blob: 2e7d4930c3144278a1ded9cde153c20f36cdbbf9
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 | }; |
96 |