Statistics
| Branch: | Revision:

ffmpeg / libavformat / movenchint.c @ 1338dc08

History | View | Annotate | Download (16.4 KB)

1
/*
2
 * MOV, 3GP, MP4 muxer RTP hinting
3
 * Copyright (c) 2010 Martin Storsjo
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 "movenc.h"
23
#include "libavutil/intreadwrite.h"
24
#include "internal.h"
25

    
26
int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index)
27
{
28
    MOVMuxContext *mov  = s->priv_data;
29
    MOVTrack *track     = &mov->tracks[index];
30
    MOVTrack *src_track = &mov->tracks[src_index];
31
    AVStream *src_st    = s->streams[src_index];
32
    int ret = AVERROR(ENOMEM);
33
    AVOutputFormat *rtp_format = av_guess_format("rtp", NULL, NULL);
34

    
35
    track->tag = MKTAG('r','t','p',' ');
36
    track->src_track = src_index;
37

    
38
    if (!rtp_format) {
39
        ret = AVERROR(ENOENT);
40
        goto fail;
41
    }
42

    
43
    track->enc = avcodec_alloc_context();
44
    if (!track->enc)
45
        goto fail;
46
    track->enc->codec_type = AVMEDIA_TYPE_DATA;
47
    track->enc->codec_tag  = track->tag;
48

    
49
    track->rtp_ctx = avformat_alloc_context();
50
    if (!track->rtp_ctx)
51
        goto fail;
52
    track->rtp_ctx->oformat = rtp_format;
53
    if (!av_new_stream(track->rtp_ctx, 0))
54
        goto fail;
55

    
56
    /* Copy stream parameters */
57
    track->rtp_ctx->streams[0]->sample_aspect_ratio =
58
                        src_st->sample_aspect_ratio;
59

    
60
    avcodec_copy_context(track->rtp_ctx->streams[0]->codec, src_st->codec);
61

    
62
    if ((ret = url_open_dyn_packet_buf(&track->rtp_ctx->pb,
63
                                       RTP_MAX_PACKET_SIZE)) < 0)
64
        goto fail;
65
    ret = av_write_header(track->rtp_ctx);
66
    if (ret)
67
        goto fail;
68

    
69
    /* Copy the RTP AVStream timebase back to the hint AVStream */
70
    track->timescale = track->rtp_ctx->streams[0]->time_base.den;
71

    
72
    /* Mark the hinted track that packets written to it should be
73
     * sent to this track for hinting. */
74
    src_track->hint_track = index;
75
    return 0;
76
fail:
77
    av_log(s, AV_LOG_WARNING,
78
           "Unable to initialize hinting of stream %d\n", src_index);
79
    if (track->rtp_ctx && track->rtp_ctx->pb) {
80
        uint8_t *buf;
81
        url_close_dyn_buf(track->rtp_ctx->pb, &buf);
82
        av_free(buf);
83
    }
84
    if (track->rtp_ctx && track->rtp_ctx->streams[0]) {
85
        av_metadata_free(&track->rtp_ctx->streams[0]->metadata);
86
        av_free(track->rtp_ctx->streams[0]->codec->extradata);
87
        av_free(track->rtp_ctx->streams[0]->codec);
88
        av_free(track->rtp_ctx->streams[0]->info);
89
        av_free(track->rtp_ctx->streams[0]);
90
    }
91
    if (track->rtp_ctx) {
92
        av_metadata_free(&track->rtp_ctx->metadata);
93
        av_free(track->rtp_ctx->priv_data);
94
        av_freep(&track->rtp_ctx);
95
    }
96
    av_freep(&track->enc);
97
    /* Set a default timescale, to avoid crashes in dump_format */
98
    track->timescale = 90000;
99
    return ret;
100
}
101

