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2ba45a60 DM |
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 | #include "rtpenc_chain.h" | |
26 | #include "avio_internal.h" | |
27 | #include "rtp.h" | |
28 | ||
29 | int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index) | |
30 | { | |
31 | MOVMuxContext *mov = s->priv_data; | |
32 | MOVTrack *track = &mov->tracks[index]; | |
33 | MOVTrack *src_track = &mov->tracks[src_index]; | |
34 | AVStream *src_st = s->streams[src_index]; | |
35 | int ret = AVERROR(ENOMEM); | |
36 | ||
37 | track->tag = MKTAG('r','t','p',' '); | |
38 | track->src_track = src_index; | |
39 | ||
40 | track->enc = avcodec_alloc_context3(NULL); | |
41 | if (!track->enc) | |
42 | goto fail; | |
43 | track->enc->codec_type = AVMEDIA_TYPE_DATA; | |
44 | track->enc->codec_tag = track->tag; | |
45 | ||
46 | ret = ff_rtp_chain_mux_open(&track->rtp_ctx, s, src_st, NULL, | |
47 | RTP_MAX_PACKET_SIZE, src_index); | |
48 | if (ret < 0) | |
49 | goto fail; | |
50 | ||
51 | /* Copy the RTP AVStream timebase back to the hint AVStream */ | |
52 | track->timescale = track->rtp_ctx->streams[0]->time_base.den; | |
53 | ||
54 | /* Mark the hinted track that packets written to it should be | |
55 | * sent to this track for hinting. */ | |
56 | src_track->hint_track = index; | |
57 | return 0; | |
58 | fail: | |
59 | av_log(s, AV_LOG_WARNING, | |
60 | "Unable to initialize hinting of stream %d\n", src_index); | |
61 | av_freep(&track->enc); | |
62 | /* Set a default timescale, to avoid crashes in av_dump_format */ | |
63 | track->timescale = 90000; | |
64 | return ret; | |
65 | } | |
66 | ||
67 | /** | |
68 | * Remove the first sample from the sample queue. | |
69 | */ | |
70 | static void sample_queue_pop(HintSampleQueue *queue) | |
71 | { | |
72 | if (queue->len <= 0) | |
73 | return; | |
74 | if (queue->samples[0].own_data) | |
75 | av_freep(&queue->samples[0].data); | |
76 | queue->len--; | |
77 | memmove(queue->samples, queue->samples + 1, sizeof(HintSample)*queue->len); | |
78 | } | |
79 | ||
80 | /** | |
81 | * Empty the sample queue, releasing all memory. | |
82 | */ | |
83 | static void sample_queue_free(HintSampleQueue *queue) | |
84 | { | |
85 | int i; | |
86 | for (i = 0; i < queue->len; i++) | |
87 | if (queue->samples[i].own_data) | |
88 | av_freep(&queue->samples[i].data); | |
89 | av_freep(&queue->samples); | |
90 | queue->len = 0; | |
91 | queue->size = 0; | |
92 | } | |
93 | ||
94 | /** | |
95 | * Add a reference to the sample data to the sample queue. The data is | |
96 | * not copied. sample_queue_retain should be called before pkt->data | |
97 | * is reused/freed. | |
98 | */ | |
99 | static void sample_queue_push(HintSampleQueue *queue, uint8_t *data, int size, | |
100 | int sample) | |
101 | { | |
102 | /* No need to keep track of smaller samples, since describing them | |
103 | * with immediates is more efficient. */ | |
104 | if (size <= 14) | |
105 | return; | |
106 | if (!queue->samples || queue->len >= queue->size) { | |
107 | HintSample *samples; | |
108 | samples = av_realloc_array(queue->samples, queue->size + 10, sizeof(HintSample)); | |
109 | if (!samples) | |
110 | return; | |
111 | queue->size += 10; | |
112 | queue->samples = samples; | |
113 | } | |
114 | queue->samples[queue->len].data = data; | |
115 | queue->samples[queue->len].size = size; | |
