[mythtv-users] Flickering lines at the bottom of TV

Brad DerManouelian myth at dermanouelian.com
Tue Jul 22 00:32:37 UTC 2008

On Jul 21, 2008, at 5:24 PM, Brian Phillips wrote:

> Hello,
> I have a problem where my recordings on one of my channels of analog  
> cable
> have a flickering line at the bottom (and sometimes top) of the  
> screen.
> It's mainly the bottom.  I've got a screenshot here:
> http://www.et.byu.edu/~bphilli7/pics/law.png
> I don't know how to describe what it is, but I was hoping someone on  
> the
> list could tell me what causes it and what I can do to fix it.
> It only happens on one of my 20 or so cable channels I get.  I was  
> thinking
> it might be a tuning issue (maybe fine tuning the frequency for that  
> channel
> could fix it) or something in that same vein.  Anyone know what  
> causes that
> flickering line?  It's not always there.  It's just always there on  
> that
> channel.

It's being broadcast that way. There is nothing to fix on your end.  
Usually a television's overscan will hide this sort of thing but since  
you're displaying the entire video, you're getting the garbage* edges  
as well.
For info on Overscan here: http://www.mythtv.org/wiki/index.php/Overscan

To hide this, you can play back your videos 1% or 2% larger than they  
actually are (whichever works for you) or you can crop your recordings  
by transcoding them with crop settings.

*The "garbage" is actually encoded information being sent along with  
the broadcast like metadata information about the program, closed  
captioning text, etc.

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