[mythtv-users] Mac OS X choppy playback at high display resolutions, such as 1080p

[Eric Robinson]

On 10/10/07, Eric Robinson <ryunokokoro at gmail.com> wrote:
> > I did some quick testing.  It looks like that anytime that the image
> > needs to be transformed (offset or scaled) it causes a problem so the
> > patch wouldn't solve the problem if you set an overscan or offset.
> >
> > I don't know of an easy solution that will allow overscan or offset
> > without using the QuickTime transform function which seems to be
> > causing the problem.
> >
> > The most likely solution would probably be to move to a CoreVideo/
> > OpenGL based VideoOutput class that could utilize the GPU for the
> > transformation.
>
> Ahh, so the problem lies in the QuickTime transform function.
> Conceivably, though admittedly unlikely, Apple could update QuickTime
> and fix the slow speed...?
>
> The other option sounds like a major shift in the way the video is
> processed on the Mac.  Mino, are you a MythTV developer?  Is that
> something that is plausible?  Should this be marked as a bug (as 1080p
> TVs get more common this will likely affect a lot of people...)?
>
> Thanks for all the help.
>
> - Eric
>

As can be seen above, it appears that falling back on QuickTime based
functions for image scaling when (VerticalScreenPixels >= 1080) AND
(VerticalVideoPixels == 1080) causes hiccuppy gameplay. In Mac OS
10.4.x at least.

We now have a new version of OSX to test on, however, with purportedly
updated video libraries (?).  Has anyone tested this scenario on
Leopard (Mac OS 10.5.x)?  Is the problem still present?

- Eric