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65 lines
2.0 KiB
65 lines
2.0 KiB
/* |
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* RAW H.261 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 "libavcodec/get_bits.h" |
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#include "avformat.h" |
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#include "rawdec.h" |
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static int h261_probe(AVProbeData *p) |
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{ |
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uint32_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 next_gn=0; |
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int src_fmt=0; |
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GetBitContext gb; |
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init_get_bits(&gb, p->buf, p->buf_size*8); |
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for(i=0; i<p->buf_size*8; i++){ |
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if ((code & 0x01ff0000) || !(code & 0xff00)) { |
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code = (code<<8) + get_bits(&gb, 8); |
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i += 7; |
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} else |
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code = (code<<1) + get_bits1(&gb); |
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if ((code & 0xffff0000) == 0x10000) { |
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int gn= (code>>12)&0xf; |
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if(!gn) |
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src_fmt= code&8; |
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if(gn != next_gn) invalid_psc++; |
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else valid_psc++; |
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if(src_fmt){ // CIF |
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next_gn= (gn+1 )%13; |
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}else{ //QCIF |
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next_gn= (gn+1+!!gn)% 7; |
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} |
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} |
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} |
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if(valid_psc > 2*invalid_psc + 6){ |
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return AVPROBE_SCORE_EXTENSION; |
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}else if(valid_psc > 2*invalid_psc + 2) |
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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(h261, "raw H.261", h261_probe, "h261", AV_CODEC_ID_H261)
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