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 40typedef 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 48typedef 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 58typedef 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 66struct MSS12Context; 67 68typedef 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 75typedef 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 94int ff_mss12_decode_rect(SliceContext *ctx, ArithCoder *acoder, 95 int x, int y, int width, int height); 96void ff_mss12_model_update(Model *m, int val); 97void ff_mss12_slicecontext_reset(SliceContext *sc); 98int ff_mss12_decode_init(MSS12Context *c, int version, 99 SliceContext *sc1, SliceContext *sc2); 100int ff_mss12_decode_end(MSS12Context *ctx); 101 102#define ARITH_GET_BIT(prefix) \ 103static 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) \ 119static 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