| 1 | /* |
| 2 | * FLAC parser |
| 3 | * Copyright (c) 2010 Michael Chinen |
| 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 | /** |
| 23 | * @file |
| 24 | * FLAC parser |
| 25 | * |
| 26 | * The FLAC parser buffers input until FLAC_MIN_HEADERS has been found. |
| 27 | * Each time it finds and verifies a CRC-8 header it sees which of the |
| 28 | * FLAC_MAX_SEQUENTIAL_HEADERS that came before it have a valid CRC-16 footer |
| 29 | * that ends at the newly found header. |
| 30 | * Headers are scored by FLAC_HEADER_BASE_SCORE plus the max of its crc-verified |
| 31 | * children, penalized by changes in sample rate, frame number, etc. |
| 32 | * The parser returns the frame with the highest score. |
| 33 | **/ |
| 34 | |
| 35 | #include "libavutil/attributes.h" |
| 36 | #include "libavutil/crc.h" |
| 37 | #include "libavutil/fifo.h" |
| 38 | #include "bytestream.h" |
| 39 | #include "parser.h" |
| 40 | #include "flac.h" |
| 41 | |
| 42 | /** maximum number of adjacent headers that compare CRCs against each other */ |
| 43 | #define FLAC_MAX_SEQUENTIAL_HEADERS 3 |
| 44 | /** minimum number of headers buffered and checked before returning frames */ |
| 45 | #define FLAC_MIN_HEADERS 10 |
| 46 | /** estimate for average size of a FLAC frame */ |
| 47 | #define FLAC_AVG_FRAME_SIZE 8192 |
| 48 | |
| 49 | /** scoring settings for score_header */ |
| 50 | #define FLAC_HEADER_BASE_SCORE 10 |
| 51 | #define FLAC_HEADER_CHANGED_PENALTY 7 |
| 52 | #define FLAC_HEADER_CRC_FAIL_PENALTY 50 |
| 53 | #define FLAC_HEADER_NOT_PENALIZED_YET 100000 |
| 54 | #define FLAC_HEADER_NOT_SCORED_YET -100000 |
| 55 | |
| 56 | /** largest possible size of flac header */ |
| 57 | #define MAX_FRAME_HEADER_SIZE 16 |
| 58 | |
| 59 | typedef struct FLACHeaderMarker { |
| 60 | int offset; /**< byte offset from start of FLACParseContext->buffer */ |
| 61 | int *link_penalty; /**< pointer to array of local scores between this header |
| 62 | and the one at a distance equal array position */ |
| 63 | int max_score; /**< maximum score found after checking each child that |
| 64 | has a valid CRC */ |
| 65 | FLACFrameInfo fi; /**< decoded frame header info */ |
| 66 | struct FLACHeaderMarker *next; /**< next CRC-8 verified header that |
| 67 | immediately follows this one in |
| 68 | the bytestream */ |
| 69 | struct FLACHeaderMarker *best_child; /**< following frame header with |
| 70 | which this frame has the best |
| 71 | score with */ |
| 72 | } FLACHeaderMarker; |
| 73 | |
| 74 | typedef struct FLACParseContext { |
| 75 | AVCodecParserContext *pc; /**< parent context */ |
| 76 | AVCodecContext *avctx; /**< codec context pointer for logging */ |
| 77 | FLACHeaderMarker *headers; /**< linked-list that starts at the first |
| 78 | CRC-8 verified header within buffer */ |
| 79 | FLACHeaderMarker *best_header; /**< highest scoring header within buffer */ |
| 80 | int nb_headers_found; /**< number of headers found in the last |
| 81 | flac_parse() call */ |
| 82 | int nb_headers_buffered; /**< number of headers that are buffered */ |
| 83 | int best_header_valid; /**< flag set when the parser returns junk; |
| 84 | if set return best_header next time */ |
| 85 | AVFifoBuffer *fifo_buf; /**< buffer to store all data until headers |
| 86 | can be verified */ |
| 87 | int end_padded; /**< specifies if fifo_buf's end is padded */ |
| 88 | uint8_t *wrap_buf; /**< general fifo read buffer when wrapped */ |
| 89 | int wrap_buf_allocated_size; /**< actual allocated size of the buffer */ |
| 90 | FLACFrameInfo last_fi; /**< last decoded frame header info */ |
| 91 | int last_fi_valid; /**< set if last_fi is valid */ |
| 92 | } FLACParseContext; |