    
102
/**
103
 * Remove the first sample from the sample queue.
104
 */
105
static void sample_queue_pop(HintSampleQueue *queue)
106
{
107
    if (queue->len <= 0)
108
        return;
109
    if (queue->samples[0].own_data)
110
        av_free(queue->samples[0].data);
111
    queue->len--;
112
    memmove(queue->samples, queue->samples + 1, sizeof(HintSample)*queue->len);
113
}
114

    
115
/**
116
 * Empty the sample queue, releasing all memory.
117
 */
118
static void sample_queue_free(HintSampleQueue *queue)
119
{
120
    int i;
121
    for (i = 0; i < queue->len; i++)
122
        if (queue->samples[i].own_data)
123
            av_free(queue->samples[i].data);
124
    av_freep(&queue->samples);
125
    queue->len = 0;
126
    queue->size = 0;
127
}
128

    
129
/**
130
 * Add a reference to the sample data to the sample queue. The data is
131
 * not copied. sample_queue_retain should be called before pkt->data
132
 * is reused/freed.
133
 */
134
static void sample_queue_push(HintSampleQueue *queue, AVPacket *pkt, int sample)
135
{
136
    /* No need to keep track of smaller samples, since describing them
137
     * with immediates is more efficient. */
138
    if (pkt->size <= 14)
139
        return;
140
    if (!queue->samples || queue->len >= queue->size) {
141
        HintSample* samples;
142
        queue->size += 10;
143
        samples = av_realloc(queue->samples, sizeof(HintSample)*queue->size);
144
        if (!samples)
145
            return;
146
        queue->samples = samples;
147
    }
148
    queue->samples[queue->len].data = pkt->data;
149
    queue->samples[queue->len].size = pkt->size;
150
    queue->samples[queue->len].sample_number = sample;
151
    queue->samples[queue->len].offset = 0;
152
    queue->samples[queue->len].own_data = 0;
153
    queue->len++;
154
}
155

    
156
/**
157
 * Make local copies of all referenced sample data in the queue.
158
 */
159
static void sample_queue_retain(HintSampleQueue *queue)
160
{
161
    int i;
162
    for (i = 0; i < queue->len; ) {
163
        HintSample *sample = &queue->samples[i];
164
        if (!sample->own_data) {
165
            uint8_t* ptr = av_malloc(sample->size);
166
            if (!ptr) {
167
                /* Unable to allocate memory for this one, remove it */
168
                memmove(queue->samples + i, queue->samples + i + 1,
169
                        sizeof(HintSample)*(queue->len - i - 1));
170
                queue->len--;
171
                continue;
172
            }
173
            memcpy(ptr, sample->data, sample->size);
174
            sample->data = ptr;
175
            sample->own_data = 1;
176
        }
177
        i++;
178
    }
179
}
180

    
181
/**
182
 * Find matches of needle[n_pos ->] within haystack. If a sufficiently
183
 * large match is found, matching bytes before n_pos are included
184
 * in the match, too (within the limits of the arrays).
185
 *
186
 * @param haystack buffer that may contain parts of needle
187
 * @param h_len length of the haystack buffer
188
 * @param needle buffer containing source data that have been used to
189
 *               construct haystack
190
 * @param n_pos start position in needle used for looking for matches
191
 * @param n_len length of the needle buffer
192
 * @param match_h_offset_ptr offset of the first matching byte within haystack
193
 * @param match_n_offset_ptr offset of the first matching byte within needle
194
 * @param match_len_ptr length of the matched segment
195
 * @return 0 if a match was found, < 0 if no match was found
196
 */
197
static int match_segments(const uint8_t *haystack, int h_len,
198
                          const uint8_t *needle, int n_pos, int n_len,
199
                          int *match_h_offset_ptr, int *match_n_offset_ptr,
200
                          int *match_len_ptr)
201
{
202
    int h_pos;
203
    for (h_pos = 0; h_pos < h_len; h_pos++) {
204
        int match_len = 0;
205
        int match_h_pos, match_n_pos;
206

