[mythtv] [PATCH] input adjust filter

Andrew Mahone andrewmahone at eml.cc
Sat Jan 31 22:27:04 EST 2004


The attached patch adds an input range/gamma adjustment filter.  The primary 
use for this filter is with bt8x8 and other cards that produce luma/chroma 
values with incorrect ranges (ie not ITU-R601).  These values can go well 
outside the correct ranges, causing video to look washed out.  The filter 
takes 6 parameters.  If no parameters or not all 6 are given, it will use a 
default set intended to correct broken bt8x8 video.  The parameters are as 
follows:

1: luma minimum input value (int)
2: luma maximum input value (int)
3: luma gamma correction (float)
4: chroma minimum input value (int)
5: chroma maximum input value (int)
6: chroma gamma correction (float)

The default bt8x8 correction values are equivalent to "16:253:1.0:2:253:1.0".  
Output ranges are fixed at ITU-R601 values (16-235 luma, 16-240 chroma).  It 
runs about 570fps on my system.
-- 
  Andrew Mahone
  andrewmahone AT eml DOT cc
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