136 lines
4.9 KiB
C
136 lines
4.9 KiB
C
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/*
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* Copyright (c) 2012 Konstantin Shishkov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Common header for Microsoft Screen 1 and 2
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*/
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#ifndef AVCODEC_MSS12_H
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#define AVCODEC_MSS12_H
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "get_bits.h"
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#include "bytestream.h"
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#define MODEL_MIN_SYMS 2
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#define MODEL_MAX_SYMS 256
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#define THRESH_ADAPTIVE -1
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#define THRESH_LOW 15
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#define THRESH_HIGH 50
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typedef struct Model {
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int16_t cum_prob[MODEL_MAX_SYMS + 1];
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int16_t weights[MODEL_MAX_SYMS + 1];
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uint8_t idx2sym[MODEL_MAX_SYMS + 1];
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int num_syms;
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int thr_weight, threshold;
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} Model;
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typedef struct ArithCoder {
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int low, high, value;
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int overread;
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#define MAX_OVERREAD 16
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union {
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GetBitContext *gb;
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GetByteContext *gB;
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} gbc;
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int (*get_model_sym)(struct ArithCoder *c, Model *m);
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int (*get_number) (struct ArithCoder *c, int n);
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} ArithCoder;
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typedef struct PixContext {
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int cache_size, num_syms;
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uint8_t cache[12];
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Model cache_model, full_model;
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Model sec_models[15][4];
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int special_initial_cache;
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} PixContext;
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struct MSS12Context;
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typedef struct SliceContext {
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struct MSS12Context *c;
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Model intra_region, inter_region;
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Model pivot, edge_mode, split_mode;
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PixContext intra_pix_ctx, inter_pix_ctx;
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} SliceContext;
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typedef struct MSS12Context {
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AVCodecContext *avctx;
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uint32_t pal[256];
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uint8_t *pal_pic;
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uint8_t *last_pal_pic;
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ptrdiff_t pal_stride;
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uint8_t *mask;
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ptrdiff_t mask_stride;
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uint8_t *rgb_pic;
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uint8_t *last_rgb_pic;
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ptrdiff_t rgb_stride;
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int free_colours;
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int keyframe;
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int mvX, mvY;
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int corrupted;
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int slice_split;
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int full_model_syms;
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} MSS12Context;
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int ff_mss12_decode_rect(SliceContext *ctx, ArithCoder *acoder,
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int x, int y, int width, int height);
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void ff_mss12_model_update(Model *m, int val);
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void ff_mss12_slicecontext_reset(SliceContext *sc);
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int ff_mss12_decode_init(MSS12Context *c, int version,
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SliceContext *sc1, SliceContext *sc2);
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int ff_mss12_decode_end(MSS12Context *ctx);
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#define ARITH_GET_BIT(prefix) \
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static int prefix ## _get_bit(ArithCoder *c) \
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{ \
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int range = c->high - c->low + 1; \
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int bit = 2 * c->value - c->low >= c->high; \
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\
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if (bit) \
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c->low += range >> 1; \
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else \
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c->high = c->low + (range >> 1) - 1; \
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\
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prefix ## _normalise(c); \
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\
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return bit; \
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}
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#define ARITH_GET_MODEL_SYM(prefix) \
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static int prefix ## _get_model_sym(ArithCoder *c, Model *m) \
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{ \
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int idx, val; \
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\
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idx = prefix ## _get_prob(c, m->cum_prob); \
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\
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val = m->idx2sym[idx]; \
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ff_mss12_model_update(m, idx); \
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\
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prefix ## _normalise(c); \
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\
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return val; \
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}
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#endif /* AVCODEC_MSS12_H */
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