Javascript Audio Room Tutorial

This tutorial will teach you how to build an audio room experience like Twitter Spaces or Clubhouse. The end result will look like the image below and will support the following features:

• Backstage mode. You can start the call with your co-hosts and chat a bit before going live
• Calls run on Stream's global edge network for optimal latency and scalability
• There is no cap to how many listeners you can have in a room
• Listeners can raise their hand, and be invited to speak by the host
• Audio tracks are sent multiple times for optimal reliability

Time to get started building an audio-room for your app.

For this tutorial, you'll need a few tools to be installed on your device. You can skip this step in case you already have them installed.

• Node.js (version 18 or higher)
• Yarn (version 1.22 or higher)

In this step, we will create a new web application using the Vite CLI, and install Stream's Video SDK. We recommend using Vite because its fast and easy to use.

Open up src/main.ts and replace it with this code:

Let's review the example above and go over the details.

First, we create a user object. You typically sync your users via a server side integration from your own backend. Alternatively, you can also use guest or anonymous users.

Next, we initialize the client by passing the API Key, user and user token.

After the user and client are created, we create a call like this:

• This enables the microphone before joining the call
• Then joins and creates a call with the type: audio_room and the specified callId
• The users with id john_smith and jane_doe are added as members to the call
• And we set the title and description custom field on the call object

To actually run this sample we need a valid user token. The user token is typically generated by your server side API. When a user logs in to your app you return the user token that gives them access to the call. To make this tutorial easier to follow, we'll generate a user token for you:

Please update REPLACE_WITH_API_KEY, REPLACE_WITH_USER_ID, REPLACE_WITH_TOKEN and REPLACE_WITH_CALL_ID with the actual values shown below:

With valid credentials in place, we can join the call.

In this next step, we'll add:

• Room title and description
• Controls to toggle live mode on/off
• A list of participants with their speaking status

Copy the following code to the index.html file:

For filling in the data, we take the state of the call by observing call.state observables. Read more about it: Call & Participant State.

Now, let's add the following code to the bottom of src/main.ts:

To make this a little more interactive, let's join the audio room from the browser.

As you probably noticed by opening the same room from the browser, audio rooms by default are not live. Regular users can only join an audio room when it is in live mode. Let's expand the Controls Panel and add a button that controls the backstage of the room.

While we're at it, let's also add a button that allows to mute/unmute the local audio track:

Now the app exposes a mic control button and a button that allows to toggle live mode on/off. If you try the web demo of the audio room, you should be able to join as a regular user.

As a next step, let's render the actual list of participants and show an indicator when they are speaking.

With these changes, things get more interesting, the app is now showing a list of all participants connected to the call and displays a (speaking) suffix to the ones that are speaking.

However, you might have noticed that you can't hear the audio from the browser. To enable this, you need to render an audio element for every participant and provide it to our SDK, so it can bind the appropriate audio track to it. Let's update our participant list rendering code:

If you now join the call from the browser you will see that the participant list updates as you open/close the browser tab.

Background noise in an audio session is never a pleasant experience for the listeners and the speaker.

Our SDK provides a plugin that helps to greatly reduce the unwanted noise caught by your microphone. Read more on how to enable it here.

Requesting permission to speak is quite straight forward. Let's first have a quick look at how the SDK call object exposes this:

Permission requests are delivered to the call object in the form of an event one can subscribe to:

Let's add another view that shows the incoming permission requests as well as the buttons to grant / reject it.

We start by updating the index.html file:

Next, let's add the code to render and update the permission requests:

It is common for audio rooms and similar interactive audio/video experiences to show users in separate groups. Let's see how we can update this application to render participants in two separate sections: Speakers and Listeners.

Building custom layout is straight forward. All we need to do is to apply some filtering to the result of call.state.participants$ observable.

Lets update our Participant Panel section:

Now, let's update the code accordingly:

With these changes applied, the app now renders participants in two separate groups: Speakers and Listeners.

There are a few more exciting features that you can use to build audio rooms

• Query Calls: You can query calls to easily show upcoming calls, calls that recently finished as well as call previews.
• Reactions & Custom events: Reactions and custom events are supported.
• Recording & Broadcasting: You can record and broadcast your calls.
• Chat: Stream's Chat SDKs are fully featured and you can integrate them in the call
• Moderation: Moderation capabilities are built-in to the product
• Transcriptions: Transcriptions aren't available yet, but they are due to launch soon

It was fun to see just how quickly you can build an audio-room for your app. Please do let us know if you ran into any issues. Our team is also happy to review your UI designs and offer recommendations on how to achieve it with Stream.

To recap what we've learned:

• You set up a call with const call = client.call('audio_room', '123')
• The call type audio_room controls which features are enabled and how permissions are set up
• The audio_room by default enables backstage mode, and only allows admins and the creator of the call to join before the call goes live
• When you join a call, realtime communication is set up for audio: await call.join()
• Call state call.state the exposed observables make it easy to build your own UI
• For audio rooms, we use Opus RED and Opus DTX for optimal audio quality.

We've used Stream's Audio Rooms API, which means calls run on a global edge network of video servers. By being closer to your users the latency and reliability of calls are better. The JavaScript Video SDK enables you to build in-app video calling, audio rooms and livestreaming in days.

We hope you've enjoyed this tutorial and please do feel free to reach out if you have any suggestions or questions. You can find the code and the stylesheet for this tutorial in this CodeSandbox.

The source code for the companion audio room app, together with all of its features, is available on GitHub.

Final Thoughts

In this video app tutorial we built a fully functioning iOS messaging app with our iOS SDK component library. We also showed how easy it is to customize the behavior and the style of the iOS video app components with minimal code changes.

Both the video SDK for Javascript and the API have plenty more features available to support more advanced use-cases.

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