Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The msAudioCategory property of the HTML <audio> element, is a read/write proprietary attribute, specific to Internet Explorer and Microsoft Edge.

msAudioCategory specifies the purpose of the audio or video media, such as background audio or alerts.


<audio controls="controls" msaudiocategory="BackgroundCapableMedia"></audio>

The msAudioCategory property offers a variety of values that can enhance the behavior of your audio-aware app.

Note that you must set the msAudioCategory before setting the src property in code.


Include a description of the property's value, including data type and what it represents.

Value Description Background Capable?
Alert Looping or longer running alert sounds:
  • Alarms
  • Ring tones
  • Ringing notification
  • Sounds that need to attenuate existing audio
BackgroundCapableMedia For audio that needs to continue playing in the background. Examples include the following local media playback scenarios:
  • Local playlist
  • Streaming radio
  • Streaming playlist
  • Music videos
  • Streaming audio/radio, YouTube, Netflix, etc.
Communications For streaming communication audio such as the following:
  • VOIP
  • Real time chat or other type of phone calls
Should not be used in non-real-time or non-communication scenarios, such as audio and/or video playback, as playback startup latency is affected. *Note that if msAudioCategory is set to Communications, msRealtime is automatically set to true.
  • Games or other sounds designed only to work in the foreground, but will mute existing background media sounds.
  • Game audio needed for the game experience (dancing games, music games)
  • Feature films (designed to pause when they go to the background)
  • Game sound effects designed to mix with existing audio
  • Characters talking
  • All non-music sounds
GameMedia Background music played by a game No
  • Game or other sound effects designed to mix with existing audio:
  • Characters talking
  • Beeps, dings, brief sounds
Other Default audio type, and recommended for all audio media that does not need to continue playing in the background. No

If msAudioDeviceType is not explicitly set, msAudioDeviceType will be set to Communications.

For hardware audio offload to be automatically applied, the audio category must be set to ForegroundOnlyMedia or BackgroundCapableMedia. Hardware audio offload optimizes audio rendering which can improve functionality and battery life.


<audio msAudioCategory="BackgroundCapableMedia" controls="controls">
  <source src="song.mp3" />