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ffmpeg / libavformat / dtsdec.c @ 2912e87a

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/*
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 * RAW DTS demuxer
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 * Copyright (c) 2008 Benjamin Larsson
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavcodec/bytestream.h"
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#include "avformat.h"
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#include "rawdec.h"
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#define DCA_MARKER_14B_BE 0x1FFFE800
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#define DCA_MARKER_14B_LE 0xFF1F00E8
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#define DCA_MARKER_RAW_BE 0x7FFE8001
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#define DCA_MARKER_RAW_LE 0xFE7F0180
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static int dts_probe(AVProbeData *p)
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{
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    const uint8_t *buf, *bufp;
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    uint32_t state = -1;
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    int markers[3] = {0};
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    int sum, max;
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    buf = p->buf;
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    for(; buf < (p->buf+p->buf_size)-2; buf+=2) {
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        bufp = buf;
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        state = (state << 16) | bytestream_get_be16(&bufp);
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        /* regular bitstream */
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        if (state == DCA_MARKER_RAW_BE || state == DCA_MARKER_RAW_LE)
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            markers[0]++;
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        /* 14 bits big-endian bitstream */
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        if (state == DCA_MARKER_14B_BE)
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            if ((bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
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                markers[1]++;
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        /* 14 bits little-endian bitstream */
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        if (state == DCA_MARKER_14B_LE)
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            if ((bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
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                markers[2]++;
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    }
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    sum = markers[0] + markers[1] + markers[2];
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    max = markers[1] > markers[0];
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    max = markers[2] > markers[max] ? 2 : max;
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    if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
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        markers[max] * 4 > sum * 3)
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        return AVPROBE_SCORE_MAX/2+1;
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    return 0;
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}
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AVInputFormat ff_dts_demuxer = {
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    "dts",
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    NULL_IF_CONFIG_SMALL("raw DTS"),
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    0,
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    dts_probe,
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    ff_raw_audio_read_header,
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    ff_raw_read_partial_packet,
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    .flags= AVFMT_GENERIC_INDEX,
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    .extensions = "dts",
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    .value = CODEC_ID_DTS,
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};