| 93 | |
| 94 | static int frame_header_is_valid(AVCodecContext *avctx, const uint8_t *buf, |
| 95 | FLACFrameInfo *fi) |
| 96 | { |
| 97 | GetBitContext gb; |
| 98 | init_get_bits(&gb, buf, MAX_FRAME_HEADER_SIZE * 8); |
| 99 | return !ff_flac_decode_frame_header(avctx, &gb, fi, 127); |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * Non-destructive fast fifo pointer fetching |
| 104 | * Returns a pointer from the specified offset. |
| 105 | * If possible the pointer points within the fifo buffer. |
| 106 | * Otherwise (if it would cause a wrap around,) a pointer to a user-specified |
| 107 | * buffer is used. |
| 108 | * The pointer can be NULL. In any case it will be reallocated to hold the size. |
| 109 | * If the returned pointer will be used after subsequent calls to flac_fifo_read_wrap |
| 110 | * then the subsequent calls should pass in a different wrap_buf so as to not |
| 111 | * overwrite the contents of the previous wrap_buf. |
| 112 | * This function is based on av_fifo_generic_read, which is why there is a comment |
| 113 | * about a memory barrier for SMP. |
| 114 | */ |
| 115 | static uint8_t* flac_fifo_read_wrap(FLACParseContext *fpc, int offset, int len, |
| 116 | uint8_t** wrap_buf, int* allocated_size) |
| 117 | { |
| 118 | AVFifoBuffer *f = fpc->fifo_buf; |
| 119 | uint8_t *start = f->rptr + offset; |
| 120 | uint8_t *tmp_buf; |
| 121 | |
| 122 | if (start >= f->end) |
| 123 | start -= f->end - f->buffer; |
| 124 | if (f->end - start >= len) |
| 125 | return start; |
| 126 | |
| 127 | tmp_buf = av_fast_realloc(*wrap_buf, allocated_size, len); |
| 128 | |
| 129 | if (!tmp_buf) { |
| 130 | av_log(fpc->avctx, AV_LOG_ERROR, |
| 131 | "couldn't reallocate wrap buffer of size %d", len); |
| 132 | return NULL; |
| 133 | } |
| 134 | *wrap_buf = tmp_buf; |
| 135 | do { |
| 136 | int seg_len = FFMIN(f->end - start, len); |
| 137 | memcpy(tmp_buf, start, seg_len); |
| 138 | tmp_buf = (uint8_t*)tmp_buf + seg_len; |
| 139 | // memory barrier needed for SMP here in theory |
| 140 | |
| 141 | start += seg_len - (f->end - f->buffer); |
| 142 | len -= seg_len; |
| 143 | } while (len > 0); |
| 144 | |
| 145 | return *wrap_buf; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Return a pointer in the fifo buffer where the offset starts at until |
| 150 | * the wrap point or end of request. |
| 151 | * len will contain the valid length of the returned buffer. |
| 152 | * A second call to flac_fifo_read (with new offset and len) should be called |
| 153 | * to get the post-wrap buf if the returned len is less than the requested. |
| 154 | **/ |
| 155 | static uint8_t* flac_fifo_read(FLACParseContext *fpc, int offset, int *len) |
| 156 | { |
| 157 | AVFifoBuffer *f = fpc->fifo_buf; |
| 158 | uint8_t *start = f->rptr + offset; |
| 159 | |
| 160 | if (start >= f->end) |
| 161 | start -= f->end - f->buffer; |
| 162 | *len = FFMIN(*len, f->end - start); |
| 163 | return start; |
| 164 | } |
| 165 | |
| 166 | static int find_headers_search_validate(FLACParseContext *fpc, int offset) |
| 167 | { |
| 168 | FLACFrameInfo fi; |
| 169 | uint8_t *header_buf; |
| 170 | int size = 0; |
| 171 | header_buf = flac_fifo_read_wrap(fpc, offset, |
| 172 | MAX_FRAME_HEADER_SIZE, |
| 173 | &fpc->wrap_buf, |
| 174 | &fpc->wrap_buf_allocated_size); |
| 175 | if (frame_header_is_valid(fpc->avctx, header_buf, &fi)) { |
| 176 | FLACHeaderMarker **end_handle = &fpc->headers; |
| 177 | int i; |
| 178 | |
| 179 | size = 0; |
| 180 | while (*end_handle) { |
| 181 | end_handle = &(*end_handle)->next; |
| 182 | size++; |
| 183 | } |
| 184 | |
| 185 | *end_handle = av_mallocz(sizeof(FLACHeaderMarker)); |
| 186 | if (!*end_handle) { |
