[mythtv-users] MacOSX frontend & 1080i

Andrew Gallatin gallatin at cs.duke.edu
Tue Mar 13 13:05:57 UTC 2007

Todd Ignasiak [ignasiak at gmail.com] wrote:
>   I also have 'save video as necessary' enabled, but on my 720p

I assume you mean 'scale' ;)

BTW, thank you for posting your logs.  They convinced me that audio
was not my problem.

> display it doesn't have any negative effects.     It would be
> interesting to see if changing that setting makes any difference on
> the original poster's problem.    Some people thought the mini's

That setting did not make a difference for me.

What *does* make a difference is displaying on an external monitor,
rather than using the builtin 1680x1050 flat panel.  When using a Dell
2001FW (1600x1200, 60Hz), 1080i video is much, much, much more smooth.
I expect that this has something to do with the refresh rate of the
Dell LCD being 60Hz, while the refresh rate for the builting LCD is
150Hz (according to myth, refresh is N/A according to the Display Pref
pane).  I guess I'll have to haul the computer downstairs and try
actually hooking it to the TV before I know if it will work.

I have only 2 problems left that I know about right now:

- Myth seems to want to enable/disable deinterlacing at random leading
  to motion artifacts:

2007-03-13 08:47:40.763 NVP: interlaced frame seen after 85 progressive frames
2007-03-13 08:47:40.846 Enabled deinterlacing
2007-03-13 08:47:41.780 NVP: progressive frame seen after 29 interlaced  frames
2007-03-13 08:47:41.847 Disabled deinterlacing
2007-03-13 08:47:41.948 NVP: interlaced frame seen after 5 progressive frames
2007-03-13 08:47:42.014 Enabled deinterlacing
2007-03-13 08:47:42.431 NVP: progressive frame seen after 14 interlaced  frames
2007-03-13 08:47:42.498 Disabled deinterlacing

- MacOSX seems to put an insanely high value on file pages in its
unified buffer cache, and even on machine with 1GB of ram, it tends to
page out nearly everything to make room for a read-once .mpg file,
which won't be needed again.  The machine got nearly unresponsive due
to paging out my normal applications.  Unmounting the /video partition
freed over 600MB!  Dec Tru64 UNIX, the last Mach based OS I worked
with, had a tuning parameter to limit the unified buffer cache
(ubc-maxpercent).  I need to see if there is one on MacOSX...


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