57 lines
1.5 KiB
C++
57 lines
1.5 KiB
C++
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/*
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* Copyright (c) 2017 The WebRTC 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 "modules/audio_processing/aec3/aec3_common.h"
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#include <stdint.h>
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#include "rtc_base/checks.h"
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#include "rtc_base/system/arch.h"
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#include "system_wrappers/include/cpu_features_wrapper.h"
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namespace webrtc {
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Aec3Optimization DetectOptimization() {
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#if defined(WEBRTC_ARCH_X86_FAMILY)
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if (WebRtc_GetCPUInfo(kSSE2) != 0) {
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return Aec3Optimization::kSse2;
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}
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#endif
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#if defined(WEBRTC_HAS_NEON)
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return Aec3Optimization::kNeon;
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#endif
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return Aec3Optimization::kNone;
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}
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float FastApproxLog2f(const float in) {
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RTC_DCHECK_GT(in, .0f);
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// Read and interpret float as uint32_t and then cast to float.
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// This is done to extract the exponent (bits 30 - 23).
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// "Right shift" of the exponent is then performed by multiplying
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// with the constant (1/2^23). Finally, we subtract a constant to
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// remove the bias (https://en.wikipedia.org/wiki/Exponent_bias).
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union {
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float dummy;
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uint32_t a;
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} x = {in};
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float out = x.a;
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out *= 1.1920929e-7f; // 1/2^23
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out -= 126.942695f; // Remove bias.
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return out;
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}
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float Log2TodB(const float in_log2) {
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return 3.0102999566398121 * in_log2;
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}
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} // namespace webrtc
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