[mythtv] Work around for the overscan A/V Sync, double buffering on XBox

Dennis Cartier pvr at trigger.net
Sat Apr 3 06:45:42 EST 2004


As Michael on the forums, discovered, you can get perfect video speed 
and be able to adjust the overscan while using a Conextant based XBox.

The normal way of dealing with the overscan is to use xbv to set the 
overscan, but this results in a hit to the fps of Myth. You can mitigate 
this by then using xvattr to disable double buffering. Unfortunately 
this causes tearing in the signal during fast motion on screen.

The way that Michael found, was to use xbv to set the vertical 
resolution to 1 line greater than you are actually using.

Previous workaround:

xbv -auto 640 480 6.0 6.0
xvattr -a XV_DOUBLE_BUFFER -v 0

New workaround:

xbv -auto 640 481 6.0 6.0
#xvattr -a XV_DOUBLE_BUFFER -v 0

See the following for the original thread.

This definitely works for Conextant based boxes for the 0.4 release and 
likely the 0.3 as well. Not yet sure about FOCUS based XBoxes though.

Way to go Michael.


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