tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

cost_enc.h (2571B)

      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@gmail.com)
     13 
     14 #ifndef WEBP_ENC_COST_ENC_H_
     15 #define WEBP_ENC_COST_ENC_H_
     16 
     17 #include <assert.h>
     18 #include <stdlib.h>
     19 
     20 #include "src/dec/common_dec.h"
     21 #include "src/dsp/dsp.h"
     22 #include "src/enc/vp8i_enc.h"
     23 #include "src/webp/types.h"
     24 
     25 #ifdef __cplusplus
     26 extern "C" {
     27 #endif
     28 
     29 // On-the-fly info about the current set of residuals. Handy to avoid
     30 // passing zillions of params.
     31 typedef struct VP8Residual VP8Residual;
     32 struct VP8Residual {
     33  int first;
     34  int last;
     35  const int16_t* coeffs;
     36 
     37  int coeff_type;
     38  ProbaArray*   prob;
     39  StatsArray*   stats;
     40  CostArrayPtr  costs;
     41 };
     42 
     43 void VP8InitResidual(int first, int coeff_type,
     44                     VP8Encoder* const enc, VP8Residual* const res);
     45 
     46 int VP8RecordCoeffs(int ctx, const VP8Residual* const res);
     47 
     48 // Record proba context used.
     49 static WEBP_INLINE int VP8RecordStats(int bit, proba_t* const stats) {
     50  proba_t p = *stats;
     51  // An overflow is inbound. Note we handle this at 0xfffe0000u instead of
     52  // 0xffff0000u to make sure p + 1u does not overflow.
     53  if (p >= 0xfffe0000u) {
     54    p = ((p + 1u) >> 1) & 0x7fff7fffu;  // -> divide the stats by 2.
     55  }
     56  // record bit count (lower 16 bits) and increment total count (upper 16 bits).
     57  p += 0x00010000u + bit;
     58  *stats = p;
     59  return bit;
     60 }
     61 
     62 // Cost of coding one event with probability 'proba'.
     63 static WEBP_INLINE int VP8BitCost(int bit, uint8_t proba) {
     64  return !bit ? VP8EntropyCost[proba] : VP8EntropyCost[255 - proba];
     65 }
     66 
     67 // Level cost calculations
     68 void VP8CalculateLevelCosts(VP8EncProba* const proba);
     69 static WEBP_INLINE int VP8LevelCost(const uint16_t* const table, int level) {
     70  return VP8LevelFixedCosts[level]
     71       + table[(level > MAX_VARIABLE_LEVEL) ? MAX_VARIABLE_LEVEL : level];
     72 }
     73 
     74 // Mode costs
     75 extern const uint16_t VP8FixedCostsUV[4];
     76 extern const uint16_t VP8FixedCostsI16[4];
     77 extern const uint16_t VP8FixedCostsI4[NUM_BMODES][NUM_BMODES][NUM_BMODES];
     78 
     79 //------------------------------------------------------------------------------
     80 
     81 #ifdef __cplusplus
     82 }    // extern "C"
     83 #endif
     84 
     85 #endif  // WEBP_ENC_COST_ENC_H_