Commit | Line | Data |
---|---|---|
2ba45a60 DM |
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 | if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { | |
74 | next = buf_size; | |
75 | } else { | |
76 | next= ff_h263_find_frame_end(pc, buf, buf_size); | |
77 | ||
78 | if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { | |
79 | *poutbuf = NULL; | |
80 | *poutbuf_size = 0; | |
81 | return buf_size; | |
82 | } | |
83 | } | |
84 | ||
85 | *poutbuf = buf; | |
86 | *poutbuf_size = buf_size; | |
87 | return next; | |
88 | } | |
89 | ||
90 | AVCodecParser ff_h263_parser = { | |
91 | .codec_ids = { AV_CODEC_ID_H263 }, | |
92 | .priv_data_size = sizeof(ParseContext), | |
93 | .parser_parse = h263_parse, | |
94 | .parser_close = ff_parse_close, | |
95 | }; |