[mythtv-users] Underscan in playback and recording, driver issue?

Carl Lewis carl.lewis at dpiw.tas.gov.au
Mon Sep 25 02:54:51 UTC 2006

David McKenzie wrote:
> Hi,
> Little background on the system:
>    MythTV built from SVN
>    ivtv driver version 0.7.0
>    Hauppauge PVR-150 card
>    1366x768 LCD TV using VGA input for computer, displays menus and WM 
> perfectly.
> The problem is that recordings and live TV using the PVR-150 doesn't 
> fill the screen completely. The left edge for up to about 1/2" is all 
> black and doesn't stretch to fill the entire screen when in 16:9 stretch 
> mode. This is a bit annoying, and it isn't a playback issue, as the 
> recorded mpegs themselves show the black stripe on the left edge in the 
> preview pane and when played in a window. Some channels are worse than 
> others, but when using the card with BeyondTV in windows this has never 
> been a problem, as it seems like it auto-centers the picture if there is 
> some sort of black space.
 > Has anyone seen this before or can offer a resolution? Right now it is
 > the only thing from letting me switch over to Myth completely.

David, I've been seeing the same thing in Australia, with ABC in
particular. I run a 100" screen (projector :-) with no
overscan. The affected channels/programs have about a 2" vertical
stripe/black-bar down one or both sides.
I've only  noticed it since setting up a border around the screen :-/
so I've no idea when it started.
Same as you I've looked at the recordings themselves and they contain
the vertical space.
My setup :
    Myth SVN
    2 x DVICO FusionHDTV DVB-T Plus Tuners
    1 x Leadtek Winfast DTV 1000T Tuner
    Panasonic AE-900 projector DISPLAY
    Debian AMD64 etch (current ~ 3 months ago)
    2.6.16 (?) kernel

I've tested both breeds of tuner and they behave the same.
Both are cx88xx based though.

I've been keeping an eye on the mailing list to see if anyone was having
similar problems. I figured most people are using devices with
overscan and so not seeing this.

I don't see the problem at all on most channels and am beginning to
suspect something in the way the signal's being converted/processed/
broadcast at the source.


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