51 lines
1.8 KiB
C
51 lines
1.8 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_AV1_ENCODER_COST_H_
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#define AOM_AV1_ENCODER_COST_H_
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#include "aom_dsp/prob.h"
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#include "aom/aom_integer.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern const uint16_t av1_prob_cost[128];
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// The factor to scale from cost in bits to cost in av1_prob_cost units.
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#define AV1_PROB_COST_SHIFT 9
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// Cost of coding an n bit literal, using 128 (i.e. 50%) probability
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// for each bit.
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#define av1_cost_literal(n) ((n) * (1 << AV1_PROB_COST_SHIFT))
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// Calculate the cost of a symbol with probability p15 / 2^15
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static inline int av1_cost_symbol(aom_cdf_prob p15) {
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// p15 can be out of range [1, CDF_PROB_TOP - 1]. Clamping it, so that the
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// following cost calculation works correctly. Otherwise, if p15 =
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// CDF_PROB_TOP, shift would be -1, and "p15 << shift" would be wrong.
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p15 = (aom_cdf_prob)clamp(p15, 1, CDF_PROB_TOP - 1);
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assert(0 < p15 && p15 < CDF_PROB_TOP);
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const int shift = CDF_PROB_BITS - 1 - get_msb(p15);
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const int prob = get_prob(p15 << shift, CDF_PROB_TOP);
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assert(prob >= 128);
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return av1_prob_cost[prob - 128] + av1_cost_literal(shift);
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}
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void av1_cost_tokens_from_cdf(int *costs, const aom_cdf_prob *cdf,
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const int *inv_map);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // AOM_AV1_ENCODER_COST_H_
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