ffmpeg/libavformat/svs.c

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/*
* SVS demuxer
* Copyright (c) 2020 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 "demux.h"
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#include "internal.h"
static int svs_probe(const AVProbeData *p)
{
if (p->buf_size < 32)
return 0;
if (memcmp(p->buf, "SVS\00", 4))
return 0;
if (AV_RL32(p->buf + 16) == 0)
return 0;
return AVPROBE_SCORE_MAX / 3;
}
static int svs_read_header(AVFormatContext *s)
{
AVStream *st;
uint32_t pitch;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avio_skip(s->pb, 16);
pitch = avio_rl32(s->pb);
avio_skip(s->pb, 12);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_ADPCM_PSX;
st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;
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st->codecpar->sample_rate = av_rescale_rnd(pitch, 48000, 4096, AV_ROUND_INF);
st->codecpar->block_align = 32;
st->start_time = 0;
if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
st->duration = av_get_audio_frame_duration2(st->codecpar,
avio_size(s->pb) - 32);
avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
return 0;
}
static int svs_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret;
if (avio_feof(s->pb))
return AVERROR_EOF;
ret = av_get_packet(s->pb, pkt, 32 * 256);
if (ret != 32 * 256) {
if (ret < 0)
return ret;
pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
}
pkt->stream_index = 0;
return ret;
}
const FFInputFormat ff_svs_demuxer = {
.p.name = "svs",
.p.long_name = NULL_IF_CONFIG_SMALL("Square SVS"),
.p.extensions = "svs",
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.read_probe = svs_probe,
.read_header = svs_read_header,
.read_packet = svs_read_packet,
};