files/en-us/web/api/mediatrackconstraints/samplesize/index.md
{{APIRef("Media Capture and Streams")}}
The {{domxref("MediaTrackConstraints")}} dictionary's
sampleSize property is a ConstrainULong
describing the requested or mandatory constraints placed upon the value of the
{{domxref("MediaTrackSettings.sampleSize", "sampleSize")}} constrainable property.
If needed, you can determine whether or not this constraint is supported by checking the value of {{domxref("MediaTrackSupportedConstraints.sampleSize")}} as returned by a call to {{domxref("MediaDevices.getSupportedConstraints()")}}. However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.
If this value is a number, the user agent will attempt to obtain media whose sample
size (in bits per linear sample) is as close as possible to this number given the
capabilities of the hardware and the other constraints specified. Otherwise, the value
of this ConstrainULong will guide the user agent in its efforts to provide
an exact match to the required sample size (if exact is specified or both
min and max are provided and have the same value) or to a
best-possible value.
[!NOTE] Since this property can only represent linear sample sizes, this constraint can only be met by devices that can produce audio with linear samples.
See the Constraint exerciser example.
{{Specifications}}
{{Compat}}