vad_sp.h (2088B)
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 // This file includes specific signal processing tools used in vad_core.c. 12 13 #ifndef COMMON_AUDIO_VAD_VAD_SP_H_ 14 #define COMMON_AUDIO_VAD_VAD_SP_H_ 15 16 #include <stddef.h> 17 #include <stdint.h> 18 19 #include "common_audio/vad/vad_core.h" 20 21 // Downsamples the signal by a factor 2, eg. 32->16 or 16->8. 22 // 23 // Inputs: 24 // - signal_in : Input signal. 25 // - in_length : Length of input signal in samples. 26 // 27 // Input & Output: 28 // - filter_state : Current filter states of the two all-pass filters. The 29 // `filter_state` is updated after all samples have been 30 // processed. 31 // 32 // Output: 33 // - signal_out : Downsampled signal (of length `in_length` / 2). 34 void WebRtcVad_Downsampling(const int16_t* signal_in, 35 int16_t* signal_out, 36 int32_t* filter_state, 37 size_t in_length); 38 39 // Updates and returns the smoothed feature minimum. As minimum we use the 40 // median of the five smallest feature values in a 100 frames long window. 41 // As long as `handle->frame_counter` is zero, that is, we haven't received any 42 // "valid" data, FindMinimum() outputs the default value of 1600. 43 // 44 // Inputs: 45 // - feature_value : New feature value to update with. 46 // - channel : Channel number. 47 // 48 // Input & Output: 49 // - handle : State information of the VAD. 50 // 51 // Returns: 52 // : Smoothed minimum value for a moving window. 53 int16_t WebRtcVad_FindMinimum(VadInstT* handle, 54 int16_t feature_value, 55 int channel); 56 57 #endif // COMMON_AUDIO_VAD_VAD_SP_H_