| 187 | av_log(fpc->avctx, AV_LOG_ERROR, |
| 188 | "couldn't allocate FLACHeaderMarker\n"); |
| 189 | return AVERROR(ENOMEM); |
| 190 | } |
| 191 | (*end_handle)->fi = fi; |
| 192 | (*end_handle)->offset = offset; |
| 193 | (*end_handle)->link_penalty = av_malloc(sizeof(int) * |
| 194 | FLAC_MAX_SEQUENTIAL_HEADERS); |
| 195 | for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS; i++) |
| 196 | (*end_handle)->link_penalty[i] = FLAC_HEADER_NOT_PENALIZED_YET; |
| 197 | |
| 198 | fpc->nb_headers_found++; |
| 199 | size++; |
| 200 | } |
| 201 | return size; |
| 202 | } |
| 203 | |
| 204 | static int find_headers_search(FLACParseContext *fpc, uint8_t *buf, int buf_size, |
| 205 | int search_start) |
| 206 | |
| 207 | { |
| 208 | int size = 0, mod_offset = (buf_size - 1) % 4, i, j; |
| 209 | uint32_t x; |
| 210 | |
| 211 | for (i = 0; i < mod_offset; i++) { |
| 212 | if ((AV_RB16(buf + i) & 0xFFFE) == 0xFFF8) |
| 213 | size = find_headers_search_validate(fpc, search_start + i); |
| 214 | } |
| 215 | |
| 216 | for (; i < buf_size - 1; i += 4) { |
| 217 | x = AV_RB32(buf + i); |
| 218 | if (((x & ~(x + 0x01010101)) & 0x80808080)) { |
| 219 | for (j = 0; j < 4; j++) { |
| 220 | if ((AV_RB16(buf + i + j) & 0xFFFE) == 0xFFF8) |
| 221 | size = find_headers_search_validate(fpc, search_start + i + j); |
| 222 | } |
| 223 | } |
| 224 | } |
| 225 | return size; |
| 226 | } |
| 227 | |
| 228 | static int find_new_headers(FLACParseContext *fpc, int search_start) |
| 229 | { |
| 230 | FLACHeaderMarker *end; |
| 231 | int search_end, size = 0, read_len, temp; |
| 232 | uint8_t *buf; |
| 233 | fpc->nb_headers_found = 0; |
| 234 | |
| 235 | /* Search for a new header of at most 16 bytes. */ |
| 236 | search_end = av_fifo_size(fpc->fifo_buf) - (MAX_FRAME_HEADER_SIZE - 1); |
| 237 | read_len = search_end - search_start + 1; |
| 238 | buf = flac_fifo_read(fpc, search_start, &read_len); |
| 239 | size = find_headers_search(fpc, buf, read_len, search_start); |
| 240 | search_start += read_len - 1; |
| 241 | |
| 242 | /* If fifo end was hit do the wrap around. */ |
| 243 | if (search_start != search_end) { |
| 244 | uint8_t wrap[2]; |
| 245 | |
| 246 | wrap[0] = buf[read_len - 1]; |
| 247 | read_len = search_end - search_start + 1; |
| 248 | |
| 249 | /* search_start + 1 is the post-wrap offset in the fifo. */ |
| 250 | buf = flac_fifo_read(fpc, search_start + 1, &read_len); |
| 251 | wrap[1] = buf[0]; |
| 252 | |
| 253 | if ((AV_RB16(wrap) & 0xFFFE) == 0xFFF8) { |
| 254 | temp = find_headers_search_validate(fpc, search_start); |
| 255 | size = FFMAX(size, temp); |
| 256 | } |
| 257 | search_start++; |
| 258 | |
| 259 | /* Continue to do the last half of the wrap. */ |
| 260 | temp = find_headers_search(fpc, buf, read_len, search_start); |
| 261 | size = FFMAX(size, temp); |
| 262 | search_start += read_len - 1; |
| 263 | } |
| 264 | |
| 265 | /* Return the size even if no new headers were found. */ |
| 266 | if (!size && fpc->headers) |
| 267 | for (end = fpc->headers; end; end = end->next) |
| 268 | size++; |
| 269 | return size; |
| 270 | } |
| 271 | |
| 272 | static int check_header_fi_mismatch(FLACParseContext *fpc, |
| 273 | FLACFrameInfo *header_fi, |
| 274 | FLACFrameInfo *child_fi, |
| 275 | int log_level_offset) |
| 276 | { |
| 277 | int deduction = 0; |
| 278 | if (child_fi->samplerate != header_fi->samplerate) { |
| 279 | deduction += FLAC_HEADER_CHANGED_PENALTY; |
| 280 | av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset, |
| 281 | "sample rate change detected in adjacent frames\n"); |
| 282 | } |
| 283 | if (child_fi->bps != header_fi->bps) { |
| 284 | deduction += FLAC_HEADER_CHANGED_PENALTY; |
