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/**
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 * @file
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 * VP5 and VP6 compatible video decoder (common features)
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 *
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 * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
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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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#ifndef AVCODEC_VP56_H
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#define AVCODEC_VP56_H
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#include "vp56data.h"
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#include "dsputil.h"
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#include "get_bits.h"
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#include "bytestream.h"
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#include "cabac.h"
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#include "vp56dsp.h"
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typedef struct vp56_context VP56Context;
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typedef struct vp56_mv VP56mv;
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typedef void (*VP56ParseVectorAdjustment)(VP56Context *s,
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                                          VP56mv *vect);
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typedef void (*VP56Filter)(VP56Context *s, uint8_t *dst, uint8_t *src,
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                           int offset1, int offset2, int stride,
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                           VP56mv mv, int mask, int select, int luma);
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typedef void (*VP56ParseCoeff)(VP56Context *s);
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typedef void (*VP56DefaultModelsInit)(VP56Context *s);
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typedef void (*VP56ParseVectorModels)(VP56Context *s);
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typedef void (*VP56ParseCoeffModels)(VP56Context *s);
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typedef int  (*VP56ParseHeader)(VP56Context *s, const uint8_t *buf,
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                                int buf_size, int *golden_frame);
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typedef struct {
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    int high;
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    int bits; /* stored negated (i.e. negative "bits" is a positive number of
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                 bits left) in order to eliminate a negate in cache refilling */
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    const uint8_t *buffer;
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    const uint8_t *end;
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    unsigned long code_word;
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} VP56RangeCoder;
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typedef struct {
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    uint8_t not_null_dc;
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    VP56Frame ref_frame;
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    DCTELEM dc_coeff;
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} VP56RefDc;
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struct vp56_mv {
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    int16_t x;
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    int16_t y;
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};
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typedef struct {
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    uint8_t type;
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    VP56mv mv;
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} VP56Macroblock;
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typedef struct {
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    uint8_t coeff_reorder[64];       /* used in vp6 only */
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    uint8_t coeff_index_to_pos[64];  /* used in vp6 only */
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    uint8_t vector_sig[2];           /* delta sign */
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    uint8_t vector_dct[2];           /* delta coding types */
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    uint8_t vector_pdi[2][2];        /* predefined delta init */
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    uint8_t vector_pdv[2][7];        /* predefined delta values */
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    uint8_t vector_fdv[2][8];        /* 8 bit delta value definition */
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    uint8_t coeff_dccv[2][11];       /* DC coeff value */
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    uint8_t coeff_ract[2][3][6][11]; /* Run/AC coding type and AC coeff value */
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    uint8_t coeff_acct[2][3][3][6][5];/* vp5 only AC coding type for coding group < 3 */
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    uint8_t coeff_dcct[2][36][5];    /* DC coeff coding type */
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    uint8_t coeff_runv[2][14];       /* run value (vp6 only) */
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    uint8_t mb_type[3][10][10];      /* model for decoding MB type */
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    uint8_t mb_types_stats[3][10][2];/* contextual, next MB type stats */
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} VP56Model;
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struct vp56_context {
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    AVCodecContext *avctx;
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    DSPContext dsp;
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    VP56DSPContext vp56dsp;
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    ScanTable scantable;
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    AVFrame frames[4];
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    AVFrame *framep[6];
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    uint8_t *edge_emu_buffer_alloc;
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    uint8_t *edge_emu_buffer;
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    VP56RangeCoder c;
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    VP56RangeCoder cc;
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    VP56RangeCoder *ccp;
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    int sub_version;
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    /* frame info */
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    int plane_width[4];
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    int plane_height[4];
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    int mb_width;   /* number of horizontal MB */
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    int mb_height;  /* number of vertical MB */
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    int block_offset[6];
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    int quantizer;
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    uint16_t dequant_dc;
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    uint16_t dequant_ac;
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    int8_t *qscale_table;
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    /* DC predictors management */
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    VP56RefDc *above_blocks;
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    VP56RefDc left_block[4];
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    int above_block_idx[6];
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    DCTELEM prev_dc[3][3];    /* [plan][ref_frame] */
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    /* blocks / macroblock */
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    VP56mb mb_type;
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    VP56Macroblock *macroblocks;
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    DECLARE_ALIGNED(16, DCTELEM, block_coeff)[6][64];
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    /* motion vectors */
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    VP56mv mv[6];  /* vectors for each block in MB */
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    VP56mv vector_candidate[2];
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    int vector_candidate_pos;
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    /* filtering hints */
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    int filter_header;               /* used in vp6 only */
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    int deblock_filtering;
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    int filter_selection;
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    int filter_mode;
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    int max_vector_length;
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    int sample_variance_threshold;
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    uint8_t coeff_ctx[4][64];              /* used in vp5 only */
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    uint8_t coeff_ctx_last[4];             /* used in vp5 only */
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    int has_alpha;
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    /* upside-down flipping hints */
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    int flip;  /* are we flipping ? */
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    int frbi;  /* first row block index in MB */
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    int srbi;  /* second row block index in MB */
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    int stride[4];  /* stride for each plan */
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    const uint8_t *vp56_coord_div;
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    VP56ParseVectorAdjustment parse_vector_adjustment;
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    VP56Filter filter;
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    VP56ParseCoeff parse_coeff;
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    VP56DefaultModelsInit default_models_init;
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    VP56ParseVectorModels parse_vector_models;
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    VP56ParseCoeffModels parse_coeff_models;
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    VP56ParseHeader parse_header;
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    VP56Model *modelp;
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    VP56Model models[2];
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    /* huffman decoding */
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    int use_huffman;
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    GetBitContext gb;
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    VLC dccv_vlc[2];
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    VLC runv_vlc[2];
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    VLC ract_vlc[2][3][6];
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    unsigned int nb_null[2][2];       /* number of consecutive NULL DC/AC */
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};
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void vp56_init(AVCodecContext *avctx, int flip, int has_alpha);
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int vp56_free(AVCodecContext *avctx);
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void vp56_init_dequant(VP56Context *s, int quantizer);
