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ffmpeg / libavformat / matroskaenc.c @ 0580a122

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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
 *
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 * 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
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21

    
22
#include "avformat.h"
23
#include "md5.h"
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#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;
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    mkv_seekhead_entry      *entries;
44
    int                     num_entries;
45
} mkv_seekhead;
46

    
47
typedef struct {
48
    uint64_t        pts;
49
    int             tracknum;
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    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
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    uint64_t        cluster_pts;
66
    offset_t        duration_offset;
67
    uint64_t        duration;
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    mkv_seekhead    *main_seekhead;
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    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 of 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 size in EBML.
115
 */
116
static int ebml_size_bytes(uint64_t size)
117
{
118
    int bytes = 1;
119
    while ((size+1) >> bytes*7) bytes++;
120
    return bytes;
121
}
122

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

    
133
    // sizes larger than this are currently undefined in EBML
134
    // so write "unknown" size
135
    if (size >= (1ULL<<56)-1) {
136
        put_ebml_size_unknown(pb, 1);
137
        return;
138
    }
139

    
140
    if (bytes == 0)
141
        // don't care how many bytes are used, so use the min
142
        bytes = needed_bytes;
143
        // the bytes needed to write the given size would exceed the bytes
144
        // that we need to use, so write unknown size. This shouldn't happen.
145
    assert(bytes >= needed_bytes);
146

    
147
    size |= 1ULL << bytes*7;
148
    for (i = bytes - 1; i >= 0; i--)
149
        put_byte(pb, size >> i*8);
150
}
151

    
152
static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
153
{
154
    int i, bytes = 1;
155
    while (val >> bytes*8) bytes++;
156

    
157
    put_ebml_id(pb, elementid);
158
    put_ebml_size(pb, bytes, 0);
159
    for (i = bytes - 1; i >= 0; i--)
160
        put_byte(pb, val >> i*8);
161
}
162

    
163
static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
164
{
165
    put_ebml_id(pb, elementid);
166
    put_ebml_size(pb, 8, 0);
167
    put_be64(pb, av_dbl2int(val));
168
}
169

    
170
static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
171
                            const uint8_t *buf, int size)
172
{
173
    put_ebml_id(pb, elementid);
174
    put_ebml_size(pb, size, 0);
175
    put_buffer(pb, buf, size);
176
}
177

    
178
static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
179
{
180
    put_ebml_binary(pb, elementid, str, strlen(str));
181
}
182

    
183
/**
184
 * Writes a void element of a given size. Useful for reserving space in
185
 * the file to be written to later.
186
 *
187
 * @param size The number of bytes to reserve, which must be at least 2.
188
 */
189
static void put_ebml_void(ByteIOContext *pb, uint64_t size)
190
{
191
    offset_t currentpos = url_ftell(pb);
192

    
193
    assert(size >= 2);
194

    
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
199
    if (size < 10)
200
        put_ebml_size(pb, size-1, 0);
201
    else
202
        put_ebml_size(pb, size-9, 8);
203
    url_fseek(pb, currentpos + size, SEEK_SET);
204
}
205

    
206
static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
207
{
208
    int bytes = expectedsize ? ebml_size_bytes(expectedsize) : 8;
209
    put_ebml_id(pb, elementid);
210
    put_ebml_size_unknown(pb, bytes);
211
    return (ebml_master){ url_ftell(pb), bytes };
212
}
213

    
214
static void end_ebml_master(ByteIOContext *pb, ebml_master master)
215
{
216
    offset_t pos = url_ftell(pb);
217

    
218
    url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
219
    put_ebml_size(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
    int new_entry = seekhead->num_entries;
266

    
267
    // don't store more elements than we reserved space for
268
    if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
269
        return -1;
270

    
271
    entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
272
    if (entries == NULL)
273
        return -1;
274

    
275
    entries[new_entry].elementid = elementid;
276
    entries[new_entry].segmentpos = filepos - seekhead->segment_offset;
277

    
278
    seekhead->entries = entries;
279
    seekhead->num_entries++;
280

    
281
    return 0;
282
}
283

    
284
/**
285
 * Write the seek head to the file and free it. If a maximum number of
286
 * elements was specified to mkv_start_seekhead(), the seek head will
287
 * be written at the location reserved for it. Otherwise, it is written
288
 * at the current location in the file.
289
 *
290
 * @return the file offset where the seekhead was written
291
 */
292
static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
293
{
294
    ebml_master metaseek, seekentry;
295
    offset_t currentpos;
296
    int i;
297

