Artem Titov 96315752d2 Use backticks not vertical bars to denote variables in comments for /common_audio
Bug: webrtc:12338
Change-Id: I884db28e6d9a87d343be7c2616571a8bee28252c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226944
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34568}
2021-07-27 18:21:35 +00:00

55 lines
2.0 KiB
C

/*
* 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 COMMON_AUDIO_VAD_VAD_SP_H_
#define COMMON_AUDIO_VAD_VAD_SP_H_
#include "common_audio/vad/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(const int16_t* signal_in,
int16_t* signal_out,
int32_t* filter_state,
size_t 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 // COMMON_AUDIO_VAD_VAD_SP_H_