mirror of
https://github.com/librempeg/librempeg
synced 2024-11-22 09:02:20 +00:00
90 lines
3.2 KiB
C
90 lines
3.2 KiB
C
/*
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* RAW MPEG video demuxer
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* Copyright (c) 2002-2003 Fabrice Bellard
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* Copyright (c) 2006 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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#include "libavutil/intreadwrite.h"
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#define SEQ_START_CODE 0x000001b3
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#define GOP_START_CODE 0x000001b8
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#define PICTURE_START_CODE 0x00000100
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#define SLICE_START_CODE 0x00000101
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#define PACK_START_CODE 0x000001ba
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#define VIDEO_ID 0x000001e0
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#define AUDIO_ID 0x000001c0
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static int mpegvideo_probe(AVProbeData *p)
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{
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uint32_t code= -1;
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int pic=0, seq=0, slice=0, pspack=0, vpes=0, apes=0, res=0, sicle=0;
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int i, j;
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uint32_t last = 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 & 0xffffff00) == 0x100) {
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switch(code){
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case SEQ_START_CODE:
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if (!(p->buf[i+1+3+1+2] & 0x20))
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break;
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j = i;
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if (p->buf[j+8] & 2)
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j+= 64;
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if (j >= p->buf_size)
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break;
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if (p->buf[j+8] & 1)
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j+= 64;
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if (j >= p->buf_size)
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break;
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if (AV_RB24(p->buf + j + 9) & 0xFFFFFE)
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break;
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seq++;
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break;
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case PICTURE_START_CODE: pic++; break;
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case PACK_START_CODE: pspack++; break;
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case 0x1b6:
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res++; break;
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}
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if (code >= SLICE_START_CODE && code <= 0x1af) {
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if (last >= SLICE_START_CODE && last <= 0x1af) {
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if (code >= last) slice++;
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else sicle++;
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}else{
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if (code == SLICE_START_CODE) slice++;
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else sicle++;
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}
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}
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if ((code & 0x1f0) == VIDEO_ID) vpes++;
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else if((code & 0x1e0) == AUDIO_ID) apes++;
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last = code;
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}
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}
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if(seq && seq*9<=pic*10 && pic*9<=slice*10 && !pspack && !apes && !res && slice > sicle) {
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if(vpes) return AVPROBE_SCORE_EXTENSION / 4;
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else return pic>1 ? AVPROBE_SCORE_EXTENSION + 1 : AVPROBE_SCORE_EXTENSION / 2; // +1 for .mpg
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}
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return 0;
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}
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FF_DEF_RAWVIDEO_DEMUXER(mpegvideo, "raw MPEG video", mpegvideo_probe, NULL, AV_CODEC_ID_MPEG1VIDEO)
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