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cavs_parser.c
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1 /*
2  * Chinese AVS video (AVS1-P2, JiZhun profile) parser.
3  * Copyright (c) 2006 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 /**
23  * @file
24  * Chinese AVS video (AVS1-P2, JiZhun profile) parser
25  * @author Stefan Gehrer <stefan.gehrer@gmx.de>
26  */
27 
28 #include "parser.h"
29 #include "cavs.h"
30 
31 
32 /**
33  * Find the end of the current frame in the bitstream.
34  * @return the position of the first byte of the next frame, or -1
35  */
37  int buf_size) {
38  int pic_found, i;
39  uint32_t state;
40 
41  pic_found= pc->frame_start_found;
42  state= pc->state;
43 
44  i=0;
45  if(!pic_found){
46  for(i=0; i<buf_size; i++){
47  state= (state<<8) | buf[i];
48  if(state == PIC_I_START_CODE || state == PIC_PB_START_CODE){
49  i++;
50  pic_found=1;
51  break;
52  }
53  }
54  }
55 
56  if(pic_found){
57  /* EOF considered as end of frame */
58  if (buf_size == 0)
59  return 0;
60  for(; i<buf_size; i++){
61  state= (state<<8) | buf[i];
62  if((state&0xFFFFFF00) == 0x100){
63  if(state > SLICE_MAX_START_CODE){
64  pc->frame_start_found=0;
65  pc->state=-1;
66  return i-3;
67  }
68  }
69  }
70  }
71  pc->frame_start_found= pic_found;
72  pc->state= state;
73  return END_NOT_FOUND;
74 }
75 
77  AVCodecContext *avctx,
78  const uint8_t **poutbuf, int *poutbuf_size,
79  const uint8_t *buf, int buf_size)
80 {
81  ParseContext *pc = s->priv_data;
82  int next;
83 
85  next= buf_size;
86  }else{
87  next= cavs_find_frame_end(pc, buf, buf_size);
88 
89  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
90  *poutbuf = NULL;
91  *poutbuf_size = 0;
92  return buf_size;
93  }
94  }
95  *poutbuf = buf;
96  *poutbuf_size = buf_size;
97  return next;
98 }
99 
102  .priv_data_size = sizeof(ParseContext),
103  .parser_parse = cavsvideo_parse,
104  .parser_close = ff_parse_close,
106 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
#define SLICE_MAX_START_CODE
Definition: cavs.h:32
int codec_ids[5]
Definition: avcodec.h:5122
int frame_start_found
Definition: parser.h:34
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:328
uint8_t
#define PIC_I_START_CODE
Definition: cavs.h:36
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:245
static char * split(char *message, char delim)
Definition: af_channelmap.c:81
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:321
static int cavs_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
Find the end of the current frame in the bitstream.
Definition: cavs_parser.c:36
main external API structure.
Definition: avcodec.h:1659
AVCodecParser ff_cavsvideo_parser
Definition: cavs_parser.c:100
void * buf
Definition: avisynth_c.h:690
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
#define END_NOT_FOUND
Definition: parser.h:40
#define PIC_PB_START_CODE
Definition: cavs.h:37
#define PARSER_FLAG_COMPLETE_FRAMES
Definition: avcodec.h:4988
static int cavsvideo_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: cavs_parser.c:76
static struct @230 state