/*

 * LOAS AudioSyncStream demuxer

 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>

 *

 * 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 "libavutil/internal.h"

#include "avformat.h"

#include "demux.h"

#include "internal.h"

#include "rawdec.h"

#define LOAS_SYNC_WORD 0x2b7

static int loas_probe(const AVProbeData *p)

{

    int max_frames = 0, first_frames = 0;

    int fsize, frames;

    const uint8_t *buf0 = p->buf;

    const uint8_t *buf2;

    const uint8_t *buf;

    const uint8_t *end = buf0 + p->buf_size - 3;

    buf = buf0;

    for (; buf < end; buf = buf2 + 1) {

        buf2 = buf;

        for (frames = 0; buf2 < end; frames++) {

            uint32_t header = AV_RB24(buf2);

            if ((header >> 13) != LOAS_SYNC_WORD)

                break;

            fsize = (header & 0x1FFF) + 3;

            if (fsize < 7)

                break;

            fsize = FFMIN(fsize, end - buf2);

            buf2 += fsize;

        }

        max_frames = FFMAX(max_frames, frames);

        if (buf == buf0)

            first_frames = frames;

    }

    if (first_frames >= 3)

        return AVPROBE_SCORE_EXTENSION + 1;

    else if (max_frames > 100)

        return AVPROBE_SCORE_EXTENSION;

    else if (max_frames >= 3)

        return AVPROBE_SCORE_EXTENSION / 2;

    else

        return 0;

}

static int loas_read_header(AVFormatContext *s)

{

    AVStream *st;

    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);

    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codecpar->codec_id   = AV_CODEC_ID_AAC_LATM;

    ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL_RAW;

    //LCM of all possible AAC sample rates

    avpriv_set_pts_info(st, 64, 1, 28224000);

    return 0;

}

const FFInputFormat ff_loas_demuxer = {

    .p.name         = "loas",

    .p.long_name    = NULL_IF_CONFIG_SMALL("LOAS AudioSyncStream"),

    .p.flags        = AVFMT_GENERIC_INDEX,

    .p.priv_class   = &ff_raw_demuxer_class,

    .read_probe     = loas_probe,

    .read_header    = loas_read_header,

    .read_packet    = ff_raw_read_partial_packet,

    .raw_codec_id = AV_CODEC_ID_AAC_LATM,

    .priv_data_size = sizeof(FFRawDemuxerContext),

};