[mythtv-users] Core 2 Duo iMac, terrible performance as front end

Todd Ignasiak todd.ignasiak at gmail.com
Sat Jan 31 18:13:47 UTC 2009


On Sat, Jan 31, 2009 at 6:56 AM, Craig Treleaven <ctreleaven at cogeco.ca> wrote:
> At 8:17 PM -0700 1/30/09, David Snider wrote:
>>When I got a new Mac Mini (Intel) I had a similar problem.  When you look at the video, does it look "scaled" to you, almost as if you are zoomed in to the video somewhat?   That's what was happening on mine.  Everything played terribly.  I had to go into the playback settings and change the video scale option.
>>
>>I had to go in to my playback settings and change the scale settings there (not the scale as necessary option).  I had to change them to a non "0" value, for example, -25%, and then the video was "properly" shrunk to a small size (lots of black around the edges), then, when I set the values back to 0, the video was scaled properly.  Very strange, but after that, everything worked great.
>
> Dave, just to be clear, you mean:
>
> Utilities/Setup -> Setup -> TV Settings -> Playback (Page 2/10)
>
> and change both Vertical Scaling and Horizontal Scaling?  I know I've tried this before but when I can pry the kids away from the Wii, I'm going to have another go.
>
> I've never had as good playback with .21-fixes as I had with .20.2.  I have two Mac Minis running OS X for Myth.  The frontend/backend is connected a Sony LCD projection set and to an A/V receiver using digital audio.  The other mini is a frontend only connected to a computer monitor and using analog audio.  For a description of the problems on the frontend/backend, see:
> http://svn.mythtv.org/trac/ticket/5552
>
> Todd Ignasiak posted earlier that he had good success with:
> Decoder: Standard
> Video renderer: quartz-blit
> OSD Renderer: softblend
>
> What deinterlacers are you using (primary/secondary)?
>
> While I'm at it, here are the Mac specific settings (pages 9/10 of the above group):
>
> Enable gamma correction for video:  Off
> Scale video as necessary:  On
> Frames to skip in fullscreen mode: 0
> Video in main window:  On
>  Frames to skip: 0
>  Opacity:  100
> Video in floating window: Off
> Video on the dock:  Off
> Video on the desktop:  Off
>
> These are good, right?

Those are the same settings I'm using, in addition to:

I set "Max CPUs" to 2,  but I'm not sure that this makes much difference.
For Deinterlacers, I have Primary set to Kernel and Fallback to Linear Blend

on page 4/10, I set "Display live preview of recordings" to OFF.
Either way no video is shown,  but when set to ON my CPU jumps to ~35%
in my recording selection screen (I noticed that long ago, should have
submitted a ticket on it.. I finally did that today)

Also, for completeness, the other important Mac setting is in the
"Settings->Setup->Appearance" area.
"Paint Engine" = Qt
"Qt Style" = Windows  (otherwise the settings menus are unreadable.
I'm not sure why the Macintosh Aqua option exists)


 Some other things I tried:

Decoder set to "Mac hardware acceleration" with Video Renderer
"quartz-accel",  this has huge potential..  it uses the Apple DVD
Player's MPEG2 acceleration interface that was reverse engineered.  I
have had limited success with it, but playback and stability issues
stopped me from using it.    Previously, I tried it on my MacBook Pro,
and if memory serves, the CPU savings was very noticeable.   Today, I
tried it with my Mini and had CPU usage at 80%+, so I am not sure if
the onboard video doesn't support this or I may have left off the
necessary build options on the frontend I'm using now.     Also, accel
mode didn't allow a de-interlacer to be set, so I got severe combing
on 1080i content.

De-interlace set to Yadif:  Video played for a fraction of a second
then froze while audio continued.
De-int to "Greedy HighMotion": same behavior as Yadif


Stability:   Overall it works quite well.  But, it's not unusual for
my frontend process to hang when exiting a recording.  I get the
spinning beach ball, and need to force quite the application.


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