    
298
    currentpos = url_ftell(pb);
299

    
300
    if (seekhead->reserved_size > 0)
301
        url_fseek(pb, seekhead->filepos, SEEK_SET);
302

    
303
    metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
304
    for (i = 0; i < seekhead->num_entries; i++) {
305
        mkv_seekhead_entry *entry = &seekhead->entries[i];
306

    
307
        seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
308

    
309
        put_ebml_id(pb, MATROSKA_ID_SEEKID);
310
        put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
311
        put_ebml_id(pb, entry->elementid);
312

    
313
        put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
314
        end_ebml_master(pb, seekentry);
315
    }
316
    end_ebml_master(pb, metaseek);
317

    
318
    if (seekhead->reserved_size > 0) {
319
        uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
320
        put_ebml_void(pb, remaining);
321
        url_fseek(pb, currentpos, SEEK_SET);
322

    
323
        currentpos = seekhead->filepos;
324
    }
325
    av_free(seekhead->entries);
326
    av_free(seekhead);
327

    
328
    return currentpos;
329
}
330

    
331
static mkv_cues * mkv_start_cues(offset_t segment_offset)
332
{
333
    mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
334
    if (cues == NULL)
335
        return NULL;
336

    
337
    cues->segment_offset = segment_offset;
338
    return cues;
339
}
340

    
341
static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
342
{
343
    mkv_cuepoint *entries = cues->entries;
344
    int new_entry = cues->num_entries;
345

    
346
    entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
347
    if (entries == NULL)
348
        return -1;
349

    
350
    entries[new_entry].pts = pkt->pts;
351
    entries[new_entry].tracknum = pkt->stream_index + 1;
352
    entries[new_entry].cluster_pos = cluster_pos - cues->segment_offset;
353

    
354
    cues->entries = entries;
355
    cues->num_entries++;
356
    return 0;
357
}
358

    
359
static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
360
{
361
    ebml_master cues_element;
362
    offset_t currentpos;
363
    int i, j;
364

    
365
    currentpos = url_ftell(pb);
366
    cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
367

    
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;
372

    
373
        cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
374
        put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
375

    
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);
383
        }
384
        i += j - 1;
385
        end_ebml_master(pb, cuepoint);
386
    }
387
    end_ebml_master(pb, cues_element);
388

    
389
    av_free(cues->entries);
390
    av_free(cues);
391
    return currentpos;
392
}
393

    
394
static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
395
{
396
    ebml_master codecprivate;
397
    uint8_t *header_start[3];
398
    int header_len[3];
399
    int first_header_size;
400
    int j;
401

    
402
    if (codec->codec_id == CODEC_ID_VORBIS)
403
        first_header_size = 30;
404
    else
405
        first_header_size = 42;
406

    
407
    if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
408
                              first_header_size, header_start, header_len) < 0) {
409
        av_log(codec, AV_LOG_ERROR, "Extradata corrupt.\n");
410
        return -1;
411
    }
412

    
413
    codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
414
    put_byte(pb, 2);                    // number packets - 1
415
    for (j = 0; j < 2; j++) {
416
        put_xiph_size(pb, header_len[j]);
417
    }
418
    for (j = 0; j < 3; j++)
419
        put_buffer(pb, header_start[j], header_len[j]);
420
    end_ebml_master(pb, codecprivate);
421

    
422
    return 0;
423
}
424

    
425
#define FLAC_STREAMINFO_SIZE 34
426

    
427
static int put_flac_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
428
{
429
    ebml_master codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
430

    
431
    // if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
432
    // assume that it's in Matroska's format already
433
    if (codec->extradata_size < FLAC_STREAMINFO_SIZE) {
434
        av_log(codec, AV_LOG_ERROR, "Invalid FLAC extradata\n");
435
        return -1;
436
    } else if (codec->extradata_size == FLAC_STREAMINFO_SIZE) {
437
        // only the streaminfo packet
438
        put_byte(pb, 0);
439
        put_xiph_size(pb, codec->extradata_size);
440
        av_log(codec, AV_LOG_ERROR, "Only one packet\n");
441
    }
442
    put_buffer(pb, codec->extradata, codec->extradata_size);
443
    end_ebml_master(pb, codecpriv);
444
    return 0;
445
}
446