| 285 | av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset, |
| 286 | "bits per sample change detected in adjacent frames\n"); |
| 287 | } |
| 288 | if (child_fi->is_var_size != header_fi->is_var_size) { |
| 289 | /* Changing blocking strategy not allowed per the spec */ |
| 290 | deduction += FLAC_HEADER_BASE_SCORE; |
| 291 | av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset, |
| 292 | "blocking strategy change detected in adjacent frames\n"); |
| 293 | } |
| 294 | if (child_fi->channels != header_fi->channels) { |
| 295 | deduction += FLAC_HEADER_CHANGED_PENALTY; |
| 296 | av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset, |
| 297 | "number of channels change detected in adjacent frames\n"); |
| 298 | } |
| 299 | return deduction; |
| 300 | } |
| 301 | |
| 302 | static int check_header_mismatch(FLACParseContext *fpc, |
| 303 | FLACHeaderMarker *header, |
| 304 | FLACHeaderMarker *child, |
| 305 | int log_level_offset) |
| 306 | { |
| 307 | FLACFrameInfo *header_fi = &header->fi, *child_fi = &child->fi; |
| 308 | int deduction, deduction_expected = 0, i; |
| 309 | deduction = check_header_fi_mismatch(fpc, header_fi, child_fi, |
| 310 | log_level_offset); |
| 311 | /* Check sample and frame numbers. */ |
| 312 | if ((child_fi->frame_or_sample_num - header_fi->frame_or_sample_num |
| 313 | != header_fi->blocksize) && |
| 314 | (child_fi->frame_or_sample_num |
| 315 | != header_fi->frame_or_sample_num + 1)) { |
| 316 | FLACHeaderMarker *curr; |
| 317 | int expected_frame_num, expected_sample_num; |
| 318 | /* If there are frames in the middle we expect this deduction, |
| 319 | as they are probably valid and this one follows it */ |
| 320 | |
| 321 | expected_frame_num = expected_sample_num = header_fi->frame_or_sample_num; |
| 322 | curr = header; |
| 323 | while (curr != child) { |
| 324 | /* Ignore frames that failed all crc checks */ |
| 325 | for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS; i++) { |
| 326 | if (curr->link_penalty[i] < FLAC_HEADER_CRC_FAIL_PENALTY) { |
| 327 | expected_frame_num++; |
| 328 | expected_sample_num += curr->fi.blocksize; |
| 329 | break; |
| 330 | } |
| 331 | } |
| 332 | curr = curr->next; |
| 333 | } |
| 334 | |
| 335 | if (expected_frame_num == child_fi->frame_or_sample_num || |
| 336 | expected_sample_num == child_fi->frame_or_sample_num) |
| 337 | deduction_expected = deduction ? 0 : 1; |
| 338 | |
| 339 | deduction += FLAC_HEADER_CHANGED_PENALTY; |
| 340 | av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset, |
| 341 | "sample/frame number mismatch in adjacent frames\n"); |
| 342 | } |
| 343 | |
| 344 | /* If we have suspicious headers, check the CRC between them */ |
| 345 | if (deduction && !deduction_expected) { |
| 346 | FLACHeaderMarker *curr; |
| 347 | int read_len; |
| 348 | uint8_t *buf; |
| 349 | uint32_t crc = 1; |
| 350 | int inverted_test = 0; |
| 351 | |
| 352 | /* Since CRC is expensive only do it if we haven't yet. |
| 353 | This assumes a CRC penalty is greater than all other check penalties */ |
| 354 | curr = header->next; |
| 355 | for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS && curr != child; i++) |
| 356 | curr = curr->next; |
| 357 | |
| 358 | if (header->link_penalty[i] < FLAC_HEADER_CRC_FAIL_PENALTY || |
| 359 | header->link_penalty[i] == FLAC_HEADER_NOT_PENALIZED_YET) { |
| 360 | FLACHeaderMarker *start, *end; |
| 361 | |
| 362 | /* Although overlapping chains are scored, the crc should never |
| 363 | have to be computed twice for a single byte. */ |
| 364 | start = header; |
| 365 | end = child; |
| 366 | if (i > 0 && |
| 367 | header->link_penalty[i - 1] >= FLAC_HEADER_CRC_FAIL_PENALTY) { |
