Audio in Web

This page only provides information about audio capabilities in the Web platform. To learn how to use audio in your Unity project, refer to Audio Overview.

Because Unity uses FMODAudio in Unity is built on top of a middleware called FMOD. FMOD is integrated with the Unity engine for creating and playing back interactive audio.
See in Glossary to manage audio for platforms, the Web platform supports limited audio functionality, which only includes the basic features. FMOD relies on threads, which the WebGLA JavaScript API that renders 2D and 3D graphics in a web browser. The Unity Web build option allows Unity to publish content as JavaScript programs which use HTML5 technologies and the WebGL rendering API to run Unity content in a web browser. More info
See in Glossary API doesn’t support. For this reason, Unity uses an implementation based on the internal Web Audio API, which enables the browser to handle audio playback and mixing.

Note: Google Chrome’s new Autoplay policy prevents autoplay of audio and video under certain conditions. For example, while your game might be set to autoplay some background music soon after the game loads, it won’t play automatically unless you click or tap on the website. For more information on how to enable or disable this policy, refer to Google Chrome’s documentation on Autoplay policy in Chrome.

Supported classes

Unity Web supports the following API classes:

AudioSource

The AudioSource API supports basic positional audio playback, including:

• Pausing and resuming
• Rolloff
• Pitch setting
• Doppler effect support

Unity WebGL supports the following AudioSource APIs:

Note: Because audio data is decoded in the browser with decodeAudioData, it is possible that the runtime sampling rate of the audio file is different from the serialized audio data (44100Hz) as the browser will match the BaseAudioContext sampling rate, generally aligned with the device audio driver setup. Considering this, we recommend validating the AudioClip.frequency value at runtime or using AudioSource.time when performing seeking operations.

AudioClip

Unity WebGL imports AudioClip files in the AAC Format, which is supported by most browsers. Unity WebGL supports the following AudioClip APIs:

Note: For audio clip support on Linux, make sure you’ve installed the ffmpeg package.

Audio Mixer

Unity Web supports some functionality of Audio Mixer assets.

You can do the following with Audio Mixers on Web:

• Create an Audio Mixer asset.
• Add AudioMixerGroups to the hierarchy.
• Adjust the volume of each group. To expose or change the volume with scripting, use AudioMixer.SetFloat.

Note: Volume is the only property you can change on Web. Other properties and sound effects aren’t supported.

Compressed audio

To use compressed audio with WebGL in Unity, set the AudioClip loadType to one of the following options:

• CompressedInMemory
• DecompressOnLoad

You can also change these settings in the Unity Editor. To change the setting, select your Audio Clip, then set Load Type in the Inspector window to your preferred option (Decompress On Load or Compressed In Memory).

Issues with Silent Mode on iOS browsers

The Silent Mode switch on iOS devices behaves differently on compressed and uncompressed audio clips in Web builds. Uncompressed sounds aren’t audible on iOS devices in Silent Mode because WebKit categorizes this audio node type differently than MediaElementSourceNode, which is used for CompressedInMemory sounds. For more information, refer to WebKit issue #262781.

If you set your audio clip’s loadType to DecompressOnLoad, the clip will not be audible on iOS devices that are in Silent Mode. To ensure audio plays regardless of Silent Mode, set your audio clip loadType to CompressedInMemory. This issue occurs only in Web builds.

If you need to load in a sound when a sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary starts, it’s recommended to load the sound completely in a temporary scene and load the target scene additively.

Audio playback and browser security

For security reasons, browsers don’t allow audio playback until an end user interacts with your application webpage via a mouse click, touch event, or key press. Use a loading screen to allow the end user to interact with your application and start audio playback before your main content begins.

Microphone

To use the Microphone class on Unity Web, you must do the following:

• Request user authorization with Application.RequestUserAuthorization.
• Host your application on a secure (HTTPS) server.
  Note: This restriction doesn’t apply during local development when you access the application via localhost.

The following example shows how to request user authorization for Microphone:

using UnityEngine;
using System.Collection;

public class MicrophoneExample : MonoBehaviour
{
  void Start()
  {
    StartCoroutine(RequestMicrophoneAuthorization());
  }

  public IEnumerator RequestMicrophoneAuthorization()
  {
    yield return Application.RequestUserAuthorization(UserAuthorization.Microphone);

    if (Application.HasUserAuthorization(UserAuthorization.Microphone))
    {
      // User gave authorization. The Microphone API can be used now.
      // ...
    } else {
      // User didn't give permission or the Microphone API isn't available, such as
      // when the website isn't running in a secure context. API can't be used.
      // ...
    }
  }
}

The following Microphone APIs have unique behaviors on the Web platform:

While the microphone is recording to AudioClip, the following methods behave differently:

Scriptable Audio Pipeline

The scriptable audio pipeline is not supported. Attempting to use it in a Web build will trigger a warning.