116 | queue->samples[queue->len].sample_number = sample; | |
117 | queue->samples[queue->len].offset = 0; | |
118 | queue->samples[queue->len].own_data = 0; | |
119 | queue->len++; | |
120 | } | |
121 | ||
122 | /** | |
123 | * Make local copies of all referenced sample data in the queue. | |
124 | */ | |
125 | static void sample_queue_retain(HintSampleQueue *queue) | |
126 | { | |
127 | int i; | |
128 | for (i = 0; i < queue->len; ) { | |
129 | HintSample *sample = &queue->samples[i]; | |
130 | if (!sample->own_data) { | |
131 | uint8_t *ptr = av_malloc(sample->size); | |
132 | if (!ptr) { | |
133 | /* Unable to allocate memory for this one, remove it */ | |
134 | memmove(queue->samples + i, queue->samples + i + 1, | |
135 | sizeof(HintSample)*(queue->len - i - 1)); | |
136 | queue->len--; | |
137 | continue; | |
138 | } | |
139 | memcpy(ptr, sample->data, sample->size); | |
140 | sample->data = ptr; | |
141 | sample->own_data = 1; | |
142 | } | |
143 | i++; | |
144 | } | |
145 | } | |
146 | ||
147 | /** | |
148 | * Find matches of needle[n_pos ->] within haystack. If a sufficiently | |
149 | * large match is found, matching bytes before n_pos are included | |
150 | * in the match, too (within the limits of the arrays). | |
151 | * | |
152 | * @param haystack buffer that may contain parts of needle | |
153 | * @param h_len length of the haystack buffer | |
154 | * @param needle buffer containing source data that have been used to | |
155 | * construct haystack | |
156 | * @param n_pos start position in needle used for looking for matches | |
157 | * @param n_len length of the needle buffer | |
158 | * @param match_h_offset_ptr offset of the first matching byte within haystack | |
159 | * @param match_n_offset_ptr offset of the first matching byte within needle | |
160 | * @param match_len_ptr length of the matched segment | |
161 | * @return 0 if a match was found, < 0 if no match was found | |
162 | */ | |
163 | static int match_segments(const uint8_t *haystack, int h_len, | |
164 | const uint8_t *needle, int n_pos, int n_len, | |
165 | int *match_h_offset_ptr, int *match_n_offset_ptr, | |
166 | int *match_len_ptr) | |
167 | { | |
168 | int h_pos; | |
169 | for (h_pos = 0; h_pos < h_len; h_pos++) { | |
170 | int match_len = 0; | |
171 | int match_h_pos, match_n_pos; | |
172 | ||
173 | /* Check how many bytes match at needle[n_pos] and haystack[h_pos] */ | |
174 | while (h_pos + match_len < h_len && n_pos + match_len < n_len && | |
175 | needle[n_pos + match_len] == haystack[h_pos + match_len]) | |
176 | match_len++; | |
177 | if (match_len <= 8) | |
178 | continue; | |
179 | ||
180 | /* If a sufficiently large match was found, try to expand | |
181 | * the matched segment backwards. */ | |
182 | match_h_pos = h_pos; | |
183 | match_n_pos = n_pos; | |
184 | while (match_n_pos > 0 && match_h_pos > 0 && | |
185 | needle[match_n_pos - 1] == haystack[match_h_pos - 1]) { | |
186 | match_n_pos--; | |
187 | match_h_pos--; | |
188 | match_len++; | |
189 | } | |
190 | if (match_len <= 14) | |
191 | continue; | |
192 | *match_h_offset_ptr = match_h_pos; | |
193 | *match_n_offset_ptr = match_n_pos; | |
194 | *match_len_ptr = match_len; | |
195 | return 0; | |
196 | } | |
197 | return -1; | |
198 | } | |
199 | ||
200 | /** | |
201 | * Look for segments in samples in the sample queue matching the data | |
