[mythtv-users] Mythfrontend idle cpu consumption help

Brian J. Murrell brian at interlinx.bc.ca
Wed Nov 11 19:18:25 UTC 2009


On Wed, 2009-11-11 at 14:03 -0500, Michael T. Dean wrote: 
> 
> All existing 4:3 themes have a native resolution of 800x600, so 800x600 
> is /not/ scaled up.

I'm not referring to the theme/UI bits but the actual content being
recorded and played back.  That is afterall, the point of all of this,
yes?  :-)  HD-aside, the content is being recorded at somewhere between
480-720 pixels wide by 480 pixels high.  640 on the horizontal plane is
a nice happy medium value between those.

> Whether it's scaled /from/ 800x600 down to 640x480 by Myth, or not 
> scaled and rendered at the native 800x600 resolution by Myth, the TV 
> encoder will sample the resultant image to create an analog signal to 
> send via the TV out.

Right.  But again, I'm talking about the scaling up of 640x480 recorded
content to 800x600 because that's what the UI/X-server are configured
to, only to have it scaled back down by the tv-encoder for the 480 lines
of vertical output available in SD.

> And, likely, based on the way the TV encoders work (assuming you're 
> using S-Video/Composite output), you'll actually get better quality at 
> 800x600 or 1024x768 than you would get at 640x480.

Interesting.  I will try this and see if I see any difference on my 32"
tube TV.  If I were going to use a higher resolution than my TV and SD
signal (and therefore recorded content) provide me, I think I would want
to use the "separate video modes for playback" option to reduce the
screen at 640x480 for content playback to avoid the up and down scaling
of the content.

> Most importantly, however, there have actually been users who said that 
> when they use the theme's native resolution (800x600 for 4:3 themes), 
> they do /not/ get the excessive CPU usage.

They might not have an Athlon 800 for their FE/BE.  :-)

b.

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