Speech Enhancement Guide

Overview

webOS Open Source Edition (OSE) provides speech enhancement feature (noise reduction and echo cancellation). This section describes how to enable or disable the speech enhancement feature during VoIP call (voice/video call).

The speech enhancement is built as a module of the PulseAudio. An audioEffectManager is included in AudioD to control audio effects.

Terminology

AudioD

Audio component, which controls the audio in webOS. It deals with audio routing, volume, etc.

PulseAudio

The PulseAudio is an open-source sound server that does signal processing, resampling, and audio data playback using the Advanced Linux Sound Architecture (ALSA). For more details on the PulseAudio, visit the PulseAudio official page.

audioEffectManager

Manager module that receives luna service API and manages audio effects.

APIs and Methods

com.webos.service.audio provides 3 kinds of methods to use the speech enhancement as below.

• getAudioEffectList
• setAudioEffectList
• checkAudioEffectStatus

The getAudioEffectList method lists all the supported audio effects. The setAudioEffectList method sets the status of an audio effect. The checkAudioEffectStatus method shows the status of an audio effect, whether is enabled or not enabled.

How to use

You can simply apply echo cancellation and noise reduction to audio input from a microphone by enabling speech enhancement audio effect using the setAudioEffect method.

1. Get audio effect list.

   webOS OSE returns a list of available audio effects. We plan to provide various audio effects in the future.

   luna-send -f -n 1 luna://com.webos.service.audio/getAudioEffectList '{}'
   
   Response:
   
   {
       "returnValue" : true
       "audioEffectList": [
           "speech enhancement"
       ]
   }
   

2. Check audio effect Status.

   Before you enable audio effect, you would check the current audio effect status.

   luna-send -f -n 1 luna://com.webos.service.audio/checkAudioEffectStatus '{"effectName":"speech enhancement"}'
   
   Response:
   {
       "returnValue": true,
       "enabled": true
   }
   

3. Set audio effect.

   You can start or stop the speech enhancement by setting the enabled property of setAudioEffect method to true or false.

   To enable the speech enhancement,

   luna-send -f -n 1 luna://com.webos.service.audio/setAudioEffect '{"effectName":"speech enhancement", "enabled":true}'
   
   Response:
   {
       "returnValue": true
   }
   

   To disable the speech enhancement,

   luna-send -f -n 1 luna://com.webos.service.audio/setAudioEffect '{"effectName":"speech enhancement", "enabled":false}'
   
   Response:
   {
       "returnValue": true
   }