Specifies whether the sample-grabber sink uses the presentation clock to schedule samples.

Data type



To get this attribute, call IMFAttributes::GetUINT32.

To set this attribute, call IMFAttributes::SetUINT32.


You can set this attribute on the activation object created by the MFCreateSampleGrabberSinkActivate function. Set the attribute before calling the IMFActivate::ActivateObject method on the activation object.

By default, when the sample-grabber sink receives a sample, it waits until the presentation time of the sample to invoke the application's callback. If the MF_SAMPLEGRABBERSINK_IGNORE_CLOCK attribute is nonzero, the sample-grabber sink ignores the presentation clock and invokes the callback as soon as it receives each sample.

Recommended usage:

  • If you want to process samples as quickly as possible, set this attribute to TRUE.
  • If you want the calls to the callback method to be synchronized with the clock, either do not set this attribute or set it to FALSE. You can get samples slightly ahead of the clock, while still remaining synchronized, by setting the MF_SAMPLEGRABBERSINK_SAMPLE_TIME_OFFSET attribute.

The GUID constant for this attribute is exported from mfuuid.lib.


Minimum supported client

Windows 7 [desktop apps only]

Minimum supported server

Windows Server 2008 R2 [desktop apps only]



See also

Alphabetical List of Media Foundation Attributes
Media Foundation Attributes