forked from KolibriOS/kolibrios
725 lines
28 KiB
C
725 lines
28 KiB
C
/*
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* FLAC parser
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* Copyright (c) 2010 Michael Chinen
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* FLAC parser
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*
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* The FLAC parser buffers input until FLAC_MIN_HEADERS has been found.
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* Each time it finds and verifies a CRC-8 header it sees which of the
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* FLAC_MAX_SEQUENTIAL_HEADERS that came before it have a valid CRC-16 footer
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* that ends at the newly found header.
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* Headers are scored by FLAC_HEADER_BASE_SCORE plus the max of its crc-verified
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* children, penalized by changes in sample rate, frame number, etc.
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* The parser returns the frame with the highest score.
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**/
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#include "libavutil/attributes.h"
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#include "libavutil/crc.h"
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#include "libavutil/fifo.h"
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#include "bytestream.h"
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#include "parser.h"
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#include "flac.h"
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/** maximum number of adjacent headers that compare CRCs against each other */
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#define FLAC_MAX_SEQUENTIAL_HEADERS 3
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/** minimum number of headers buffered and checked before returning frames */
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#define FLAC_MIN_HEADERS 10
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/** estimate for average size of a FLAC frame */
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#define FLAC_AVG_FRAME_SIZE 8192
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/** scoring settings for score_header */
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#define FLAC_HEADER_BASE_SCORE 10
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#define FLAC_HEADER_CHANGED_PENALTY 7
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#define FLAC_HEADER_CRC_FAIL_PENALTY 50
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#define FLAC_HEADER_NOT_PENALIZED_YET 100000
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#define FLAC_HEADER_NOT_SCORED_YET -100000
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/** largest possible size of flac header */
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#define MAX_FRAME_HEADER_SIZE 16
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typedef struct FLACHeaderMarker {
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int offset; /**< byte offset from start of FLACParseContext->buffer */
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int *link_penalty; /**< pointer to array of local scores between this header
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and the one at a distance equal array position */
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int max_score; /**< maximum score found after checking each child that
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has a valid CRC */
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FLACFrameInfo fi; /**< decoded frame header info */
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struct FLACHeaderMarker *next; /**< next CRC-8 verified header that
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immediately follows this one in
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the bytestream */
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struct FLACHeaderMarker *best_child; /**< following frame header with
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which this frame has the best
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score with */
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} FLACHeaderMarker;
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typedef struct FLACParseContext {
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AVCodecParserContext *pc; /**< parent context */
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AVCodecContext *avctx; /**< codec context pointer for logging */
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FLACHeaderMarker *headers; /**< linked-list that starts at the first
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CRC-8 verified header within buffer */
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FLACHeaderMarker *best_header; /**< highest scoring header within buffer */
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int nb_headers_found; /**< number of headers found in the last
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flac_parse() call */
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int nb_headers_buffered; /**< number of headers that are buffered */
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int best_header_valid; /**< flag set when the parser returns junk;
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if set return best_header next time */
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AVFifoBuffer *fifo_buf; /**< buffer to store all data until headers
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can be verified */
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int end_padded; /**< specifies if fifo_buf's end is padded */
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uint8_t *wrap_buf; /**< general fifo read buffer when wrapped */
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int wrap_buf_allocated_size; /**< actual allocated size of the buffer */
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FLACFrameInfo last_fi; /**< last decoded frame header info */
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int last_fi_valid; /**< set if last_fi is valid */
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} FLACParseContext;
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static int frame_header_is_valid(AVCodecContext *avctx, const uint8_t *buf,
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FLACFrameInfo *fi)
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{
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GetBitContext gb;
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init_get_bits(&gb, buf, MAX_FRAME_HEADER_SIZE * 8);
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return !ff_flac_decode_frame_header(avctx, &gb, fi, 127);
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}
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/**
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* Non-destructive fast fifo pointer fetching
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* Returns a pointer from the specified offset.
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* If possible the pointer points within the fifo buffer.
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* Otherwise (if it would cause a wrap around,) a pointer to a user-specified
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* buffer is used.
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* The pointer can be NULL. In any case it will be reallocated to hold the size.
