avcodec/idctdsp: Clear idct/idct_add for studio profile
[ffmpeg.git] / libavcodec / mjpeg_parser.c
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
31 typedef 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  */
40 static 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>=0xFFD80000 && 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>=0xFFD80000 && state<=0xFFD8FFFF){
80                     pc->frame_start_found=0;
81                     pc->state=0;
82                     return i-3;
83                 } else if(state<0xFFD00000 || state>0xFFD9FFFF){
84                     m->size= (state&0xFFFF)-1;
85                 }
86             }
87             if(m->size>0){
88                 int size= FFMIN(buf_size-i, m->size);
89                 i+=size;
90                 m->size-=size;
91                 state=0;
92                 continue;
93             }else
94                 i++;
95         }
96     }
97     pc->frame_start_found= vop_found;
98     pc->state= state;
99     return END_NOT_FOUND;
100 }
101
102 static int jpeg_parse(AVCodecParserContext *s,
103                       AVCodecContext *avctx,
104                       const uint8_t **poutbuf, int *poutbuf_size,
105                       const uint8_t *buf, int buf_size)
106 {
107     MJPEGParserContext *m = s->priv_data;
108     ParseContext *pc = &m->pc;
109     int next;
110
111     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
112         next= buf_size;
113     }else{
114         next= find_frame_end(m, buf, buf_size);
115
116         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
117             *poutbuf = NULL;
118             *poutbuf_size = 0;
119             return buf_size;
120         }
121     }
122
123     *poutbuf = buf;
124     *poutbuf_size = buf_size;
125     return next;
126 }
127
128
129 AVCodecParser ff_mjpeg_parser = {
130     .codec_ids      = { AV_CODEC_ID_MJPEG, AV_CODEC_ID_JPEGLS },
131     .priv_data_size = sizeof(MJPEGParserContext),
132     .parser_parse   = jpeg_parse,
133     .parser_close   = ff_parse_close,
134 };