1/* 2 * Copyright (c) 2011 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// Gaussian probability calculations internally used in vad_core.c. 12 13#ifndef WEBRTC_COMMON_AUDIO_VAD_VAD_GMM_H_ 14#define WEBRTC_COMMON_AUDIO_VAD_VAD_GMM_H_ 15 16#include "typedefs.h" 17 18// Calculates the probability for |input|, given that |input| comes from a 19// normal distribution with mean and standard deviation (|mean|, |std|). 20// 21// Inputs: 22// - input : input sample in Q4. 23// - mean : mean input in the statistical model, Q7. 24// - std : standard deviation, Q7. 25// 26// Output: 27// 28// - delta : input used when updating the model, Q11. 29// |delta| = (|input| - |mean|) / |std|^2. 30// 31// Return: 32// (probability for |input|) = 33// 1 / |std| * exp(-(|input| - |mean|)^2 / (2 * |std|^2)); 34int32_t WebRtcVad_GaussianProbability(int16_t input, 35 int16_t mean, 36 int16_t std, 37 int16_t* delta); 38 39#endif // WEBRTC_COMMON_AUDIO_VAD_VAD_GMM_H_ 40