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FFmpeg/libavformat/flacdec.c
Clément Bœsch e887d685f7 Merge commit 'ed1cd81076434b76f37576d4d806973476a8e96c' 
* 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>
2017-03-15 23:17:32 +01:00

343 lines
12 KiB
C
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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 "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 {
int found_seektable;
} FLACDecContext;
static void reset_index_position(int64_t metadata_head_size, AVStream *st)
{
/* the real seek index offset should be the size of metadata blocks with the offset in the frame blocks */
int i;
for(i=0; i<st->nb_index_entries; i++) {
st->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;
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);
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;
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(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(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)
{
AVPacket pkt, out_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;
av_init_packet(&pkt);
parser = av_parser_init(st->codecpar->codec_id);
if (!parser){
return AV_NOPTS_VALUE;
}
parser->flags |= PARSER_FLAG_USE_CODEC_TS;
for (;;){
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_init_packet(&out_pkt);
av_parser_parse2(parser, st->internal->avctx,
&out_pkt.data, &out_pkt.size, pkt.data, pkt.size,
pkt.pts, pkt.dts, *ppos);
av_packet_unref(&pkt);
if (out_pkt.size){
int size = out_pkt.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) {
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(s->streams[0], timestamp, flags);
if(index<0 || index >= s->streams[0]->nb_index_entries)
return -1;
e = s->streams[0]->index_entries[index];
pos = avio_seek(s->pb, e.pos, SEEK_SET);
if (pos >= 0) {
return 0;
}
return -1;
}
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),
};
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