47 lines
1.3 KiB
C
47 lines
1.3 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "vp9/common/vp9_common.h"
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#include "vp9/common/vp9_quant_common.h"
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static int16_t dc_qlookup[QINDEX_RANGE];
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static int16_t ac_qlookup[QINDEX_RANGE];
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#define ACDC_MIN 4
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// TODO(dkovalev) move to common and reuse
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static double poly3(double a, double b, double c, double d, double x) {
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return a*x*x*x + b*x*x + c*x + d;
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}
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void vp9_init_quant_tables() {
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int i, val = 4;
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for (i = 0; i < QINDEX_RANGE; i++) {
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const int ac_val = val;
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val = (int)(val * 1.02);
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if (val == ac_val)
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++val;
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ac_qlookup[i] = (int16_t)ac_val;
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dc_qlookup[i] = (int16_t)MAX(ACDC_MIN, poly3(0.000000305, -0.00065, 0.9,
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0.5, ac_val));
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}
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}
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int16_t vp9_dc_quant(int qindex, int delta) {
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return dc_qlookup[clamp(qindex + delta, 0, MAXQ)];
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}
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int16_t vp9_ac_quant(int qindex, int delta) {
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return ac_qlookup[clamp(qindex + delta, 0, MAXQ)];
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}
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