blob: 45c4074652753a554634df7d1f12b6f96aebf8e0
1 | /* |
2 | * Copyright (c) 2012 Konstantin Shishkov |
3 | * |
4 | * This file is part of FFmpeg. |
5 | * |
6 | * FFmpeg is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public |
8 | * License as published by the Free Software Foundation; either |
9 | * version 2.1 of the License, or (at your option) any later version. |
10 | * |
11 | * FFmpeg is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | * Lesser General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU Lesser General Public |
17 | * License along with FFmpeg; if not, write to the Free Software |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
19 | */ |
20 | |
21 | /** |
22 | * @file |
23 | * Common header for Microsoft Screen 1 and 2 |
24 | */ |
25 | |
26 | #ifndef AVCODEC_MSS12_H |
27 | #define AVCODEC_MSS12_H |
28 | |
29 | #include "libavutil/intreadwrite.h" |
30 | #include "avcodec.h" |
31 | #include "get_bits.h" |
32 | #include "bytestream.h" |
33 | |
34 | #define MODEL_MIN_SYMS 2 |
35 | #define MODEL_MAX_SYMS 256 |
36 | #define THRESH_ADAPTIVE -1 |
37 | #define THRESH_LOW 15 |
38 | #define THRESH_HIGH 50 |
39 | |
40 | typedef struct Model { |
41 | int16_t cum_prob[MODEL_MAX_SYMS + 1]; |
42 | int16_t weights[MODEL_MAX_SYMS + 1]; |
43 | uint8_t idx2sym[MODEL_MAX_SYMS + 1]; |
44 | int num_syms; |
45 | int thr_weight, threshold; |
46 | } Model; |
47 | |
48 | typedef struct ArithCoder { |
49 | int low, high, value; |
50 | union { |
51 | GetBitContext *gb; |
52 | GetByteContext *gB; |
53 | } gbc; |
54 | int (*get_model_sym)(struct ArithCoder *c, Model *m); |
55 | int (*get_number) (struct ArithCoder *c, int n); |
56 | } ArithCoder; |
57 | |
58 | typedef struct PixContext { |
59 | int cache_size, num_syms; |
60 | uint8_t cache[12]; |
61 | Model cache_model, full_model; |
62 | Model sec_models[15][4]; |
63 | int special_initial_cache; |
64 | } PixContext; |
65 | |
66 | struct MSS12Context; |
67 | |
68 | typedef struct SliceContext { |
69 | struct MSS12Context *c; |
70 | Model intra_region, inter_region; |
71 | Model pivot, edge_mode, split_mode; |
72 | PixContext intra_pix_ctx, inter_pix_ctx; |
73 | } SliceContext; |
74 | |
75 | typedef struct MSS12Context { |
76 | AVCodecContext *avctx; |
77 | uint32_t pal[256]; |
78 | uint8_t *pal_pic; |
79 | uint8_t *last_pal_pic; |
80 | ptrdiff_t pal_stride; |
81 | uint8_t *mask; |
82 | ptrdiff_t mask_stride; |
83 | uint8_t *rgb_pic; |
84 | uint8_t *last_rgb_pic; |
85 | ptrdiff_t rgb_stride; |
86 | int free_colours; |
87 | int keyframe; |
88 | int mvX, mvY; |
89 | int corrupted; |
90 | int slice_split; |
91 | int full_model_syms; |
92 | } MSS12Context; |
93 | |
94 | int ff_mss12_decode_rect(SliceContext *ctx, ArithCoder *acoder, |
95 | int x, int y, int width, int height); |
96 | void ff_mss12_model_update(Model *m, int val); |
97 | void ff_mss12_slicecontext_reset(SliceContext *sc); |
98 | int ff_mss12_decode_init(MSS12Context *c, int version, |
99 | SliceContext *sc1, SliceContext *sc2); |
100 | int ff_mss12_decode_end(MSS12Context *ctx); |
101 | |
102 | #define ARITH_GET_BIT(prefix) \ |
103 | static int prefix ## _get_bit(ArithCoder *c) \ |
104 | { \ |
105 | int range = c->high - c->low + 1; \ |
106 | int bit = 2 * c->value - c->low >= c->high; \ |
107 | \ |
108 | if (bit) \ |
109 | c->low += range >> 1; \ |
110 | else \ |
111 | c->high = c->low + (range >> 1) - 1; \ |
112 | \ |
113 | prefix ## _normalise(c); \ |
114 | \ |
115 | return bit; \ |
116 | } |
117 | |
118 | #define ARITH_GET_MODEL_SYM(prefix) \ |
119 | static int prefix ## _get_model_sym(ArithCoder *c, Model *m) \ |
120 | { \ |
121 | int idx, val; \ |
122 | \ |
123 | idx = prefix ## _get_prob(c, m->cum_prob); \ |
124 | \ |
125 | val = m->idx2sym[idx]; \ |
126 | ff_mss12_model_update(m, idx); \ |
127 | \ |
128 | prefix ## _normalise(c); \ |
129 | \ |
130 | return val; \ |
131 | } |
132 | |
133 | #endif /* AVCODEC_MSS12_H */ |
134 |