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* If the returned pointer will be used after subsequent calls to flac_fifo_read_wrap
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* then the subsequent calls should pass in a different wrap_buf so as to not
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* overwrite the contents of the previous wrap_buf.
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* This function is based on av_fifo_generic_read, which is why there is a comment
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* about a memory barrier for SMP.
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*/
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static uint8_t* flac_fifo_read_wrap(FLACParseContext *fpc, int offset, int len,
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uint8_t** wrap_buf, int* allocated_size)
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{
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AVFifoBuffer *f = fpc->fifo_buf;
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uint8_t *start = f->rptr + offset;
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uint8_t *tmp_buf;
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if (start >= f->end)
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start -= f->end - f->buffer;
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if (f->end - start >= len)
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return start;
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tmp_buf = av_fast_realloc(*wrap_buf, allocated_size, len);
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if (!tmp_buf) {
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av_log(fpc->avctx, AV_LOG_ERROR,
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"couldn't reallocate wrap buffer of size %d", len);
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return NULL;
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}
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*wrap_buf = tmp_buf;
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do {
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int seg_len = FFMIN(f->end - start, len);
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memcpy(tmp_buf, start, seg_len);
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tmp_buf = (uint8_t*)tmp_buf + seg_len;
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// memory barrier needed for SMP here in theory
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start += seg_len - (f->end - f->buffer);
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len -= seg_len;
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} while (len > 0);
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return *wrap_buf;
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}
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/**
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* Return a pointer in the fifo buffer where the offset starts at until
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* the wrap point or end of request.
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* len will contain the valid length of the returned buffer.
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* A second call to flac_fifo_read (with new offset and len) should be called
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* to get the post-wrap buf if the returned len is less than the requested.
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**/
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static uint8_t* flac_fifo_read(FLACParseContext *fpc, int offset, int *len)
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{
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AVFifoBuffer *f = fpc->fifo_buf;
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uint8_t *start = f->rptr + offset;
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if (start >= f->end)
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start -= f->end - f->buffer;
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*len = FFMIN(*len, f->end - start);
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return start;
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}
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static int find_headers_search_validate(FLACParseContext *fpc, int offset)
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{
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FLACFrameInfo fi;
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uint8_t *header_buf;
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int size = 0;
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header_buf = flac_fifo_read_wrap(fpc, offset,
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MAX_FRAME_HEADER_SIZE,
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&fpc->wrap_buf,
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&fpc->wrap_buf_allocated_size);
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if (frame_header_is_valid(fpc->avctx, header_buf, &fi)) {
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FLACHeaderMarker **end_handle = &fpc->headers;
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int i;
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size = 0;
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while (*end_handle) {
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end_handle = &(*end_handle)->next;
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size++;
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}
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*end_handle = av_mallocz(sizeof(FLACHeaderMarker));
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if (!*end_handle) {
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av_log(fpc->avctx, AV_LOG_ERROR,
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"couldn't allocate FLACHeaderMarker\n");
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return AVERROR(ENOMEM);
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}
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(*end_handle)->fi = fi;
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(*end_handle)->offset = offset;
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(*end_handle)->link_penalty = av_malloc(sizeof(int) *
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FLAC_MAX_SEQUENTIAL_HEADERS);
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for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS; i++)
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(*end_handle)->link_penalty[i] = FLAC_HEADER_NOT_PENALIZED_YET;
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fpc->nb_headers_found++;
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size++;
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}
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return size;
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}
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static int find_headers_search(FLACParseContext *fpc, uint8_t *buf, int buf_size,
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int search_start)
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{
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int size = 0, mod_offset = (buf_size - 1) % 4, i, j;
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uint32_t x;
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for (i = 0; i < mod_offset; i++) {
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if ((AV_RB16(buf + i) & 0xFFFE) == 0xFFF8)
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size = find_headers_search_validate(fpc, search_start + i);
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}
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for (; i < buf_size - 1; i += 4) {
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x = AV_RB32(buf + i);
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if (((x & ~(x + 0x01010101)) & 0x80808080)) {
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for (j = 0; j < 4; j++) {
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if ((AV_RB16(buf + i + j) & 0xFFFE) == 0xFFF8)
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size = find_headers_search_validate(fpc, search_start + i + j);
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}
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}
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}
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return size;
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}
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static int find_new_headers(FLACParseContext *fpc, int search_start)
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{
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FLACHeaderMarker *end;
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int search_end, size = 0, read_len, temp;
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uint8_t *buf;
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fpc->nb_headers_found = 0;
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/* Search for a new header of at most 16 bytes. */
