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FFmpeg/libavformat/flacdec.c
Andreas Rheinhardt fadefe356a avformat/flacdec: Also set channels when setting channel_layout 
This brings the FLAC demuxer in line with all the other demuxers.
Furthermore, if it is not done and the FLAC decoder is disabled,
the FLAC parser will overwrite the channel layout with the standard
channel layout for that number of channels.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2021-10-07 22:06:27 +02:00

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/*
* Raw FLAC demuxer
* Copyright (c) 2001 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/channel_layout.h"
#include "libavcodec/flac.h"
#include "avformat.h"
#include "flac_picture.h"
#include "internal.h"
#include "rawdec.h"
#include "oggdec.h"
#include "vorbiscomment.h"
#include "replaygain.h"
#define SEEKPOINT_SIZE 18
typedef struct FLACDecContext {
FFRawDemuxerContext rawctx;
int found_seektable;
} FLACDecContext;
static void reset_index_position(int64_t metadata_head_size, AVStream *st)
{
FFStream *const sti = ffstream(st);
/* the real seek index offset should be the size of metadata blocks with the offset in the frame blocks */
for (int i = 0; i < sti->nb_index_entries; i++)
sti->index_entries[i].pos += metadata_head_size;
}
static int flac_read_header(AVFormatContext *s)
{
int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
uint8_t header[4];
uint8_t *buffer=NULL;
FLACDecContext *flac = s->priv_data;
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_FLAC;
ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL_RAW;
/* the parameters will be extracted from the compressed bitstream */
/* if fLaC marker is not found, assume there is no header */
if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {
avio_seek(s->pb, -4, SEEK_CUR);
return 0;
}
/* process metadata blocks */
while (!avio_feof(s->pb) && !metadata_last) {
if (avio_read(s->pb, header, 4) != 4)
return AVERROR(AVERROR_INVALIDDATA);
flac_parse_block_header(header, &metadata_last, &metadata_type,
&metadata_size);
switch (metadata_type) {
/* allocate and read metadata block for supported types */
case FLAC_METADATA_TYPE_STREAMINFO:
case FLAC_METADATA_TYPE_CUESHEET:
case FLAC_METADATA_TYPE_PICTURE:
case FLAC_METADATA_TYPE_VORBIS_COMMENT:
case FLAC_METADATA_TYPE_SEEKTABLE:
buffer = av_mallocz(metadata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!buffer) {
return AVERROR(ENOMEM);
}
if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
RETURN_ERROR(AVERROR(EIO));
}
break;
/* skip metadata block for unsupported types */
default:
ret = avio_skip(s->pb, metadata_size);
if (ret < 0)
return ret;
}
if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
uint32_t samplerate;
uint64_t samples;
/* STREAMINFO can only occur once */
if (found_streaminfo) {
RETURN_ERROR(AVERROR_INVALIDDATA);
}
if (metadata_size != FLAC_STREAMINFO_SIZE) {
RETURN_ERROR(AVERROR_INVALIDDATA);
}
found_streaminfo = 1;
st->codecpar->extradata = buffer;
st->codecpar->extradata_size = metadata_size;
buffer = NULL;
/* get sample rate and sample count from STREAMINFO header;
* other parameters will be extracted by the parser */
samplerate = AV_RB24(st->codecpar->extradata + 10) >> 4;
samples = (AV_RB64(st->codecpar->extradata + 13) >> 24) & ((1ULL << 36) - 1);
/* set time base and duration */
if (samplerate > 0) {
avpriv_set_pts_info(st, 64, 1, samplerate);
if (samples > 0)
st->duration = samples;
}
} else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {
uint8_t isrc[13];
uint64_t start;
const uint8_t *offset;
int i, chapters, track, ti;
if (metadata_size < 431)
RETURN_ERROR(AVERROR_INVALIDDATA);
offset = buffer + 395;
chapters = bytestream_get_byte(&offset) - 1;
if (chapters <= 0)
RETURN_ERROR(AVERROR_INVALIDDATA);
for (i = 0; i < chapters; i++) {
if (offset + 36 - buffer > metadata_size)
RETURN_ERROR(AVERROR_INVALIDDATA);
start = bytestream_get_be64(&offset);
track = bytestream_get_byte(&offset);
bytestream_get_buffer(&offset, isrc, 12);
isrc[12] = 0;
offset += 14;
ti = bytestream_get_byte(&offset);
if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);
offset += ti * 12;
avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
}
av_freep(&buffer);
} else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {
ret = ff_flac_parse_picture(s, &buffer, metadata_size, 1);
av_freep(&buffer);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");
return ret;
}
} else if (metadata_type == FLAC_METADATA_TYPE_SEEKTABLE) {
const uint8_t *seekpoint = buffer;
int i, seek_point_count = metadata_size/SEEKPOINT_SIZE;
flac->found_seektable = 1;
if ((s->flags&AVFMT_FLAG_FAST_SEEK)) {
for(i=0; i<seek_point_count; i++) {
