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 "./vp8i_enc.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 VP8Residual VP8Residual; 28 struct VP8Residual { 29 int first; 30 int last; 31 const int16_t* coeffs; 32 33 int coeff_type; 34 ProbaArray* prob; 35 StatsArray* stats; 36 CostArrayPtr costs; 37 }; 38 39 void VP8InitResidual(int first, int coeff_type, 40 VP8Encoder* const enc, VP8Residual* const res); 41 42 int VP8RecordCoeffs(int ctx, const VP8Residual* const res); 43 44 // Record proba context used. 45 static WEBP_INLINE int VP8RecordStats(int bit, proba_t* const stats) { 46 proba_t p = *stats; 47 // An overflow is inbound. Note we handle this at 0xfffe0000u instead of 48 // 0xffff0000u to make sure p + 1u does not overflow. 49 if (p >= 0xfffe0000u) { 50 p = ((p + 1u) >> 1) & 0x7fff7fffu; // -> divide the stats by 2. 51 } 52 // record bit count (lower 16 bits) and increment total count (upper 16 bits). 53 p += 0x00010000u + bit; 54 *stats = p; 55 return bit; 56 } 57 58 // Cost of coding one event with probability 'proba'. 59 static WEBP_INLINE int VP8BitCost(int bit, uint8_t proba) { 60 return !bit ? VP8EntropyCost[proba] : VP8EntropyCost[255 - proba]; 61 } 62 63 // Level cost calculations 64 extern const uint16_t VP8LevelCodes[MAX_VARIABLE_LEVEL][2]; 65 void VP8CalculateLevelCosts(VP8EncProba* const proba); 66 static WEBP_INLINE int VP8LevelCost(const uint16_t* const table, int level) { 67 return VP8LevelFixedCosts[level] 68 + table[(level > MAX_VARIABLE_LEVEL) ? MAX_VARIABLE_LEVEL : level]; 69 } 70 71 // Mode costs 72 extern const uint16_t VP8FixedCostsUV[4]; 73 extern const uint16_t VP8FixedCostsI16[4]; 74 extern const uint16_t VP8FixedCostsI4[NUM_BMODES][NUM_BMODES][NUM_BMODES]; 75 76 //------------------------------------------------------------------------------ 77 78 #ifdef __cplusplus 79 } // extern "C" 80 #endif 81 82 #endif /* WEBP_ENC_COST_H_ */ 83
