[mythtv-users] VDPAU High CPU Usage

Nick Morrott knowledgejunkie at gmail.com
Tue Sep 7 06:50:28 UTC 2010


On 7 September 2010 07:10, Robert Lynn Jr <rjlynn at sixteentwelvemedia.net> wrote:
> Hi guys,
>
> I just can't seem to get my CPU usage down. Right now, on a Atom 330 (2
> cores, hyperthreaded), I'm getting 82% CPU usage by mythbackend and 44% by
> the frontend. I'm using a Happague HVR-950Q framegrabber, and encoding to
> MPEG4. It's not much better using RTJPEG. The sound skips, and I get buffer
> underrun errors in the frontend's log.
>
> I've disabled realtime threads, I've tried VDPAU Slim profile, I just can't
> find anything that'll work. I've told MythTV to use 2, 3 and 4 "cores" to
> encode video, to no avail.

I have no solutions to offer or empirical evidence that it should work
smoothly, but this scenario is probably the worst case scenario for an
Ion machine:

i) combined backend/frontend
ii) software encoding video
iii) playing back a non-VDPAU-supported* codec

* In addition to MPEG-1/2 and VC-1, Ion will accelerate MPEG-4 Part 10
video (H.264) but /not/ the MPEG-4 Part 2 video that the software
encoder produces. To accelerate that via VDPAU, you need an Ion2-based
machine or suitable NVidia card.

Is there any chance you could replace the framegrabber with a capture
card/tuner that can provide an MPEG-2 stream direct to the backend? If
I was running an Ion machine as a combo unit (I run one as a
frontend), I would require this. Not only are the CPU requirements
lowered considerably, you also get video in a format that Ion/VDPAU
can handle.

Cheers,
Nick

-- 
Nick Morrott

MythTV Official wiki: http://mythtv.org/wiki/
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