[mythtv-users] HD Playback jerkey until I exit and resume show

Rod Smith mythtv at rodsbooks.com
Thu Dec 11 19:57:45 UTC 2008

On Thursday 11 December 2008 01:26:43 pm Allen Edwards wrote:
> This is an issue I deal with and thought I would throw it out to the group.
> When I play HD shows on my 2.6GHz P4 FE only system, whenever I skip ahead
> the show is very jerky, basically unwatchable.  I hit escape and exit the
> show then hit enter to start again from where I left off (auto bookmarking
> is on) and it plays perfectly.  Pausing is not the same as exiting so
> basically I never pause, I just exit and restart.
> SD plays fine.
> I can live with it, but it is annoying.  I never have this problem on my
> BE/FE main system that has a much more powerful processor.

I had a similar problem (but not as 100% repeatable) on my 3.0GHz Celeron-D 
system until I added the following line to the "Device" section of 
my /etc/X11/xorg.conf file:

    Option         "UseEvents" "True"

My system has an nVidia FX5200 video chipset with nVidia's proprietary 
drivers, and this might not work with other video cards or drivers. 
Basically, the problem for me was that X was usually (but not always) 
consuming about 50% of my CPU time, while mythfrontend also wanted about 50% 
of the CPU time. When one or both spiked, something had to give, resulting in 
jerky playback. With the above option added, X consumes much less CPU time 
(about 10-20% for HD content, IIRC), so problems don't occur unless something 
else is chewing a lot of CPU time. (If mythfilldatabase runs, playback 
suffers, for instance.)

You can check your CPU use with the "top" command, preferably from a remote 
login (so that X is actually displaying data).

Rod Smith

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