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search_end = av_fifo_size(fpc->fifo_buf) - (MAX_FRAME_HEADER_SIZE - 1);
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read_len = search_end - search_start + 1;
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buf = flac_fifo_read(fpc, search_start, &read_len);
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size = find_headers_search(fpc, buf, read_len, search_start);
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search_start += read_len - 1;
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/* If fifo end was hit do the wrap around. */
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if (search_start != search_end) {
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uint8_t wrap[2];
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wrap[0] = buf[read_len - 1];
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read_len = search_end - search_start + 1;
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/* search_start + 1 is the post-wrap offset in the fifo. */
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buf = flac_fifo_read(fpc, search_start + 1, &read_len);
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wrap[1] = buf[0];
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if ((AV_RB16(wrap) & 0xFFFE) == 0xFFF8) {
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temp = find_headers_search_validate(fpc, search_start);
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size = FFMAX(size, temp);
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}
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search_start++;
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/* Continue to do the last half of the wrap. */
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temp = find_headers_search(fpc, buf, read_len, search_start);
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size = FFMAX(size, temp);
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search_start += read_len - 1;
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}
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/* Return the size even if no new headers were found. */
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if (!size && fpc->headers)
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for (end = fpc->headers; end; end = end->next)
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size++;
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return size;
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}
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static int check_header_fi_mismatch(FLACParseContext *fpc,
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FLACFrameInfo *header_fi,
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FLACFrameInfo *child_fi,
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int log_level_offset)
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{
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int deduction = 0;
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if (child_fi->samplerate != header_fi->samplerate) {
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deduction += FLAC_HEADER_CHANGED_PENALTY;
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av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
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"sample rate change detected in adjacent frames\n");
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}
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if (child_fi->bps != header_fi->bps) {
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deduction += FLAC_HEADER_CHANGED_PENALTY;
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av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
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"bits per sample change detected in adjacent frames\n");
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}
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if (child_fi->is_var_size != header_fi->is_var_size) {
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/* Changing blocking strategy not allowed per the spec */
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deduction += FLAC_HEADER_BASE_SCORE;
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av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
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"blocking strategy change detected in adjacent frames\n");
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}
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if (child_fi->channels != header_fi->channels) {
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deduction += FLAC_HEADER_CHANGED_PENALTY;
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av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
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"number of channels change detected in adjacent frames\n");
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}
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return deduction;
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}
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static int check_header_mismatch(FLACParseContext *fpc,
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FLACHeaderMarker *header,
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FLACHeaderMarker *child,
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int log_level_offset)
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{
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FLACFrameInfo *header_fi = &header->fi, *child_fi = &child->fi;
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int deduction, deduction_expected = 0, i;
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deduction = check_header_fi_mismatch(fpc, header_fi, child_fi,
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log_level_offset);
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/* Check sample and frame numbers. */
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if ((child_fi->frame_or_sample_num - header_fi->frame_or_sample_num
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!= header_fi->blocksize) &&
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(child_fi->frame_or_sample_num
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!= header_fi->frame_or_sample_num + 1)) {
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FLACHeaderMarker *curr;
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int expected_frame_num, expected_sample_num;
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/* If there are frames in the middle we expect this deduction,
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as they are probably valid and this one follows it */
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expected_frame_num = expected_sample_num = header_fi->frame_or_sample_num;
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curr = header;
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while (curr != child) {
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/* Ignore frames that failed all crc checks */
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for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS; i++) {
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if (curr->link_penalty[i] < FLAC_HEADER_CRC_FAIL_PENALTY) {
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expected_frame_num++;
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expected_sample_num += curr->fi.blocksize;
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break;
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}
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}
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curr = curr->next;
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}
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if (expected_frame_num == child_fi->frame_or_sample_num ||
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expected_sample_num == child_fi->frame_or_sample_num)
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deduction_expected = deduction ? 0 : 1;
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deduction += FLAC_HEADER_CHANGED_PENALTY;
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av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
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"sample/frame number mismatch in adjacent frames\n");
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}
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/* If we have suspicious headers, check the CRC between them */
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if (deduction && !deduction_expected) {
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FLACHeaderMarker *curr;
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int read_len;
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uint8_t *buf;
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uint32_t crc = 1;
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int inverted_test = 0;
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/* Since CRC is expensive only do it if we haven't yet.
