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/*
* RAW MPEG video demuxer
* Copyright (c) 2002-2003 Fabrice Bellard
* Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "rawdec.h"
#include "libavutil/intreadwrite.h"
#include "libavcodec/startcode.h"
#define SEQ_START_CODE 0x000001b3
#define GOP_START_CODE 0x000001b8
#define PICTURE_START_CODE 0x00000100
#define SLICE_START_CODE 0x00000101
#define PACK_START_CODE 0x000001ba
#define VIDEO_ID 0x000001e0
#define AUDIO_ID 0x000001c0
static int mpegvideo_probe(const AVProbeData *p)
{
uint32_t code= -1;
int pic=0, seq=0, slice=0, pspack=0, vpes=0, apes=0, res=0, sicle=0;
const uint8_t *ptr = p->buf, *end = ptr + p->buf_size;
uint32_t last = 0;
int j;
while (ptr < end) {
ptr = avpriv_find_start_code(ptr, end, &code);
if ((code & 0xffffff00) == 0x100) {
switch(code){
case SEQ_START_CODE:
if (!(ptr[3 + 1 + 2] & 0x20))
break;
j = -1;
if (ptr[j + 8] & 2)
j+= 64;
if (j >= end - ptr)
break;
if (ptr[j + 8] & 1)
j+= 64;
if (j >= end - ptr)
break;
if (AV_RB24(ptr + j + 9) & 0xFFFFFE)
break;
seq++;
break;
case PICTURE_START_CODE: pic++; break;
case PACK_START_CODE: pspack++; break;
case 0x1b6:
res++; break;
}
if (code >= SLICE_START_CODE && code <= 0x1af) {
if (last >= SLICE_START_CODE && last <= 0x1af) {
if (code >= last) slice++;
else sicle++;
}else{
if (code == SLICE_START_CODE) slice++;
else sicle++;
}
}
if ((code & 0x1f0) == VIDEO_ID) vpes++;
else if((code & 0x1e0) == AUDIO_ID) apes++;
last = code;
}
}
if(seq && seq*9<=pic*10 && pic*9<=slice*10 && !pspack && !apes && !res && slice > sicle) {
if(vpes) return AVPROBE_SCORE_EXTENSION / 4;
else return pic>1 ? AVPROBE_SCORE_EXTENSION + 1 : AVPROBE_SCORE_EXTENSION / 2; // +1 for .mpg
}
return 0;
}
FF_DEF_RAWVIDEO_DEMUXER(mpegvideo, "raw MPEG video", mpegvideo_probe, NULL, AV_CODEC_ID_MPEG1VIDEO)
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