IAMVideoCompression::get_KeyFrameRate 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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 get_KeyFrameRate method retrieves the current key-frame rate.

Syntax

HRESULT get_KeyFrameRate(
  [out] long *pKeyFrameRate
);

Parameters

[out] pKeyFrameRate

Pointer to a variable that receives the current key-frame rate. If the value is negative, the filter will use the default key-frame rate. If the value is zero, only the first frame is a key frame.

Return value

Returns an HRESULT value.

Remarks

The key-frame rate is the number of frames per key frame. For example, if the rate is 15, then a key frame occurs every 15 frames.

To determine if the filter supports this method, call the IAMVideoCompression::GetInfo method and check for the CompressionCaps_CanKeyFrame flag in the pCapabilities parameter. The GetInfo method also returns the default key-frame rate.

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