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 // This file includes specific signal processing tools used in vad_core.c. 13 14 #ifndef WEBRTC_COMMON_AUDIO_VAD_VAD_SP_H_ 15 #define WEBRTC_COMMON_AUDIO_VAD_VAD_SP_H_ 16 17 #include "webrtc/common_audio/vad/vad_core.h" 18 #include "webrtc/typedefs.h" 19 20 // Downsamples the signal by a factor 2, eg. 32->16 or 16->8. 21 // 22 // Inputs: 23 // - signal_in : Input signal. 24 // - in_length : Length of input signal in samples. 25 // 26 // Input & Output: 27 // - filter_state : Current filter states of the two all-pass filters. The 28 // |filter_state| is updated after all samples have been 29 // processed. 30 // 31 // Output: 32 // - signal_out : Downsampled signal (of length |in_length| / 2). 33 void WebRtcVad_Downsampling(const int16_t* signal_in, 34 int16_t* signal_out, 35 int32_t* filter_state, 36 size_t in_length); 37 38 // Updates and returns the smoothed feature minimum. As minimum we use the 39 // median of the five smallest feature values in a 100 frames long window. 40 // As long as |handle->frame_counter| is zero, that is, we haven't received any 41 // "valid" data, FindMinimum() outputs the default value of 1600. 42 // 43 // Inputs: 44 // - feature_value : New feature value to update with. 45 // - channel : Channel number. 46 // 47 // Input & Output: 48 // - handle : State information of the VAD. 49 // 50 // Returns: 51 // : Smoothed minimum value for a moving window. 52 int16_t WebRtcVad_FindMinimum(VadInstT* handle, 53 int16_t feature_value, 54 int channel); 55 56 #endif // WEBRTC_COMMON_AUDIO_VAD_VAD_SP_H_ 57