IAMDroppedFrames::GetNumDropped method (strmif.h)

Article
02/22/2024

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The GetNumDropped method retrieves the total number of frames that the filter has dropped since it started streaming.

Syntax

HRESULT GetNumDropped(
  [out] long *plDropped
);

Parameters

[out] plDropped

Pointer to a variable that receives the number of dropped frames.

Return value

Returns an HRESULT value. Possible values include the following.

Return code	Description
S_OK	Success.
E_POINTER	NULL pointer argument.

Remarks

The filter resets the count to zero when it transitions from stopped to paused.

If your application uses the IAMStreamControl interface to control a pin, the driver might continue to count dropped and non-dropped frames while the pin is off. To get an accurate count, call this method once when you turn on the pin, and again when you turn off the pin. The difference is the total number of dropped frames. (If the start time occurs later than the call to IAMStreamControl::StartAt, the application should listen for the EC_STREAM_CONTROL_STARTED event.) These remarks also apply if your application uses the ICaptureGraphBuilder2::ControlStream method.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib