FFmpeg/libavformat/sdxdec.c

/*
 * SDX demuxer
 * Copyright (c) 2017 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/avstring.h"
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#include "pcm.h"

static int sdx_probe(const AVProbeData *p)
{
    if (AV_RB32(p->buf) == AV_RB32("SDX:"))
        return AVPROBE_SCORE_EXTENSION;
    return 0;
}

static int sdx_read_header(AVFormatContext *s)
{
    AVStream *st;
    int depth, length;

    avio_skip(s->pb, 4);
    while (!avio_feof(s->pb)) {
        if (avio_r8(s->pb) == 0x1a)
            break;
    }
    if (avio_r8(s->pb) != 1)
        return AVERROR_INVALIDDATA;
    length = avio_r8(s->pb);
    avio_skip(s->pb, length);
    avio_skip(s->pb, 4);
    depth = avio_r8(s->pb);

    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);

    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
    st->codecpar->ch_layout.nb_channels = 1;
    st->codecpar->sample_rate = avio_rl32(s->pb);
    switch (depth) {
    case 8:
        st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
        break;
    case 16:
        st->codecpar->codec_id = AV_CODEC_ID_PCM_U16LE;
        break;
    case 24:
        st->codecpar->codec_id = AV_CODEC_ID_PCM_U24LE;
        break;
    case 32:
        st->codecpar->codec_id = AV_CODEC_ID_PCM_U32LE;
        break;
    default:
        return AVERROR_INVALIDDATA;
    }
    avio_skip(s->pb, 16);
    st->codecpar->block_align = depth / 8;

    return 0;
}

const AVInputFormat ff_sdx_demuxer = {
    .name           = "sdx",
    .long_name      = NULL_IF_CONFIG_SMALL("Sample Dump eXchange"),
    .read_probe     = sdx_probe,
    .read_header    = sdx_read_header,
    .read_packet    = ff_pcm_read_packet,
    .read_seek      = ff_pcm_read_seek,
    .extensions     = "sdx",
    .flags          = AVFMT_GENERIC_INDEX,
};