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Multi-Sound Playback

If you implement an app that plays multiple sounds, which are background music and sound effects, you need to read the following guidelines and sample code carefully.

Important

In this article, we explain both the audio element and the Web Audio API for playing multiple sounds. Due to restrictions, however, we strongly recommend you to use the audio element for playing background music.

Using audio element

You should use only one audio element in your app. As the audio tag uses the hardware decoder on webOS TV, sometimes media resource conflict occurs while apps are switching. To prevent the media resource conflict on webOS TV, you should use only one audio element in your app. If you declare one or more audio elements in your app, sounds are not played at the same time.

Note
  • The duration of audio content must be at least 1 second.
  • On app suspend, you should pause the sound and resume it when the app goes foreground. Refer to the sample code.
  • Multi-sound works with multiple audio elements on the webOS TV Emulator that are working differently from the real device.

Use case for audio element

Playing background music in your app.

Supported MIME types

Following MIME types are supported in the audio element:

  • audio/aac
  • audio/mp4
  • audio/x-m4a
  • audio/mpeg
  • audio/x-mpeg
  • audio/x-mp3
  • audio/mp3

The following example shows that a file of the mp3 format is played with the audio element.

<audio controls autoplay>
  <source type="audio/mp3" src="http://media.w3.org/2010/05/sound/sound_300.mp3"/>
</audio>

Using Web Audio API

Web Audio API is a high-level JavaScript API for processing and synthesizing audio in a web application.

For your reference, see Web Audio API specifications and references below.

Note

createMediaElementSource() method is not supported on the webOS TV.

As only one audio element can be used in an app, you should use Web Audio API for playing sound effects.

When playing sound with Web Audio API, it has the about 500-millisecond latency issue in webOS TV, so you should be aware of this before using Web Audio API in your app. When you use sound effect longer than 1 second, you must stop the sound on your app suspend because the platform does not automatically stop the sound of Web Audio API with app suspend. Refer to the sample code.

Use case for Web Audio API

Playing sound effects in your app.

Supported media formats

See Supported Media and DRM Format.

Other sound formats

You cannot use SoundFont on webOS TV, which is a file format and associated technology for the computer music composition, which mostly contains multiple sounds inside.

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