[mythtv] Proof of concept: Chromakey OSD

[Ivor Hewitt]

Andy Poling wrote:
> I've been struggling for some time with HDTV viewing and XvMC.  There has been
> a great deal of fundamental progress on XvMC, but I still felt we were hitting
> a wall of sorts in terms of what we could do with the current approach.  So I
> got myself motivated and decided to try a radical approach to solving the
> problem.  I was inspired in particular by the comments and work of Daniel
> Kristiansson and Ivor Hewitt.  Daniel mentioned last Fall the possibility of
> taking advantage of the chromakey background, and Ivor presented the IA44 OSD
> rendering late last year.
> 
Hi,

Interesting.

> The problem, as I see it, is that rendering and blending the OSD takes too
> much time during what turns out to be very time-sensitive code when viewing
> high-resolution HDTV content.  The OSD processing is basically preventing us
> from completing the rendering work in the time the framerate gives us.
>
Correct. One of the main jobs of the epia-osd changes were to try and 
speed up the rendering.

  > In the process, I also decided to try removing the OSD processing 
from the
> timing-critical frame rendering code, and moved it instead into a low-priority
> NuppelVideoPlayer thread.  I think the results are pretty interesting.
>
I'd be interested in trying that (moving the rendering) but still using 
the subpicture overlay code. I think it's nice visually having the OSD 
overlaid with transparency.

> Given the gnashing of teeth on this list lately, this sort of relatively
> radical work may not be welcome by all.  I hope that it will be taken in the
> spirit that it's given: as a stimulant to discussion, and an interesting
> experiment.
> 
Yeah well this is development code. If nothing gets broken, nothing gets 
improved.

-- 
Ivor
http://www.ivor.it