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This assumes a CRC penalty is greater than all other check penalties */
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curr = header->next;
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for (i = 0; i < FLAC_MAX_SEQUENTIAL_HEADERS && curr != child; i++)
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curr = curr->next;
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if (header->link_penalty[i] < FLAC_HEADER_CRC_FAIL_PENALTY ||
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header->link_penalty[i] == FLAC_HEADER_NOT_PENALIZED_YET) {
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FLACHeaderMarker *start, *end;
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/* Although overlapping chains are scored, the crc should never
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have to be computed twice for a single byte. */
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start = header;
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end = child;
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if (i > 0 &&
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header->link_penalty[i - 1] >= FLAC_HEADER_CRC_FAIL_PENALTY) {
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while (start->next != child)
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start = start->next;
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inverted_test = 1;
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} else if (i > 0 &&
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header->next->link_penalty[i-1] >=
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FLAC_HEADER_CRC_FAIL_PENALTY ) {
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end = header->next;
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inverted_test = 1;
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}
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read_len = end->offset - start->offset;
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buf = flac_fifo_read(fpc, start->offset, &read_len);
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crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf, read_len);
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read_len = (end->offset - start->offset) - read_len;
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if (read_len) {
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buf = flac_fifo_read(fpc, end->offset - read_len, &read_len);
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crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), crc, buf, read_len);
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}
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}
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if (!crc ^ !inverted_test) {
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deduction += FLAC_HEADER_CRC_FAIL_PENALTY;
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av_log(fpc->avctx, AV_LOG_WARNING + log_level_offset,
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"crc check failed from offset %i (frame %"PRId64") to %i (frame %"PRId64")\n",
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header->offset, header_fi->frame_or_sample_num,
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child->offset, child_fi->frame_or_sample_num);
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}
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}
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return deduction;
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}
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/**
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* Score a header.
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*
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* Give FLAC_HEADER_BASE_SCORE points to a frame for existing.
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* If it has children, (subsequent frames of which the preceding CRC footer
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* validates against this one,) then take the maximum score of the children,
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* with a penalty of FLAC_HEADER_CHANGED_PENALTY applied for each change to
