| 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 | } |