Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
       3             :  *
       4             :  *  Use of this source code is governed by a BSD-style license
       5             :  *  that can be found in the LICENSE file in the root of the source
       6             :  *  tree. An additional intellectual property rights grant can be found
       7             :  *  in the file PATENTS.  All contributing project authors may
       8             :  *  be found in the AUTHORS file in the root of the source tree.
       9             :  */
      10             : 
      11             : #ifndef VPX_DSP_PROB_H_
      12             : #define VPX_DSP_PROB_H_
      13             : 
      14             : #include <assert.h>
      15             : 
      16             : #include "./vpx_config.h"
      17             : #include "./vpx_dsp_common.h"
      18             : 
      19             : #include "vpx_ports/mem.h"
      20             : 
      21             : #ifdef __cplusplus
      22             : extern "C" {
      23             : #endif
      24             : 
      25             : typedef uint8_t vpx_prob;
      26             : 
      27             : #define MAX_PROB 255
      28             : 
      29             : #define vpx_prob_half ((vpx_prob)128)
      30             : 
      31             : typedef int8_t vpx_tree_index;
      32             : 
      33             : #define TREE_SIZE(leaf_count) (2 * (leaf_count)-2)
      34             : 
      35             : #define vpx_complement(x) (255 - x)
      36             : 
      37             : #define MODE_MV_COUNT_SAT 20
      38             : 
      39             : /* We build coding trees compactly in arrays.
      40             :    Each node of the tree is a pair of vpx_tree_indices.
      41             :    Array index often references a corresponding probability table.
      42             :    Index <= 0 means done encoding/decoding and value = -Index,
      43             :    Index > 0 means need another bit, specification at index.
      44             :    Nonnegative indices are always even;  processing begins at node 0. */
      45             : 
      46             : typedef const vpx_tree_index vpx_tree[];
      47             : 
      48           0 : static INLINE vpx_prob get_prob(unsigned int num, unsigned int den) {
      49           0 :   assert(den != 0);
      50             :   {
      51           0 :     const int p = (int)(((int64_t)num * 256 + (den >> 1)) / den);
      52             :     // (p > 255) ? 255 : (p < 1) ? 1 : p;
      53           0 :     const int clipped_prob = p | ((255 - p) >> 23) | (p == 0);
      54           0 :     return (vpx_prob)clipped_prob;
      55             :   }
      56             : }
      57             : 
      58           0 : static INLINE vpx_prob get_binary_prob(unsigned int n0, unsigned int n1) {
      59           0 :   const unsigned int den = n0 + n1;
      60           0 :   if (den == 0) return 128u;
      61           0 :   return get_prob(n0, den);
      62             : }
      63             : 
      64             : /* This function assumes prob1 and prob2 are already within [1,255] range. */
      65           0 : static INLINE vpx_prob weighted_prob(int prob1, int prob2, int factor) {
      66           0 :   return ROUND_POWER_OF_TWO(prob1 * (256 - factor) + prob2 * factor, 8);
      67             : }
      68             : 
      69           0 : static INLINE vpx_prob merge_probs(vpx_prob pre_prob, const unsigned int ct[2],
      70             :                                    unsigned int count_sat,
      71             :                                    unsigned int max_update_factor) {
      72           0 :   const vpx_prob prob = get_binary_prob(ct[0], ct[1]);
      73           0 :   const unsigned int count = VPXMIN(ct[0] + ct[1], count_sat);
      74           0 :   const unsigned int factor = max_update_factor * count / count_sat;
      75           0 :   return weighted_prob(pre_prob, prob, factor);
      76             : }
      77             : 
      78             : // MODE_MV_MAX_UPDATE_FACTOR (128) * count / MODE_MV_COUNT_SAT;
      79             : static const int count_to_update_factor[MODE_MV_COUNT_SAT + 1] = {
      80             :   0,  6,  12, 19, 25, 32,  38,  44,  51,  57, 64,
      81             :   70, 76, 83, 89, 96, 102, 108, 115, 121, 128
      82             : };
      83             : 
      84           0 : static INLINE vpx_prob mode_mv_merge_probs(vpx_prob pre_prob,
      85             :                                            const unsigned int ct[2]) {
      86           0 :   const unsigned int den = ct[0] + ct[1];
      87           0 :   if (den == 0) {
      88           0 :     return pre_prob;
      89             :   } else {
      90           0 :     const unsigned int count = VPXMIN(den, MODE_MV_COUNT_SAT);
      91           0 :     const unsigned int factor = count_to_update_factor[count];
      92           0 :     const vpx_prob prob = get_prob(ct[0], den);
      93           0 :     return weighted_prob(pre_prob, prob, factor);
      94             :   }
      95             : }
      96             : 
      97             : void vpx_tree_merge_probs(const vpx_tree_index *tree, const vpx_prob *pre_probs,
      98             :                           const unsigned int *counts, vpx_prob *probs);
      99             : 
     100             : DECLARE_ALIGNED(16, extern const uint8_t, vpx_norm[256]);
     101             : 
     102             : #ifdef __cplusplus
     103             : }  // extern "C"
     104             : #endif
     105             : 
     106             : #endif  // VPX_DSP_PROB_H_