[mythtv] Re: bttv luma filter

Andrew Mahone andrewmahone at eml.cc
Fri Jan 30 03:04:29 EST 2004

On Thu, 29 Jan 2004 23:27:35 -0800, "Bruce Markey" <bjm at lvcm.com> said:
> Apparently there is a well known bug in the chip design. There is a
> filter in tvtime (tvtime.sf.net) that remaps the luma values and the
> result clearly fixes image problems with colors and shades at or near
> white (see tvtime-0.9.12/src/videocorrection.c).

I'm looking now.  Is the gamma correction that's being done there
necessary, or do I just need to scale the values to the correct range?  I
ask because I think that I can write a very fast vectorized filter for
simple range scaling in MMX, but the gamma stuff needs a lookup table,
and can't be vectorized at all AFAIK.  Anyways, I have to take care of
some other work right now, but I'll get back to this shortly.
  Andrew Mahone
  andrewmahone AT eml DOT cc

http://www.fastmail.fm - And now for something completely different…

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