202 | * in ptr. Samples not matching are removed from the queue. If a match | |
203 | * is found, the next time it will look for matches starting from the | |
204 | * end of the previous matched segment. | |
205 | * | |
206 | * @param data data to find matches for in the sample queue | |
207 | * @param len length of the data buffer | |
208 | * @param queue samples used for looking for matching segments | |
209 | * @param pos the offset in data of the matched segment | |
210 | * @param match_sample the number of the sample that contained the match | |
211 | * @param match_offset the offset of the matched segment within the sample | |
212 | * @param match_len the length of the matched segment | |
213 | * @return 0 if a match was found, < 0 if no match was found | |
214 | */ | |
215 | static int find_sample_match(const uint8_t *data, int len, | |
216 | HintSampleQueue *queue, int *pos, | |
217 | int *match_sample, int *match_offset, | |
218 | int *match_len) | |
219 | { | |
220 | while (queue->len > 0) { | |
221 | HintSample *sample = &queue->samples[0]; | |
222 | /* If looking for matches in a new sample, skip the first 5 bytes, | |
223 | * since they often may be modified/removed in the output packet. */ | |
224 | if (sample->offset == 0 && sample->size > 5) | |
225 | sample->offset = 5; | |
226 | ||
227 | if (match_segments(data, len, sample->data, sample->offset, | |
228 | sample->size, pos, match_offset, match_len) == 0) { | |
229 | *match_sample = sample->sample_number; | |
230 | /* Next time, look for matches at this offset, with a little | |
231 | * margin to this match. */ | |
232 | sample->offset = *match_offset + *match_len + 5; | |
233 | if (sample->offset + 10 >= sample->size) | |
234 | sample_queue_pop(queue); /* Not enough useful data left */ | |
235 | return 0; | |
236 | } | |
237 | ||
238 | if (sample->offset < 10 && sample->size > 20) { | |
239 | /* No match found from the start of the sample, | |
240 | * try from the middle of the sample instead. */ | |
241 | sample->offset = sample->size/2; | |
242 | } else { | |
243 | /* No match for this sample, remove it */ | |
244 | sample_queue_pop(queue); | |
245 | } | |
246 | } | |
247 | return -1; | |
248 | } | |
249 | ||
250 | static void output_immediate(const uint8_t *data, int size, | |
251 | AVIOContext *out, int *entries) | |
252 | { | |
253 | while (size > 0) { | |
254 | int len = size; | |
255 | if (len > 14) | |
256 | len = 14; | |
257 | avio_w8(out, 1); /* immediate constructor */ | |
258 | avio_w8(out, len); /* amount of valid data */ | |
259 | avio_write(out, data, len); | |
260 | data += len; | |
261 | size -= len; | |
262 | ||
263 | for (; len < 14; len++) | |
264 | avio_w8(out, 0); | |
265 | ||
266 | (*entries)++; | |
267 | } | |
268 | } | |
269 | ||
270 | static void output_match(AVIOContext *out, int match_sample, | |
271 | int match_offset, int match_len, int *entries) | |
272 | { | |
273 | avio_w8(out, 2); /* sample constructor */ | |
274 | avio_w8(out, 0); /* track reference */ | |
275 | avio_wb16(out, match_len); | |
276 | avio_wb32(out, match_sample); | |
277 | avio_wb32(out, match_offset); | |
278 | avio_wb16(out, 1); /* bytes per block */ | |
279 | avio_wb16(out, 1); /* samples per block */ | |
280 | (*entries)++; | |
281 | } | |
282 | ||
283 | static void describe_payload(const uint8_t *data, int size, | |
