70 строки
2.1 KiB
C
70 строки
2.1 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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#include "vp9/common/vp9_seg_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 8
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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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// A "real" q of 1.0 forces lossless mode.
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// In practice non lossless Q's between 1.0 and 2.0 (represented here by
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// integer values from 5-7 give poor rd results (lower psnr and often
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// larger size than the lossless encode. To block out those "not very useful"
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// values we increment the ac and dc q lookup values by 4 after position 0.
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ac_qlookup[0] = val;
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dc_qlookup[0] = val;
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val += 4;
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for (i = 1; i < QINDEX_RANGE; i++) {
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const int ac_val = val;
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val = (int)(val * 1.01975);
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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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int vp9_get_qindex(MACROBLOCKD *xd, int segment_id, int base_qindex) {
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if (vp9_segfeature_active(xd, segment_id, SEG_LVL_ALT_Q)) {
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const int data = vp9_get_segdata(xd, segment_id, SEG_LVL_ALT_Q);
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return xd->mb_segment_abs_delta == SEGMENT_ABSDATA ?
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data : // Abs value
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clamp(base_qindex + data, 0, MAXQ); // Delta value
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} else {
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return base_qindex;
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}
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}
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