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/*
* LEGO Racers ALP (.tun & .pcm) demuxer
*
* Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)
*
* 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 "avformat.h"
#include "internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/internal.h"
#define ALP_TAG MKTAG('A', 'L', 'P', ' ')
#define ALP_MAX_READ_SIZE 4096
typedef struct ALPHeader {
uint32_t magic; /*< Magic Number, {'A', 'L', 'P', ' '} */
uint32_t header_size; /*< Header size (after this). */
char adpcm[6]; /*< "ADPCM" */
uint8_t unk1; /*< Unknown */
uint8_t num_channels; /*< Channel Count. */
uint32_t sample_rate; /*< Sample rate, only if header_size >= 12. */
} ALPHeader;
static int alp_probe(const AVProbeData *p)
{
uint32_t i;
if (AV_RL32(p->buf) != ALP_TAG)
return 0;
/* Only allowed header sizes are 8 and 12. */
i = AV_RL32(p->buf + 4);
if (i != 8 && i != 12)
return 0;
if (strncmp("ADPCM", p->buf + 8, 6) != 0)
return 0;
return AVPROBE_SCORE_MAX - 1;
}
static int alp_read_header(AVFormatContext *s)
{
int ret;
AVStream *st;
ALPHeader hdr;
AVCodecParameters *par;
if ((hdr.magic = avio_rl32(s->pb)) != ALP_TAG)
return AVERROR_INVALIDDATA;
hdr.header_size = avio_rl32(s->pb);
if (hdr.header_size != 8 && hdr.header_size != 12) {
return AVERROR_INVALIDDATA;
}
if ((ret = avio_read(s->pb, hdr.adpcm, sizeof(hdr.adpcm))) < 0)
return ret;
else if (ret != sizeof(hdr.adpcm))
return AVERROR(EIO);
if (strncmp("ADPCM", hdr.adpcm, sizeof(hdr.adpcm)) != 0)
return AVERROR_INVALIDDATA;
hdr.unk1 = avio_r8(s->pb);
hdr.num_channels = avio_r8(s->pb);
if (hdr.header_size == 8) {
/* .TUN music file */
hdr.sample_rate = 11025 * hdr.num_channels;
} else {
/* .PCM sound file */
hdr.sample_rate = avio_rl32(s->pb);
}
if (hdr.sample_rate > 44100) {
avpriv_request_sample(s, "Sample Rate > 44100");
return AVERROR_PATCHWELCOME;
}
if (!(st = avformat_new_stream(s, NULL)))
return AVERROR(ENOMEM);
par = st->codecpar;
par->codec_type = AVMEDIA_TYPE_AUDIO;
par->codec_id = AV_CODEC_ID_ADPCM_IMA_ALP;
par->format = AV_SAMPLE_FMT_S16;
par->sample_rate = hdr.sample_rate;
par->channels = hdr.num_channels;
if (hdr.num_channels == 1)
par->channel_layout = AV_CH_LAYOUT_MONO;
else if (hdr.num_channels == 2)
par->channel_layout = AV_CH_LAYOUT_STEREO;
else
return AVERROR_INVALIDDATA;
par->bits_per_coded_sample = 4;
par->bits_per_raw_sample = 16;
par->block_align = 1;
par->bit_rate = par->channels *
par->sample_rate *
par->bits_per_coded_sample;
avpriv_set_pts_info(st, 64, 1, par->sample_rate);
return 0;
}
static int alp_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret;
AVCodecParameters *par = s->streams[0]->codecpar;
if ((ret = av_get_packet(s->pb, pkt, ALP_MAX_READ_SIZE)) < 0)
return ret;
pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
pkt->stream_index = 0;
pkt->duration = ret * 2 / par->channels;
return 0;
}
AVInputFormat ff_alp_demuxer = {
.name = "alp",
.long_name = NULL_IF_CONFIG_SMALL("LEGO Racers ALP"),
.read_probe = alp_probe,
.read_header = alp_read_header,
.read_packet = alp_read_packet
};
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