| 368 | while (start->next != child) |
| 369 | start = start->next; |
| 370 | inverted_test = 1; |
| 371 | } else if (i > 0 && |
| 372 | header->next->link_penalty[i-1] >= |
| 373 | FLAC_HEADER_CRC_FAIL_PENALTY ) { |
| 374 | end = header->next; |
| 375 | inverted_test = 1; |
| 376 | } |
| 377 | |
| 378 | read_len = end->offset - start->offset; |
| 379 | buf = flac_fifo_read(fpc, start->offset, &read_len); |
| 380 | crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf, read_len); |
| 381 | read_len = (end->offset - start->offset) - read_len; |
| 382 | |
| 383 | if (read_len) { |
| 384 | buf = flac_fifo_read(fpc, end->offset - read_len, &read_len); |
| 385 | crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), crc, buf, read_len); |
| 386 | } |
| 387 | } |
| 388 | |
| 389 | if (!crc ^ !inverted_test) { |
| 390 | deduction += FLAC_HEADER_CRC_FAIL_PENALTY; |
| 391 | av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset, |
| 392 | "crc check failed from offset %i (frame %"PRId64") to %i (frame %"PRId64")\n", |
| 393 | header->offset, header_fi->frame_or_sample_num, |
| 394 | child->offset, child_fi->frame_or_sample_num); |
| 395 | } |
| 396 | } |
| 397 | return deduction; |
| 398 | } |
| 399 | |
| 400 | /** |
| 401 | * Score a header. |
| 402 | * |
| 403 | * Give FLAC_HEADER_BASE_SCORE points to a frame for existing. |
| 404 | * If it has children, (subsequent frames of which the preceding CRC footer |
| 405 | * validates against this one,) then take the maximum score of the children, |
| 406 | * with a penalty of FLAC_HEADER_CHANGED_PENALTY applied for each change to |
| 407 | * bps, sample rate, channels, but not decorrelation mode, or blocksize, |
| 408 | * because it can change often. |
| 409 | **/ |
| 410 | static int score_header(FLACParseContext *fpc, FLACHeaderMarker *header) |
| 411 | { |
| 412 | FLACHeaderMarker *child; |
| 413 | int dist = 0; |
| 414 | int child_score; |
| 415 | int base_score = FLAC_HEADER_BASE_SCORE; |
| 416 | if (header->max_score != FLAC_HEADER_NOT_SCORED_YET) |
| 417 | return header->max_score; |
| 418 | |
| 419 | /* Modify the base score with changes from the last output header */ |
| 420 | if (fpc->last_fi_valid) { |
| 421 | /* Silence the log since this will be repeated if selected */ |
| 422 | base_score -= check_header_fi_mismatch(fpc, &fpc->last_fi, &header->fi, |
| 423 | AV_LOG_DEBUG); |
| 424 | } |
| 425 | |
| 426 | header->max_score = base_score; |
| 427 | |
| 428 | /* Check and compute the children's scores. */ |
| 429 | child = header->next; |
| 430 | for (dist = 0; dist < FLAC_MAX_SEQUENTIAL_HEADERS && child; dist++) { |
| 431 | /* Look at the child's frame header info and penalize suspicious |
| 432 | changes between the headers. */ |
| 433 | if (header->link_penalty[dist] == FLAC_HEADER_NOT_PENALIZED_YET) { |
| 434 | header->link_penalty[dist] = check_header_mismatch(fpc, header, |
| 435 | child, AV_LOG_DEBUG); |
| 436 | } |
| 437 | child_score = score_header(fpc, child) - header->link_penalty[dist]; |
| 438 | |
| 439 | if (FLAC_HEADER_BASE_SCORE + child_score > header->max_score) { |
| 440 | /* Keep the child because the frame scoring is dynamic. */ |
| 441 | header->best_child = child; |
| 442 | header->max_score = base_score + child_score; |
| 443 | } |
| 444 | child = child->next; |
| 445 | } |
| 446 | |
| 447 | return header->max_score; |
| 448 | } |
| 449 | |
| 450 | static void score_sequences(FLACParseContext *fpc) |
| 451 | { |
| 452 | FLACHeaderMarker *curr; |
| 453 | int best_score = 0;//FLAC_HEADER_NOT_SCORED_YET; |
| 454 | /* First pass to clear all old scores. */ |
| 455 | for (curr = fpc->headers; curr; curr = curr->next) |