    
207
        /* Check how many bytes match at needle[n_pos] and haystack[h_pos] */
208
        while (h_pos + match_len < h_len && n_pos + match_len < n_len &&
209
               needle[n_pos + match_len] == haystack[h_pos + match_len])
210
            match_len++;
211
        if (match_len <= 8)
212
            continue;
213

    
214
        /* If a sufficiently large match was found, try to expand
215
         * the matched segment backwards. */
216
        match_h_pos = h_pos;
217
        match_n_pos = n_pos;
218
        while (match_n_pos > 0 && match_h_pos > 0 &&
219
               needle[match_n_pos - 1] == haystack[match_h_pos - 1]) {
220
            match_n_pos--;
221
            match_h_pos--;
222
            match_len++;
223
        }
224
        if (match_len <= 14)
225
            continue;
226
        *match_h_offset_ptr = match_h_pos;
227
        *match_n_offset_ptr = match_n_pos;
228
        *match_len_ptr = match_len;
229
        return 0;
230
    }
231
    return -1;
232
}
233

    
234
/**
235
 * Look for segments in samples in the sample queue matching the data
236
 * in ptr. Samples not matching are removed from the queue. If a match
237
 * is found, the next time it will look for matches starting from the
238
 * end of the previous matched segment.
239
 *
240
 * @param data data to find matches for in the sample queue
241
 * @param len length of the data buffer
242
 * @param queue samples used for looking for matching segments
243
 * @param pos the offset in data of the matched segment
244
 * @param match_sample the number of the sample that contained the match
245
 * @param match_offset the offset of the matched segment within the sample
246
 * @param match_len the length of the matched segment
247
 * @return 0 if a match was found, < 0 if no match was found
248
 */
249
static int find_sample_match(const uint8_t *data, int len,
250
                             HintSampleQueue *queue, int *pos,
251
                             int *match_sample, int *match_offset,
252
                             int *match_len)
253
{
254
    while (queue->len > 0) {
255
        HintSample *sample = &queue->samples[0];
256
        /* If looking for matches in a new sample, skip the first 5 bytes,
257
         * since they often may be modified/removed in the output packet. */
258
        if (sample->offset == 0 && sample->size > 5)
259
            sample->offset = 5;
260

    
261
        if (match_segments(data, len, sample->data, sample->offset,
262
                           sample->size, pos, match_offset, match_len) == 0) {
263
            *match_sample = sample->sample_number;
264
            /* Next time, look for matches at this offset, with a little
265
             * margin to this match. */
266
            sample->offset = *match_offset + *match_len + 5;
267
            if (sample->offset + 10 >= sample->size)
268
                sample_queue_pop(queue); /* Not enough useful data left */
269
            return 0;
270
        }
271

    
272
        if (sample->offset < 10 && sample->size > 20) {
273
            /* No match found from the start of the sample,
274
             * try from the middle of the sample instead. */
275
            sample->offset = sample->size/2;
276
        } else {
277
            /* No match for this sample, remove it */
278
            sample_queue_pop(queue);
279
        }
280
    }
281
    return -1;
282
}
283

    
284
static void output_immediate(const uint8_t *data, int size,
285
                             ByteIOContext *out, int *entries)
286
{
287
    while (size > 0) {
288
        int len = size;
289
        if (len > 14)
290
            len = 14;
291
        put_byte(out, 1); /* immediate constructor */
292
        put_byte(out, len); /* amount of valid data */
293
        put_buffer(out, data, len);
294
        data += len;
295
        size -= len;
296

    
297
        for (; len < 14; len++)
298
            put_byte(out, 0);
299

    
300
        (*entries)++;
301
    }
302
}
303

    
304
static void output_match(ByteIOContext *out, int match_sample,
305
                         int match_offset, int match_len, int *entries)
306
{
307
    put_byte(out, 2); /* sample constructor */
308
    put_byte(out, 0); /* track reference */
309
    put_be16(out, match_len);
310
    put_be32(out, match_sample);
311
    put_be32(out, match_offset);
312
    put_be16(out, 1); /* bytes per block */
313
    put_be16(out, 1); /* samples per block */
314
    (*entries)++;
315
}
316