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int vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
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                      AVPacket *avpkt);
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/**
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 * vp56 specific range coder implementation
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 */
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static inline void vp56_init_range_decoder(VP56RangeCoder *c,
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                                           const uint8_t *buf, int buf_size)
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{
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    c->high = 255;
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    c->bits = -8;
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    c->buffer = buf;
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    c->end = buf + buf_size;
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    c->code_word = bytestream_get_be16(&c->buffer);
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}
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static inline int vp56_rac_get_prob(VP56RangeCoder *c, uint8_t prob)
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{
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    /* Don't put c->high in a local variable; if we do that, gcc gets
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     * the stupids and turns the code below into a branch again. */
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    int bits = c->bits;
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    unsigned long code_word = c->code_word;
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    unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
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    unsigned int low_shift = low << 8;
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    int bit = code_word >= low_shift;
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    int shift;
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    /* Incantation to convince GCC to turn these into conditional moves
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     * instead of branches -- faster, as this branch is basically
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     * unpredictable. */
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    c->high = bit ? c->high - low : low;
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    code_word = bit ? code_word - low_shift : code_word;
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    /* normalize */
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    shift = ff_h264_norm_shift[c->high] - 1;
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    c->high   <<= shift;
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    code_word <<= shift;
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    bits       += shift;
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    if(bits >= 0 && c->buffer < c->end) {
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        code_word |= *c->buffer++ << bits;
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        bits -= 8;
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    }
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    c->bits = bits;
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    c->code_word = code_word;
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    return bit;
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}
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static inline int vp56_rac_get(VP56RangeCoder *c)
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{
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    /* equiprobable */
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    int low = (c->high + 1) >> 1;
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    unsigned int low_shift = low << 8;
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    int bit = c->code_word >= low_shift;
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    if (bit) {
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        c->high = (c->high - low) << 1;
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        c->code_word -= low_shift;
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    } else {
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        c->high = low << 1;
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    }
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    /* normalize */
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    c->code_word <<= 1;
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    if (++c->bits == 0 && c->buffer < c->end) {
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        c->bits = -8;
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        c->code_word |= *c->buffer++;
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    }
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    return bit;
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}
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// rounding is different than vp56_rac_get, is vp56_rac_get wrong?
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static inline int vp8_rac_get(VP56RangeCoder *c)
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{
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    return vp56_rac_get_prob(c, 128);
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}
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static inline int vp56_rac_gets(VP56RangeCoder *c, int bits)
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{
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    int value = 0;
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    while (bits--) {
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        value = (value << 1) | vp56_rac_get(c);
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    }
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    return value;
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}
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static inline int vp8_rac_get_uint(VP56RangeCoder *c, int bits)
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{
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    int value = 0;
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    while (bits--) {
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        value = (value << 1) | vp8_rac_get(c);
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    }
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    return value;
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}
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// fixme: add 1 bit to all the calls to this?
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static inline int vp8_rac_get_sint(VP56RangeCoder *c, int bits)
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{
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    int v;
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    if (!vp8_rac_get(c))
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        return 0;
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    v = vp8_rac_get_uint(c, bits);
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    if (vp8_rac_get(c))
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        v = -v;
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    return v;
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}
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// P(7)
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static inline int vp56_rac_gets_nn(VP56RangeCoder *c, int bits)
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{
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    int v = vp56_rac_gets(c, 7) << 1;
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    return v + !v;
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}
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static inline int vp8_rac_get_nn(VP56RangeCoder *c)
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{
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    int v = vp8_rac_get_uint(c, 7) << 1;
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    return v + !v;
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}
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static inline int vp56_rac_get_tree(VP56RangeCoder *c,
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                                    const VP56Tree *tree,
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                                    const uint8_t *probs)
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{
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    while (tree->val > 0) {
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        if (vp56_rac_get_prob(c, probs[tree->prob_idx]))
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            tree += tree->val;
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        else
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            tree++;
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    }
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    return -tree->val;
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}
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/**
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 * This is identical to vp8_rac_get_tree except for the possibility of starting
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 * on a node other than the root node, needed for coeff decode where this is
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 * used to save a bit after a 0 token (by disallowing EOB to immediately follow.)
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 */
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static inline int vp8_rac_get_tree_with_offset(VP56RangeCoder *c, const int8_t (*tree)[2],
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                                               const uint8_t *probs, int i)
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{
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    do {
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        i = tree[i][vp56_rac_get_prob(c, probs[i])];
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    } while (i > 0);
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    return -i;
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}
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// how probabilities are associated with decisions is different I think
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// well, the new scheme fits in the old but this way has one fewer branches per decision
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static inline int vp8_rac_get_tree(VP56RangeCoder *c, const int8_t (*tree)[2],
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                                   const uint8_t *probs)
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{
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    return vp8_rac_get_tree_with_offset(c, tree, probs, 0);
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}
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// DCTextra
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static inline int vp8_rac_get_coeff(VP56RangeCoder *c, const uint8_t *prob)
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{
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    int v = 0;
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    do {
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        v = (v<<1) + vp56_rac_get_prob(c, *prob++);
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    } while (*prob);
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    return v;
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}
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#endif /* AVCODEC_VP56_H */