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 #include "src/enc/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.
VP8RecordStats(int bit,proba_t * const stats)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'.
VP8BitCost(int bit,uint8_t 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);
VP8LevelCost(const uint16_t * const table,int level)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_ENC_H_
83