IAMVideoCompression::get_PFramesPerKeyFrame
A version of this page is also available for
4/8/2010
This method retrieves the rate of predicted (P) frames per key frame.
Syntax
HRESULT get_PFramesPerKeyFrame(
long* pPFramesPerKeyFrame
);
Parameters
- pPFramesPerKeyFrame
[out] Pointer to a long variable that receives the number of P frames per key frame. If the value is negative, the filter will use the default rate.
Return Value
Returns an HRESULT value.
Remarks
To determine if the filter supports this method, call the IAMVideoCompression::GetInfo method and check for the CompressionCaps_CanBFrame (see CompressionCaps) flag in the pCapabilities parameter. The GetInfo method also returns the default P-frame rate.
P frames are used in MPEG compression; in general, this property does not apply to other compression formats. For example, suppose a key frame occurs once every 10 frames, and there are three P frames per key frame. The P frames will be spaced evenly between the key frames. The remaining six frames are bidirectional (B) frames.
Requirements
| Windows Embedded CE | Windows Embedded CE 6.0 and later |
| Windows Mobile | Pocket PC for Windows Mobile Version 5.0 and later, Smartphone for Windows Mobile Version 5.0 and later |
| Note | Microsoft DirectShow applications and DirectShow filters have different include file and Library requirements For more information, see Setting Up the Build Environment |
See Also
Reference
IAMVideoCompression Interface
IAMVideoCompression::put_KeyFrameRate
IAMVideoCompression::GetInfo
CompressionCaps