[mythtv] color/hue/etc not adjusting?

Bruce Markey bjm at lvcm.com
Mon Nov 24 01:10:21 EST 2003

[Top posting 'cause I damn well feel like it ;-]

The f-keys can fail to work and display -1% if the X server
"v4l" module isn't loaded. Check your XF86Config-4 file's
"Module" Section to see that you have:

        Load    "v4l"

Also, check your /var/log/XFree86.0.log to verify that it
does load.

Chris Petersen wrote:
> using cvs from a day or two ago..  when I hit the f-keys to adjust
> color/hue/etc it displays -1% and doesn't seem to do anything.  When I
> check the database values, they do seem to be going up/down (or down,
> anyway - sometimes to zero with very few keystrokes).
> Any ideas?  Did these keys change again when I wasn't looking?

This module didn't used to be required so it may have changed
due to an upgrade of your X server, bttv driver or if your
XF86Config-4 file was replaced. There may be other reasons
why this might fail but I know that leaving out the X "v4l"
will cause this problem and adding it has been the solution
for other people.

Once you've resolved this, you can reset your database
values with:

update channel set contrast=32768,brightness=32768,colour=32768,hue=32768;

If you are using bttv cards, you may want to use:

update channel set contrast=24500,brightness=35000,colour=32768,hue=32768;

to compensate for the incorrect luma ranges from the bt
chips. This will fix the distortion in white and near white
colors so this should give you a much better picture.

--  bjm

$ grep 253 /usr/include/linux/videodev2.h
 /* broken BT878 extents (601, luma range 16-253 instead of 16-235) */

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