3 * Copyright (c) 2010 Michael Chinen
5 * This file is part of FFmpeg.
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.
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.
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
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.
35 #include "libavutil/attributes.h"
36 #include "libavutil/crc.h"
37 #include "libavutil/fifo.h"
38 #include "bytestream.h"
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
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
56 /** largest possible size of flac header */
57 #define MAX_FRAME_HEADER_SIZE 16
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
65 FLACFrameInfo fi; /**< decoded frame header info */
66 struct FLACHeaderMarker *next; /**< next CRC-8 verified header that
67 immediately follows this one in
69 struct FLACHeaderMarker *best_child; /**< following frame header with
70 which this frame has the best
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
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
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 */
94 static int frame_header_is_valid(AVCodecContext *avctx, const uint8_t *buf,
98 init_get_bits(&gb, buf, MAX_FRAME_HEADER_SIZE * 8);
99 return !ff_flac_decode_frame_header(avctx, &gb, fi, 127);
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
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.
115 static uint8_t* flac_fifo_read_wrap(FLACParseContext *fpc, int offset, int len,
116 uint8_t** wrap_buf, int* allocated_size)
118 AVFifoBuffer *f = fpc->fifo_buf;
119 uint8_t *start = f->rptr + offset;
123 start -= f->end - f->buffer;
124 if (f->end - start >= len)
127 tmp_buf = av_fast_realloc(*wrap_buf, allocated_size, len);
130 av_log(fpc->avctx, AV_LOG_ERROR,
131 "couldn't reallocate wrap buffer of size %d", len);
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
141 start += seg_len - (f->end - f->buffer);
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.
155 static uint8_t* flac_fifo_read(FLACParseContext *fpc, int offset, int *len)
157 AVFifoBuffer *f = fpc->fifo_buf;
158 uint8_t *start = f->rptr + offset;
161 start -= f->end - f->buffer;
162 *len = FFMIN(*len, f->end - start);
166 static int find_headers_search_validate(FLACParseContext *fpc, int offset)
171 header_buf = flac_fifo_read_wrap(fpc, offset,
172 MAX_FRAME_HEADER_SIZE,
174 &fpc->wrap_buf_allocated_size);
175 if (frame_header_is_valid(fpc->avctx, header_buf, &fi)) {
176 FLACHeaderMarker **end_handle = &fpc->headers;
180 while (*end_handle) {
181 end_handle = &(*end_handle)->next;
185 *end_handle = av_mallocz(sizeof(**end_handle));
187 av_log(fpc->avctx, AV_LOG_ERROR,
188 "couldn't allocate FLACHeaderMarker\n");
189 return AVERROR(ENOMEM);
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 if (!(*end_handle)->link_penalty) {
196 av_freep(end_handle);
197 return AVERROR(ENOMEM);
200 for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS; i++)
201 (*end_handle)->link_penalty[i] = FLAC_HEADER_NOT_PENALIZED_YET;
203 fpc->nb_headers_found++;
209 static int find_headers_search(FLACParseContext *fpc, uint8_t *buf, int buf_size,
213 int size = 0, mod_offset = (buf_size - 1) % 4, i, j;
216 for (i = 0; i < mod_offset; i++) {
217 if ((AV_RB16(buf + i) & 0xFFFE) == 0xFFF8)
218 size = find_headers_search_validate(fpc, search_start + i);
221 for (; i < buf_size - 1; i += 4) {
222 x = AV_RB32(buf + i);
223 if (((x & ~(x + 0x01010101)) & 0x80808080)) {
224 for (j = 0; j < 4; j++) {
225 if ((AV_RB16(buf + i + j) & 0xFFFE) == 0xFFF8)
226 size = find_headers_search_validate(fpc, search_start + i + j);
233 static int find_new_headers(FLACParseContext *fpc, int search_start)
235 FLACHeaderMarker *end;
236 int search_end, size = 0, read_len, temp;
238 fpc->nb_headers_found = 0;
240 /* Search for a new header of at most 16 bytes. */
