|Microsoft DirectX 9.0|
The GetStdDev method estimates the standard deviation in milliseconds between when each frame is due and when it is actually rendered, for per-frame statistics.
HRESULT GetStdDev( int nSamples, int *piResult, LONGLONG llSumSq, LONGLONG iTot );
Integer value that contains the number of video samples received by the video renderer.
Pointer to an integer value that will contain the standard deviation.
Value that represents the standard deviation, in milliseconds, of all rendered video samples. The lower the value, the more consistent the rendering.
Value that represents the mean value, in milliseconds, between the stamped time and rendered time for all rendered video samples.