aac5773f
 hucm
功能基本完成，接口待打磨
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/*
* AST demuxer
* Copyright (c) 2012 Paul B Mahol
*
* 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 "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#include "ast.h"
static int ast_probe(const AVProbeData *p)
{
if (AV_RL32(p->buf) != MKTAG('S','T','R','M'))
return 0;
if (!AV_RB16(p->buf + 10) ||
!AV_RB16(p->buf + 12) || AV_RB16(p->buf + 12) > 256 ||
!AV_RB32(p->buf + 16) || AV_RB32(p->buf + 16) > 8*48000)
return AVPROBE_SCORE_MAX / 8;
return AVPROBE_SCORE_MAX / 3 * 2;
}
static int ast_read_header(AVFormatContext *s)
{
int depth;
AVStream *st;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avio_skip(s->pb, 8);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb));
depth = avio_rb16(s->pb);
if (depth != 16) {
avpriv_request_sample(s, "depth %d", depth);
return AVERROR_INVALIDDATA;
}
st->codecpar->channels = avio_rb16(s->pb);
if (!st->codecpar->channels)
return AVERROR_INVALIDDATA;
if (st->codecpar->channels == 2)
st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
else if (st->codecpar->channels == 4)
st->codecpar->channel_layout = AV_CH_LAYOUT_4POINT0;
avio_skip(s->pb, 2);
st->codecpar->sample_rate = avio_rb32(s->pb);
if (st->codecpar->sample_rate <= 0)
return AVERROR_INVALIDDATA;
st->start_time = 0;
st->duration = avio_rb32(s->pb);
avio_skip(s->pb, 40);
avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
return 0;
}
static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
{
uint32_t type, size;
int64_t pos;
int ret;
if (avio_feof(s->pb))
return AVERROR_EOF;
pos = avio_tell(s->pb);
type = avio_rl32(s->pb);
size = avio_rb32(s->pb);
if (!s->streams[0]->codecpar->channels || size > INT_MAX / s->streams[0]->codecpar->channels)
return AVERROR_INVALIDDATA;
size *= s->streams[0]->codecpar->channels;
if ((ret = avio_skip(s->pb, 24)) < 0) // padding
return ret;
if (type == MKTAG('B','L','C','K')) {
ret = av_get_packet(s->pb, pkt, size);
pkt->stream_index = 0;
pkt->pos = pos;
} else {
av_log(s, AV_LOG_ERROR, "unknown chunk %"PRIx32"\n", type);
avio_skip(s->pb, size);
ret = AVERROR_INVALIDDATA;
}
return ret;
}
AVInputFormat ff_ast_demuxer = {
.name = "ast",
.long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
.read_probe = ast_probe,
.read_header = ast_read_header,
.read_packet = ast_read_packet,
.extensions = "ast",
.flags = AVFMT_GENERIC_INDEX,
.codec_tag = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
};
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