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* bps, sample rate, channels, but not decorrelation mode, or blocksize,
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* because it can change often.
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**/
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static int score_header(FLACParseContext *fpc, FLACHeaderMarker *header)
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{
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FLACHeaderMarker *child;
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int dist = 0;
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int child_score;
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int base_score = FLAC_HEADER_BASE_SCORE;
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if (header->max_score != FLAC_HEADER_NOT_SCORED_YET)
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return header->max_score;
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/* Modify the base score with changes from the last output header */
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if (fpc->last_fi_valid) {
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/* Silence the log since this will be repeated if selected */
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base_score -= check_header_fi_mismatch(fpc, &fpc->last_fi, &header->fi,
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AV_LOG_DEBUG);
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}
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header->max_score = base_score;
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/* Check and compute the children's scores. */
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child = header->next;
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for (dist = 0; dist < FLAC_MAX_SEQUENTIAL_HEADERS && child; dist++) {
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/* Look at the child's frame header info and penalize suspicious
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changes between the headers. */
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if (header->link_penalty[dist] == FLAC_HEADER_NOT_PENALIZED_YET) {
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header->link_penalty[dist] = check_header_mismatch(fpc, header,
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child, AV_LOG_DEBUG);
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}
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child_score = score_header(fpc, child) - header->link_penalty[dist];
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if (FLAC_HEADER_BASE_SCORE + child_score > header->max_score) {
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/* Keep the child because the frame scoring is dynamic. */
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header->best_child = child;
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header->max_score = base_score + child_score;
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}
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child = child->next;
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}
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return header->max_score;
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}
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static void score_sequences(FLACParseContext *fpc)
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{
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FLACHeaderMarker *curr;
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int best_score = 0;//FLAC_HEADER_NOT_SCORED_YET;
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/* First pass to clear all old scores. */
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for (curr = fpc->headers; curr; curr = curr->next)
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curr->max_score = FLAC_HEADER_NOT_SCORED_YET;
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|
/* Do a second pass to score them all. */
|
|
for (curr = fpc->headers; curr; curr = curr->next) {
|
|
if (score_header(fpc, curr) > best_score) {
|
|
fpc->best_header = curr;
|
|
best_score = curr->max_score;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int get_best_header(FLACParseContext* fpc, const uint8_t **poutbuf,
