144 lines
6.5 KiB
C
144 lines
6.5 KiB
C
/*
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* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
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*
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* This source code is subject to the terms of the BSD 2 Clause License and
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* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
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* was not distributed with this source code in the LICENSE file, you can
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* obtain it at www.aomedia.org/license/software. If the Alliance for Open
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* Media Patent License 1.0 was not distributed with this source code in the
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* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
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*/
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#ifndef AOM_AOM_DSP_PROB_H_
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#define AOM_AOM_DSP_PROB_H_
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#include <assert.h>
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#include <stdio.h>
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#include "config/aom_config.h"
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#include "aom_dsp/aom_dsp_common.h"
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#include "aom_dsp/entcode.h"
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#include "aom_ports/bitops.h"
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#include "aom_ports/mem.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef uint16_t aom_cdf_prob;
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#define CDF_SIZE(x) ((x) + 1)
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#define CDF_PROB_BITS 15
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#define CDF_PROB_TOP (1 << CDF_PROB_BITS)
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/*The value stored in an iCDF is CDF_PROB_TOP minus the actual cumulative
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probability (an "inverse" CDF).
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This function converts from one representation to the other (and is its own
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inverse).*/
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#define AOM_ICDF(x) (CDF_PROB_TOP - (x))
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#define AOM_CDF2(a0) AOM_ICDF(a0), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF3(a0, a1) AOM_ICDF(a0), AOM_ICDF(a1), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF4(a0, a1, a2) \
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AOM_ICDF(a0), AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF5(a0, a1, a2, a3) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF6(a0, a1, a2, a3, a4) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), \
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AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF7(a0, a1, a2, a3, a4, a5) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF8(a0, a1, a2, a3, a4, a5, a6) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF9(a0, a1, a2, a3, a4, a5, a6, a7) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF10(a0, a1, a2, a3, a4, a5, a6, a7, a8) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF11(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), \
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AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF12(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
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AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF13(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
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AOM_ICDF(a11), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF14(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
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AOM_ICDF(a11), AOM_ICDF(a12), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF15(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
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AOM_ICDF(a11), AOM_ICDF(a12), AOM_ICDF(a13), AOM_ICDF(CDF_PROB_TOP), 0
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#define AOM_CDF16(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, \
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a14) \
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AOM_ICDF(a0) \
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, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
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AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
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AOM_ICDF(a11), AOM_ICDF(a12), AOM_ICDF(a13), AOM_ICDF(a14), \
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AOM_ICDF(CDF_PROB_TOP), 0
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static inline uint8_t get_prob(unsigned int num, unsigned int den) {
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assert(den != 0);
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{
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const int p = (int)(((uint64_t)num * 256 + (den >> 1)) / den);
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// (p > 255) ? 255 : (p < 1) ? 1 : p;
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const int clipped_prob = p | ((255 - p) >> 23) | (p == 0);
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return (uint8_t)clipped_prob;
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}
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}
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static inline void update_cdf(aom_cdf_prob *cdf, int8_t val, int nsymbs) {
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assert(nsymbs < 17);
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const int count = cdf[nsymbs];
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// rate is computed in the spec as:
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// 3 + ( cdf[N] > 15 ) + ( cdf[N] > 31 ) + Min(FloorLog2(N), 2)
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// In this case cdf[N] is |count|.
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// Min(FloorLog2(N), 2) is 1 for nsymbs == {2, 3} and 2 for all
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// nsymbs > 3. So the equation becomes:
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// 4 + (count > 15) + (count > 31) + (nsymbs > 3).
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// Note that the largest value for count is 32 (it is not incremented beyond
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// 32). So using that information:
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// count >> 4 is 0 for count from 0 to 15.
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// count >> 4 is 1 for count from 16 to 31.
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// count >> 4 is 2 for count == 31.
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// Now, the equation becomes:
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// 4 + (count >> 4) + (nsymbs > 3).
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const int rate = 4 + (count >> 4) + (nsymbs > 3);
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int i = 0;
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do {
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if (i < val) {
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cdf[i] += (CDF_PROB_TOP - cdf[i]) >> rate;
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} else {
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cdf[i] -= cdf[i] >> rate;
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}
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} while (++i < nsymbs - 1);
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cdf[nsymbs] += (count < 32);
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}
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // AOM_AOM_DSP_PROB_H_
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