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 "webrtc/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)); 34 int32_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