aom/vpx_dsp/prob.h

102 строки
3.2 KiB
C

/*
* Copyright (c) 2013 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef VPX_DSP_PROB_H_
#define VPX_DSP_PROB_H_
#include "./vpx_config.h"
#include "./vpx_dsp_common.h"
#include "vpx_ports/mem.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef uint8_t vpx_prob;
#define MAX_PROB 255
#define vpx_prob_half ((vpx_prob)128)
typedef int8_t vpx_tree_index;
#define TREE_SIZE(leaf_count) (2 * (leaf_count)-2)
#define vpx_complement(x) (255 - x)
#define MODE_MV_COUNT_SAT 20
/* We build coding trees compactly in arrays.
Each node of the tree is a pair of vpx_tree_indices.
Array index often references a corresponding probability table.
Index <= 0 means done encoding/decoding and value = -Index,
Index > 0 means need another bit, specification at index.
Nonnegative indices are always even; processing begins at node 0. */
typedef const vpx_tree_index vpx_tree[];
static INLINE vpx_prob clip_prob(int p) {
return (p > 255) ? 255 : (p < 1) ? 1 : p;
}
static INLINE vpx_prob get_prob(int num, int den) {
return (den == 0) ? 128u : clip_prob(((int64_t)num * 256 + (den >> 1)) / den);
}
static INLINE vpx_prob get_binary_prob(int n0, int n1) {
return get_prob(n0, n0 + n1);
}
/* This function assumes prob1 and prob2 are already within [1,255] range. */
static INLINE vpx_prob weighted_prob(int prob1, int prob2, int factor) {
return ROUND_POWER_OF_TWO(prob1 * (256 - factor) + prob2 * factor, 8);
}
static INLINE vpx_prob merge_probs(vpx_prob pre_prob, const unsigned int ct[2],
unsigned int count_sat,
unsigned int max_update_factor) {
const vpx_prob prob = get_binary_prob(ct[0], ct[1]);
const unsigned int count = VPXMIN(ct[0] + ct[1], count_sat);
const unsigned int factor = max_update_factor * count / count_sat;
return weighted_prob(pre_prob, prob, factor);
}
// MODE_MV_MAX_UPDATE_FACTOR (128) * count / MODE_MV_COUNT_SAT;
static const int count_to_update_factor[MODE_MV_COUNT_SAT + 1] = {
0, 6, 12, 19, 25, 32, 38, 44, 51, 57, 64,
70, 76, 83, 89, 96, 102, 108, 115, 121, 128
};
static INLINE vpx_prob mode_mv_merge_probs(vpx_prob pre_prob,
const unsigned int ct[2]) {
const unsigned int den = ct[0] + ct[1];
if (den == 0) {
return pre_prob;
} else {
const unsigned int count = VPXMIN(den, MODE_MV_COUNT_SAT);
const unsigned int factor = count_to_update_factor[count];
const vpx_prob prob =
clip_prob(((int64_t)(ct[0]) * 256 + (den >> 1)) / den);
return weighted_prob(pre_prob, prob, factor);
}
}
void vpx_tree_merge_probs(const vpx_tree_index *tree, const vpx_prob *pre_probs,
const unsigned int *counts, vpx_prob *probs);
DECLARE_ALIGNED(16, extern const uint8_t, vpx_norm[256]);
#ifdef __cplusplus
} // extern "C"
#endif
#endif // VPX_DSP_PROB_H_