_ID_SEEKID);
223 put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
224 put_ebml_id(pb, entry->elementid);
226 put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
227 end_ebml_master(pb, seekentry);
229 end_ebml_master(pb, metaseek);
231 if (seekhead->reserved_size > 0) {
232 uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
233 put_ebml_void(pb, remaining);
234 url_fseek(pb, currentpos, SEEK_SET);
236 currentpos = seekhead->filepos;
238 av_free(seekhead->entries);
244 static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
246 offset_t codecprivate;
247 uint8_t *header_start[3];
249 int first_header_size;
252 if (codec->codec_id == CODEC_ID_VORBIS)
253 first_header_size = 30;
255 first_header_size = 42;
257 if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
258 first_header_size, header_start, header_len) < 0) {
259 av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
263 codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
264 put_byte(pb, 2); // number packets - 1
265 for (j = 0; j < 2; j++) {
266 for (k = 0; k < header_len[j] / 255; k++)
268 put_byte(pb, header_len[j] % 255);
270 for (j = 0; j < 3; j++)
271 put_buffer(pb, header_start[j], header_len[j]);
272 end_ebml_master(pb, codecprivate);
277 static int mkv_write_tracks(AVFormatContext *s)
279 MatroskaMuxContext *mkv = s->priv_data;
280 ByteIOContext *pb = &s->pb;
284 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb)) < 0)
287 tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS);
288 for (i = 0; i < s->nb_streams; i++) {
289 AVStream *st = s->streams[i];
290 AVCodecContext *codec = st->codec;
291 offset_t subinfo, track;
294 track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
295 put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
296 put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
297 put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
300 put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
302 // look for a codec id string specific to mkv to use, if none are found, use AVI codes
303 for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
304 if (ff_mkv_codec_tags[j].id == codec->codec_id) {
305 put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
311 // XXX: CodecPrivate for vorbis, theora, aac, native mpeg4, ...
313 if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
314 if (put_xiph_codecpriv(pb, codec) < 0)
317 put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
321 switch (codec->codec_type) {
322 case CODEC_TYPE_VIDEO:
323 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
327 // if there is no mkv-specific codec id, use VFW mode
328 if (!codec->codec_tag)
329 codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
331 put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
332 // XXX: codec private isn't a master; is there a better way to re-use put_bmp_header?
333 bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
334 put_bmp_header(pb, codec, codec_bmp_tags, 0);
335 end_ebml_master(pb, bmp_header);
337 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO);
338 // XXX: interlace flag?
339 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
340 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
341 // XXX: display width/height
342 end_ebml_master(pb, subinfo);
345 case CODEC_TYPE_AUDIO:
346 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
349 subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO);
350 put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
351 put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, codec->sample_rate);
352 // XXX: output sample freq (for sbr) and bitdepth (for pcm)
353 end_ebml_master(pb, subinfo);
357 av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
360 end_ebml_master(pb, track);
362 // ms precision is the de-facto standard timescale for mkv files
363 av_set_pts_info(st, 64, 1, 1000);
365 end_ebml_master(pb, tracks);
369 static int mkv_write_header(AVFormatContext *s)
371 MatroskaMuxContext *mkv = s->priv_data;
372 ByteIOContext *pb = &s->pb;
373 offset_t ebml_header, segment_info;
375 ebml_header = start_ebml_master(pb, EBML_ID_HEADER);
376 put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
377 put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
378 put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
379 put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
380 put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
381 put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
382 put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
383 end_ebml_master(pb, ebml_header);
385 mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT);
386 mkv->segment_offset = url_ftell(pb);
388 // we write 2 seek heads - one at the end of the file to point to each cluster, and
389 // one at the beginning to point to all other level one elements (including the seek
390 // head at the end of the file), which isn't more than 10 elements if we only write one
391 // of each other currently defined level 1 element
392 mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
393 mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
395 if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb)) < 0)
398 segment_info = start_ebml_master(pb, MATROSKA_ID_INFO);
399 put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
400 if (strlen(s->title))
401 put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
402 if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
403 put_ebml_string(pb, MATROSKA_ID_MUXINGAPP, LIBAVFORMAT_IDENT);
404 // XXX: both are required; something better for writing app?
405 put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
408 // reserve space for the duration
410 mkv->duration_offset = url_ftell(pb);
411 put_ebml_void(pb, 11); // assumes double-precision float to be written
412 end_ebml_master(pb, segment_info);
414 if (mkv_write_tracks(s) < 0)
417 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
420 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
421 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
422 mkv->cluster_pts = 0;
427 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
429 MatroskaMuxContext *mkv = s->priv_data;
430 ByteIOContext *pb = &s->pb;
432 // start a new cluster every 5 MB or 5 sec
433 if (url_ftell(pb) > mkv->cluster + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
434 end_ebml_master(pb, mkv->cluster);
436 if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
439 mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
440 put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
441 mkv->cluster_pts = pkt->pts;
444 put_ebml_id(pb, MATROSKA_ID_SIMPLEBLOCK);
445 put_ebml_size(pb, pkt->size + 4, 0);
446 put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
447 put_be16(pb, pkt->pts - mkv->cluster_pts);
448 put_byte(pb, !!(pkt->flags & PKT_FLAG_KEY));
449 put_buffer(pb, pkt->data, pkt->size);
451 mkv->duration = pkt->pts + pkt->duration;
455 static int mkv_write_trailer(AVFormatContext *s)
457 MatroskaMuxContext *mkv = s->priv_data;
458 ByteIOContext *pb = &s->pb;
459 offset_t currentpos, second_seekhead;
461 end_ebml_master(pb, mkv->cluster);
463 second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
464 mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
465 mkv_write_seekhead(pb, mkv->main_seekhead);
467 // update the duration
468 currentpos = url_ftell(pb);
469 url_fseek(pb, mkv->duration_offset, SEEK_SET);
470 put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
471 url_fseek(pb, currentpos, SEEK_SET);
473 end_ebml_master(pb, mkv->segment);
477 AVOutputFormat matroska_muxer = {
479 "Matroska File Format",
482 sizeof(MatroskaMuxContext),
488 .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},