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/*
* 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;
int overread;
#define MAX_OVERREAD 16
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;
ptrdiff_t pal_stride;
uint8_t *mask;
ptrdiff_t mask_stride;
uint8_t *rgb_pic;
uint8_t *last_rgb_pic;
ptrdiff_t 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);
int ff_mss12_decode_init(MSS12Context *c, int version,
SliceContext *sc1, SliceContext *sc2);
int ff_mss12_decode_end(MSS12Context *ctx);
#define ARITH_GET_BIT(prefix) \
static int prefix ## _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; \
\
prefix ## _normalise(c); \
\
return bit; \
}
#define ARITH_GET_MODEL_SYM(prefix) \
static int prefix ## _get_model_sym(ArithCoder *c, Model *m) \
{ \
int idx, val; \
\
idx = prefix ## _get_prob(c, m->cum_prob); \
\
val = m->idx2sym[idx]; \
ff_mss12_model_update(m, idx); \
\
prefix ## _normalise(c); \
\
return val; \
}
#endif /* AVCODEC_MSS12_H */
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