[mythtv-users] Very slight jitter on high power machine

Brad Templeton brad+myth at templetons.com
Tue Dec 14 10:05:28 UTC 2004

> Been reading up, most stuff I'm finding still says 1080i sets are more common, 
> though most of that data may be outdated. I give up on understanding how many 
> lines a 1080i set can actually display... I know only 540 lines make it to 
> the screen per frame, but it does seem that they don't overwrite the previous 
> field, so you would lose a little bit running a 1920x540p mode versus a 
> 1920x1080i mode. I'm punting, time for sleep. :-)

Sets are being required to handle 1080i.  They all advertise they take
1080i these days but their real resolution is much more commonly 1280x720,
except for some of the CRTs.

Amusingly my set and many others won't take 720p!  They take the 720p,
covert it "up" to 1080i, and then reconvert it down to 720 lines at
their own internal refresh rate.

But it looks OK.

Anyway, point is, we should resist (if we have 720 lines or 1080 lines)
running with just 540 lines, progressive or otherwise.

However, I do still get skipping, even with glx fixed, and with nicing
the X server and the mythfrontend.  Will plug on it.

Note that mythfrontend complains, even though it is suid root, that:

    "Running as SUID root would allow some threads to run with realtime priority, improving video smoothness."

I have seen it report that it can't change thread priority.  Some
bug relating to Fecora Core 3 and how it does the thread priorities,

I haven't tried the non-SMP kernel.  Perhaps the hyperthreading is actually
bad for me.

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