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Old 20th May 2010, 16:20   #47  |  Link
WorBry
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Join Date: Jan 2004
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Posts: 1,197
Now that I've got the 'luma' component of these blends sorted (I hope), I've been experimenting with some (maybe acheivable) chroma effects (I know...YUV chroma....not for the faint hearted...why not just do it in RGB?). To this end I want to create some (YV12) U and V reference spectra . Figured I could do this using a greyscale gradient and YtoUV, like so:

Code:
GSG    =  colorbars().converttoyv12().mt_lutspa(relative=true,expr="x 255 *").Greyscale().LanczosResize(640,640)
GSG2   =  GSG.Reduceby2()
NGry2  =  GSG.mt_lut("x 128 ", y=3).Reduceby2() 
Uspec  =  YtoUV(GSG2, NGry2)
VSpec  =  YtoUV(NGry2, GSG2)
Return Interleave(USpec, VSpec)
But with both spectra, there is obviously some clipping/scale issue going on. Any idea how to resolve?
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Last edited by WorBry; 20th May 2010 at 16:36.
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