Statistics
| Branch: | Revision:

ffmpeg / libavformat / matroskaenc.c @ 0ab1ebea

History | View | Annotate | Download (27.9 KB)

1
/*
2
 * Matroska muxer
3
 * Copyright (c) 2007 David Conrad
4
 *
5
 * This file is part of FFmpeg.
6
 *
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.
11
 *
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.
16
 *
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
20
 */
21

    
22
#include "avformat.h"
23
#include "md5.h"
24
#include "riff.h"
25
#include "xiph.h"
26
#include "matroska.h"
27

    
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
31
} ebml_master;
32

    
33
typedef struct mkv_seekhead_entry {
34
    unsigned int    elementid;
35
    uint64_t        segmentpos;
36
} mkv_seekhead_entry;
37

    
38
typedef struct mkv_seekhead {
39
    offset_t                filepos;
40
    offset_t                segment_offset;     ///< the file offset to the beginning of the segment
41
    int                     reserved_size;      ///< -1 if appending to file
42
    int                     max_entries;
43
    mkv_seekhead_entry      *entries;
44
    int                     num_entries;
45
} mkv_seekhead;
46

    
47
typedef struct {
48
    uint64_t        pts;
49
    int             tracknum;
50
    offset_t        cluster_pos;        ///< file offset of the cluster containing the block
51
} mkv_cuepoint;
52

    
53
typedef struct {
54
    offset_t        segment_offset;
55
    mkv_cuepoint    *entries;
56
    int             num_entries;
57
} mkv_cues;
58

    
59
typedef struct MatroskaMuxContext {
60
    ebml_master     segment;
61
    offset_t        segment_offset;
62
    offset_t        segment_uid;
63
    ebml_master     cluster;
64
    offset_t        cluster_pos;        ///< file offset of the current cluster
65
    uint64_t        cluster_pts;
66
    offset_t        duration_offset;
67
    uint64_t        duration;
68
    mkv_seekhead    *main_seekhead;
69
    mkv_seekhead    *cluster_seekhead;
70
    mkv_cues        *cues;
71

    
72
    struct AVMD5    *md5_ctx;
73
} MatroskaMuxContext;
74

    
75

    
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
79

    
80
/** per-cuepoint-track - 3 1-byte EBML IDs, 3 1-byte EBML sizes, 2
81
 * 8-byte uint max */
82
#define MAX_CUETRACKPOS_SIZE 22
83

    
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
86

    
87

    
88
static int ebml_id_size(unsigned int id)
89
{
90
    return (av_log2(id+1)-1)/7+1;
91
}
92

    
93
static void put_ebml_id(ByteIOContext *pb, unsigned int id)
94
{
95
    int i = ebml_id_size(id);
96
    while (i--)
97
        put_byte(pb, id >> (i*8));
98
}
99

    
100
/**
101
 * Write an EBML size meaning "unknown size".
102
 *
103
 * @param bytes The number of bytes the size should occupy (maximum: 8).
104
 */
105
static void put_ebml_size_unknown(ByteIOContext *pb, int bytes)
106
{
107
    assert(bytes <= 8);
108
    put_byte(pb, 0x1ff >> bytes);
109
    while (--bytes)
110
        put_byte(pb, 0xff);
111
}
112

    
113
/**
114
 * Calculate how many bytes are needed to represent a given number in EBML.
115
 */
116
static int ebml_num_size(uint64_t num)
117
{
118
    int bytes = 1;
119
    while ((num+1) >> bytes*7) bytes++;
120
    return bytes;
121
}
122

    
123
/**
124
 * Write a number in EBML variable length format.
125
 *
126
 * @param bytes The number of bytes that need to be used to write the number.
127
 *              If zero, any number of bytes can be used.
128
 */
129
static void put_ebml_num(ByteIOContext *pb, uint64_t num, int bytes)
130
{
131
    int i, needed_bytes = ebml_num_size(num);
132

    
133
    // sizes larger than this are currently undefined in EBML
134
    assert(num < (1ULL<<56)-1);
135

    
136
    if (bytes == 0)
137
        // don't care how many bytes are used, so use the min
138
        bytes = needed_bytes;
139
    // the bytes needed to write the given size would exceed the bytes
140
    // that we need to use, so write unknown size. This shouldn't happen.
141
    assert(bytes >= needed_bytes);
142

