mirror of
https://github.com/librempeg/librempeg
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79 lines
2.4 KiB
C
79 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 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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static int h263_probe(const 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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int tr, last_tr = -1;
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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 & 0xfffffc000000) == 0x80000000) {
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tr = (code >> 18) & 0xFF;
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src_fmt= (code>>10)&7;
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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 (tr == last_tr) {
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invalid_psc++;
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continue;
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}
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if (src_fmt != 7 && !(code&(1<<9)) && (code&(1<<5))) {
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invalid_psc++;
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continue;
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}
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if((code&0x30000)==0x20000 && 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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last_tr = tr;
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} else if((code & 0xffff80000000) == 0x80000000) {
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int gn= (code>>(31-5)) & 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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if(valid_psc > 2*invalid_psc + 2*res_change + 3){
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return AVPROBE_SCORE_EXTENSION;
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}else if(valid_psc > 2*invalid_psc)
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return AVPROBE_SCORE_EXTENSION / 2;
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return 0;
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}
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FF_DEF_RAWVIDEO_DEMUXER(h263, "raw H.263", h263_probe, NULL, AV_CODEC_ID_H263)
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