241 search_end = av_fifo_size(fpc->fifo_buf) - (MAX_FRAME_HEADER_SIZE - 1);
242 read_len = search_end - search_start + 1;
243 buf = flac_fifo_read(fpc, search_start, &read_len);
244 size = find_headers_search(fpc, buf, read_len, search_start);
245 search_start += read_len - 1;
247 /* If fifo end was hit do the wrap around. */
248 if (search_start != search_end) {
251 wrap[0] = buf[read_len - 1];
252 read_len = search_end - search_start + 1;
254 /* search_start + 1 is the post-wrap offset in the fifo. */
255 buf = flac_fifo_read(fpc, search_start + 1, &read_len);
258 if ((AV_RB16(wrap) & 0xFFFE) == 0xFFF8) {
259 temp = find_headers_search_validate(fpc, search_start);
260 size = FFMAX(size, temp);
264 /* Continue to do the last half of the wrap. */
265 temp = find_headers_search(fpc, buf, read_len, search_start);
266 size = FFMAX(size, temp);
267 search_start += read_len - 1;
270 /* Return the size even if no new headers were found. */
271 if (!size && fpc->headers)
272 for (end = fpc->headers; end; end = end->next)
277 static int check_header_fi_mismatch(FLACParseContext *fpc,
278 FLACFrameInfo *header_fi,
279 FLACFrameInfo *child_fi,
280 int log_level_offset)
283 if (child_fi->samplerate != header_fi->samplerate) {
284 deduction += FLAC_HEADER_CHANGED_PENALTY;
285 av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
286 "sample rate change detected in adjacent frames\n");
288 if (child_fi->bps != header_fi->bps) {
289 deduction += FLAC_HEADER_CHANGED_PENALTY;
290 av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
291 "bits per sample change detected in adjacent frames\n");
293 if (child_fi->is_var_size != header_fi->is_var_size) {
294 /* Changing blocking strategy not allowed per the spec */
295 deduction += FLAC_HEADER_BASE_SCORE;
296 av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
297 "blocking strategy change detected in adjacent frames\n");
299 if (child_fi->channels != header_fi->channels) {
300 deduction += FLAC_HEADER_CHANGED_PENALTY;
301 av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
302 "number of channels change detected in adjacent frames\n");
307 static int check_header_mismatch(FLACParseContext *fpc,
308 FLACHeaderMarker *header,
309 FLACHeaderMarker *child,
310 int log_level_offset)
312 FLACFrameInfo *header_fi = &header->fi, *child_fi = &child->fi;
313 int deduction, deduction_expected = 0, i;
314 deduction = check_header_fi_mismatch(fpc, header_fi, child_fi,
316 /* Check sample and frame numbers. */
317 if ((child_fi->frame_or_sample_num - header_fi->frame_or_sample_num
318 != header_fi->blocksize) &&
319 (child_fi->frame_or_sample_num
320 != header_fi->frame_or_sample_num + 1)) {
321 FLACHeaderMarker *curr;
322 int expected_frame_num, expected_sample_num;
323 /* If there are frames in the middle we expect this deduction,
324 as they are probably valid and this one follows it */
326 expected_frame_num = expected_sample_num = header_fi->frame_or_sample_num;
328 while (curr != child) {
329 /* Ignore frames that failed all crc checks */
330 for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS; i++) {
331 if (curr->link_penalty[i] < FLAC_HEADER_CRC_FAIL_PENALTY) {
332 expected_frame_num++;
333 expected_sample_num += curr->fi.blocksize;
340 if (expected_frame_num == child_fi->frame_or_sample_num ||
341 expected_sample_num == child_fi->frame_or_sample_num)
342 deduction_expected = deduction ? 0 : 1;
344 deduction += FLAC_HEADER_CHANGED_PENALTY;
345 av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
346 "sample/frame number mismatch in adjacent frames\n");
349 /* If we have suspicious headers, check the CRC between them */
350 if (deduction && !deduction_expected) {
351 FLACHeaderMarker *curr;
355 int inverted_test = 0;
357 /* Since CRC is expensive only do it if we haven't yet.
