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      1 // Copyright 2011 Google Inc.
      2 //
      3 // This code is licensed under the same terms as WebM:
      4 //  Software License Agreement:  http://www.webmproject.org/license/software/
      5 //  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
      6 // -----------------------------------------------------------------------------
      7 //
      8 // Cost tables for level and modes.
      9 //
     10 // Author: Skal (pascal.massimino (at) gmail.com)
     11 
     12 #ifndef WEBP_ENC_COST_H_
     13 #define WEBP_ENC_COST_H_
     14 
     15 #include "vp8enci.h"
     16 
     17 #if defined(__cplusplus) || defined(c_plusplus)
     18 extern "C" {
     19 #endif
     20 
     21 extern const uint16_t VP8LevelFixedCosts[2048];   // approximate cost per level
     22 extern const uint16_t VP8EntropyCost[256];        // 8bit fixed-point log(p)
     23 
     24 // Cost of coding one event with probability 'proba'.
     25 static inline int VP8BitCost(int bit, uint8_t proba) {
     26   return !bit ? VP8EntropyCost[proba] : VP8EntropyCost[255 - proba];
     27 }
     28 
     29 // Cost of coding 'nb' 1's and 'total-nb' 0's using 'proba' probability.
     30 static inline uint64_t VP8BranchCost(uint64_t nb, uint64_t total,
     31                                      uint8_t proba) {
     32   return nb * VP8BitCost(1, proba) + (total - nb) * VP8BitCost(0, proba);
     33 }
     34 
     35 // Level cost calculations
     36 extern const uint16_t VP8LevelCodes[MAX_VARIABLE_LEVEL][2];
     37 void VP8CalculateLevelCosts(VP8Proba* const proba);
     38 static inline int VP8LevelCost(const uint16_t* const table, int level) {
     39   return VP8LevelFixedCosts[level]
     40        + table[level > MAX_VARIABLE_LEVEL ? MAX_VARIABLE_LEVEL : level];
     41 }
     42 
     43 // Mode costs
     44 extern const uint16_t VP8FixedCostsUV[4];
     45 extern const uint16_t VP8FixedCostsI16[4];
     46 extern const uint16_t VP8FixedCostsI4[NUM_BMODES][NUM_BMODES][NUM_BMODES];
     47 
     48 //-----------------------------------------------------------------------------
     49 
     50 #if defined(__cplusplus) || defined(c_plusplus)
     51 }    // extern "C"
     52 #endif
     53 
     54 #endif  // WEBP_ENC_COST_H_
     55