IMFClockStateSink::OnClockSetRate method (mfidl.h)

Called when the rate changes on the presentation clock.


HRESULT OnClockSetRate(
  [in] MFTIME hnsSystemTime,
  [in] float  flRate


[in] hnsSystemTime

The system time when the rate was set, in 100-nanosecond units.

[in] flRate

The new rate, as a multiplier of the normal playback rate.

Return value

If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.


When the presentation clock's IMFRateControl::SetRate method is called, the clock notifies the presentation time source by calling the time source's OnClockSetRate method. This call occurs synchronously within the SetRate method. If the time source returns an error from OnClockSetRate, the presentation clock's SetRate method returns an error and the state change does not take place.

For any object that is not the presentation time source, the OnClockSetRate method is called asynchronously, after the state change is completed. In that case, the return value from this method is ignored.


Minimum supported client Windows Vista [desktop apps | UWP apps]
Minimum supported server Windows Server 2008 [desktop apps | UWP apps]
Target Platform Windows
Header mfidl.h
Library Mfuuid.lib

See also



Presentation Clock