|
|
int *poutbuf_size)
|
|
{
|
|
FLACHeaderMarker *header = fpc->best_header;
|
|
FLACHeaderMarker *child = header->best_child;
|
|
if (!child) {
|
|
*poutbuf_size = av_fifo_size(fpc->fifo_buf) - header->offset;
|
|
} else {
|
|
*poutbuf_size = child->offset - header->offset;
|
|
|
|
/* If the child has suspicious changes, log them */
|
|
check_header_mismatch(fpc, header, child, 0);
|
|
}
|
|
|
|
if (header->fi.channels != fpc->avctx->channels ||
|
|
!fpc->avctx->channel_layout) {
|
|
fpc->avctx->channels = header->fi.channels;
|
|
ff_flac_set_channel_layout(fpc->avctx);
|
|
}
|
|
fpc->avctx->sample_rate = header->fi.samplerate;
|
|
fpc->pc->duration = header->fi.blocksize;
|
|
*poutbuf = flac_fifo_read_wrap(fpc, header->offset, *poutbuf_size,
|
|
&fpc->wrap_buf,
|
|
&fpc->wrap_buf_allocated_size);
|
|
|
|
fpc->best_header_valid = 0;
|
|
fpc->last_fi_valid = 1;
|
|
fpc->last_fi = header->fi;
|
|
|
|
/* Return the negative overread index so the client can compute pos.
|
|
This should be the amount overread to the beginning of the child */
|
|
if (child)
|
|
return child->offset - av_fifo_size(fpc->fifo_buf);
|
|
return 0;
|
|
}
|
|
|
|
static int flac_parse(AVCodecParserContext *s, AVCodecContext *avctx,
|
|
const uint8_t **poutbuf, int *poutbuf_size,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
FLACParseContext *fpc = s->priv_data;
|
|
FLACHeaderMarker *curr;
|
|
int nb_headers;
|
|
const uint8_t *read_end = buf;
|
|
const uint8_t *read_start = buf;
|
|
|
|
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
|
|
FLACFrameInfo fi;
|
|
if (frame_header_is_valid(avctx, buf, &fi)) {
|
|
s->duration = fi.blocksize;
|
|
if (!avctx->sample_rate)
|
|
avctx->sample_rate = fi.samplerate;
|
|
}
|
|
*poutbuf = buf;
|
|
*poutbuf_size = buf_size;
|
|
return buf_size;
|
|
}
|
|
|
|
fpc->avctx = avctx;
|
|
if (fpc->best_header_valid)
|
|
return get_best_header(fpc, poutbuf, poutbuf_size);
|
|
|
|
/* If a best_header was found last call remove it with the buffer data. */
|
|
if (fpc->best_header && fpc->best_header->best_child) {
|
|
FLACHeaderMarker *temp;
|
|
FLACHeaderMarker *best_child = fpc->best_header->best_child;
|
|
|
|
/* Remove headers in list until the end of the best_header. */
|
|
for (curr = fpc->headers; curr != best_child; curr = temp) {
|
|
if (curr != fpc->best_header) {
|
|
av_log(avctx, AV_LOG_DEBUG,
|
|
"dropping low score %i frame header from offset %i to %i\n",
|
|
curr->max_score, curr->offset, curr->next->offset);
|
|
}
|
|
temp = curr->next;
|
|
av_freep(&curr->link_penalty);
|
|
av_free(curr);
|
|
fpc->nb_headers_buffered--;
|
|
}
|
|
/* Release returned data from ring buffer. */
|
|
av_fifo_drain(fpc->fifo_buf, best_child->offset);
|
|
|
|
/* Fix the offset for the headers remaining to match the new buffer. */
|
|
for (curr = best_child->next; curr; curr = curr->next)
|
|
curr->offset -= best_child->offset;
|
|
|
|
fpc->nb_headers_buffered--;
|
|
best_child->offset = 0;
|
|
fpc->headers = best_child;
|
|
if (fpc->nb_headers_buffered >= FLAC_MIN_HEADERS) {
|
|
fpc->best_header = best_child;
|
|
return get_best_header(fpc, poutbuf, poutbuf_size);
|
|
}
|
|
fpc->best_header = NULL;
|
|
} else if (fpc->best_header) {
|
|
/* No end frame no need to delete the buffer; probably eof */
|
|
FLACHeaderMarker *temp;
|
|
|
|
for (curr = fpc->headers; curr != fpc->best_header; curr = temp) {
|
|
temp = curr->next;
|
|
av_freep(&curr->link_penalty);
|
|
av_free(curr);
|
|
}
|
|
fpc->headers = fpc->best_header->next;
|
|
av_freep(&fpc->best_header->link_penalty);
|
|
av_freep(&fpc->best_header);
|
|
}
|
|
|
|
/* Find and score new headers. */
|
|
/* buf_size is to zero when padding, so check for this since we do */
|
|
/* not want to try to read more input once we have found the end. */
|
|
/* Note that as (non-modified) parameters, buf can be non-NULL, */
|
|
/* while buf_size is 0. */
|
|
while ((buf && buf_size && read_end < buf + buf_size &&
|
|
fpc->nb_headers_buffered < FLAC_MIN_HEADERS)
|
|
|| ((!buf || !buf_size) && !fpc->end_padded)) {
|
|
int start_offset;
|
|
|
|
/* Pad the end once if EOF, to check the final region for headers. */
|
|
if (!buf || !buf_size) {
|
|
fpc->end_padded = 1;
|
|
buf_size = MAX_FRAME_HEADER_SIZE;
|
|
read_end = read_start + MAX_FRAME_HEADER_SIZE;
|
|
