[mythtv-users] Channel Fine Tuning

[Andrew Dodd]

Quoting Curt Parker <dirt at dixie-net.com>:

> I have search the archives for "Channel" and "Tuning" but I can't seem 
> to find what I am looking for in the 3000+ messages it returns.
> 
> ivtv .1.9
> mythtv .13
> PVR-250
> Cable
> 
> I have everything working fine.  Recording, live tv, everything.  The 
> one problem I am having is with the color red on any channel.  Red is 
> giving me a blue ghost in both mtythtv and a cat capture from 
> /dev/video0.  For instance, if I tune in to CNN and the logo is at the 
> bottom, the red CNN logo appears to have a blue shadow.  Its like this 
> on every channel.  How do you go about fine tuning this, or is this an 
> indication of some problem?  I can post any other information that may 
> help, I just didn't want to start with a bunch of information that is 
> not needed.
Hmm.  Well, it COULD be one of the following:
a)  Hue/saturation/etc. values are incorrect.  Try using ivtv's test_ioctl while
watching a direct capture to tweak these.  A good example of a direct capture is:
cat /dev/video0 | xine -
b)  Your frequency is off (the general definition of "fine tuning" is fixing
minor center frequency errors).  You can use test_ioctl to get the current
center frequency for a given channel and then start tweaking that to see if it
changes things.

Then you can change the finetune variable for a given channel in the channel
table of the mythconverg database to define an offset from the default center
freq of a channel.
For example, if the normal center frequency of a channel is 3188 (Note, this is
not in MHz, I believe the formula is n * 6.25/100 MHz.), and your optimum
reception is 3184, the value of the finetune variable would be -4.

See recent archives (within the past 3-4 days) for info on tweaking channel
settings directly within the database.