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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 | int pal_stride; | |
81 | uint8_t *mask; | |
82 | int mask_stride; | |
83 | uint8_t *rgb_pic; | |
84 | uint8_t *last_rgb_pic; | |
85 | int 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 */ |