358 This assumes a CRC penalty is greater than all other check penalties */
360 for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS && curr != child; i++)
363 if (header->link_penalty[i] < FLAC_HEADER_CRC_FAIL_PENALTY ||
364 header->link_penalty[i] == FLAC_HEADER_NOT_PENALIZED_YET) {
365 FLACHeaderMarker *start, *end;
367 /* Although overlapping chains are scored, the crc should never
368 have to be computed twice for a single byte. */
372 header->link_penalty[i - 1] >= FLAC_HEADER_CRC_FAIL_PENALTY) {
373 while (start->next != child)
377 header->next->link_penalty[i-1] >=
378 FLAC_HEADER_CRC_FAIL_PENALTY ) {
383 read_len = end->offset - start->offset;
384 buf = flac_fifo_read(fpc, start->offset, &read_len);
385 crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf, read_len);
386 read_len = (end->offset - start->offset) - read_len;
389 buf = flac_fifo_read(fpc, end->offset - read_len, &read_len);
390 crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), crc, buf, read_len);
394 if (!crc ^ !inverted_test) {
395 deduction += FLAC_HEADER_CRC_FAIL_PENALTY;
396 av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
397 "crc check failed from offset %i (frame %"PRId64") to %i (frame %"PRId64")\n",
398 header->offset, header_fi->frame_or_sample_num,
399 child->offset, child_fi->frame_or_sample_num);
408 * Give FLAC_HEADER_BASE_SCORE points to a frame for existing.
409 * If it has children, (subsequent frames of which the preceding CRC footer
410 * validates against this one,) then take the maximum score of the children,
411 * with a penalty of FLAC_HEADER_CHANGED_PENALTY applied for each change to
412 * bps, sample rate, channels, but not decorrelation mode, or blocksize,
413 * because it can change often.
415 static int score_header(FLACParseContext *fpc, FLACHeaderMarker *header)
417 FLACHeaderMarker *child;
420 int base_score = FLAC_HEADER_BASE_SCORE;
421 if (header->max_score != FLAC_HEADER_NOT_SCORED_YET)
422 return header->max_score;
424 /* Modify the base score with changes from the last output header */
425 if (fpc->last_fi_valid) {
426 /* Silence the log since this will be repeated if selected */
427 base_score -= check_header_fi_mismatch(fpc, &fpc->last_fi, &header->fi,
431 header->max_score = base_score;
433 /* Check and compute the children's scores. */
434 child = header->next;
435 for (dist = 0; dist < FLAC_MAX_SEQUENTIAL_HEADERS && child; dist++) {
436 /* Look at the child's frame header info and penalize suspicious
437 changes between the headers. */
438 if (header->link_penalty[dist] == FLAC_HEADER_NOT_PENALIZED_YET) {
439 header->link_penalty[dist] = check_header_mismatch(fpc, header,
440 child, AV_LOG_DEBUG);
442 child_score = score_header(fpc, child) - header->link_penalty[dist];
444 if (FLAC_HEADER_BASE_SCORE + child_score > header->max_score) {
445 /* Keep the child because the frame scoring is dynamic. */
446 header->best_child = child;
447 header->max_score = base_score + child_score;
452 return header->max_score;
455 static void score_sequences(FLACParseContext *fpc)
457 FLACHeaderMarker *curr;
458 int best_score = 0;//FLAC_HEADER_NOT_SCORED_YET;
459 /* First pass to clear all old scores. */
460 for (curr = fpc->headers; curr; curr = curr->next)
461 curr->max_score = FLAC_HEADER_NOT_SCORED_YET;
463 /* Do a second pass to score them all. */
464 for (curr = fpc->headers; curr; curr = curr->next) {
465 if (score_header(fpc, curr) > best_score) {
466 fpc->best_header = curr;
467 best_score = curr->max_score;
472 static int get_best_header(FLACParseContext* fpc, const uint8_t **poutbuf,
475 FLACHeaderMarker *header = fpc->best_header;
476 FLACHeaderMarker *child = header->best_child;
478 *poutbuf_size = av_fifo_size(fpc->fifo_buf) - header->offset;
480 *poutbuf_size = child->offset - header->offset;
482 /* If the child has suspicious changes, log them */
483 check_header_mismatch(fpc, header, child, 0);
486 if (header->fi.channels != fpc->avctx->channels ||
487 !fpc->avctx->channel_layout) {
488 fpc->avctx->channels = header->fi.channels;
489 ff_flac_set_channel_layout(fpc->avctx);
491 fpc->avctx->sample_rate = header->fi.samplerate;
492 fpc->pc->duration = header->fi.blocksize;
493 *poutbuf = flac_fifo_read_wrap(fpc, header->offset, *poutbuf_size,
495 &fpc->wrap_buf_allocated_size);
498 if (fpc->pc->flags & PARSER_FLAG_USE_CODEC_TS){
499 if (header->fi.is_var_size)
500 fpc->pc->pts = header->fi.frame_or_sample_num;
501 else if (header->best_child)
502 fpc->pc->pts = header->fi.frame_or_sample_num * header->fi.blocksize;
505 fpc->best_header_valid = 0;
506 fpc->last_fi_valid = 1;
507 fpc->last_fi = header->fi;
509 /* Return the negative overread index so the client can compute pos.
510 This should be the amount overread to the beginning of the child */
512 return child->offset - av_fifo_size(fpc->fifo_buf);
516 static int flac_parse(AVCodecParserContext *s, AVCodecContext *avctx,
517 const uint8_t **poutbuf, int *poutbuf_size,
518 const uint8_t *buf, int buf_size)
520 FLACParseContext *fpc = s->priv_data;
521 FLACHeaderMarker *curr;
523 const uint8_t *read_end = buf;
524 const uint8_t *read_start = buf;
526 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
528 if (frame_header_is_valid(avctx, buf, &fi)) {
529 s->duration = fi.blocksize;
530 if (!avctx->sample_rate)
531 avctx->sample_rate = fi.samplerate;
532 if (fpc->pc->flags & PARSER_FLAG_USE_CODEC_TS){
533 fpc->pc->pts = fi.frame_or_sample_num;
535 fpc->pc->pts *= fi.blocksize;
539 *poutbuf_size = buf_size;
544 if (fpc->best_header_valid)
545 return get_best_header(fpc, poutbuf, poutbuf_size);
547 /* If a best_header was found last call remove it with the buffer data. */
548 if (fpc->best_header && fpc->best_header->best_child) {
549 FLACHeaderMarker *temp;
550 FLACHeaderMarker *best_child = fpc->best_header->best_child;
552 /* Remove headers in list until the end of the best_header. */
553 for (curr = fpc->headers; curr != best_child; curr = temp) {
554 if (curr != fpc->best_header) {
555 av_log(avctx, AV_LOG_DEBUG,
556 "dropping low score %i frame header from offset %i to %i\n",
557 curr->max_score, curr->offset, curr->next->offset);
560 av_freep(&curr->link_penalty);
562 fpc->nb_headers_buffered--;
564 /* Release returned data from ring buffer. */
565 av_fifo_drain(fpc->fifo_buf, best_child->offset);
567 /* Fix the offset for the headers remaining to match the new buffer. */
568 for (curr = best_child->next; curr; curr = curr->next)
569 curr->offset -= best_child->offset;
571 fpc->nb_headers_buffered--;
572 best_child->offset = 0;
573 fpc->headers = best_child;
574 if (fpc->nb_headers_buffered >= FLAC_MIN_HEADERS) {
575 fpc->best_header = best_child;
576 return get_best_header(fpc, poutbuf, poutbuf_size);
578 fpc->best_header = NULL;
579 } else if (fpc->best_header) {
580 /* No end frame no need to delete the buffer; probably eof */
581 FLACHeaderMarker *temp;
583 for (curr = fpc->headers; curr != fpc->best_header; curr = temp) {
585 av_freep(&curr->link_penalty);
588 fpc->headers = fpc->best_header->next;
589 av_freep(&fpc->best_header->link_penalty);
590 av_freep(&fpc->best_header);
593 /* Find and score new headers. */
594 /* buf_size is to zero when padding, so check for this since we do */
595 /* not want to try to read more input once we have found the end. */
596 /* Note that as (non-modified) parameters, buf can be non-NULL, */
597 /* while buf_size is 0. */
598 while ((buf && buf_size && read_end < buf + buf_size &&
599 fpc->nb_headers_buffered < FLAC_MIN_HEADERS)
600 || ((!buf || !buf_size) && !fpc->end_padded)) {
603 /* Pad the end once if EOF, to check the final region for headers. */
604 if (!buf || !buf_size) {
606 buf_size = MAX_FRAME_HEADER_SIZE;
607 read_end = read_start + MAX_FRAME_HEADER_SIZE;
609 /* The maximum read size is the upper-bound of what the parser
610 needs to have the required number of frames buffered */
611 int nb_desired = FLAC_MIN_HEADERS - fpc->nb_headers_buffered + 1;
612 read_end = read_end + FFMIN(buf + buf_size - read_end,
613 nb_desired * FLAC_AVG_FRAME_SIZE);
616 /* Fill the buffer. */
617 if ( av_fifo_space(fpc->fifo_buf) < read_end - read_start
618 && av_fifo_realloc2(fpc->fifo_buf, (read_end - read_start) + 2*av_fifo_size(fpc->fifo_buf)) < 0) {
619 av_log(avctx, AV_LOG_ERROR,
620 "couldn't reallocate buffer of size %"PTRDIFF_SPECIFIER"\n",
621 (read_end - read_start) + av_fifo_size(fpc->fifo_buf));
625 if (buf && buf_size) {
626 av_fifo_generic_write(fpc->fifo_buf, (void*) read_start,
627 read_end - read_start, NULL);
629 int8_t pad[MAX_FRAME_HEADER_SIZE] = { 0 };
630 av_fifo_generic_write(fpc->fifo_buf, (void*) pad, sizeof(pad), NULL);
633 /* Tag headers and update sequences. */
634 start_offset = av_fifo_size(fpc->fifo_buf) -
635 ((read_end - read_start) + (MAX_FRAME_HEADER_SIZE - 1));
636 start_offset = FFMAX(0, start_offset);
637 nb_headers = find_new_headers(fpc, start_offset);
639 if (nb_headers < 0) {
640 av_log(avctx, AV_LOG_ERROR,
641 "find_new_headers couldn't allocate FLAC header\n");
645 fpc->nb_headers_buffered = nb_headers;
646 /* Wait till FLAC_MIN_HEADERS to output a valid frame. */
647 if (!fpc->end_padded && fpc->nb_headers_buffered < FLAC_MIN_HEADERS) {
648 if (buf && read_end < buf + buf_size) {
649 read_start = read_end;
656 /* If headers found, update the scores since we have longer chains. */
657 if (fpc->end_padded || fpc->nb_headers_found)
658 score_sequences(fpc);
660 /* restore the state pre-padding */
661 if (fpc->end_padded) {
662 int warp = fpc->fifo_buf->wptr - fpc->fifo_buf->buffer < MAX_FRAME_HEADER_SIZE;
663 /* HACK: drain the tail of the fifo */
664 fpc->fifo_buf->wptr -= MAX_FRAME_HEADER_SIZE;
665 fpc->fifo_buf->wndx -= MAX_FRAME_HEADER_SIZE;
667 fpc->fifo_buf->wptr += fpc->fifo_buf->end -
668 fpc->fifo_buf->buffer;
671 read_start = read_end = NULL;
675 for (curr = fpc->headers; curr; curr = curr->next) {
676 if (curr->max_score > 0 &&
677 (!fpc->best_header || curr->max_score > fpc->best_header->max_score)) {
678 fpc->best_header = curr;
682 if (fpc->best_header) {
683 fpc->best_header_valid = 1;
684 if (fpc->best_header->offset > 0) {
685 /* Output a junk frame. */
686 av_log(avctx, AV_LOG_DEBUG, "Junk frame till offset %i\n",
687 fpc->best_header->offset);
689 /* Set duration to 0. It is unknown or invalid in a junk frame. */
691 *poutbuf_size = fpc->best_header->offset;
692 *poutbuf = flac_fifo_read_wrap(fpc, 0, *poutbuf_size,
694 &fpc->wrap_buf_allocated_size);
695 return buf_size ? (read_end - buf) : (fpc->best_header->offset -
696 av_fifo_size(fpc->fifo_buf));
699 return get_best_header(fpc, poutbuf, poutbuf_size);
705 return read_end - buf;
708 static av_cold int flac_parse_init(AVCodecParserContext *c)
710 FLACParseContext *fpc = c->priv_data;
712 /* There will generally be FLAC_MIN_HEADERS buffered in the fifo before
713 it drains. This is allocated early to avoid slow reallocation. */
714 fpc->fifo_buf = av_fifo_alloc_array(FLAC_MIN_HEADERS + 3, FLAC_AVG_FRAME_SIZE);
716 return AVERROR(ENOMEM);
720 static void flac_parse_close(AVCodecParserContext *c)
722 FLACParseContext *fpc = c->priv_data;
723 FLACHeaderMarker *curr = fpc->headers, *temp;
727 av_freep(&curr->link_penalty);
731 av_fifo_freep(&fpc->fifo_buf);
732 av_freep(&fpc->wrap_buf);
735 AVCodecParser ff_flac_parser = {
736 .codec_ids = { AV_CODEC_ID_FLAC },
737 .priv_data_size = sizeof(FLACParseContext),
738 .parser_init = flac_parse_init,
739 .parser_parse = flac_parse,
740 .parser_close = flac_parse_close,