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ffmpeg / libavformat / m4vdec.c @ 2ee45361

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/*
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 * RAW MPEG-4 video demuxer
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 * Copyright (c) 2006  Thijs Vermeir <thijs.vermeir@barco.com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg 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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 * FFmpeg 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 FFmpeg; 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 "avformat.h"
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#include "rawdec.h"
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#define VISUAL_OBJECT_START_CODE       0x000001b5
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#define VOP_START_CODE                 0x000001b6
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static int mpeg4video_probe(AVProbeData *probe_packet)
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{
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    uint32_t temp_buffer= -1;
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    int VO=0, VOL=0, VOP = 0, VISO = 0, res=0;
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    int i;
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    for(i=0; i<probe_packet->buf_size; i++){
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        temp_buffer = (temp_buffer<<8) + probe_packet->buf[i];
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        if ((temp_buffer & 0xffffff00) != 0x100)
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            continue;
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        if (temp_buffer == VOP_START_CODE)                         VOP++;
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        else if (temp_buffer == VISUAL_OBJECT_START_CODE)          VISO++;
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        else if (temp_buffer < 0x120)                              VO++;
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        else if (temp_buffer < 0x130)                              VOL++;
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        else if (   !(0x1AF < temp_buffer && temp_buffer < 0x1B7)
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                 && !(0x1B9 < temp_buffer && temp_buffer < 0x1C4)) res++;
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    }
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    if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && res==0)
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        return VOP+VO > 3 ? AVPROBE_SCORE_MAX/2 : AVPROBE_SCORE_MAX/4;
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    return 0;
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}
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AVInputFormat ff_m4v_demuxer = {
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    "m4v",
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    NULL_IF_CONFIG_SMALL("raw MPEG-4 video format"),
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    0,
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    mpeg4video_probe, /** probing for MPEG-4 data */
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    ff_raw_video_read_header,
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    ff_raw_read_partial_packet,
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    .flags= AVFMT_GENERIC_INDEX,
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    .extensions = "m4v",
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    .value = CODEC_ID_MPEG4,
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};