1/*
2 * MJPEG parser
3 * Copyright (c) 2000, 2001 Fabrice Bellard
4 * Copyright (c) 2003 Alex Beregszaszi
5 * Copyright (c) 2003-2004 Michael Niedermayer
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24/**
25 * @file
26 * MJPEG parser.
27 */
28
29#include "parser.h"
30
31typedef struct MJPEGParserContext{
32    ParseContext pc;
33    int size;
34}MJPEGParserContext;
35
36/**
37 * Find the end of the current frame in the bitstream.
38 * @return the position of the first byte of the next frame, or -1
39 */
40static int find_frame_end(MJPEGParserContext *m, const uint8_t *buf, int buf_size){
41    ParseContext *pc= &m->pc;
42    int vop_found, i;
43    uint32_t state;
44
45    vop_found= pc->frame_start_found;
46    state= pc->state;
47
48    i=0;
49    if(!vop_found){
50        for(i=0; i<buf_size;){
51            state= (state<<8) | buf[i];
52            if(state>=0xFFC00000 && state<=0xFFFEFFFF){
53                if(state>=0xFFD8FFC0 && state<=0xFFD8FFFF){
54                    i++;
55                    vop_found=1;
56                    break;
57                }else if(state<0xFFD00000 || state>0xFFD9FFFF){
58                    m->size= (state&0xFFFF)-1;
59                }
60            }
61            if(m->size>0){
62                int size= FFMIN(buf_size-i, m->size);
63                i+=size;
64                m->size-=size;
65                state=0;
66                continue;
67            }else
68                i++;
69        }
70    }
71
72    if(vop_found){
73        /* EOF considered as end of frame */
74        if (buf_size == 0)
75            return 0;
76        for(; i<buf_size;){
77            state= (state<<8) | buf[i];
78            if(state>=0xFFC00000 && state<=0xFFFEFFFF){
79                if(state>=0xFFD8FFC0 && state<=0xFFD8FFFF){
80                    pc->frame_start_found=0;
81                    pc->state=0;
82                    return i-3;
83                } else if((state>>16)==0xFFD9 && (state&0xFFFF)!=0xFFD8){
84                    state= 0xFFD900|(state&0xFF);
85                } else if(state<0xFFD00000 || state>0xFFD9FFFF){
86                    m->size= (state&0xFFFF)-1;
87                }
88            }
89            if(m->size>0){
90                int size= FFMIN(buf_size-i, m->size);
91                i+=size;
92                m->size-=size;
93                state=0;
94                continue;
95            }else
96                i++;
97        }
98    }
99    pc->frame_start_found= vop_found;
100    pc->state= state;
101    return END_NOT_FOUND;
102}
103
104static int jpeg_parse(AVCodecParserContext *s,
105                      AVCodecContext *avctx,
106                      const uint8_t **poutbuf, int *poutbuf_size,
107                      const uint8_t *buf, int buf_size)
108{
109    MJPEGParserContext *m = s->priv_data;
110    ParseContext *pc = &m->pc;
111    int next;
112
113    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
114        next= buf_size;
115    }else{
116        next= find_frame_end(m, buf, buf_size);
117
118        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
119            *poutbuf = NULL;
120            *poutbuf_size = 0;
121            return buf_size;
122        }
123    }
124
125    *poutbuf = buf;
126    *poutbuf_size = buf_size;
127    return next;
128}
129
130
131const AVCodecParser ff_mjpeg_parser = {
132    .codec_ids      = { AV_CODEC_ID_MJPEG, AV_CODEC_ID_JPEGLS },
133    .priv_data_size = sizeof(MJPEGParserContext),
134    .parser_parse   = jpeg_parse,
135    .parser_close   = ff_parse_close,
136};
137