The MediaTrackSupportedConstraints dictionary's channelCount property is a read-only Boolean value which is present (and set to true) in the object returned by MediaDevices.getSupportedConstraints() if and only if the user agent supports the channelCount constraint. If the constraint isn't supported, it's not included in the list, so this value will never be false.

You can access the supported constraints dictionary by calling navigator.mediaDevices.getSupportedConstraints().


channelCountConstraintSupported = supportedConstraintsDictionary.channelCount;


This property is present in the dictionary (and its value is always true) if the user agent supports the channelCount constraint. If the property isn't present, this property is missing from the supported constraints dictionary, and you'll get undefined if you try to look at its value.


let result = document.getElementById("result");

if (navigator.mediaDevices.getSupportedConstraints().channelCount) {
  result.innerHTML = "Supported!";
} else {
  result.innerHTML = "Not supported!";



Specification Status Comment
Media Capture and Streams
The definition of 'channelCount' in that specification.
Candidate Recommendation Initial specification.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
channelCountChrome Full support 52Edge ? Firefox Full support 56IE ? Opera Full support YesSafari ? WebView Android Full support 52Chrome Android Full support 52Firefox Android Full support 56Opera Android Full support YesSafari iOS ? Samsung Internet Android ?


Full support  
Full support
Compatibility unknown  
Compatibility unknown

See also

Document Tags and Contributors

Contributors to this page: Jib, mdnwebdocs-bot, fscholz, Sheppy
Last updated by: Jib,