    
143
    num |= 1ULL << bytes*7;
144
    for (i = bytes - 1; i >= 0; i--)
145
        put_byte(pb, num >> i*8);
146
}
147

    
148
static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
149
{
150
    int i, bytes = 1;
151
    while (val >> bytes*8) bytes++;
152

    
153
    put_ebml_id(pb, elementid);
154
    put_ebml_num(pb, bytes, 0);
155
    for (i = bytes - 1; i >= 0; i--)
156
        put_byte(pb, val >> i*8);
157
}
158

    
159
static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
160
{
161
    put_ebml_id(pb, elementid);
162
    put_ebml_num(pb, 8, 0);
163
    put_be64(pb, av_dbl2int(val));
164
}
165

    
166
static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
167
                            const uint8_t *buf, int size)
168
{
169
    put_ebml_id(pb, elementid);
170
    put_ebml_num(pb, size, 0);
171
    put_buffer(pb, buf, size);
172
}
173

    
174
static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
175
{
176
    put_ebml_binary(pb, elementid, str, strlen(str));
177
}
178

    
179
/**
180
 * Writes a void element of a given size. Useful for reserving space in
181
 * the file to be written to later.
182
 *
183
 * @param size The number of bytes to reserve, which must be at least 2.
184
 */
185
static void put_ebml_void(ByteIOContext *pb, uint64_t size)
186
{
187
    offset_t currentpos = url_ftell(pb);
188

    
189
    assert(size >= 2);
190

    
191
    put_ebml_id(pb, EBML_ID_VOID);
192
    // we need to subtract the length needed to store the size from the
193
    // size we need to reserve so 2 cases, we use 8 bytes to store the
194
    // size if possible, 1 byte otherwise
195
    if (size < 10)
196
        put_ebml_num(pb, size-1, 0);
197
    else
198
        put_ebml_num(pb, size-9, 8);
199
    url_fseek(pb, currentpos + size, SEEK_SET);
200
}
201

    
202
static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
203
{
204
    int bytes = expectedsize ? ebml_num_size(expectedsize) : 8;
205
    put_ebml_id(pb, elementid);
206
    put_ebml_size_unknown(pb, bytes);
207
    return (ebml_master){ url_ftell(pb), bytes };
208
}
209

    
210
static void end_ebml_master(ByteIOContext *pb, ebml_master master)
211
{
212
    offset_t pos = url_ftell(pb);
213

    
214
    // leave the unknown size for masters when streaming
215
    if (url_is_streamed(pb))
216
        return;
217

    
218
    url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
219
    put_ebml_num(pb, pos - master.pos, master.sizebytes);
220
    url_fseek(pb, pos, SEEK_SET);
221
}
222

    
223
static void put_xiph_size(ByteIOContext *pb, int size)
224
{
225
    int i;
226
    for (i = 0; i < size / 255; i++)
227
        put_byte(pb, 255);
228
    put_byte(pb, size % 255);
229
}
230

    
231
/**
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
235
 * that size.
236
 *
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.
241
 */
242
static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_offset, int numelements)
243
{
244
    mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
245
    if (new_seekhead == NULL)
246
        return NULL;
247

    
248
    new_seekhead->segment_offset = segment_offset;
249

    
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);
258
    }
259
    return new_seekhead;
260
}
261

    
262
static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
263
{
264
    mkv_seekhead_entry *entries = seekhead->entries;
265

    
266
    // don't store more elements than we reserved space for
267
    if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
268
        return -1;
269

    
270
    entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
271
    if (entries == NULL)
272
        return AVERROR(ENOMEM);
273

    
274
    entries[seekhead->num_entries  ].elementid = elementid;
275
    entries[seekhead->num_entries++].segmentpos = filepos - seekhead->segment_offset;
276

    
277
    seekhead->entries = entries;
278
    return 0;
279
}
280

    
281
/**
282
 * Write the seek head to the file and free it. If a maximum number of
283
 * elements was specified to mkv_start_seekhead(), the seek head will
284
 * be written at the location reserved for it. Otherwise, it is written
285
 * at the current location in the file.
286
 *
287
 * @return The file offset where the seekhead was written.
288
 */
289
static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
290
{
291
    ebml_master metaseek, seekentry;
292
    offset_t currentpos;
293
    int i;
294

    
295
    currentpos = url_ftell(pb);
296

    
297
    if (seekhead->reserved_size > 0)
298
        url_fseek(pb, seekhead->filepos, SEEK_SET);
299

    
300
    metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
301
    for (i = 0; i < seekhead->num_entries; i++) {
302
        mkv_seekhead_entry *entry = &seekhead->entries[i];
303

    
304
        seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
305

    
306
        put_ebml_id(pb, MATROSKA_ID_SEEKID);
307
        put_ebml_num(pb, ebml_id_size(entry->elementid), 0);
308
        put_ebml_id(pb, entry->elementid);
309

    
310
        put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
311
        end_ebml_master(pb, seekentry);
312
    }
313
    end_ebml_master(pb, metaseek);
314

    
315
    if (seekhead->reserved_size > 0) {
316
        uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
317
        put_ebml_void(pb, remaining);
318
        url_fseek(pb, currentpos, SEEK_SET);
319

    
320
        currentpos = seekhead->filepos;
321
    }
322
    av_free(seekhead->entries);
323
    av_free(seekhead);
324

    
325
    return currentpos;
326
}
327

    
328
static mkv_cues * mkv_start_cues(offset_t segment_offset)
329
{
330
    mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
331
    if (cues == NULL)
332
        return NULL;
333

    
334
    cues->segment_offset = segment_offset;
335
    return cues;
336
}
337

    
338
static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
339
{
340
    mkv_cuepoint *entries = cues->entries;
341

    
342
    entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
343
    if (entries == NULL)
344
        return AVERROR(ENOMEM);
345

    
346
    entries[cues->num_entries  ].pts = pkt->pts;
347
    entries[cues->num_entries  ].tracknum = pkt->stream_index + 1;
348
    entries[cues->num_entries++].cluster_pos = cluster_pos - cues->segment_offset;
349

    
350
    cues->entries = entries;
351
    return 0;
352
}
353

    
354
static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
355
{
356
    ebml_master cues_element;
357
    offset_t currentpos;
358
    int i, j;
359

    
360
    currentpos = url_ftell(pb);
361
    cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
362

    
363
    for (i = 0; i < cues->num_entries; i++) {
364
        ebml_master cuepoint, track_positions;
365
        mkv_cuepoint *entry = &cues->entries[i];
366
        uint64_t pts = entry->pts;
367

    
368
        cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
369
        put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
370

    
371
        // put all the entries from different tracks that have the exact same
372
        // timestamp into the same CuePoint
373
        for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
374
            track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
375
            put_ebml_uint(pb, MATROSKA_ID_CUETRACK          , entry[j].tracknum   );
376
            put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
377
            end_ebml_master(pb, track_positions);
378
        }
379
        i += j - 1;
380
        end_ebml_master(pb, cuepoint);
381
    }
382
    end_ebml_master(pb, cues_element);
383

    
384
    av_free(cues->entries);
385
    av_free(cues);
386
    return currentpos;
387
}
388

    
389
static int put_xiph_codecpriv(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec)
390
{
391
    uint8_t *header_start[3];
392
    int header_len[3];
393
    int first_header_size;
394
    int j;
395

    
396
    if (codec->codec_id == CODEC_ID_VORBIS)
397
        first_header_size = 30;
398
    else
399
        first_header_size = 42;
400

    
401
    if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
402
                              first_header_size, header_start, header_len) < 0) {
403
        av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
404
        return -1;
405
    }
406

    
407
    put_byte(pb, 2);                    // number packets - 1
408
    for (j = 0; j < 2; j++) {
409
        put_xiph_size(pb, header_len[j]);
410
    }
411
    for (j = 0; j < 3; j++)
412
        put_buffer(pb, header_start[j], header_len[j]);
413

    
414
    return 0;
415
}
416

    
417
#define FLAC_STREAMINFO_SIZE 34
418

    
419
static int put_flac_codecpriv(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec)
420
{
421
    // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
422
    // assume that it's in Matroska's format already
423
    if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
424
        av_log(s, AV_LOG_ERROR, "Invalid FLAC extradata\n");
425
        return -1;
426
    } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
427
        // only the streaminfo packet
428
        put_byte(pb, 0);
429
        put_xiph_size(pb, codec->extradata_size);
430
        av_log(s, AV_LOG_ERROR, "Only one packet\n");
431
    }
432
    put_buffer(pb, codec->extradata, codec->extradata_size);
433
    return 0;
434
}
435

    
436
static void get_aac_sample_rates(AVFormatContext *s, AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
437
{
438
    static const int aac_sample_rates[] = {
439
        96000, 88200, 64000, 48000, 44100, 32000,
440
        24000, 22050, 16000, 12000, 11025,  8000,
441
    };
442
    int sri;
443

    
444
    if (codec->extradata_size < 2) {
445
        av_log(s, AV_LOG_WARNING, "No AAC extradata, unable to determine samplerate.\n");
446
        return;
447
    }
448

    
449
    sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
450
    if (sri > 12) {
451
        av_log(s, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
452
        return;
453
    }
454
    *sample_rate = aac_sample_rates[sri];
455

    
456
    // if sbr, get output sample rate as well
457
    if (codec->extradata_size == 5) {
458
        sri = (codec->extradata[4] >> 3) & 0xF;
459
        if (sri > 12) {
460
            av_log(s, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
461
            return;
462
        }
463
        *output_sample_rate = aac_sample_rates[sri];
464
    }
465
}
466

    
467
static int mkv_write_codecprivate(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec, int native_id)
468
{
469
    ByteIOContext dyn_cp;
470
    uint8_t *codecpriv;
471
    int ret = 0, codecpriv_size;
472

    
473
    url_open_dyn_buf(&dyn_cp);
474

    
475
    if (native_id) {
476
        if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA)
477
            ret = put_xiph_codecpriv(s, &dyn_cp, codec);
478
        else if (codec->codec_id == CODEC_ID_FLAC)
479
            ret = put_flac_codecpriv(s, &dyn_cp, codec);
480
        else if (codec->extradata_size)
481
            put_buffer(&dyn_cp, codec->extradata, codec->extradata_size);
482
    } else if (codec->codec_type == CODEC_TYPE_VIDEO) {
483
        if (!codec->codec_tag)
484
            codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
485
        if (!codec->codec_tag) {
486
            av_log(s, AV_LOG_ERROR, "No bmp codec ID found.");
487
            ret = -1;
488
        }
489

    
490
        put_bmp_header(&dyn_cp, codec, codec_bmp_tags, 0);
491

    
492
    } else if (codec->codec_type == CODEC_TYPE_AUDIO) {
493
        if (!codec->codec_tag)
494
            codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
495
        if (!codec->codec_tag) {
496
            av_log(s, AV_LOG_ERROR, "No wav codec ID found.");
497
            ret = -1;
498
        }
499

    
500
        put_wav_header(&dyn_cp, codec);
501
    }
502

    
503
    codecpriv_size = url_close_dyn_buf(&dyn_cp, &codecpriv);
504
    if (codecpriv_size)
505
        put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codecpriv, codecpriv_size);
506
    av_free(codecpriv);
507
    return ret;
508
}
509

    
510
static int mkv_write_tracks(AVFormatContext *s)
511
{
512
    MatroskaMuxContext *mkv = s->priv_data;
513
    ByteIOContext *pb = &s->pb;
514
    ebml_master tracks;
515
    int i, j, ret;
516

    
517
    ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb));
518
    if (ret < 0) return ret;
519

    
520
    tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
521
    for (i = 0; i < s->nb_streams; i++) {
522
        AVStream *st = s->streams[i];
523
        AVCodecContext *codec = st->codec;
524
        ebml_master subinfo, track;
525
        int native_id = 0;
526
        int bit_depth = av_get_bits_per_sample(codec->codec_id);
527
        int sample_rate = codec->sample_rate;
528
        int output_sample_rate = 0;
529

    
530
        if (!bit_depth)
531
            bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
532

    
533
        if (codec->codec_id == CODEC_ID_AAC)
534
            get_aac_sample_rates(s, codec, &sample_rate, &output_sample_rate);
535

    
536
        track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
537
        put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER     , i + 1);
538
        put_ebml_uint (pb, MATROSKA_ID_TRACKUID        , i + 1);
539
        put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0);    // no lacing (yet)
540

    
541
        if (st->language[0])
542
            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
543
        else
544
            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, "und");
545

    
546
        // look for a codec ID string specific to mkv to use,
547
        // if none are found, use AVI codes
548
        for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
549
            if (ff_mkv_codec_tags[j].id == codec->codec_id) {
550
                put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
551
                native_id = 1;
552
                break;
553
            }
554
        }
555

    
556
        switch (codec->codec_type) {
557
            case CODEC_TYPE_VIDEO:
558
                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
559

    
560
                if (!native_id)
561
                    // if there is no mkv-specific codec ID, use VFW mode
562
                    put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
563

    
564
                subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
565
                // XXX: interlace flag?
566
                put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
567
                put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
568
                if (codec->sample_aspect_ratio.num) {
569
                    AVRational dar = av_mul_q(codec->sample_aspect_ratio,
570
                                    (AVRational){codec->width, codec->height});
571
                    put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , dar.num);
572
                    put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, dar.den);
573
                }
574
                end_ebml_master(pb, subinfo);
575
                break;
576

    
577
            case CODEC_TYPE_AUDIO:
578
                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
579

    
580
                if (!native_id)
581
                    // no mkv-specific ID, use ACM mode
582
                    put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
583

    
584
                subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
585
                put_ebml_uint  (pb, MATROSKA_ID_AUDIOCHANNELS    , codec->channels);
586
                put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
587
                if (output_sample_rate)
588
                    put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
589
                if (bit_depth)
590
                    put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
591
                end_ebml_master(pb, subinfo);
592
                break;
593

    
594
            case CODEC_TYPE_SUBTITLE:
595
                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
596
                break;
597
            default:
598
                av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.");
599
                break;
600
        }
601
        ret = mkv_write_codecprivate(s, pb, codec, native_id);
602
        if (ret < 0) return ret;
603

    
604
        end_ebml_master(pb, track);
605

    
606
        // ms precision is the de-facto standard timescale for mkv files
607
        av_set_pts_info(st, 64, 1, 1000);
608
    }
609
    end_ebml_master(pb, tracks);
610
    return 0;
611
}
612

    
613
static int mkv_write_header(AVFormatContext *s)
614
{
615
    MatroskaMuxContext *mkv = s->priv_data;
616
    ByteIOContext *pb = &s->pb;
617
    ebml_master ebml_header, segment_info;
618
    int ret;
619

    
620
    mkv->md5_ctx = av_mallocz(av_md5_size);
621
    av_md5_init(mkv->md5_ctx);
622

    
623
    ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
624
    put_ebml_uint   (pb, EBML_ID_EBMLVERSION        ,           1);
625
    put_ebml_uint   (pb, EBML_ID_EBMLREADVERSION    ,           1);
626
    put_ebml_uint   (pb, EBML_ID_EBMLMAXIDLENGTH    ,           4);
627
    put_ebml_uint   (pb, EBML_ID_EBMLMAXSIZELENGTH  ,           8);
628
    put_ebml_string (pb, EBML_ID_DOCTYPE            ,  "matroska");
629
    put_ebml_uint   (pb, EBML_ID_DOCTYPEVERSION     ,           2);
630
    put_ebml_uint   (pb, EBML_ID_DOCTYPEREADVERSION ,           2);
631
    end_ebml_master(pb, ebml_header);
632

    
633
    mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
634
    mkv->segment_offset = url_ftell(pb);
635

    
636
    // we write 2 seek heads - one at the end of the file to point to each
637
    // cluster, and one at the beginning to point to all other level one
638
    // elements (including the seek head at the end of the file), which
639
    // isn't more than 10 elements if we only write one of each other
640
    // currently defined level 1 element
641
    mkv->main_seekhead    = mkv_start_seekhead(pb, mkv->segment_offset, 10);
642
    mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
643
    if (mkv->main_seekhead == NULL || mkv->cluster_seekhead == NULL)
644
        return AVERROR(ENOMEM);
645

    
646
    ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb));
647
    if (ret < 0) return ret;
648

    
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);
656

    
657
        // reserve space to write the segment UID later
658
        mkv->segment_uid = url_ftell(pb);
659
        put_ebml_void(pb, 19);
660
    }
661

    
662
    // reserve space for the duration
663
    mkv->duration = 0;
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);
667

    
668
    ret = mkv_write_tracks(s);
669
    if (ret < 0) return ret;
670

    
671
    ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
672
    if (ret < 0) return ret;
673

    
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;
678

    
679
    mkv->cues = mkv_start_cues(mkv->segment_offset);
680
    if (mkv->cues == NULL)
681
        return AVERROR(ENOMEM);
682

    
683
    return 0;
684
}
685

    
686
static int mkv_block_size(AVPacket *pkt)
687
{
688
    int size = 4;           // track num + timecode + flags
689
    return size + pkt->size;
690
}
691