| 456 | curr->max_score = FLAC_HEADER_NOT_SCORED_YET; |
| 457 | |
| 458 | /* Do a second pass to score them all. */ |
| 459 | for (curr = fpc->headers; curr; curr = curr->next) { |
| 460 | if (score_header(fpc, curr) > best_score) { |
| 461 | fpc->best_header = curr; |
| 462 | best_score = curr->max_score; |
| 463 | } |
| 464 | } |
| 465 | } |
| 466 | |
| 467 | static int get_best_header(FLACParseContext* fpc, const uint8_t **poutbuf, |
| 468 | int *poutbuf_size) |
| 469 | { |
| 470 | FLACHeaderMarker *header = fpc->best_header; |
| 471 | FLACHeaderMarker *child = header->best_child; |
| 472 | if (!child) { |
| 473 | *poutbuf_size = av_fifo_size(fpc->fifo_buf) - header->offset; |
| 474 | } else { |
| 475 | *poutbuf_size = child->offset - header->offset; |
| 476 | |
| 477 | /* If the child has suspicious changes, log them */ |
| 478 | check_header_mismatch(fpc, header, child, 0); |
| 479 | } |
| 480 | |
| 481 | if (header->fi.channels != fpc->avctx->channels || |
| 482 | !fpc->avctx->channel_layout) { |
| 483 | fpc->avctx->channels = header->fi.channels; |
| 484 | ff_flac_set_channel_layout(fpc->avctx); |
| 485 | } |
| 486 | fpc->avctx->sample_rate = header->fi.samplerate; |
| 487 | fpc->pc->duration = header->fi.blocksize; |
| 488 | *poutbuf = flac_fifo_read_wrap(fpc, header->offset, *poutbuf_size, |
| 489 | &fpc->wrap_buf, |
| 490 | &fpc->wrap_buf_allocated_size); |
| 491 | |
| 492 | |
| 493 | if (fpc->pc->flags & PARSER_FLAG_USE_CODEC_TS){ |
| 494 | if (header->fi.is_var_size) |
| 495 | fpc->pc->pts = header->fi.frame_or_sample_num; |
| 496 | else if (header->best_child) |
| 497 | fpc->pc->pts = header->fi.frame_or_sample_num * header->fi.blocksize; |
| 498 | } |
| 499 | |
| 500 | fpc->best_header_valid = 0; |
| 501 | fpc->last_fi_valid = 1; |
| 502 | fpc->last_fi = header->fi; |
| 503 | |
| 504 | /* Return the negative overread index so the client can compute pos. |
| 505 | This should be the amount overread to the beginning of the child */ |
| 506 | if (child) |
| 507 | return child->offset - av_fifo_size(fpc->fifo_buf); |
| 508 | return 0; |
| 509 | } |
| 510 | |
| 511 | static int flac_parse(AVCodecParserContext *s, AVCodecContext *avctx, |
| 512 | const uint8_t **poutbuf, int *poutbuf_size, |
| 513 | const uint8_t *buf, int buf_size) |
| 514 | { |
| 515 | FLACParseContext *fpc = s->priv_data; |
| 516 | FLACHeaderMarker *curr; |
| 517 | int nb_headers; |
| 518 | const uint8_t *read_end = buf; |
| 519 | const uint8_t *read_start = buf; |
| 520 | |
| 521 | if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
| 522 | FLACFrameInfo fi; |
| 523 | if (frame_header_is_valid(avctx, buf, &fi)) { |
| 524 | s->duration = fi.blocksize; |
| 525 | if (!avctx->sample_rate) |
| 526 | avctx->sample_rate = fi.samplerate; |
| 527 | if (fpc->pc->flags & PARSER_FLAG_USE_CODEC_TS){ |
| 528 | fpc->pc->pts = fi.frame_or_sample_num; |
| 529 | if (!fi.is_var_size) |
| 530 | fpc->pc->pts *= fi.blocksize; |
| 531 | } |
| 532 | } |
| 533 | *poutbuf = buf; |
| 534 | *poutbuf_size = buf_size; |
| 535 | return buf_size; |
| 536 | } |
| 537 | |
| 538 | fpc->avctx = avctx; |
| 539 | if (fpc->best_header_valid) |
| 540 | return get_best_header(fpc, poutbuf, poutbuf_size); |
| 541 | |
| 542 | /* If a best_header was found last call remove it with the buffer data. */ |
| 543 | if (fpc->best_header && fpc->best_header->best_child) { |
| 544 | FLACHeaderMarker *temp; |
| 545 | FLACHeaderMarker *best_child = fpc->best_header->best_child; |
| 546 | |
| 547 | /* Remove headers in list until the end of the best_header. */ |
| 548 | for (curr = fpc->headers; curr != best_child; curr = temp) { |
| 549 | if (curr != fpc->best_header) { |
| 550 | av_log(avctx, AV_LOG_DEBUG, |
