How can I double frame rate with the ffavisynth?

[edison]

I want to use the ffdshow's "framerate doubler" for some FRC compare.

here is my script:

Load_Stdcall_Plugin("C:\Program Files (x86)\AviSynth 2.5\plugins\ffavisynth.dll")

LoadPlugin("D:\backup\tools\video\MeGUI_0.3.5_x86_WithoutInstaller_OfflinePackage\tools\dgavcindex\DGAVCDecode.dll")
AVCSource("H:\movies\x.dga")

ffdshow("doubleframe")

but the frame rate of output does not change.