The MediaTrackConstraints dictionary's channelCount property is a ConstrainLong describing the requested or mandatory constraints placed upon the value of the channelCount constrainable property.

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.channelCount as returned by a call to MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.


var constraintsObject = { channelCount: constraint };

constraintsObject.channelCount = constraint;


If this value is a number, the user agent will attempt to obtain media whose channel count is as close as possible to this number given the capabilities of the hardware and the other constraints specified. Otherwise, the value of this ConstrainLong will guide the user agent in its efforts to provide an exact match to the required channel count (if exact is specified or both min and max are provided and have the same value) or to a best-possible value.

The channel count is 1 for monaural sound, 2 for stereo, and so forth.


See "Example: Constraint exerciser" in Capabilities, constraints, and settings for an example.


Specification Status Comment
Media Capture and Streams
The definition of 'channelCount' in that specification.
Editor's Draft Initial specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) No support No support (Yes) ?
Feature Android Android Webview Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support ? (Yes) No support No support ? ? (Yes)

See also

Document Tags and Contributors

 Contributors to this page: Sheppy
 Last updated by: Sheppy,