1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
* VC-1 and WMV3 parser
* Copyright (c) 2006-2007 Konstantin Shishkov
* Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* VC-1 and WMV3 parser
*/
#include "parser.h"
#include "vc1.h"
#include "get_bits.h"
typedef struct {
ParseContext pc;
VC1Context v;
} VC1ParseContext;
static void vc1_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t *buf, int buf_size)
{
VC1ParseContext *vpc = s->priv_data;
GetBitContext gb;
const uint8_t *start, *end, *next;
uint8_t *buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
vpc->v.s.avctx = avctx;
vpc->v.parse_only = 1;
next = buf;
for(start = buf, end = buf + buf_size; next < end; start = next){
int buf2_size, size;
next = find_next_marker(start + 4, end);
size = next - start - 4;
buf2_size = vc1_unescape_buffer(start + 4, size, buf2);
init_get_bits(&gb, buf2, buf2_size * 8);
if(size <= 0) continue;
switch(AV_RB32(start)){
case VC1_CODE_SEQHDR:
vc1_decode_sequence_header(avctx, &vpc->v, &gb);
break;
case VC1_CODE_ENTRYPOINT:
vc1_decode_entry_point(avctx, &vpc->v, &gb);
break;
case VC1_CODE_FRAME:
if(vpc->v.profile < PROFILE_ADVANCED)
vc1_parse_frame_header (&vpc->v, &gb);
else
vc1_parse_frame_header_adv(&vpc->v, &gb);
/* keep FF_BI_TYPE internal to VC1 */
if (vpc->v.s.pict_type == FF_BI_TYPE)
s->pict_type = FF_B_TYPE;
else
s->pict_type = vpc->v.s.pict_type;
break;
}
}
av_free(buf2);
}
/**
* finds the end of the current frame in the bitstream.
* @return the position of the first byte of the next frame, or -1
*/
static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf,
int buf_size) {
int pic_found, i;
uint32_t state;
pic_found= pc->frame_start_found;
state= pc->state;
i=0;
if(!pic_found){
for(i=0; i<buf_size; i++){
state= (state<<8) | buf[i];
if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){
i++;
pic_found=1;
break;
}
}
}
if(pic_found){
/* EOF considered as end of frame */
if (buf_size == 0)
return 0;
for(; i<buf_size; i++){
state= (state<<8) | buf[i];
if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){
pc->frame_start_found=0;
pc->state=-1;
return i-3;
}
}
}
pc->frame_start_found= pic_found;
pc->state= state;
return END_NOT_FOUND;
}
static int vc1_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
VC1ParseContext *vpc = s->priv_data;
int next;
if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
next= buf_size;
}else{
next= vc1_find_frame_end(&vpc->pc, buf, buf_size);
if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
}
vc1_extract_headers(s, avctx, buf, buf_size);
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
static int vc1_split(AVCodecContext *avctx,
const uint8_t *buf, int buf_size)
{
int i;
uint32_t state= -1;
int charged=0;
for(i=0; i<buf_size; i++){
state= (state<<8) | buf[i];
if(IS_MARKER(state)){
if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){
charged=1;
}else if(charged){
return i-3;
}
}
}
return 0;
}
AVCodecParser vc1_parser = {
{ CODEC_ID_VC1 },
sizeof(VC1ParseContext),
NULL,
vc1_parse,
ff_parse1_close,
vc1_split,
};
|