40 lines
1.4 KiB
C
40 lines
1.4 KiB
C
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/*
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* Copyright (c) 2011 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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// Gaussian probability calculations internally used in vad_core.c.
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#ifndef WEBRTC_COMMON_AUDIO_VAD_VAD_GMM_H_
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#define WEBRTC_COMMON_AUDIO_VAD_VAD_GMM_H_
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#include "webrtc/typedefs.h"
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// Calculates the probability for |input|, given that |input| comes from a
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// normal distribution with mean and standard deviation (|mean|, |std|).
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//
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// Inputs:
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// - input : input sample in Q4.
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// - mean : mean input in the statistical model, Q7.
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// - std : standard deviation, Q7.
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//
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// Output:
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//
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// - delta : input used when updating the model, Q11.
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// |delta| = (|input| - |mean|) / |std|^2.
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//
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// Return:
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// (probability for |input|) =
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// 1 / |std| * exp(-(|input| - |mean|)^2 / (2 * |std|^2));
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int32_t WebRtcVad_GaussianProbability(int16_t input,
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int16_t mean,
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int16_t std,
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int16_t* delta);
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#endif // WEBRTC_COMMON_AUDIO_VAD_VAD_GMM_H_
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