    
447
static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
448
{
449
    static const int aac_sample_rates[] = {
450
        96000, 88200, 64000, 48000, 44100, 32000,
451
        24000, 22050, 16000, 12000, 11025,  8000,
452
    };
453
    int sri;
454

    
455
    if (codec->extradata_size < 2) {
456
        av_log(codec, AV_LOG_WARNING, "no AAC extradata, unable to determine samplerate\n");
457
        return;
458
    }
459

    
460
    sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
461
    if (sri > 12) {
462
        av_log(codec, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
463
        return;
464
    }
465
    *sample_rate = aac_sample_rates[sri];
466

    
467
    // if sbr, get output sample rate as well
468
    if (codec->extradata_size == 5) {
469
        sri = (codec->extradata[4] >> 3) & 0xF;
470
        if (sri > 12) {
471
            av_log(codec, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
472
            return;
473
        }
474
        *output_sample_rate = aac_sample_rates[sri];
475
    }
476
}
477

    
478
static int mkv_write_tracks(AVFormatContext *s)
479
{
480
    MatroskaMuxContext *mkv = s->priv_data;
481
    ByteIOContext *pb = &s->pb;
482
    ebml_master tracks;
483
    int i, j;
484

    
485
    if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb)) < 0)
486
        return -1;
487

    
488
    tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
489
    for (i = 0; i < s->nb_streams; i++) {
490
        AVStream *st = s->streams[i];
491
        AVCodecContext *codec = st->codec;
492
        ebml_master subinfo, track;
493
        int native_id = 0;
494
        int bit_depth = av_get_bits_per_sample(codec->codec_id);
495
        int sample_rate = codec->sample_rate;
496
        int output_sample_rate = 0;
497

    
498
        if (!bit_depth)
499
            bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
500

    
501
        if (codec->codec_id == CODEC_ID_AAC)
502
            get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
503

    
504
        track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
505
        put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER     , i + 1);
506
        put_ebml_uint (pb, MATROSKA_ID_TRACKUID        , i + 1);
507
        put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0);    // no lacing (yet)
508

    
509
        if (st->language[0])
510
            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
511
        else
512
            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, "und");
513

    
514
        // look for a codec id string specific to mkv to use,
515
        // if none are found, use AVI codes
516
        for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
517
            if (ff_mkv_codec_tags[j].id == codec->codec_id) {
518
                put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
519
                native_id = 1;
520
                break;
521
            }
522
        }
523

    
524
        if (native_id) {
525
            if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
526
                if (put_xiph_codecpriv(pb, codec) < 0)
527
                    return -1;
528
            } else if (codec->codec_id == CODEC_ID_FLAC) {
529
                if (put_flac_codecpriv(pb, codec) < 0)
530
                    return -1;
531
            } else if (codec->extradata_size) {
532
                put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
533
            }
534
        }
535

    
536
        switch (codec->codec_type) {
537
            case CODEC_TYPE_VIDEO:
538
                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
539

    
540
                if (!native_id) {
541
                    ebml_master bmp_header;
542
                    // if there is no mkv-specific codec id, use VFW mode
543
                    if (!codec->codec_tag)
544
                        codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
545

    
546
                    put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
547
                    bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
548
                    put_bmp_header(pb, codec, codec_bmp_tags, 0);
549
                    end_ebml_master(pb, bmp_header);
550
                }
551
                subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
552
                // XXX: interlace flag?
553
                put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
554
                put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
555
                if (codec->sample_aspect_ratio.num) {
556
                    AVRational dar = av_mul_q(codec->sample_aspect_ratio, (AVRational){codec->width, codec->height});
557
                    put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , dar.num);
558
                    put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, dar.den);
559
                }
560
                end_ebml_master(pb, subinfo);
561
                break;
562

    
563
            case CODEC_TYPE_AUDIO:
564
                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
565