} else {
|
|
/* The maximum read size is the upper-bound of what the parser
|
|
needs to have the required number of frames buffered */
|
|
int nb_desired = FLAC_MIN_HEADERS - fpc->nb_headers_buffered + 1;
|
|
read_end = read_end + FFMIN(buf + buf_size - read_end,
|
|
nb_desired * FLAC_AVG_FRAME_SIZE);
|
|
}
|
|
|
|
/* Fill the buffer. */
|
|
if ( av_fifo_space(fpc->fifo_buf) < read_end - read_start
|
|
&& av_fifo_realloc2(fpc->fifo_buf, (read_end - read_start) + 2*av_fifo_size(fpc->fifo_buf)) < 0) {
|
|
av_log(avctx, AV_LOG_ERROR,
|
|
"couldn't reallocate buffer of size %td\n",
|
|
(read_end - read_start) + av_fifo_size(fpc->fifo_buf));
|
|
goto handle_error;
|
|
}
|
|
|
|
if (buf && buf_size) {
|
|
av_fifo_generic_write(fpc->fifo_buf, (void*) read_start,
|
|
read_end - read_start, NULL);
|
|
} else {
|
|
int8_t pad[MAX_FRAME_HEADER_SIZE] = { 0 };
|
|
av_fifo_generic_write(fpc->fifo_buf, (void*) pad, sizeof(pad), NULL);
|
|
}
|
|
|
|
/* Tag headers and update sequences. */
|
|
start_offset = av_fifo_size(fpc->fifo_buf) -
|
|
((read_end - read_start) + (MAX_FRAME_HEADER_SIZE - 1));
|
|
start_offset = FFMAX(0, start_offset);
|
|
nb_headers = find_new_headers(fpc, start_offset);
|
|
|
|
if (nb_headers < 0) {
|
|
av_log(avctx, AV_LOG_ERROR,
|
|
"find_new_headers couldn't allocate FLAC header\n");
|
|
goto handle_error;
|
|
}
|
|
|
|
fpc->nb_headers_buffered = nb_headers;
|
|
/* Wait till FLAC_MIN_HEADERS to output a valid frame. */
|
|
if (!fpc->end_padded && fpc->nb_headers_buffered < FLAC_MIN_HEADERS) {
|
|
if (buf && read_end < buf + buf_size) {
|
|
read_start = read_end;
|
|
continue;
|
|
} else {
|
|
goto handle_error;
|
|
}
|
|
}
|
|
|
|
/* If headers found, update the scores since we have longer chains. */
|
|
if (fpc->end_padded || fpc->nb_headers_found)
|
|
score_sequences(fpc);
|
|
|
|
/* restore the state pre-padding */
|
|
if (fpc->end_padded) {
|
|
int warp = fpc->fifo_buf->wptr - fpc->fifo_buf->buffer < MAX_FRAME_HEADER_SIZE;
|
|
/* HACK: drain the tail of the fifo */
|
|
fpc->fifo_buf->wptr -= MAX_FRAME_HEADER_SIZE;
|
|
fpc->fifo_buf->wndx -= MAX_FRAME_HEADER_SIZE;
|
|
if (warp) {
|
|
fpc->fifo_buf->wptr += fpc->fifo_buf->end -
|
|
fpc->fifo_buf->buffer;
|
|
}
|
|
buf_size = 0;
|
|
read_start = read_end = NULL;
|
|
}
|
|
}
|
|
|
|
curr = fpc->headers;
|
|
for (curr = fpc->headers; curr; curr = curr->next) {
|
|
if (curr->max_score > 0 &&
|
|
(!fpc->best_header || curr->max_score > fpc->best_header->max_score)) {
|
|
fpc->best_header = curr;
|
|
}
|
|
}
|
|
|
|
if (fpc->best_header) {
|
|
fpc->best_header_valid = 1;
|
|
if (fpc->best_header->offset > 0) {
|
|
/* Output a junk frame. */
|
|
av_log(avctx, AV_LOG_DEBUG, "Junk frame till offset %i\n",
|
|
fpc->best_header->offset);
|
|
|
|
/* Set duration to 0. It is unknown or invalid in a junk frame. */
|
|
s->duration = 0;
|
|
*poutbuf_size = fpc->best_header->offset;
|
|
*poutbuf = flac_fifo_read_wrap(fpc, 0, *poutbuf_size,
|
|
&fpc->wrap_buf,
|
|
&fpc->wrap_buf_allocated_size);
|
|
return buf_size ? (read_end - buf) : (fpc->best_header->offset -
|
|
av_fifo_size(fpc->fifo_buf));
|
|
}
|
|
if (!buf_size)
|
|
return get_best_header(fpc, poutbuf, poutbuf_size);
|
|
}
|
|
|
|
handle_error:
|
|
*poutbuf = NULL;
|
|
*poutbuf_size = 0;
|
|
return read_end - buf;
|
|
}
|
|
|
|
static av_cold int flac_parse_init(AVCodecParserContext *c)
|
|
{
|
|
FLACParseContext *fpc = c->priv_data;
|
|
fpc->pc = c;
|
|
/* There will generally be FLAC_MIN_HEADERS buffered in the fifo before
|
|
it drains. This is allocated early to avoid slow reallocation. */
|
|
fpc->fifo_buf = av_fifo_alloc(FLAC_AVG_FRAME_SIZE * (FLAC_MIN_HEADERS + 3));
|
|
if (!fpc->fifo_buf)
|
|
return AVERROR(ENOMEM);
|
|
return 0;
|
|
}
|
|
|
|
static void flac_parse_close(AVCodecParserContext *c)
|
|
{
|
|
FLACParseContext *fpc = c->priv_data;
|
|
FLACHeaderMarker *curr = fpc->headers, *temp;
|
|
|
|
while (curr) {
|
|
temp = curr->next;
|
|
av_freep(&curr->link_penalty);
|
|
av_free(curr);
|
|
curr = temp;
|
|
}
|
|
av_fifo_free(fpc->fifo_buf);
|
|
av_free(fpc->wrap_buf);
|
|
}
|
|
|
|
AVCodecParser ff_flac_parser = {
|
|
.codec_ids = { AV_CODEC_ID_FLAC },
|
|
.priv_data_size = sizeof(FLACParseContext),
|
|
.parser_init = flac_parse_init,
|
|
.parser_parse = flac_parse,
|
|
.parser_close = flac_parse_close,
|
|
};
|