aec3_common.cc (1651B)
1 /* 2 * Copyright (c) 2017 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "modules/audio_processing/aec3/aec3_common.h" 12 13 #include <cstdint> 14 15 #include "rtc_base/checks.h" 16 #include "rtc_base/cpu_info.h" 17 #include "rtc_base/system/arch.h" 18 19 namespace webrtc { 20 21 Aec3Optimization DetectOptimization() { 22 #if defined(WEBRTC_ARCH_X86_FAMILY) 23 if (cpu_info::Supports(cpu_info::ISA::kAVX2)) { 24 return Aec3Optimization::kAvx2; 25 } else if (cpu_info::Supports(cpu_info::ISA::kSSE2)) { 26 return Aec3Optimization::kSse2; 27 } 28 #endif 29 30 #if defined(WEBRTC_HAS_NEON) 31 return Aec3Optimization::kNeon; 32 #else 33 return Aec3Optimization::kNone; 34 #endif 35 } 36 37 float FastApproxLog2f(const float in) { 38 RTC_DCHECK_GT(in, .0f); 39 // Read and interpret float as uint32_t and then cast to float. 40 // This is done to extract the exponent (bits 30 - 23). 41 // "Right shift" of the exponent is then performed by multiplying 42 // with the constant (1/2^23). Finally, we subtract a constant to 43 // remove the bias (https://en.wikipedia.org/wiki/Exponent_bias). 44 union { 45 float dummy; 46 uint32_t a; 47 } x = {in}; 48 float out = x.a; 49 out *= 1.1920929e-7f; // 1/2^23 50 out -= 126.942695f; // Remove bias. 51 return out; 52 } 53 54 float Log2TodB(const float in_log2) { 55 return 3.0102999566398121 * in_log2; 56 } 57 58 } // namespace webrtc