A package to dynamically measure sound input level in React Native applications. Can be used to help user to adjust microphone sensitivity.

Installation

Install the npm package and link it to your project:

npm i react-native-sound-level --save

On iOS you need to add a usage description to Info.plist:

<key>NSMicrophoneUsageDescription</key>
<string>This sample uses the microphone to analyze sound level.</string>

On Android you need to add a permission to AndroidManifest.xml:

<uses-permission android:name="android.permission.RECORD_AUDIO" />

Manual installation on iOS

In XCode, in the project navigator:

* Right click _Libraries_
* Add Files to _[your project's name]_
* Go to `node_modules/react-native-sound-level`
* Add the `.xcodeproj` file

In XCode, in the project navigator, select your project.

* Add the `libRNSoundLevel.a` from the _soundlevel_ project to your project's _Build Phases ➜ Link Binary With Libraries_

Installation on Ubuntu

1. Add to package.json: "desktopExternalModules": [ "node_modules/react-native-sound-level/desktop" ]
2. You may need to make QT's multimedia library accessible for linker sudo ln -s $YOUR_QT_DIR/5.9.1/gcc_64/lib/libQt5Multimedia.so /usr/local/lib/libQt5Multimedia.so

React Native 0.60+

To make it run correctly on iOS you may need the following:

1. Add pod 'react-native-sound-level', :podspec => '../node_modules/react-native-sound-level/RNSoundLevel.podspec' to your ios/Podfile file.
2. Unlink the library if linked before (react-native unlink react-native-sound-level).
3. Run pod install from within your project ios directory

Usage

1. Request permission to access microphone, handle the UI by yourself. You may use react-native-permissions package or simply PermissionsAndroid module.
2. Configure the monitor and start it.
3. Makes sense to stop it when not used.

import RNSoundLevel from 'react-native-sound-level'

const MONITOR_INTERVAL = 250 // in ms

const requestPermission = async () => {
  // request permission to access microphone
  // ...
  if (success) {
    // start monitoring
    RNSoundLevel.start()
    
    // you may also specify a monitor interval (default is 250ms)
    RNSoundLevel.start(MONITOR_INTERVAL)
    
    // or add even more options
    RNSoundLevel.start({
      monitorInterval: MONITOR_INTERVAL,
      samplingRate: 16000, // default is 22050
    })
  }
}

useEffect(() => {
  RNSoundLevel.onNewFrame = (data) => {
    // see "Returned data" section below
    console.log('Sound level info', data)
  }
  
  return () => {
    // don't forget to stop it
    RNSoundLevel.stop()
  }
}, [])

Returned data

{
  "id",             // frame number
  "value",          // sound level in decibels, -160 is a silence level
  "rawValue"        // raw level value, OS-dependent
}