acm.c

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/*
 * ACM demuxer
 * Copyright (c) 2015 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/intreadwrite.h"
#include "avformat.h"
#include "rawdec.h"
#include "internal.h"

static int acm_probe(AVProbeData *p)
{
    if (AV_RB32(p->buf) != 0x97280301)
        return 0;

    return AVPROBE_SCORE_MAX / 3 * 2;
}

static int acm_read_header(AVFormatContext *s)
{
    AVStream *st;
    int ret;

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

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
    st->codec->codec_id   = AV_CODEC_ID_INTERPLAY_ACM;

    ff_alloc_extradata(st->codec, 14);
    if (!st->codec->extradata)
        return AVERROR(ENOMEM);
    ret = avio_read(s->pb, st->codec->extradata, 14);
    if (ret < 10)
        return ret < 0 ? ret : AVERROR_EOF;

    st->codec->channels    = AV_RL16(st->codec->extradata +  8);
    st->codec->sample_rate = AV_RL16(st->codec->extradata + 10);
    if (st->codec->channels <= 0 || st->codec->sample_rate <= 0)
        return AVERROR_INVALIDDATA;
    st->start_time         = 0;
    st->duration           = AV_RL32(st->codec->extradata +  4) / st->codec->channels;
    st->need_parsing       = AVSTREAM_PARSE_FULL_RAW;
    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);

    return 0;
}

AVInputFormat ff_acm_demuxer = {
    .name           = "acm",
    .long_name      = NULL_IF_CONFIG_SMALL("Interplay ACM"),
    .read_probe     = acm_probe,
    .read_header    = acm_read_header,
    .read_packet    = ff_raw_read_partial_packet,
    .flags          = AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | AVFMT_NO_BYTE_SEEK | AVFMT_NOTIMESTAMPS,
    .extensions     = "acm",
    .raw_codec_id   = AV_CODEC_ID_INTERPLAY_ACM,
};