[mythtv-users] Random lockups on Mythbackend

Joe jfwd at phlobus.net
Mon Dec 20 23:38:34 UTC 2010

On Mon, Dec 20, 2010 at 2:16 PM, dwoody1 <dwoody1 at charter.net> wrote:
> Brian Wood wrote:
>>> I record OTA and Mythtv shows 720, 1080, HD and sometimes blank. But,
>>> we live in Texas, so I assume it is all digital if that makes a
>>> difference.
>> So we're talking about HD. I suspect your CPU is not capable of that much
>> activity with HD, especially since you are using software decoding.

Years ago I was running a frontend based on on a single-core sempron.
Can't remember the clock rate, but it wasn't high.  It would barely
keep up with decoding HD in software; the CPU would be running over
90% constantly while playing 1080i, slightly less for 720p but still
quite high.  This was all captured OTA using pcHDTV 5500 cards.

But the point is that it DID keep up, so your athlon X2 should be
handling it without a problem.  As long as you have proper cooling and
hardware that works, a cpu can be pegged at 100% all day and never
lock up.

>>> I have been using the HDMI output. I thought that used less cpu than
>>> using VGA output. But perhaps still too much.
>> I wasn't aware that HDMI made any difference in CPU usage, first I had
>> heard of that.
> I read some where that with the HDMI output the computer did not have to
> convert to analog, which would take more processing. Do not really know
> if this is true or not.

The part about there being no analog conversion is true, but it is all
handled in hardware by the video card and it makes no difference in
CPU usage.  HDMI is just a connection type.

>>> If so, from your comments above, a VDPAU-capable video card would be
>>> called for. From your experience, are there cards that you would
>>> recommend or avoid?
>>> From comments here and other places I'd go with an nVidia GT220 or 240,
>> they are reasonably priced and seem to work well.

Personally, I wouldn't jump to conclusions about the video card and go
upgrading it unnecessarily.  If you have the cpu power to do software
decoding then it is perfectly fine, and in some cases even better to
just use that.

Your problem definitely sounds like faulty hardware and it seems like
you may have already found the problem w/the mce usb receiver.  After
replacing that, long as your system is stable and you are not having
problems that are actually traceable to lack of free CPU cycles, why
mess with it?

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