ffmpeg/libavformat/davs2.c

72 lines
2.3 KiB
C

/*
* AVS2 video stream probe.
*
* Copyright (C) 2018 Huiwen Ren, <hwrenx@126.com>
*
* 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 "libavcodec/internal.h"
#include "libavutil/intreadwrite.h"
#define ISSQH(x) ((x) == 0xB0 )
#define ISEND(x) ((x) == 0xB1 )
#define ISPIC(x) ((x) == 0xB3 || (x) == 0xB6)
#define ISUNIT(x) ( ISSQH(x) || ISEND(x) || (x) == 0xB2 || ISPIC(x) || (x) == 0xB5 || (x) == 0xB7 )
#define ISAVS2(x) ((x) == 0x20 || (x) == 0x22 || (x) == 0x30 || (x) == 0x32 )
static int avs2_probe(AVProbeData *p)
{
if (AV_RB32(p->buf) != 0x1B0){
return 0;
}
uint32_t code= -1, hds=0, pic=0, seq=0;
uint8_t state=0;
const uint8_t *ptr = p->buf, *end = p->buf + p->buf_size, *sqb=0;
while (ptr < end) {
ptr = avpriv_find_start_code(ptr, end, &code);
state = code & 0xFF;
if ((code & 0xffffff00) == 0x100) {
if (ISUNIT(state)) {
if (sqb && !hds) {
hds = ptr - sqb;
}
if (ISSQH(state)) {
if (!ISAVS2(*ptr))
return 0;
sqb = ptr;
seq++;
} else if (ISPIC(state)) {
pic++;
} else if (ISEND(state)) {
break;
}
}
}
}
if (seq && hds >= 21 && pic){
return AVPROBE_SCORE_EXTENSION + 2; // more than cavs
}
return 0;
}
FF_DEF_RAWVIDEO_DEMUXER(avs2, "raw AVS2-P2/IEEE1857.4", avs2_probe, "avs,avs2", AV_CODEC_ID_AVS2)