    
566
                if (!native_id) {
567
                    ebml_master wav_header;
568
                    // no mkv-specific ID, use ACM mode
569
                    codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
570
                    if (!codec->codec_tag) {
571
                        av_log(s, AV_LOG_ERROR, "no codec id found for stream %d", i);
572
                        return -1;
573
                    }
574

    
575
                    put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
576
                    wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
577
                    put_wav_header(pb, codec);
578
                    end_ebml_master(pb, wav_header);
579
                }
580
                subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
581
                put_ebml_uint  (pb, MATROSKA_ID_AUDIOCHANNELS    , codec->channels);
582
                put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
583
                if (output_sample_rate)
584
                    put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
585
                if (bit_depth)
586
                    put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
587
                end_ebml_master(pb, subinfo);
588
                break;
589

    
590
                case CODEC_TYPE_SUBTITLE:
591
                    put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
592
                    break;
593
            default:
594
                av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
595
                break;
596
        }
597
        end_ebml_master(pb, track);
598

    
599
        // ms precision is the de-facto standard timescale for mkv files
600
        av_set_pts_info(st, 64, 1, 1000);
601
    }
602
    end_ebml_master(pb, tracks);
603
    return 0;
604
}
605

    
606
static int mkv_write_header(AVFormatContext *s)
607
{
608
    MatroskaMuxContext *mkv = s->priv_data;
609
    ByteIOContext *pb = &s->pb;
610
    ebml_master ebml_header, segment_info;
611

    
612
    mkv->md5_ctx = av_mallocz(av_md5_size);
613
    av_md5_init(mkv->md5_ctx);
614

    
615
    ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
616
    put_ebml_uint   (pb, EBML_ID_EBMLVERSION        ,           1);
617
    put_ebml_uint   (pb, EBML_ID_EBMLREADVERSION    ,           1);
618
    put_ebml_uint   (pb, EBML_ID_EBMLMAXIDLENGTH    ,           4);
619
    put_ebml_uint   (pb, EBML_ID_EBMLMAXSIZELENGTH  ,           8);
620
    put_ebml_string (pb, EBML_ID_DOCTYPE            ,  "matroska");
621
    put_ebml_uint   (pb, EBML_ID_DOCTYPEVERSION     ,           2);
622
    put_ebml_uint   (pb, EBML_ID_DOCTYPEREADVERSION ,           2);
623
    end_ebml_master(pb, ebml_header);
624

    
625
    mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
626
    mkv->segment_offset = url_ftell(pb);
627

    
628
    // we write 2 seek heads - one at the end of the file to point to each
629
    // cluster, and one at the beginning to point to all other level one
630
    // elements (including the seek head at the end of the file), which
631
    // isn't more than 10 elements if we only write one of each other
632
    // currently defined level 1 element
633
    mkv->main_seekhead    = mkv_start_seekhead(pb, mkv->segment_offset, 10);
634
    mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
635

    
636
    if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb)) < 0)
637
        return -1;
638

    
639
    segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
640
    put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
641
    if (strlen(s->title))
642
        put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
643
    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
644
        put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
645
        put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
646

    
647
        // reserve space to write the segment UID later
648
        mkv->segment_uid = url_ftell(pb);
649
        put_ebml_void(pb, 19);
650
    }
651

    
652
    // reserve space for the duration
653
    mkv->duration = 0;
654
    mkv->duration_offset = url_ftell(pb);
655
    put_ebml_void(pb, 11);                  // assumes double-precision float to be written
656
    end_ebml_master(pb, segment_info);
657

    
658
    if (mkv_write_tracks(s) < 0)
659
        return -1;
660

    
661
    if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
662
        return -1;
663

    
664
    mkv->cluster_pos = url_ftell(pb);
665
    mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
666
    put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
667
    mkv->cluster_pts = 0;
668

    
669
    mkv->cues = mkv_start_cues(mkv->segment_offset);
670
    if (mkv->cues == NULL)
671
        return -1;
672

    
673
    return 0;
674
}
675

    
676
static int mkv_block_size(AVPacket *pkt)
677
{
678
    int size = 4;           // track num + timecode + flags
679
    return size + pkt->size;
680
}
681

    
682
static int mkv_blockgroup_size(AVPacket *pkt)
683
{
684
    int size = mkv_block_size(pkt);
685
    size += ebml_size_bytes(size);
686
    size += 2;              // EBML ID for block and block duration
687
    size += 8;              // max size of block duration
688
    size += ebml_size_bytes(size);
689
    size += 1;              // blockgroup EBML ID
690
    return size;
691
}
692

