| /* |
| * Copyright (c) 2011 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. |
| */ |
| |
| |
| // This file includes specific signal processing tools used in vad_core.c. |
| |
| #ifndef WEBRTC_COMMON_AUDIO_VAD_VAD_SP_H_ |
| #define WEBRTC_COMMON_AUDIO_VAD_VAD_SP_H_ |
| |
| #include "typedefs.h" |
| #include "vad_core.h" |
| |
| // Downsamples the signal by a factor 2, eg. 32->16 or 16->8. |
| // |
| // Inputs: |
| // - signal_in : Input signal. |
| // - in_length : Length of input signal in samples. |
| // |
| // Input & Output: |
| // - filter_state : Current filter states of the two all-pass filters. The |
| // |filter_state| is updated after all samples have been |
| // processed. |
| // |
| // Output: |
| // - signal_out : Downsampled signal (of length |in_length| / 2). |
| void WebRtcVad_Downsampling(int16_t* signal_in, |
| int16_t* signal_out, |
| int32_t* filter_state, |
| int in_length); |
| |
| // Updates and returns the smoothed feature minimum. As minimum we use the |
| // median of the five smallest feature values in a 100 frames long window. |
| // As long as |handle->frame_counter| is zero, that is, we haven't received any |
| // "valid" data, FindMinimum() outputs the default value of 1600. |
| // |
| // Inputs: |
| // - feature_value : New feature value to update with. |
| // - channel : Channel number. |
| // |
| // Input & Output: |
| // - handle : State information of the VAD. |
| // |
| // Returns: |
| // : Smoothed minimum value for a moving window. |
| int16_t WebRtcVad_FindMinimum(VadInstT* handle, |
| int16_t feature_value, |
| int channel); |
| |
| #endif // WEBRTC_COMMON_AUDIO_VAD_VAD_SP_H_ |
