ffmpeg/libavformat/cavsvideodec.c

78 lines
2.5 KiB
C

/*
* RAW Chinese AVS video demuxer
* Copyright (c) 2009 Stefan Gehrer <stefan.gehrer@gmx.de>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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"
#define CAVS_SEQ_START_CODE 0x000001b0
#define CAVS_PIC_I_START_CODE 0x000001b3
#define CAVS_UNDEF_START_CODE 0x000001b4
#define CAVS_PIC_PB_START_CODE 0x000001b6
#define CAVS_VIDEO_EDIT_CODE 0x000001b7
#define CAVS_PROFILE_JIZHUN 0x20
static int cavsvideo_probe(AVProbeData *p)
{
uint32_t code= -1;
int pic=0, seq=0, slice_pos = 0;
int i;
for(i=0; i<p->buf_size; i++){
code = (code<<8) + p->buf[i];
if ((code & 0xffffff00) == 0x100) {
if(code < CAVS_SEQ_START_CODE) {
/* slices have to be consecutive */
if(code < slice_pos)
return 0;
slice_pos = code;
} else {
slice_pos = 0;
}
if (code == CAVS_SEQ_START_CODE) {
seq++;
/* check for the only currently supported profile */
if(p->buf[i+1] != CAVS_PROFILE_JIZHUN)
return 0;
} else if ((code == CAVS_PIC_I_START_CODE) ||
(code == CAVS_PIC_PB_START_CODE)) {
pic++;
} else if ((code == CAVS_UNDEF_START_CODE) ||
(code > CAVS_VIDEO_EDIT_CODE)) {
return 0;
}
}
}
if(seq && seq*9<=pic*10)
return AVPROBE_SCORE_MAX/2;
return 0;
}
AVInputFormat ff_cavsvideo_demuxer = {
"cavsvideo",
NULL_IF_CONFIG_SMALL("raw Chinese AVS video"),
0,
cavsvideo_probe,
ff_raw_video_read_header,
ff_raw_read_partial_packet,
.flags= AVFMT_GENERIC_INDEX,
.value = CODEC_ID_CAVS,
};