[mythtv] Proof of concept: Chromakey OSD

Brad Templeton brad+mydev at templetons.com
Thu Mar 24 07:12:42 UTC 2005


On Thu, Mar 24, 2005 at 12:15:49AM -0500, Andy Poling wrote:
> 
> The result of my experiment: an OSD for Xv and XvMC that is rendered (in full
> color) on the chromakey background instead of as an overlay.  Why Xv and XvMC?
> I use XvMC for HDTV, and I tend to transcode my normal captures to MPEG4, so
> I must use Xv to view them.  I also think those two display methods cover alot
> of people's needs...

I think this is an excellent way to do it, and would gladly sacrifice
the anti-aliasing and translucency for this much more efficient
system.   At HD resolutions you can live without those things I think.

(In a 1024x768 scaled to TV-out, you would get some effective anti-aliasing
from the scale-down.)

Also possibly in line with the future ability to put the OSD into the
overlay bitmap used for closed captions in mpeg 2 streams.  My TV,
and many other new ones, has a firewire port to which you can stream
mpeg-2.   Some day it would be cool to have the pvr use this for output,
meaning no cpu load on the pvr to play video, and absolutely 100% quality
equivalence to live TV.    The downsides of course are OSD and menus which
need more work.

You note the ability to display OSD in the pillarboxes and letterboxes.
That would be very cool, in fact it seems right to me to deliberately
do this to avoid stomping on the actual video.   Of course, if the
pillars or letterbox bars are in the actual video signal you would
have to figure that out which is a whole other ballgame.


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