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
|
/*
* Copyright (c) 2012 Konstantin Shishkov
*
* 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
* Common header for Microsoft Screen 1 and 2
*/
#ifndef AVCODEC_MSS12_H
#define AVCODEC_MSS12_H
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#define MODEL_MIN_SYMS 2
#define MODEL_MAX_SYMS 256
#define THRESH_ADAPTIVE -1
#define THRESH_LOW 15
#define THRESH_HIGH 50
typedef struct Model {
int16_t cum_prob[MODEL_MAX_SYMS + 1];
int16_t weights[MODEL_MAX_SYMS + 1];
uint8_t idx2sym[MODEL_MAX_SYMS + 1];
int num_syms;
int thr_weight, threshold;
} Model;
typedef struct ArithCoder {
int low, high, value;
union {
GetBitContext *gb;
GetByteContext *gB;
} gbc;
int (*get_model_sym)(struct ArithCoder *c, Model *m);
int (*get_number) (struct ArithCoder *c, int n);
} ArithCoder;
typedef struct PixContext {
int cache_size, num_syms;
uint8_t cache[12];
Model cache_model, full_model;
Model sec_models[15][4];
int special_initial_cache;
} PixContext;
struct MSS12Context;
typedef struct SliceContext {
struct MSS12Context *c;
Model intra_region, inter_region;
Model pivot, edge_mode, split_mode;
PixContext intra_pix_ctx, inter_pix_ctx;
} SliceContext;
typedef struct MSS12Context {
AVCodecContext *avctx;
uint32_t pal[256];
uint8_t *pal_pic;
uint8_t *last_pal_pic;
int pal_stride;
uint8_t *mask;
int mask_stride;
uint8_t *rgb_pic;
uint8_t *last_rgb_pic;
int rgb_stride;
int free_colours;
int keyframe;
int mvX, mvY;
int corrupted;
int slice_split;
int full_model_syms;
} MSS12Context;
int ff_mss12_decode_rect(SliceContext *ctx, ArithCoder *acoder,
int x, int y, int width, int height);
void ff_mss12_model_update(Model *m, int val);
void ff_mss12_slicecontext_reset(SliceContext *sc);
av_cold int ff_mss12_decode_init(MSS12Context *c, int version,
SliceContext* sc1, SliceContext *sc2);
av_cold int ff_mss12_decode_end(MSS12Context *ctx);
#define ARITH_GET_BIT(VERSION) \
static int arith ## VERSION ## _get_bit(ArithCoder *c) \
{ \
int range = c->high - c->low + 1; \
int bit = 2 * c->value - c->low >= c->high; \
\
if (bit) \
c->low += range >> 1; \
else \
c->high = c->low + (range >> 1) - 1; \
\
arith ## VERSION ## _normalise(c); \
\
return bit; \
}
#define ARITH_GET_MODEL_SYM(VERSION) \
static int arith ## VERSION ## _get_model_sym(ArithCoder *c, Model *m) \
{ \
int idx, val; \
\
idx = arith ## VERSION ## _get_prob(c, m->cum_prob); \
\
val = m->idx2sym[idx]; \
ff_mss12_model_update(m, idx); \
\
arith ## VERSION ## _normalise(c); \
\
return val; \
}
#endif /* AVCODEC_MSS12_H */
|
