andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 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 | |
pbos@webrtc.org | abf0cd8 | 2013-05-27 09:49:58 +0000 | [diff] [blame] | 17 | #include "webrtc/common_audio/vad/vad_core.h" |
| 18 | #include "webrtc/typedefs.h" |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 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). |
andrew@webrtc.org | c2e6438 | 2014-04-30 16:44:13 +0000 | [diff] [blame] | 33 | void WebRtcVad_Downsampling(const int16_t* signal_in, |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 34 | int16_t* signal_out, |
| 35 | int32_t* filter_state, |
| 36 | int 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_ |