| 551 | "dropping low score %i frame header from offset %i to %i\n", |
| 552 | curr->max_score, curr->offset, curr->next->offset); |
| 553 | } |
| 554 | temp = curr->next; |
| 555 | av_freep(&curr->link_penalty); |
| 556 | av_free(curr); |
| 557 | fpc->nb_headers_buffered--; |
| 558 | } |
| 559 | /* Release returned data from ring buffer. */ |
| 560 | av_fifo_drain(fpc->fifo_buf, best_child->offset); |
| 561 | |
| 562 | /* Fix the offset for the headers remaining to match the new buffer. */ |
| 563 | for (curr = best_child->next; curr; curr = curr->next) |
| 564 | curr->offset -= best_child->offset; |
| 565 | |
| 566 | fpc->nb_headers_buffered--; |
| 567 | best_child->offset = 0; |
| 568 | fpc->headers = best_child; |
| 569 | if (fpc->nb_headers_buffered >= FLAC_MIN_HEADERS) { |
| 570 | fpc->best_header = best_child; |
| 571 | return get_best_header(fpc, poutbuf, poutbuf_size); |
| 572 | } |
| 573 | fpc->best_header = NULL; |
| 574 | } else if (fpc->best_header) { |
| 575 | /* No end frame no need to delete the buffer; probably eof */ |
| 576 | FLACHeaderMarker *temp; |
| 577 | |
| 578 | for (curr = fpc->headers; curr != fpc->best_header; curr = temp) { |
| 579 | temp = curr->next; |
| 580 | av_freep(&curr->link_penalty); |
| 581 | av_free(curr); |
| 582 | } |
| 583 | fpc->headers = fpc->best_header->next; |
| 584 | av_freep(&fpc->best_header->link_penalty); |
| 585 | av_freep(&fpc->best_header); |
| 586 | } |
| 587 | |
| 588 | /* Find and score new headers. */ |
| 589 | /* buf_size is to zero when padding, so check for this since we do */ |
| 590 | /* not want to try to read more input once we have found the end. */ |
| 591 | /* Note that as (non-modified) parameters, buf can be non-NULL, */ |
| 592 | /* while buf_size is 0. */ |
| 593 | while ((buf && buf_size && read_end < buf + buf_size && |
| 594 | fpc->nb_headers_buffered < FLAC_MIN_HEADERS) |
| 595 | || ((!buf || !buf_size) && !fpc->end_padded)) { |
| 596 | int start_offset; |
| 597 | |
| 598 | /* Pad the end once if EOF, to check the final region for headers. */ |
| 599 | if (!buf || !buf_size) { |
| 600 | fpc->end_padded = 1; |
| 601 | buf_size = MAX_FRAME_HEADER_SIZE; |
| 602 | read_end = read_start + MAX_FRAME_HEADER_SIZE; |
| 603 | } else { |
| 604 | /* The maximum read size is the upper-bound of what the parser |
| 605 | needs to have the required number of frames buffered */ |
| 606 | int nb_desired = FLAC_MIN_HEADERS - fpc->nb_headers_buffered + 1; |
| 607 | read_end = read_end + FFMIN(buf + buf_size - read_end, |
| 608 | nb_desired * FLAC_AVG_FRAME_SIZE); |
| 609 | } |
| 610 | |
| 611 | /* Fill the buffer. */ |
| 612 | if ( av_fifo_space(fpc->fifo_buf) < read_end - read_start |
| 613 | && av_fifo_realloc2(fpc->fifo_buf, (read_end - read_start) + 2*av_fifo_size(fpc->fifo_buf)) < 0) { |
| 614 | av_log(avctx, AV_LOG_ERROR, |
| 615 | "couldn't reallocate buffer of size %"PTRDIFF_SPECIFIER"\n", |
| 616 | (read_end - read_start) + av_fifo_size(fpc->fifo_buf)); |
| 617 | goto handle_error; |
| 618 | } |
| 619 | |
| 620 | if (buf && buf_size) { |
| 621 | av_fifo_generic_write(fpc->fifo_buf, (void*) read_start, |
| 622 | read_end - read_start, NULL); |
| 623 | } else { |
| 624 | int8_t pad[MAX_FRAME_HEADER_SIZE] = { 0 }; |
| 625 | av_fifo_generic_write(fpc->fifo_buf, (void*) pad, sizeof(pad), NULL); |
| 626 | } |
| 627 | |
| 628 | /* Tag headers and update sequences. */ |
| 629 | start_offset = av_fifo_size(fpc->fifo_buf) - |
| 630 | ((read_end - read_start) + (MAX_FRAME_HEADER_SIZE - 1)); |
| 631 | start_offset = FFMAX(0, start_offset); |
| 632 | nb_headers = find_new_headers(fpc, start_offset); |
| 633 | |
| 634 | if (nb_headers < 0) { |
