ffmpeg / libavcodec / h263_parser.c @ d36beb3f
History | View | Annotate | Download (2.31 KB)
1 |
/*
|
---|---|
2 |
* H.263 parser
|
3 |
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
|
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 |
* H.263 parser
|
25 |
*/
|
26 |
|
27 |
#include "parser.h" |
28 |
#include "h263_parser.h" |
29 |
|
30 |
int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){ |
31 |
int vop_found, i;
|
32 |
uint32_t state; |
33 |
|
34 |
vop_found= pc->frame_start_found; |
35 |
state= pc->state; |
36 |
|
37 |
i=0;
|
38 |
if(!vop_found){
|
39 |
for(i=0; i<buf_size; i++){ |
40 |
state= (state<<8) | buf[i];
|
41 |
if(state>>(32-22) == 0x20){ |
42 |
i++; |
43 |
vop_found=1;
|
44 |
break;
|
45 |
} |
46 |
} |
47 |
} |
48 |
|
49 |
if(vop_found){
|
50 |
for(; i<buf_size; i++){
|
51 |
state= (state<<8) | buf[i];
|
52 |
if(state>>(32-22) == 0x20){ |
53 |
pc->frame_start_found=0;
|
54 |
pc->state=-1;
|
55 |
return i-3; |
56 |
} |
57 |
} |
58 |
} |
59 |
pc->frame_start_found= vop_found; |
60 |
pc->state= state; |
61 |
|
62 |
return END_NOT_FOUND;
|
63 |
} |
64 |
|
65 |
static int h263_parse(AVCodecParserContext *s, |
66 |
AVCodecContext *avctx, |
67 |
const uint8_t **poutbuf, int *poutbuf_size, |
68 |
const uint8_t *buf, int buf_size) |
69 |
{ |
70 |
ParseContext *pc = s->priv_data; |
71 |
int next;
|
72 |
|
73 |
next= ff_h263_find_frame_end(pc, buf, buf_size); |
74 |
|
75 |
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
76 |
*poutbuf = NULL;
|
77 |
*poutbuf_size = 0;
|
78 |
return buf_size;
|
79 |
} |
80 |
|
81 |
*poutbuf = buf; |
82 |
*poutbuf_size = buf_size; |
83 |
return next;
|
84 |
} |
85 |
|
86 |
AVCodecParser ff_h263_parser = { |
87 |
{ CODEC_ID_H263 }, |
88 |
sizeof(ParseContext),
|
89 |
NULL,
|
90 |
h263_parse, |
91 |
ff_parse_close, |
92 |
}; |