    
317
static void describe_payload(const uint8_t *data, int size,
318
                             ByteIOContext *out, int *entries,
319
                             HintSampleQueue *queue)
320
{
321
    /* Describe the payload using different constructors */
322
    while (size > 0) {
323
        int match_sample, match_offset, match_len, pos;
324
        if (find_sample_match(data, size, queue, &pos, &match_sample,
325
                              &match_offset, &match_len) < 0)
326
            break;
327
        output_immediate(data, pos, out, entries);
328
        data += pos;
329
        size -= pos;
330
        output_match(out, match_sample, match_offset, match_len, entries);
331
        data += match_len;
332
        size -= match_len;
333
    }
334
    output_immediate(data, size, out, entries);
335
}
336

    
337
/**
338
 * Write an RTP hint (that may contain one or more RTP packets)
339
 * for the packets in data. data contains one or more packets with a
340
 * BE32 size header.
341
 *
342
 * @param out buffer where the hints are written
343
 * @param data buffer containing RTP packets
344
 * @param size the size of the data buffer
345
 * @param trk the MOVTrack for the hint track
346
 * @param pts pointer where the timestamp for the written RTP hint is stored
347
 * @return the number of RTP packets in the written hint
348
 */
349
static int write_hint_packets(ByteIOContext *out, const uint8_t *data,
350
                              int size, MOVTrack *trk, int64_t *pts)
351
{
352
    int64_t curpos;
353
    int64_t count_pos, entries_pos;
354
    int count = 0, entries;
355

    
356
    count_pos = url_ftell(out);
357
    /* RTPsample header */
358
    put_be16(out, 0); /* packet count */
359
    put_be16(out, 0); /* reserved */
360

    
361
    while (size > 4) {
362
        uint32_t packet_len = AV_RB32(data);
363
        uint16_t seq;
364
        uint32_t ts;
365

    
366
        data += 4;
367
        size -= 4;
368
        if (packet_len > size || packet_len <= 12)
369
            break;
370
        if (data[1] >= 200 && data[1] <= 204) {
371
            /* RTCP packet, just skip */
372
            data += packet_len;
373
            size -= packet_len;
374
            continue;
375
        }
376

    
377
        if (packet_len > trk->max_packet_size)
378
            trk->max_packet_size = packet_len;
379

    
380
        seq = AV_RB16(&data[2]);
381
        ts = AV_RB32(&data[4]);
382

    
383
        if (trk->prev_rtp_ts == 0)
384
            trk->prev_rtp_ts = ts;
385
        /* Unwrap the 32-bit RTP timestamp that wraps around often
386
         * into a not (as often) wrapping 64-bit timestamp. */
387
        trk->cur_rtp_ts_unwrapped += (int32_t) (ts - trk->prev_rtp_ts);
388
        trk->prev_rtp_ts = ts;
389
        if (*pts == AV_NOPTS_VALUE)
390
            *pts = trk->cur_rtp_ts_unwrapped;
391

    
392
        count++;
393
        /* RTPpacket header */
394
        put_be32(out, 0); /* relative_time */
395
        put_buffer(out, data, 2); /* RTP header */
396
        put_be16(out, seq); /* RTPsequenceseed */
397
        put_be16(out, 0); /* reserved + flags */
398
        entries_pos = url_ftell(out);
399
        put_be16(out, 0); /* entry count */
400

    
401
        data += 12;
402
        size -= 12;
403
        packet_len -= 12;
404

    
405
        entries = 0;
406
        /* Write one or more constructors describing the payload data */
407
        describe_payload(data, packet_len, out, &entries, &trk->sample_queue);
408
        data += packet_len;
409
        size -= packet_len;
410

