[mythtv-users] Potential hardware - or underpowered ?

Raymond Wagner raymond at wagnerrp.com
Sun May 16 17:44:06 UTC 2010

On 5/16/2010 13:18, Simon Hobson wrote:
> At first I was thinking one of these would run a backend as long as 
> your requirements weren't too demanding - but when I think a bit more, 
> by the time you've added a hard disk and power supply, then it quickly 
> becomes rather less attractive as the cable count goes up.

They compare this to the 'average 175W desktop', while in actuality, 
175W idle is a high end machine with multiple CPUs and/or GPUs.  Your 
real world average desktop (dual core, 2GB of memory, onboard graphics, 
one hard drive) will be maybe 50W idle and 80W under full load.  Sure, 
5W is considerably lower, but 175W is an outright lie.  You should take 
any claims of the performance of that system with similar skepticism.

The backend has two types of intensive tasks.  You've got long duration 
intensive tasks such as recording from a framegrabber, transcoding, 
commflagging, and other jobqueue tasks.  The can either be disabled or 
offloaded elsewhere.  Then you've got short duration intensive tasks 
like mythfilldatabase, the scheduler, and mysql access.  These must be 
performed, and cannot be offloaded to a more capable processor.  A weak 
processor is going to directly impact the responsiveness of things using 
any of these tasks, such as scheduling new shows and navigating the 
watch recordings screen.

Besides that, you have a single eSATA port, and two USB ports.  Add a 
hard drive, two tuner cards, and you have quadrupled your power 
consumption, and completely filled your expansion capacity.  You don't 
want to run one of these as your backend.

> But would the display version have enough power to run as a frontend ? 
> It's a 1.2G ARM based processor, with a TDA9989 HDMI interface (spec 
> sheet says it supports 1080p) and no GPU. I'm guessing this wouldn't 
> be a high performance setup !

MythTV is going to make a push to move to OpenGL for everything in the 
next few versions.  Anything without a GPU is not preferred.  Beyond 
that, the ARM CPU isn't going to have support for anything beyond 
standard definition video, and even if that device does have some sort 
of hardware video decoder, it is not currently supported for use by 
MythTV.  The ability to push 1920x1080 doesn't mean anything if it can't 
actually play any content.

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