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

[Eric Robinson]

> What I think is happening is that in order to keep the line count a
> multiple of 16 the video height is being set to 1088 but the actual
> content is 1080.  When this happens the pixel aspect ratio difference
> becomes 0.013 which causes a transform matrix to be created so
> Quicktime will try to "transform" the image to maintain the aspect
> ratio.  By allowing a 0.015 difference in pixel aspect ratio to be
> ignored it should remove the need for the transform.

Would that have an effect on a screen that's been translated or zoomed
in on?  I found that changing the setting mentioned before ONLY works
if you *haven't* changed any of the settings in the Overscan Settings
menu.

The video through one of my tuners comes through with garbage to the
left and bottom on NBC in HD.  I tried shifting the image with the
Playback overscan options to compensate.  The picture looked good but
the jerkiness came back again.  I then put the screen-translating
options back to 0 and set an overscan percentage of 1 for both
horizontal and vertical.  This also got rid of the garbage but brought
back the jerky picture.

Would the proposed patch address these little gotchas, too?

Awesome work, by the way.