FFmpeg
cavsvideodec.c
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1 /*
2  * RAW Chinese AVS video demuxer
3  * Copyright (c) 2009 Stefan Gehrer <stefan.gehrer@gmx.de>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 #include "rawdec.h"
24 #include "libavcodec/internal.h"
25 
26 #define CAVS_SEQ_START_CODE 0x000001b0
27 #define CAVS_PIC_I_START_CODE 0x000001b3
28 #define CAVS_UNDEF_START_CODE 0x000001b4
29 #define CAVS_PIC_PB_START_CODE 0x000001b6
30 #define CAVS_VIDEO_EDIT_CODE 0x000001b7
31 #define CAVS_PROFILE_JIZHUN 0x20
32 
33 static int cavsvideo_probe(const AVProbeData *p)
34 {
35  uint32_t code= -1;
36  int pic=0, seq=0, slice_pos = 0;
37  const uint8_t *ptr = p->buf, *end = p->buf + p->buf_size;
38 
39  while (ptr < end) {
40  ptr = avpriv_find_start_code(ptr, end, &code);
41  if ((code & 0xffffff00) == 0x100) {
42  if(code < CAVS_SEQ_START_CODE) {
43  /* slices have to be consecutive */
44  if(code < slice_pos)
45  return 0;
46  slice_pos = code;
47  } else {
48  slice_pos = 0;
49  }
50  if (code == CAVS_SEQ_START_CODE) {
51  seq++;
52  /* check for the only currently supported profile */
53  if (*ptr != CAVS_PROFILE_JIZHUN)
54  return 0;
55  } else if ((code == CAVS_PIC_I_START_CODE) ||
56  (code == CAVS_PIC_PB_START_CODE)) {
57  pic++;
58  } else if ((code == CAVS_UNDEF_START_CODE) ||
59  (code > CAVS_VIDEO_EDIT_CODE)) {
60  return 0;
61  }
62  }
63  }
64  if(seq && seq*9<=pic*10)
65  return AVPROBE_SCORE_EXTENSION+1;
66  return 0;
67 }
68 
69 FF_DEF_RAWVIDEO_DEMUXER(cavsvideo, "raw Chinese AVS (Audio Video Standard)", cavsvideo_probe, NULL, AV_CODEC_ID_CAVS)
#define NULL
Definition: coverity.c:32
#define FF_DEF_RAWVIDEO_DEMUXER(shortname, longname, probe, ext, id)
Definition: rawdec.h:71
static int cavsvideo_probe(const AVProbeData *p)
Definition: cavsvideodec.c:33
#define CAVS_PIC_I_START_CODE
Definition: cavsvideodec.c:27
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
const uint8_t * avpriv_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state)
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
#define CAVS_SEQ_START_CODE
Definition: cavsvideodec.c:26
#define CAVS_VIDEO_EDIT_CODE
Definition: cavsvideodec.c:30
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Main libavformat public API header.
common internal api header.
#define CAVS_PROFILE_JIZHUN
Definition: cavsvideodec.c:31
#define CAVS_UNDEF_START_CODE
Definition: cavsvideodec.c:28
#define CAVS_PIC_PB_START_CODE
Definition: cavsvideodec.c:29