284 | AVIOContext *out, int *entries, | |
285 | HintSampleQueue *queue) | |
286 | { | |
287 | /* Describe the payload using different constructors */ | |
288 | while (size > 0) { | |
289 | int match_sample, match_offset, match_len, pos; | |
290 | if (find_sample_match(data, size, queue, &pos, &match_sample, | |
291 | &match_offset, &match_len) < 0) | |
292 | break; | |
293 | output_immediate(data, pos, out, entries); | |
294 | data += pos; | |
295 | size -= pos; | |
296 | output_match(out, match_sample, match_offset, match_len, entries); | |
297 | data += match_len; | |
298 | size -= match_len; | |
299 | } | |
300 | output_immediate(data, size, out, entries); | |
301 | } | |
302 | ||
303 | /** | |
304 | * Write an RTP hint (that may contain one or more RTP packets) | |
305 | * for the packets in data. data contains one or more packets with a | |
306 | * BE32 size header. | |
307 | * | |
308 | * @param out buffer where the hints are written | |
309 | * @param data buffer containing RTP packets | |
310 | * @param size the size of the data buffer | |
311 | * @param trk the MOVTrack for the hint track | |
312 | * @param dts pointer where the timestamp for the written RTP hint is stored | |
313 | * @return the number of RTP packets in the written hint | |
314 | */ | |
315 | static int write_hint_packets(AVIOContext *out, const uint8_t *data, | |
316 | int size, MOVTrack *trk, int64_t *dts) | |
317 | { | |
318 | int64_t curpos; | |
319 | int64_t count_pos, entries_pos; | |
320 | int count = 0, entries; | |
321 | ||
322 | count_pos = avio_tell(out); | |
323 | /* RTPsample header */ | |
324 | avio_wb16(out, 0); /* packet count */ | |
325 | avio_wb16(out, 0); /* reserved */ | |
326 | ||
327 | while (size > 4) { | |
328 | uint32_t packet_len = AV_RB32(data); | |
329 | uint16_t seq; | |
330 | uint32_t ts; | |
331 | int32_t ts_diff; | |
332 | ||
333 | data += 4; | |
334 | size -= 4; | |
335 | if (packet_len > size || packet_len <= 12) | |
336 | break; | |
337 | if (RTP_PT_IS_RTCP(data[1])) { | |
338 | /* RTCP packet, just skip */ | |
339 | data += packet_len; | |
340 | size -= packet_len; | |
341 | continue; | |
342 | } | |
343 | ||
344 | if (packet_len > trk->max_packet_size) | |
345 | trk->max_packet_size = packet_len; | |
346 | ||
347 | seq = AV_RB16(&data[2]); | |
348 | ts = AV_RB32(&data[4]); | |
349 | ||
350 | if (trk->prev_rtp_ts == 0) | |
351 | trk->prev_rtp_ts = ts; | |
352 | /* Unwrap the 32-bit RTP timestamp that wraps around often | |
353 | * into a not (as often) wrapping 64-bit timestamp. */ | |
354 | ts_diff = ts - trk->prev_rtp_ts; | |
355 | if (ts_diff > 0) { | |
356 | trk->cur_rtp_ts_unwrapped += ts_diff; | |
357 | trk->prev_rtp_ts = ts; | |
358 | ts_diff = 0; | |
359 | } | |
360 | if (*dts == AV_NOPTS_VALUE) | |
361 | *dts = trk->cur_rtp_ts_unwrapped; | |
362 | ||
363 | count++; | |
364 | /* RTPpacket header */ | |
365 | avio_wb32(out, 0); /* relative_time */ | |
366 | avio_write(out, data, 2); /* RTP header */ | |
367 | avio_wb16(out, seq); /* RTPsequenceseed */ | |
368 | avio_wb16(out, ts_diff ? 4 : 0); /* reserved + flags (extra_flag) */ | |
369 | entries_pos = avio_tell(out); | |
370 | avio_wb16(out, 0); /* entry count */ | |
371 | if (ts_diff) { /* if extra_flag is set */ | |
372 | avio_wb32(out, 16); /* extra_information_length */ | |
373 | avio_wb32(out, 12); /* rtpoffsetTLV box */ | |
