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#if FF_API_FLAG_TRUNCATED
29/* Nuke this header when removing FF_API_FLAG_TRUNCATED */
30#include "h263_parser.h"
31
32int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
33#else
34
35static int h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
36{
37#endif
38    int vop_found, i;
39    uint32_t state;
40
41    vop_found= pc->frame_start_found;
42    state= pc->state;
43
44    i=0;
45    if(!vop_found){
46        for(i=0; i<buf_size; i++){
47            state= (state<<8) | buf[i];
48            if(state>>(32-22) == 0x20){
49                i++;
50                vop_found=1;
51                break;
52            }
53        }
54    }
55
56    if(vop_found){
57      for(; i<buf_size; i++){
58        state= (state<<8) | buf[i];
59        if(state>>(32-22) == 0x20){
60            pc->frame_start_found=0;
61            pc->state=-1;
62            return i-3;
63        }
64      }
65    }
66    pc->frame_start_found= vop_found;
67    pc->state= state;
68
69    return END_NOT_FOUND;
70}
71
72static int h263_parse(AVCodecParserContext *s,
73                           AVCodecContext *avctx,
74                           const uint8_t **poutbuf, int *poutbuf_size,
75                           const uint8_t *buf, int buf_size)
76{
77    ParseContext *pc = s->priv_data;
78    int next;
79
80    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
81        next = buf_size;
82    } else {
83#if FF_API_FLAG_TRUNCATED
84        next= ff_h263_find_frame_end(pc, buf, buf_size);
85#else
86        next = h263_find_frame_end(pc, buf, buf_size);
87#endif
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
96    *poutbuf = buf;
97    *poutbuf_size = buf_size;
98    return next;
99}
100
101const AVCodecParser ff_h263_parser = {
102    .codec_ids      = { AV_CODEC_ID_H263 },
103    .priv_data_size = sizeof(ParseContext),
104    .parser_parse   = h263_parse,
105    .parser_close   = ff_parse_close,
106};
107