[mythtv] Patch to autodetect 4:3 Zoom aspect ratio

[Mårten Bohlin]

>
>  http://miffteevee.co.uk/imagebin/letterbox_debug.jpg
>
>  This format generally works best with the 'Full' fill.
>  --
>  Stuart Morgan


I understand you but I do not agree. Since I will only see half of my
subtitle. But to make everybody happy I have made it possible to
adjust where the detection lines should be in the latest version of my
patch (detectLetterboxV4-21fixes.patch). But it is not possible to
change this from the settings screen yet. So either add
"DetectLetterboxLimit" to your settings table or on the command line.

 mythfrontend -O DetectLeterboxLimit=40

This should be set to something between 0 and 100 and it is the
percentage of the part of the image that will be "hidden" that has to
be black when it switch to Full fill. The default is 70.

If anybody has a good suggestion on what to call this parameter, let me know.

Mårten