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![Clément Bœsch](/assets/img/avatar_default.png)
* commit 'ed1cd81076434b76f37576d4d806973476a8e96c': flac demuxer: improve probing Suggested commit very closely matches our code, except with regards to AVPROBE_SCORE_EXTENSION. The code layout is mostly merged but preserves our behaviour. Merged-by: Clément Bœsch <u@pkh.me>
343 lines
12 KiB
C
343 lines
12 KiB
C
/*
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* Raw FLAC demuxer
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* Copyright (c) 2001 Fabrice Bellard
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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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#include "libavcodec/flac.h"
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#include "avformat.h"
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#include "flac_picture.h"
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#include "internal.h"
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#include "rawdec.h"
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#include "oggdec.h"
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#include "vorbiscomment.h"
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#include "replaygain.h"
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#define SEEKPOINT_SIZE 18
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typedef struct FLACDecContext {
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int found_seektable;
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} FLACDecContext;
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static void reset_index_position(int64_t metadata_head_size, AVStream *st)
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{
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/* the real seek index offset should be the size of metadata blocks with the offset in the frame blocks */
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int i;
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for(i=0; i<st->nb_index_entries; i++) {
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st->index_entries[i].pos += metadata_head_size;
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}
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}
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static int flac_read_header(AVFormatContext *s)
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{
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int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
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uint8_t header[4];
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uint8_t *buffer=NULL;
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FLACDecContext *flac = s->priv_data;
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AVStream *st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codecpar->codec_id = AV_CODEC_ID_FLAC;
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st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
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/* the parameters will be extracted from the compressed bitstream */
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/* if fLaC marker is not found, assume there is no header */
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if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {
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avio_seek(s->pb, -4, SEEK_CUR);
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return 0;
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}
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/* process metadata blocks */
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while (!avio_feof(s->pb) && !metadata_last) {
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if (avio_read(s->pb, header, 4) != 4)
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return AVERROR(AVERROR_INVALIDDATA);
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flac_parse_block_header(header, &metadata_last, &metadata_type,
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&metadata_size);
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switch (metadata_type) {
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/* allocate and read metadata block for supported types */
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case FLAC_METADATA_TYPE_STREAMINFO:
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case FLAC_METADATA_TYPE_CUESHEET:
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case FLAC_METADATA_TYPE_PICTURE:
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case FLAC_METADATA_TYPE_VORBIS_COMMENT:
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case FLAC_METADATA_TYPE_SEEKTABLE:
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buffer = av_mallocz(metadata_size + AV_INPUT_BUFFER_PADDING_SIZE);
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if (!buffer) {
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return AVERROR(ENOMEM);
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}
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if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
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RETURN_ERROR(AVERROR(EIO));
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}
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break;
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/* skip metadata block for unsupported types */
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default:
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ret = avio_skip(s->pb, metadata_size);
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if (ret < 0)
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return ret;
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}
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if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
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uint32_t samplerate;
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uint64_t samples;
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/* STREAMINFO can only occur once */
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if (found_streaminfo) {
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RETURN_ERROR(AVERROR_INVALIDDATA);
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}
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if (metadata_size != FLAC_STREAMINFO_SIZE) {
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RETURN_ERROR(AVERROR_INVALIDDATA);
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}
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found_streaminfo = 1;
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st->codecpar->extradata = buffer;
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st->codecpar->extradata_size = metadata_size;
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buffer = NULL;
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/* get sample rate and sample count from STREAMINFO header;
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* other parameters will be extracted by the parser */
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samplerate = AV_RB24(st->codecpar->extradata + 10) >> 4;
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samples = (AV_RB64(st->codecpar->extradata + 13) >> 24) & ((1ULL << 36) - 1);
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/* set time base and duration */
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if (samplerate > 0) {
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avpriv_set_pts_info(st, 64, 1, samplerate);
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if (samples > 0)
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st->duration = samples;
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}
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} else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {
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uint8_t isrc[13];
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uint64_t start;
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const uint8_t *offset;
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int i, chapters, track, ti;
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if (metadata_size < 431)
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RETURN_ERROR(AVERROR_INVALIDDATA);
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offset = buffer + 395;
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chapters = bytestream_get_byte(&offset) - 1;
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if (chapters <= 0)
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RETURN_ERROR(AVERROR_INVALIDDATA);
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for (i = 0; i < chapters; i++) {
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if (offset + 36 - buffer > metadata_size)
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RETURN_ERROR(AVERROR_INVALIDDATA);
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start = bytestream_get_be64(&offset);
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track = bytestream_get_byte(&offset);
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bytestream_get_buffer(&offset, isrc, 12);
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isrc[12] = 0;
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offset += 14;
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ti = bytestream_get_byte(&offset);
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if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);
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offset += ti * 12;
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avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
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}
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av_freep(&buffer);
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} else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {
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ret = ff_flac_parse_picture(s, buffer, metadata_size);
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av_freep(&buffer);
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if (ret < 0) {
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av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");
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return ret;
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}
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} else if (metadata_type == FLAC_METADATA_TYPE_SEEKTABLE) {
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const uint8_t *seekpoint = buffer;
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int i, seek_point_count = metadata_size/SEEKPOINT_SIZE;
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flac->found_seektable = 1;
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if ((s->flags&AVFMT_FLAG_FAST_SEEK)) {
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for(i=0; i<seek_point_count; i++) {
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int64_t timestamp = bytestream_get_be64(&seekpoint);
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int64_t pos = bytestream_get_be64(&seekpoint);
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/* skip number of samples */
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bytestream_get_be16(&seekpoint);
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av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);
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}
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}
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av_freep(&buffer);
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}
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else {
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/* STREAMINFO must be the first block */
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if (!found_streaminfo) {
