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      1 // Copyright 2011 Google Inc. All Rights Reserved.
      2 //
      3 // Use of this source code is governed by a BSD-style license
      4 // that can be found in the COPYING file in the root of the source
      5 // tree. An additional intellectual property rights grant can be found
      6 // in the file PATENTS. All contributing project authors may
      7 // be found in the AUTHORS file in the root of the source tree.
      8 // -----------------------------------------------------------------------------
      9 //
     10 // Cost tables for level and modes.
     11 //
     12 // Author: Skal (pascal.massimino (at) gmail.com)
     13 
     14 #ifndef WEBP_ENC_COST_H_
     15 #define WEBP_ENC_COST_H_
     16 
     17 #include <assert.h>
     18 #include <stdlib.h>
     19 #include "./vp8enci.h"
     20 
     21 #ifdef __cplusplus
     22 extern "C" {
     23 #endif
     24 
     25 // On-the-fly info about the current set of residuals. Handy to avoid
     26 // passing zillions of params.
     27 typedef struct {
     28   int first;
     29   int last;
     30   const int16_t* coeffs;
     31 
     32   int coeff_type;
     33   ProbaArray* prob;
     34   StatsArray* stats;
     35   CostArray*  cost;
     36 } VP8Residual;
     37 
     38 void VP8InitResidual(int first, int coeff_type,
     39                      VP8Encoder* const enc, VP8Residual* const res);
     40 
     41 typedef void (*VP8SetResidualCoeffsFunc)(const int16_t* const coeffs,
     42                                          VP8Residual* const res);
     43 extern VP8SetResidualCoeffsFunc VP8SetResidualCoeffs;
     44 
     45 void VP8SetResidualCoeffsInit(void);  // must be called first
     46 
     47 int VP8RecordCoeffs(int ctx, const VP8Residual* const res);
     48 
     49 // approximate cost per level:
     50 extern const uint16_t VP8LevelFixedCosts[MAX_LEVEL + 1];
     51 extern const uint16_t VP8EntropyCost[256];        // 8bit fixed-point log(p)
     52 
     53 // Cost of coding one event with probability 'proba'.
     54 static WEBP_INLINE int VP8BitCost(int bit, uint8_t proba) {
     55   return !bit ? VP8EntropyCost[proba] : VP8EntropyCost[255 - proba];
     56 }
     57 
     58 // Cost calculation function.
     59 typedef int (*VP8GetResidualCostFunc)(int ctx0, const VP8Residual* const res);
     60 extern VP8GetResidualCostFunc VP8GetResidualCost;
     61 
     62 void VP8GetResidualCostInit(void);  // must be called first
     63 
     64 // Level cost calculations
     65 extern const uint16_t VP8LevelCodes[MAX_VARIABLE_LEVEL][2];
     66 void VP8CalculateLevelCosts(VP8Proba* const proba);
     67 static WEBP_INLINE int VP8LevelCost(const uint16_t* const table, int level) {
     68   return VP8LevelFixedCosts[level]
     69        + table[(level > MAX_VARIABLE_LEVEL) ? MAX_VARIABLE_LEVEL : level];
     70 }
     71 
     72 // Mode costs
     73 extern const uint16_t VP8FixedCostsUV[4];
     74 extern const uint16_t VP8FixedCostsI16[4];
     75 extern const uint16_t VP8FixedCostsI4[NUM_BMODES][NUM_BMODES][NUM_BMODES];
     76 
     77 //------------------------------------------------------------------------------
     78 
     79 #ifdef __cplusplus
     80 }    // extern "C"
     81 #endif
     82 
     83 #endif  /* WEBP_ENC_COST_H_ */
     84