[mythtv-users] Line of garbage at top of screen

Jarod Wilson jarod at wilsonet.com
Tue Jan 31 18:57:52 UTC 2006


On Tuesday 31 January 2006 10:47, Endaf Jones wrote:
[...]
> > > that's just VBI data. It's in every broadcast. You don't see it on your
> > > regular TV with it's tuner because the mfr sets the overscan so high
> > > that it's not seen. You can too. It's easy to do with the overscan
> > > setting in mythtv frontend>>Utilities/Setup>>Setup>>TV
> > > Settings>>Playback>>Overscan
> > >
> > > Set the Vertical over/underscan setting to something small like 2 or 4
> > > and check your video playback. I play both NTSC and ATSC 6:9 and it
> > > works fine.
> >
> > Or just use the custom filter "crop". I forget the exact parameters, but
> > you basically specify how many pixels to chop off the top, bottom and
> > sides. Details can be found in the list archives, I'm sure.
>
> If I'm not mistaken, the "crop" filter is in multiples of 16 pixels.
> You can't just specify 6 pixels, you can only specify 0,16,32 ...

Appears that you are correct about the multiples of 16 pixels (16 pixels == 1 
macroblock), but should be specified in macroblocks, not pixels, so your 
0,16,32... example should actually be 0,1,2... At least, if I'm reading 
things right. I've never actually tried it out. :)

> For a lot of people, that's just too much of the picture to remove.
> Overscan is your best option I think in this case.  Unless something
> has changed recently.

If you're recording at full-resolution, chopping 16 pixels off the top doesn't 
seem so bad to me (you normally lose that many when watching SDTV anyhow), 
but I'd have to actually try it to see what I really think.

-- 
Jarod Wilson
jarod at wilsonet.com
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