[MPlayer-dev-eng] Re: [PATCH] New video filter: deblendlogo
mplayer at hzoli.2y.net
Sun Feb 27 04:46:41 CET 2005
> Doing alpha deblending on chroma channels is utter nonsense. It only works
> if the logo mask is all white, which means there is no chroma, so the
> unblended chroma is preserved and only the luminance is corrected. With
> colored logo's this won't work.
Why not? RGB -> YUV is an affine tansformation, and affine
transformation of convex combination of points (i.e. alpha-bending) is
the convex combination of the affine transformed points. This means
that alpha-bending works just fine in YUV, as long as you use the YUV
transformed logo image.
More information about the MPlayer-dev-eng