[mythtv] brightness contrast etc.

[Bruce Markey]

Brent Hills wrote:
> Prior to Myth I used to control brightness and color etc. for the tuner
> with xvattr and xvinfo.

The contrast controls and such are the v4l settings for
the capture card, not the Xv display settings. This is
so the card settings can be adjusted so that recordings
will not have distortion.

For example, the default value for contrast is usually too
high and causes white and near white to be out of proportion
compared to medium colors causing a dingy look. Once a file
is recorded like this, you can't really adjust the monitor
to compensate. I've found that recordings don't look life-
like unless the the v4l contrast is set to something below
40%. These controls are also on a per channel basis so you
can compensate for one channel being brighter than another.

You should continue to xvattr if you believe you need to
adjust the overall display when viewing.

--  bjm