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RETURN_ERROR(AVERROR_INVALIDDATA);
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}
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/* process supported blocks other than STREAMINFO */
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if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
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AVDictionaryEntry *chmask;
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ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
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if (ret < 0) {
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av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
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} else if (ret > 0) {
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s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;
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}
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/* parse the channels mask if present */
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chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
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if (chmask) {
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uint64_t mask = strtol(chmask->value, NULL, 0);
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if (!mask || mask & ~0x3ffffULL) {
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av_log(s, AV_LOG_WARNING,
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"Invalid value of WAVEFORMATEXTENSIBLE_CHANNEL_MASK\n");
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} else {
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st->codecpar->channel_layout = mask;
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av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
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}
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}
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}
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av_freep(&buffer);
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}
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}
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ret = ff_replaygain_export(st, s->metadata);
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if (ret < 0)
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return ret;
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reset_index_position(avio_tell(s->pb), st);
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return 0;
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fail:
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av_free(buffer);
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return ret;
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}
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static int raw_flac_probe(AVProbeData *p)
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{
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if ((p->buf[2] & 0xF0) == 0) // blocksize code invalid
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return 0;
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if ((p->buf[2] & 0x0F) == 0x0F) // sample rate code invalid
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return 0;
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if ((p->buf[3] & 0xF0) >= FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE << 4)
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// channel mode invalid
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return 0;
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if ((p->buf[3] & 0x06) == 0x06) // bits per sample code invalid
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return 0;
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if ((p->buf[3] & 0x01) == 0x01) // reserved bit set
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return 0;
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return AVPROBE_SCORE_EXTENSION / 4 + 1;
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}
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static int flac_probe(AVProbeData *p)
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{
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if ((AV_RB16(p->buf) & 0xFFFE) == 0xFFF8)
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return raw_flac_probe(p);
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/* file header + metadata header + checked bytes of streaminfo */
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if (p->buf_size >= 4 + 4 + 13) {
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int type = p->buf[4] & 0x7f;
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int size = AV_RB24(p->buf + 5);
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int min_block_size = AV_RB16(p->buf + 8);
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int max_block_size = AV_RB16(p->buf + 10);
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int sample_rate = AV_RB24(p->buf + 18) >> 4;
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if (memcmp(p->buf, "fLaC", 4))
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return 0;
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if (type == FLAC_METADATA_TYPE_STREAMINFO &&
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size == FLAC_STREAMINFO_SIZE &&
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min_block_size >= 16 &&
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max_block_size >= min_block_size &&
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sample_rate && sample_rate <= 655350)
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return AVPROBE_SCORE_MAX;
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return AVPROBE_SCORE_EXTENSION;
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}
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return 0;
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}
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static av_unused int64_t flac_read_timestamp(AVFormatContext *s, int stream_index,
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int64_t *ppos, int64_t pos_limit)
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{
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AVPacket pkt, out_pkt;
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AVStream *st = s->streams[stream_index];
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AVCodecParserContext *parser;
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int ret;
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int64_t pts = AV_NOPTS_VALUE;
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if (avio_seek(s->pb, *ppos, SEEK_SET) < 0)
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return AV_NOPTS_VALUE;
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av_init_packet(&pkt);
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parser = av_parser_init(st->codecpar->codec_id);
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if (!parser){
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return AV_NOPTS_VALUE;
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}
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parser->flags |= PARSER_FLAG_USE_CODEC_TS;
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for (;;){
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ret = ff_raw_read_partial_packet(s, &pkt);
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if (ret < 0){
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if (ret == AVERROR(EAGAIN))
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continue;
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else {
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av_packet_unref(&pkt);
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av_assert1(!pkt.size);
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}
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}
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av_init_packet(&out_pkt);
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av_parser_parse2(parser, st->internal->avctx,
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&out_pkt.data, &out_pkt.size, pkt.data, pkt.size,
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pkt.pts, pkt.dts, *ppos);
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av_packet_unref(&pkt);
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if (out_pkt.size){
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int size = out_pkt.size;
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if (parser->pts != AV_NOPTS_VALUE){
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// seeking may not have started from beginning of a frame
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// calculate frame start position from next frame backwards
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*ppos = parser->next_frame_offset - size;
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pts = parser->pts;
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break;
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}
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} else if (ret < 0)
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break;
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}
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av_parser_close(parser);
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return pts;
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}
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static int flac_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
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int index;
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int64_t pos;
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AVIndexEntry e;
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FLACDecContext *flac = s->priv_data;
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if (!flac->found_seektable || !(s->flags&AVFMT_FLAG_FAST_SEEK)) {
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return -1;
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}
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index = av_index_search_timestamp(s->streams[0], timestamp, flags);
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if(index<0 || index >= s->streams[0]->nb_index_entries)
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return -1;
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e = s->streams[0]->index_entries[index];
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pos = avio_seek(s->pb, e.pos, SEEK_SET);
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if (pos >= 0) {
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return 0;
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}
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return -1;
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}
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AVInputFormat ff_flac_demuxer = {
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.name = "flac",
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.long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
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.read_probe = flac_probe,
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.read_header = flac_read_header,
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.read_packet = ff_raw_read_partial_packet,
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.read_seek = flac_seek,
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.read_timestamp = flac_read_timestamp,
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.flags = AVFMT_GENERIC_INDEX,
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.extensions = "flac",
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.raw_codec_id = AV_CODEC_ID_FLAC,
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.priv_data_size = sizeof(FLACDecContext),
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};
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