[mythtv] Zoom -vs- Aspect -- need a custom setting

[David Frascone]

> Try setting the screen physical size, not the DPI
>
> DisplaySize    372.32 301.56
>
>   

This worked perfectly for my HD and SD sizes.  Now everything looks 
perfect *except* for video captured over firewire.  It is still top and 
bottom letterboxed.

-Dave