blob: 964026ec71fa5e87217b65294c6d65f89278a5e0
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->par = avcodec_parameters_alloc(); |
41 | if (!track->par) |
42 | goto fail; |
43 | track->par->codec_type = AVMEDIA_TYPE_DATA; |
44 | track->par->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 | avcodec_parameters_free(&track->par); |
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 | |
463 | avcodec_parameters_free(&track->par); |
464 | sample_queue_free(&track->sample_queue); |
465 | if (!rtp_ctx) |
466 | return; |
467 | if (rtp_ctx->pb) { |
468 | av_write_trailer(rtp_ctx); |
469 | ffio_free_dyn_buf(&rtp_ctx->pb); |
470 | } |
471 | avformat_free_context(rtp_ctx); |
472 | } |
473 |