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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
/*
* MPEG-1/2 decoder
* Copyright (c) 2000, 2001 Fabrice Bellard
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
*
* 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
* MPEG-1/2 decoder
*/
#define UNCHECKED_BITSTREAM_READER 1
#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "libavutil/timecode.h"
#include "internal.h"
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "error_resilience.h"
#include "mpeg12.h"
#include "mpeg12data.h"
#include "mpeg12decdata.h"
#include "bytestream.h"
#include "vdpau_internal.h"
#include "xvmc_internal.h"
#include "thread.h"
uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
#define INIT_2D_VLC_RL(rl, static_size)\
{\
static RL_VLC_ELEM rl_vlc_table[static_size];\
INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\
&rl.table_vlc[0][1], 4, 2,\
&rl.table_vlc[0][0], 4, 2, static_size);\
\
rl.rl_vlc[0] = rl_vlc_table;\
init_2d_vlc_rl(&rl);\
}
static av_cold void init_2d_vlc_rl(RLTable *rl)
{
int i;
for (i = 0; i < rl->vlc.table_size; i++) {
int code = rl->vlc.table[i][0];
int len = rl->vlc.table[i][1];
int level, run;
if (len == 0) { // illegal code
run = 65;
level = MAX_LEVEL;
} else if (len<0) { //more bits needed
run = 0;
level = code;
} else {
if (code == rl->n) { //esc
run = 65;
level = 0;
} else if (code == rl->n+1) { //eob
run = 0;
level = 127;
} else {
run = rl->table_run [code] + 1;
level = rl->table_level[code];
}
}
rl->rl_vlc[0][i].len = len;
rl->rl_vlc[0][i].level = level;
rl->rl_vlc[0][i].run = run;
}
}
av_cold void ff_mpeg12_common_init(MpegEncContext *s)
{
s->y_dc_scale_table =
s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
}
void ff_mpeg1_clean_buffers(MpegEncContext *s)
{
s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
s->last_dc[1] = s->last_dc[0];
s->last_dc[2] = s->last_dc[0];
memset(s->last_mv, 0, sizeof(s->last_mv));
}
/******************************************/
/* decoding */
VLC ff_mv_vlc;
VLC ff_dc_lum_vlc;
VLC ff_dc_chroma_vlc;
VLC ff_mbincr_vlc;
VLC ff_mb_ptype_vlc;
VLC ff_mb_btype_vlc;
VLC ff_mb_pat_vlc;
av_cold void ff_mpeg12_init_vlcs(void)
{
static int done = 0;
if (!done) {
done = 1;
INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
ff_mpeg12_vlc_dc_lum_bits, 1, 1,
ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
&ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
&ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518);
INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
&ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
&ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
&ff_mpeg12_mbPatTable[0][1], 2, 1,
&ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
&table_mb_ptype[0][1], 2, 1,
&table_mb_ptype[0][0], 2, 1, 64);
INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
&table_mb_btype[0][1], 2, 1,
&table_mb_btype[0][0], 2, 1, 64);
ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);
INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
}
}
/**
* Find the end of the current frame in the bitstream.
* @return the position of the first byte of the next frame, or -1
*/
int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
{
int i;
uint32_t state = pc->state;
/* EOF considered as end of frame */
if (buf_size == 0)
return 0;
/*
0 frame start -> 1/4
1 first_SEQEXT -> 0/2
2 first field start -> 3/0
3 second_SEQEXT -> 2/0
4 searching end
*/
for (i = 0; i < buf_size; i++) {
av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
if (pc->frame_start_found & 1) {
if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
pc->frame_start_found--;
else if (state == EXT_START_CODE + 2) {
if ((buf[i] & 3) == 3)
pc->frame_start_found = 0;
else
pc->frame_start_found = (pc->frame_start_found + 1) & 3;
}
state++;
} else {
i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
i++;
pc->frame_start_found = 4;
}
if (state == SEQ_END_CODE) {
pc->frame_start_found = 0;
pc->state=-1;
return i+1;
}
if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
pc->frame_start_found = 0;
if (pc->frame_start_found < 4 && state == EXT_START_CODE)
pc->frame_start_found++;
if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
pc->frame_start_found = 0;
pc->state = -1;
return i - 3;
}
}
if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
ff_fetch_timestamp(s, i - 3, 1);
}
}
}
pc->state = state;
return END_NOT_FOUND;
}
|
