[mythtv-users] picture quality help?

[Brian Wood]

On Mar 7, 2007, at 6:18 AM, John Welch wrote:

> I running ivtv .10 and 2.6.20.1 kernel with mythtv
> 20.1 fixes.  My issue is the picture quality on
> channels 2, 4 and 5.  I am using Comcast in New
> England.  I have tried fine tuning the channels, but
> the defaults frequencies are the best picture I can
> get.  I don't believe this to be a mythtv issue,
> because mplayer /dev/video0 shows the same quality.  I
> am using a 250 and a 500 in my backend and the quality
> is about the same on both cards.
>
> I had a similar problem, also with Comcast - North of Boston area,  
> when I first setup my Myth box with a PVR-150  card about a year  
> ago.  My problems were mostly on channels 5  (ABC) and 6 (NECN).   
> Unfortunately it was so long ago (at least for my memory) that I  
> don't recall the exact steps I took to fix it.  I believe I used  
> the ivtv tools to tune to the channel.  That gave me the frequency  
> of the channel.  Then I bumped it up by increments of 25 or 50  
> until I got a good picture with mplayer.  I took the frequency from  
> there, went into the mtytv-setup Channel editor, and entered the  
> frequency instead of the channel number.  The bump up was more than  
> I could get with the fine-tuning in mythtv.
>
> I wouldn't totally discount the other post about a bad cable,  
> connection, etc., but I have a feeling that Comcast does something  
> funky with some of these low numbered channels.
>
> Sorry I don't have my exact troubleshooting steps, but I hope this  
> info can lead you on the right path.
>

A problem with channels 5 and 6 is most likely an incorrect channel  
table (ie: cable when it should be cable-HRC or vice versa).

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