    
693
static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
694
{
695
    MatroskaMuxContext *mkv = s->priv_data;
696
    ByteIOContext *pb = &s->pb;
697

    
698
    av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
699
           url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
700
    put_ebml_id(pb, blockid);
701
    put_ebml_size(pb, mkv_block_size(pkt), 0);
702
    put_byte(pb, 0x80 | (pkt->stream_index + 1));     // this assumes stream_index is less than 126
703
    put_be16(pb, pkt->pts - mkv->cluster_pts);
704
    put_byte(pb, flags);
705
    put_buffer(pb, pkt->data, pkt->size);
706
}
707

    
708
static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
709
{
710
    MatroskaMuxContext *mkv = s->priv_data;
711
    ByteIOContext *pb = &s->pb;
712
    AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
713
    int keyframe = !!(pkt->flags & PKT_FLAG_KEY);
714

    
715
    // start a new cluster every 5 MB or 5 sec
716
    if (url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
717
        av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64 " bytes, pts %" PRIu64 "\n", url_ftell(pb), pkt->pts);
718
        end_ebml_master(pb, mkv->cluster);
719

    
720
        if (mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb)) < 0)
721
            return -1;
722

    
723
        mkv->cluster_pos = url_ftell(pb);
724
        mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
725
        put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
726
        mkv->cluster_pts = pkt->pts;
727
        av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
728
    }
729

    
730
    if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
731
        mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
732
    } else {
733
        ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
734
        mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
735
        put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
736
        end_ebml_master(pb, blockgroup);
737
    }
738

    
739
    if (codec->codec_type == CODEC_TYPE_VIDEO && keyframe) {
740
        if (mkv_add_cuepoint(mkv->cues, pkt, mkv->cluster_pos) < 0)
741
            return -1;
742
    }
743

    
744
    mkv->duration = pkt->pts + pkt->duration;
745
    return 0;
746
}
747

    
748
static int mkv_write_trailer(AVFormatContext *s)
749
{
750
    MatroskaMuxContext *mkv = s->priv_data;
751
    ByteIOContext *pb = &s->pb;
752
    offset_t currentpos, second_seekhead, cuespos;
753

    
754
    end_ebml_master(pb, mkv->cluster);
755

    
756
    cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
757
    second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
758

    
759
    mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES    , cuespos);
760
    mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
761
    mkv_write_seekhead(pb, mkv->main_seekhead);
762

    
763
    // update the duration
764
    av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
765
    currentpos = url_ftell(pb);
766
    url_fseek(pb, mkv->duration_offset, SEEK_SET);
767
    put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
768

    
769
    // write the md5sum of some frames as the segment UID
770
    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
771
        uint8_t segment_uid[16];
772
        av_md5_final(mkv->md5_ctx, segment_uid);
773
        url_fseek(pb, mkv->segment_uid, SEEK_SET);
774
        put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
775
    }
776
    url_fseek(pb, currentpos, SEEK_SET);
777

    
778
    end_ebml_master(pb, mkv->segment);
779
    av_free(mkv->md5_ctx);
780
    return 0;
781
}
782

    
783
AVOutputFormat matroska_muxer = {
784
    "matroska",
785
    "Matroska File Format",
786
    "video/x-matroska",
787
    "mkv",
788
    sizeof(MatroskaMuxContext),
789
    CODEC_ID_MP2,
790
    CODEC_ID_MPEG4,
791
    mkv_write_header,
792
    mkv_write_packet,
793
    mkv_write_trailer,
794
    .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
795
    .subtitle_codec = CODEC_ID_TEXT,
796
};
797

    
798
AVOutputFormat matroska_audio_muxer = {
799
    "matroska",
800
    "Matroska File Format",
801
    "audio/x-matroska",
802
    "mka",
803
    sizeof(MatroskaMuxContext),
804
    CODEC_ID_MP2,
805
    CODEC_ID_NONE,
806
    mkv_write_header,
807
    mkv_write_packet,
808
    mkv_write_trailer,
809
    .codec_tag = (const AVCodecTag*[]){codec_wav_tags, 0},
810
};