[mythtv] Aspect ratios and non-linear stretching

[Daniel Kristjansson]

On Tue, 2006-10-31 at 17:36 -0500, Sean McVeigh wrote:
> It's my understanding from a quick skim through the code that display 
> aspect ratios (the W-key stuff) are just handled by altering the 
> geometry passed to the X blitter.
Yup.

>   Short of writing a new X-blitter, or 
> a filter plugin, it would seem that a reasonable approach would be to 
> hook in somewhere before Show(), ie. ProcessFrame() and generate frames 
> with a new geometry.
> I'd rather not explicitly do it as a filter, since it's my understanding 
> that filters can't be arbitrarily enabled and disabled at runtime with 
> the press of a button.  (if that's not the case, please let me know).  
> Also, I am unsure as to whether filters work with frame images in-place 
> or can return new frames with new geometries.. haven't read that far 
> into things.
Do it as a filter. You can see how filters are enabled and disabled
at run-time by looking at the deinterlacing code. It's messy but
it's this should be improved in the mythtv-vid branch in the next
few months.

At the moment a filter must work in place, but this should not be
a huge problem, just compress the whole image in the horizontal
direction as part of the re-sampling, then uncompress it in XVideo.
We will eventually support output to a different output resolution
in the filters, but I'm not going to look at this until at least
the basics of the mythtv-vid branch changes are working properly.

-- Daniel