[mythtv] blurry osd colour text for Xv output

[Martin Barnasconi]

For teletext and subtitle fonts I tried using the existing osd colour font 
implementation in the OSD classes for standard Xv output.
The results are rather poor, as the colour pixels are unregularly distributed, 
resulting in blurry fonts. Has probably to do with the YUV420 algorithms, but 
are there some better overlay routines in development?
Currently the colored subtitles and teletext is unreadable, and forcing me to 
use B&W fonts only.

Any idea's how to improve this? 

Martin