int64_t timestamp = bytestream_get_be64(&seekpoint);
int64_t pos = bytestream_get_be64(&seekpoint);
/* skip number of samples */
bytestream_get_be16(&seekpoint);
av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);
}
}
av_freep(&buffer);
}
else {
/* STREAMINFO must be the first block */
if (!found_streaminfo) {
RETURN_ERROR(AVERROR_INVALIDDATA);
}
/* process supported blocks other than STREAMINFO */
if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
AVDictionaryEntry *chmask;
ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
if (ret < 0) {
av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
} else if (ret > 0) {
s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;
}
/* parse the channels mask if present */
chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
if (chmask) {
uint64_t mask = strtol(chmask->value, NULL, 0);
if (!mask || mask & ~0x3ffffULL) {
av_log(s, AV_LOG_WARNING,
"Invalid value of WAVEFORMATEXTENSIBLE_CHANNEL_MASK\n");
} else {
st->codecpar->channel_layout = mask;
st->codecpar->channels = av_get_channel_layout_nb_channels(mask);
av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
}
}
}
av_freep(&buffer);
}
}
ret = ff_replaygain_export(st, s->metadata);
if (ret < 0)
return ret;
reset_index_position(avio_tell(s->pb), st);
return 0;
fail:
av_free(buffer);
return ret;
}
static int raw_flac_probe(const AVProbeData *p)
{
if ((p->buf[2] & 0xF0) == 0) // blocksize code invalid
return 0;
if ((p->buf[2] & 0x0F) == 0x0F) // sample rate code invalid
return 0;
if ((p->buf[3] & 0xF0) >= FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE << 4)
// channel mode invalid
return 0;
if ((p->buf[3] & 0x06) == 0x06) // bits per sample code invalid
return 0;
if ((p->buf[3] & 0x01) == 0x01) // reserved bit set
return 0;
return AVPROBE_SCORE_EXTENSION / 4 + 1;
}
static int flac_probe(const AVProbeData *p)
{
if ((AV_RB16(p->buf) & 0xFFFE) == 0xFFF8)
return raw_flac_probe(p);
/* file header + metadata header + checked bytes of streaminfo */
if (p->buf_size >= 4 + 4 + 13) {
int type = p->buf[4] & 0x7f;
int size = AV_RB24(p->buf + 5);
int min_block_size = AV_RB16(p->buf + 8);
int max_block_size = AV_RB16(p->buf + 10);
int sample_rate = AV_RB24(p->buf + 18) >> 4;
if (memcmp(p->buf, "fLaC", 4))
return 0;
if (type == FLAC_METADATA_TYPE_STREAMINFO &&
size == FLAC_STREAMINFO_SIZE &&
min_block_size >= 16 &&
max_block_size >= min_block_size &&
sample_rate && sample_rate <= 655350)
return AVPROBE_SCORE_MAX;
return AVPROBE_SCORE_EXTENSION;
}
return 0;
}
static av_unused int64_t flac_read_timestamp(AVFormatContext *s, int stream_index,
int64_t *ppos, int64_t pos_limit)
{
FFFormatContext *const si = ffformatcontext(s);
AVPacket *const pkt = si->parse_pkt;
AVStream *st = s->streams[stream_index];
AVCodecParserContext *parser;
int ret;
int64_t pts = AV_NOPTS_VALUE;
if (avio_seek(s->pb, *ppos, SEEK_SET) < 0)
return AV_NOPTS_VALUE;
parser = av_parser_init(st->codecpar->codec_id);
if (!parser){
return AV_NOPTS_VALUE;
}
parser->flags |= PARSER_FLAG_USE_CODEC_TS;
for (;;){
uint8_t *data;
int size;
ret = ff_raw_read_partial_packet(s, pkt);
if (ret < 0){
if (ret == AVERROR(EAGAIN))
continue;
else {
av_packet_unref(pkt);
av_assert1(!pkt->size);
}
}
av_parser_parse2(parser, ffstream(st)->avctx,
&data, &size, pkt->data, pkt->size,
pkt->pts, pkt->dts, *ppos);
av_packet_unref(pkt);
if (size) {
if (parser->pts != AV_NOPTS_VALUE){
// seeking may not have started from beginning of a frame
// calculate frame start position from next frame backwards
*ppos = parser->next_frame_offset - size;
pts = parser->pts;
break;
}
} else if (ret < 0)
break;
}
av_parser_close(parser);
return pts;
}
static int flac_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
AVStream *const st = s->streams[0];
FFStream *const sti = ffstream(st);
int index;
int64_t pos;
AVIndexEntry e;
FLACDecContext *flac = s->priv_data;
if (!flac->found_seektable || !(s->flags&AVFMT_FLAG_FAST_SEEK)) {
return -1;
}
index = av_index_search_timestamp(st, timestamp, flags);
if (index < 0 || index >= sti->nb_index_entries)
return -1;
e = sti->index_entries[index];
pos = avio_seek(s->pb, e.pos, SEEK_SET);
if (pos >= 0) {
return 0;
}
return -1;
}
const AVInputFormat ff_flac_demuxer = {
.name = "flac",
.long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
.read_probe = flac_probe,
.read_header = flac_read_header,
.read_packet = ff_raw_read_partial_packet,
.read_seek = flac_seek,
.read_timestamp = flac_read_timestamp,
.flags = AVFMT_GENERIC_INDEX,
.extensions = "flac",
.raw_codec_id = AV_CODEC_ID_FLAC,
.priv_data_size = sizeof(FLACDecContext),
.priv_class = &ff_raw_demuxer_class,
};
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