Getting started with sound (audio) in React Native
By: Maciej Matuszewski
Tags: Expo, React, React Native, Music, Native

React Native is getting more and more popular, however there are still areas that it doesn’t handle that well. I love sound, and everything it comes with, so naturally I wanted to play around, and check how React Native handles recording and playing sound.

Playing sound

It isn’t obvious! At the time of writing (v. 0.52-rc), there is nothing about playback support or recording in the react-native docs. Fortunately, the open-source community never sleeps! There are many libraries that add those functionalities, but I focused on the ones that are the most popular and are widely used.

It was the first library I started to play around with. It seems really simple, has a small API and a good support for all the things one would like to do with sound (volume control, pausing, playing, setting time etc.). The great thing about this library is that it even supports playing sounds from the network. This option is not well documented, but to use it, we have to pass null as the second parameter, while creating a Sound instance. It looks something like this:

The only downside is that it looks like the project is not being actively maintained, and there are 20 open pull-requests. Other than that I didn’t have any bigger problems with it so far.

This may seem like a weird choice but it isn’t. React-native-video is meant mostly for video playback, but as it turns out, a lot of people use it just to control sound.

This project has a bigger community behind it, and there are some functionalities that are not yet available or are not well supported in react-native-sound, like playing sounds in the background or access to events like onProgress, onLoadStart, onLoad, onPlay and others.

In this case, authors wanted to create something that is a bit more similar to HTML5 video specification. It works perfectly good with audio as well, since those two APIs are similar by design.

Recording sound

Recording is also not supported by default yet. Fortunately, there is a library called react-native-audio, that helps with that. The API is really simple. It basically allows just to start/stop recording, and specify where and how do we want to save our recording. There is no player that comes with this library, which means that probably you will need one of the above, to play recorded sounds.

This library allows us to control Sample Rate, Audio Quality, Channels, Audio Encoding, Metering (iOS only) and Audio Encoding Bit Rate (Android only). All the available encodings are listed in the react-native-audio documentation.

What about Expo?

When developing with Expo, there is support for playing and recording sound, by default. Personally, I didn’t try it out, but the API seems well documented and simple. All the information on how to use it is available in the Expo SDK documentation.

A thing to remember…

Because those libraries are using features that need permissions, e.g. microphone, there will be a need to edit platform specific files, like Info.plist and AndroidManifest.xml. Usually, library authors also remind about that in libs readme and provide a basic instructions on how to do it.