| 635 | av_log(avctx, AV_LOG_ERROR, |
| 636 | "find_new_headers couldn't allocate FLAC header\n"); |
| 637 | goto handle_error; |
| 638 | } |
| 639 | |
| 640 | fpc->nb_headers_buffered = nb_headers; |
| 641 | /* Wait till FLAC_MIN_HEADERS to output a valid frame. */ |
| 642 | if (!fpc->end_padded && fpc->nb_headers_buffered < FLAC_MIN_HEADERS) { |
| 643 | if (buf && read_end < buf + buf_size) { |
| 644 | read_start = read_end; |
| 645 | continue; |
| 646 | } else { |
| 647 | goto handle_error; |
| 648 | } |
| 649 | } |
| 650 | |
| 651 | /* If headers found, update the scores since we have longer chains. */ |
| 652 | if (fpc->end_padded || fpc->nb_headers_found) |
| 653 | score_sequences(fpc); |
| 654 | |
| 655 | /* restore the state pre-padding */ |
| 656 | if (fpc->end_padded) { |
| 657 | int warp = fpc->fifo_buf->wptr - fpc->fifo_buf->buffer < MAX_FRAME_HEADER_SIZE; |
| 658 | /* HACK: drain the tail of the fifo */ |
| 659 | fpc->fifo_buf->wptr -= MAX_FRAME_HEADER_SIZE; |
| 660 | fpc->fifo_buf->wndx -= MAX_FRAME_HEADER_SIZE; |
| 661 | if (warp) { |
| 662 | fpc->fifo_buf->wptr += fpc->fifo_buf->end - |
| 663 | fpc->fifo_buf->buffer; |
| 664 | } |
| 665 | buf_size = 0; |
| 666 | read_start = read_end = NULL; |
| 667 | } |
| 668 | } |
| 669 | |
| 670 | for (curr = fpc->headers; curr; curr = curr->next) { |
| 671 | if (curr->max_score > 0 && |
| 672 | (!fpc->best_header || curr->max_score > fpc->best_header->max_score)) { |
| 673 | fpc->best_header = curr; |
| 674 | } |
| 675 | } |
| 676 | |
| 677 | if (fpc->best_header) { |
| 678 | fpc->best_header_valid = 1; |
| 679 | if (fpc->best_header->offset > 0) { |
| 680 | /* Output a junk frame. */ |
| 681 | av_log(avctx, AV_LOG_DEBUG, "Junk frame till offset %i\n", |
| 682 | fpc->best_header->offset); |
| 683 | |
| 684 | /* Set duration to 0. It is unknown or invalid in a junk frame. */ |
| 685 | s->duration = 0; |
| 686 | *poutbuf_size = fpc->best_header->offset; |
| 687 | *poutbuf = flac_fifo_read_wrap(fpc, 0, *poutbuf_size, |
| 688 | &fpc->wrap_buf, |
| 689 | &fpc->wrap_buf_allocated_size); |
| 690 | return buf_size ? (read_end - buf) : (fpc->best_header->offset - |
| 691 | av_fifo_size(fpc->fifo_buf)); |
| 692 | } |
| 693 | if (!buf_size) |
| 694 | return get_best_header(fpc, poutbuf, poutbuf_size); |
| 695 | } |
| 696 | |
| 697 | handle_error: |
| 698 | *poutbuf = NULL; |
| 699 | *poutbuf_size = 0; |
| 700 | return read_end - buf; |
| 701 | } |
| 702 | |
| 703 | static av_cold int flac_parse_init(AVCodecParserContext *c) |
| 704 | { |
| 705 | FLACParseContext *fpc = c->priv_data; |
| 706 | fpc->pc = c; |
| 707 | /* There will generally be FLAC_MIN_HEADERS buffered in the fifo before |
| 708 | it drains. This is allocated early to avoid slow reallocation. */ |
| 709 | fpc->fifo_buf = av_fifo_alloc_array(FLAC_MIN_HEADERS + 3, FLAC_AVG_FRAME_SIZE); |
| 710 | if (!fpc->fifo_buf) |
| 711 | return AVERROR(ENOMEM); |
| 712 | return 0; |
| 713 | } |
| 714 | |
| 715 | static void flac_parse_close(AVCodecParserContext *c) |
| 716 | { |
| 717 | FLACParseContext *fpc = c->priv_data; |
| 718 | FLACHeaderMarker *curr = fpc->headers, *temp; |
| 719 | |
| 720 | while (curr) { |
| 721 | temp = curr->next; |
| 722 | av_freep(&curr->link_penalty); |
| 723 | av_free(curr); |
| 724 | curr = temp; |
| 725 | } |
| 726 | av_fifo_freep(&fpc->fifo_buf); |
| 727 | av_freep(&fpc->wrap_buf); |
| 728 | } |
| 729 | |
| 730 | AVCodecParser ff_flac_parser = { |
| 731 | .codec_ids = { AV_CODEC_ID_FLAC }, |
| 732 | .priv_data_size = sizeof(FLACParseContext), |
| 733 | .parser_init = flac_parse_init, |
| 734 | .parser_parse = flac_parse, |
| 735 | .parser_close = flac_parse_close, |
| 736 | }; |