374 | avio_write(out, "rtpo", 4); | |
375 | avio_wb32(out, ts_diff); | |
376 | } | |
377 | ||
378 | data += 12; | |
379 | size -= 12; | |
380 | packet_len -= 12; | |
381 | ||
382 | entries = 0; | |
383 | /* Write one or more constructors describing the payload data */ | |
384 | describe_payload(data, packet_len, out, &entries, &trk->sample_queue); | |
385 | data += packet_len; | |
386 | size -= packet_len; | |
387 | ||
388 | curpos = avio_tell(out); | |
389 | avio_seek(out, entries_pos, SEEK_SET); | |
390 | avio_wb16(out, entries); | |
391 | avio_seek(out, curpos, SEEK_SET); | |
392 | } | |
393 | ||
394 | curpos = avio_tell(out); | |
395 | avio_seek(out, count_pos, SEEK_SET); | |
396 | avio_wb16(out, count); | |
397 | avio_seek(out, curpos, SEEK_SET); | |
398 | return count; | |
399 | } | |
400 | ||
401 | int ff_mov_add_hinted_packet(AVFormatContext *s, AVPacket *pkt, | |
402 | int track_index, int sample, | |
403 | uint8_t *sample_data, int sample_size) | |
404 | { | |
405 | MOVMuxContext *mov = s->priv_data; | |
406 | MOVTrack *trk = &mov->tracks[track_index]; | |
407 | AVFormatContext *rtp_ctx = trk->rtp_ctx; | |
408 | uint8_t *buf = NULL; | |
409 | int size; | |
410 | AVIOContext *hintbuf = NULL; | |
411 | AVPacket hint_pkt; | |
412 | int ret = 0, count; | |
413 | ||
414 | if (!rtp_ctx) | |
415 | return AVERROR(ENOENT); | |
416 | if (!rtp_ctx->pb) | |
417 | return AVERROR(ENOMEM); | |
418 | ||
419 | if (sample_data) | |
420 | sample_queue_push(&trk->sample_queue, sample_data, sample_size, sample); | |
421 | else | |
422 | sample_queue_push(&trk->sample_queue, pkt->data, pkt->size, sample); | |
423 | ||
424 | /* Feed the packet to the RTP muxer */ | |
425 | ff_write_chained(rtp_ctx, 0, pkt, s, 0); | |
426 | ||
427 | /* Fetch the output from the RTP muxer, open a new output buffer | |
428 | * for next time. */ | |
429 | size = avio_close_dyn_buf(rtp_ctx->pb, &buf); | |
430 | if ((ret = ffio_open_dyn_packet_buf(&rtp_ctx->pb, | |
431 | RTP_MAX_PACKET_SIZE)) < 0) | |
432 | goto done; | |
433 | ||
434 | if (size <= 0) | |
435 | goto done; | |
436 | ||
437 | /* Open a buffer for writing the hint */ | |
438 | if ((ret = avio_open_dyn_buf(&hintbuf)) < 0) | |
439 | goto done; | |
440 | av_init_packet(&hint_pkt); | |
441 | count = write_hint_packets(hintbuf, buf, size, trk, &hint_pkt.dts); | |
442 | av_freep(&buf); | |
443 | ||
444 | /* Write the hint data into the hint track */ | |
445 | hint_pkt.size = size = avio_close_dyn_buf(hintbuf, &buf); | |
446 | hint_pkt.data = buf; | |
447 | hint_pkt.pts = hint_pkt.dts; | |
448 | hint_pkt.stream_index = track_index; | |
449 | if (pkt->flags & AV_PKT_FLAG_KEY) | |
450 | hint_pkt.flags |= AV_PKT_FLAG_KEY; | |
451 | if (count > 0) | |
452 | ff_mov_write_packet(s, &hint_pkt); | |
453 | done: | |
454 | av_free(buf); | |
455 | sample_queue_retain(&trk->sample_queue); | |
456 | return ret; | |
457 | } | |
458 | ||
459 | void ff_mov_close_hinting(MOVTrack *track) | |
460 | { | |
461 | AVFormatContext *rtp_ctx = track->rtp_ctx; | |
462 | uint8_t *ptr; | |
463 | ||
464 | av_freep(&track->enc); | |
465 | sample_queue_free(&track->sample_queue); | |
466 | if (!rtp_ctx) | |
467 | return; | |
468 | if (rtp_ctx->pb) { | |
469 | av_write_trailer(rtp_ctx); | |
470 | avio_close_dyn_buf(rtp_ctx->pb, &ptr); | |
471 | av_free(ptr); | |
472 | } | |
473 | avformat_free_context(rtp_ctx); | |
474 | } |