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https://github.com/FFmpeg/FFmpeg.git
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78 lines
2.4 KiB
C
78 lines
2.4 KiB
C
/*
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* RAW H.263 video demuxer
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* Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
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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 "avformat.h"
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#include "rawdec.h"
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static int h263_probe(AVProbeData *p)
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{
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uint64_t code= -1;
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int i;
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int valid_psc=0;
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int invalid_psc=0;
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int res_change=0;
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int src_fmt, last_src_fmt=-1;
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int last_gn=0;
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for(i=0; i<p->buf_size; i++){
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code = (code<<8) + p->buf[i];
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if ((code & 0xfffffc0000) == 0x800000) {
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src_fmt= (code>>2)&3;
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if( src_fmt != last_src_fmt
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&& last_src_fmt>0 && last_src_fmt<6
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&& src_fmt<6)
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res_change++;
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if((code&0x300)==0x200 && src_fmt){
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valid_psc++;
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last_gn=0;
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}else
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invalid_psc++;
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last_src_fmt= src_fmt;
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} else if((code & 0xffff800000) == 0x800000) {
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int gn= (code>>(23-5)) & 0x1F;
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if(gn<last_gn){
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invalid_psc++;
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}else
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last_gn= gn;
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}
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}
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//av_log(NULL, AV_LOG_ERROR, "h263_probe: psc:%d invalid:%d res_change:%d\n", valid_psc, invalid_psc, res_change);
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//h263_probe: psc:3 invalid:0 res_change:0 (1588/recent_ffmpeg_parses_mpg_incorrectly.mpg)
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if(valid_psc > 2*invalid_psc + 2*res_change + 3){
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return 50;
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}else if(valid_psc > 2*invalid_psc)
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return 25;
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return 0;
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}
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AVInputFormat ff_h263_demuxer = {
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"h263",
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NULL_IF_CONFIG_SMALL("raw H.263"),
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0,
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h263_probe,
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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 = "h263", //FIXME remove after writing mpeg4_probe
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.value = CODEC_ID_H263,
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};
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