    
692
static int mkv_blockgroup_size(AVPacket *pkt)
693
{
694
    int size = mkv_block_size(pkt);
695
    size += ebml_num_size(size);
696
    size += 2;              // EBML ID for block and block duration
697
    size += 8;              // max size of block duration
698
    size += ebml_num_size(size);
699
    size += 1;              // blockgroup EBML ID
700
    return size;
701
}
702

    
703
static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
704
{
705
    MatroskaMuxContext *mkv = s->priv_data;
706
    ByteIOContext *pb = &s->pb;
707

    
708
    av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, "
709
           "pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
710
           url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
711
    put_ebml_id(pb, blockid);
712
    put_ebml_num(pb, mkv_block_size(pkt), 0);
713
    put_byte(pb, 0x80 | (pkt->stream_index + 1));     // this assumes stream_index is less than 126
714
    put_be16(pb, pkt->pts - mkv->cluster_pts);
715
    put_byte(pb, flags);
716
    put_buffer(pb, pkt->data, pkt->size);
717
}
718

    
719
static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
720
{
721
    MatroskaMuxContext *mkv = s->priv_data;
722
    ByteIOContext *pb = &s->pb;
723
    AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
724
    int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
725
    int ret;
726

    
727
    // start a new cluster every 5 MB or 5 sec
728
    if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
729
        av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64
730
               " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
731
        end_ebml_master(pb, mkv->cluster);
732

    
733
        ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
734
        if (ret < 0) return ret;
735

    
736
        mkv->cluster_pos = url_ftell(pb);
737
        mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
738
        put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
739
        mkv->cluster_pts = pkt->pts;
740
        av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
741
    }
742

    
743
    if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
744
        mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
745
    } else {
746
        ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
747
        mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
748
        put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
749
        end_ebml_master(pb, blockgroup);
750
    }
751

    
752
    if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
753
        ret = mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos);
754
        if (ret < 0) return ret;
755
    }
756

    
757
    mkv->duration = FFMAX(mkv->duration, pkt->pts + pkt->duration);
758
    return 0;
759
}
760

    
761
static int mkv_write_trailer(AVFormatContext *s)
762
{
763
    MatroskaMuxContext *mkv = s->priv_data;
764
    ByteIOContext *pb = &s->pb;
765
    offset_t currentpos, second_seekhead, cuespos;
766
    int ret;
767

    
768
    end_ebml_master(pb, mkv->cluster);
769

    
770
    if (!url_is_streamed(pb)) {
771
        cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
772
        second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
773

    
774
        ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES    , cuespos);
775
        if (ret < 0) return ret;
776
        ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
777
        if (ret < 0) return ret;
778
        mkv_write_seekhead(pb, mkv->main_seekhead);
779

    
780
        // update the duration
781
        av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
782
        currentpos = url_ftell(pb);
783
        url_fseek(pb, mkv->duration_offset, SEEK_SET);
784
        put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
785

    
786
        // write the md5sum of some frames as the segment UID
787
        if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
788
            uint8_t segment_uid[16];
789
            av_md5_final(mkv->md5_ctx, segment_uid);
790
            url_fseek(pb, mkv->segment_uid, SEEK_SET);
791
            put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
792
        }
793
        url_fseek(pb, currentpos, SEEK_SET);
794
    }
795

    
796
    end_ebml_master(pb, mkv->segment);
797
    av_free(mkv->md5_ctx);
798
    return 0;
799
}
800

    
801
AVOutputFormat matroska_muxer = {
802
    "matroska",
803
    "Matroska File Format",
804
    "video/x-matroska",
805
    "mkv",
806
    sizeof(MatroskaMuxContext),
807
    CODEC_ID_MP2,
808
    CODEC_ID_MPEG4,
809
    mkv_write_header,
810
    mkv_write_packet,
811
    mkv_write_trailer,
812
    .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
813
    .subtitle_codec = CODEC_ID_TEXT,
814
};
815

    
816
AVOutputFormat matroska_audio_muxer = {
817
    "matroska",
818
    "Matroska File Format",
819
    "audio/x-matroska",
820
    "mka",
821
    sizeof(MatroskaMuxContext),
822
    CODEC_ID_MP2,
823
    CODEC_ID_NONE,
824
    mkv_write_header,
825
    mkv_write_packet,
826
    mkv_write_trailer,
827
    .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},
828
};