    
411
        curpos = url_ftell(out);
412
        url_fseek(out, entries_pos, SEEK_SET);
413
        put_be16(out, entries);
414
        url_fseek(out, curpos, SEEK_SET);
415
    }
416

    
417
    curpos = url_ftell(out);
418
    url_fseek(out, count_pos, SEEK_SET);
419
    put_be16(out, count);
420
    url_fseek(out, curpos, SEEK_SET);
421
    return count;
422
}
423

    
424
int ff_mov_add_hinted_packet(AVFormatContext *s, AVPacket *pkt,
425
                             int track_index, int sample)
426
{
427
    MOVMuxContext *mov = s->priv_data;
428
    MOVTrack *trk = &mov->tracks[track_index];
429
    AVFormatContext *rtp_ctx = trk->rtp_ctx;
430
    uint8_t *buf = NULL;
431
    int size;
432
    ByteIOContext *hintbuf = NULL;
433
    AVPacket hint_pkt;
434
    int ret = 0, count;
435

    
436
    if (!rtp_ctx)
437
        return AVERROR(ENOENT);
438
    if (!rtp_ctx->pb)
439
        return AVERROR(ENOMEM);
440

    
441
    sample_queue_push(&trk->sample_queue, pkt, sample);
442

    
443
    /* Feed the packet to the RTP muxer */
444
    ff_write_chained(rtp_ctx, 0, pkt, s);
445

    
446
    /* Fetch the output from the RTP muxer, open a new output buffer
447
     * for next time. */
448
    size = url_close_dyn_buf(rtp_ctx->pb, &buf);
449
    if ((ret = url_open_dyn_packet_buf(&rtp_ctx->pb,
450
                                       RTP_MAX_PACKET_SIZE)) < 0)
451
        goto done;
452

    
453
    if (size <= 0)
454
        goto done;
455

    
456
    /* Open a buffer for writing the hint */
457
    if ((ret = url_open_dyn_buf(&hintbuf)) < 0)
458
        goto done;
459
    av_init_packet(&hint_pkt);
460
    count = write_hint_packets(hintbuf, buf, size, trk, &hint_pkt.dts);
461
    av_freep(&buf);
462

    
463
    /* Write the hint data into the hint track */
464
    hint_pkt.size = size = url_close_dyn_buf(hintbuf, &buf);
465
    hint_pkt.data = buf;
466
    hint_pkt.pts  = hint_pkt.dts;
467
    hint_pkt.stream_index = track_index;
468
    if (pkt->flags & AV_PKT_FLAG_KEY)
469
        hint_pkt.flags |= AV_PKT_FLAG_KEY;
470
    if (count > 0)
471
        ff_mov_write_packet(s, &hint_pkt);
472
done:
473
    av_free(buf);
474
    sample_queue_retain(&trk->sample_queue);
475
    return ret;
476
}
477

    
478
void ff_mov_close_hinting(MOVTrack *track) {
479
    AVFormatContext* rtp_ctx = track->rtp_ctx;
480
    uint8_t *ptr;
481

    
482
    av_freep(&track->enc);
483
    sample_queue_free(&track->sample_queue);
484
    if (!rtp_ctx)
485
        return;
486
    if (rtp_ctx->pb) {
487
        av_write_trailer(rtp_ctx);
488
        url_close_dyn_buf(rtp_ctx->pb, &ptr);
489
        av_free(ptr);
490
    }
491
    av_metadata_free(&rtp_ctx->streams[0]->metadata);
492
    av_metadata_free(&rtp_ctx->metadata);
493
    av_free(rtp_ctx->streams[0]->codec->extradata);
494
    av_free(rtp_ctx->streams[0]->codec);
495
    av_free(rtp_ctx->streams[0]->info);
496
    av_free(rtp_ctx->streams[0]);
497
    av_freep(&rtp_ctx);
498
}
499