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 12 /* 13 * This header file includes the VAD internal calls for Downsampling and FindMinimum. 14 * Specific function calls are given below. 15 */ 16 17 #ifndef WEBRTC_VAD_SP_H_ 18 #define WEBRTC_VAD_SP_H_ 19 20 #include "vad_core.h" 21 22 /**************************************************************************** 23 * WebRtcVad_Downsampling(...) 24 * 25 * Downsamples the signal a factor 2, eg. 32->16 or 16->8 26 * 27 * Input: 28 * - signal_in : Input signal 29 * - in_length : Length of input signal in samples 30 * 31 * Input & Output: 32 * - filter_state : Filter state for first all-pass filters 33 * 34 * Output: 35 * - signal_out : Downsampled signal (of length len/2) 36 */ 37 void WebRtcVad_Downsampling(WebRtc_Word16* signal_in, 38 WebRtc_Word16* signal_out, 39 WebRtc_Word32* filter_state, 40 int in_length); 41 42 /**************************************************************************** 43 * WebRtcVad_FindMinimum(...) 44 * 45 * Find the five lowest values of x in 100 frames long window. Return a mean 46 * value of these five values. 47 * 48 * Input: 49 * - feature_value : Feature value 50 * - channel : Channel number 51 * 52 * Input & Output: 53 * - inst : State information 54 * 55 * Output: 56 * return value : Weighted minimum value for a moving window. 57 */ 58 WebRtc_Word16 WebRtcVad_FindMinimum(VadInstT* inst, WebRtc_Word16 feature_value, int channel); 59 60 #endif // WEBRTC_VAD_SP_H_ 61
