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 /* * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #ifndef MODULES_AUDIO_PROCESSING_VAD_GMM_H_ #define MODULES_AUDIO_PROCESSING_VAD_GMM_H_ namespace webrtc { // A structure that specifies a GMM. // A GMM is formulated as // f(x) = w * mixture + w * mixture + ... + // w[num_mixtures - 1] * mixture[num_mixtures - 1]; // Where a 'mixture' is a Gaussian density. struct GmmParameters { // weight[n] = log(w[n]) - `dimension`/2 * log(2*pi) - 1/2 * log(det(cov[n])); // where cov[n] is the covariance matrix of mixture n; const double* weight; // pointer to the first element of a `num_mixtures`x`dimension` matrix // where kth row is the mean of the kth mixture. const double* mean; // pointer to the first element of a `num_mixtures`x`dimension`x`dimension` // 3D-matrix, where the kth 2D-matrix is the inverse of the covariance // matrix of the kth mixture. const double* covar_inverse; // Dimensionality of the mixtures. int dimension; // number of the mixtures. int num_mixtures; }; // Evaluate the given GMM, according to `gmm_parameters`, at the given point // `x`. If the dimensionality of the given GMM is larger that the maximum // acceptable dimension by the following function -1 is returned. double EvaluateGmm(const double* x, const GmmParameters& gmm_parameters); } // namespace webrtc #endif // MODULES_AUDIO_PROCESSING_VAD_GMM_H_