[mythtv] Box Processor Limits

Brian Foddy bfoddy at visi.com
Tue Jan 21 10:39:22 EST 2003


If its bad enough, you will see skips or jerky motion.  Also, there
are messages left on the shell that started mythtv (stdout or stderr)
that to me indicate some dropped frames.

You note raises a new question for me however...

Is there a limited collection of resolutions the capture will work
with?  For instance, I've had good luck with
320x240, 480x480, and 640x480.  However I tried 480x360 (1.5 times 
320x240) and it dies (some core capable error). 
 So I was about resigned  to the standards
then I saw your note of yet a new combination that apparently works.
I was trying to stay with the same 4x3 ratio, but apparently that's
not needed either.  I've never seen any docs or writeup as to
what resolutions are ok.

Brian




On Tue, 21 Jan 2003, Doug Wiltanger wrote:

> I have a quick question, how can one tell that it's dropping frames?
> 
> I've been running on an Athlon 1100 with 512X384.  640X480 doesn't seem to
> work well with live TV and MPEG4 encoding.
> 
> 
> ----- Original Message -----
> From: "Bruce Markey" <bjm at lvcm.com>
> To: "Development of mythtv" <mythtv-dev at snowman.net>
> Sent: Tuesday, January 21, 2003 5:03 AM
> Subject: Re: [mythtv] Box Processor Limits
> 
> 
> > Jarret R wrote:
> > > I was reading the Myth site and was slightly confused by the figures. On
> > > the site it says that high quality takes 50-60% of an Athlon 1800+. The
> > > TiVo only has a twenty-something megahertz processor in it and it can
> > > encode etc without problems. Which process is taking all the CPU time?
> > > Is it the encoding scheme used? I decided to build a myth box, and we
> > > are trying to figure out if the Duron 650 I have will work or if I
> > > should use the Athlon 1100 currently in my extra box. Is the problem
> > > when encoding and decoding at the same time?
> > >
> > > Sorry for the newbie questions ;)
> >
> > Janet, no problem. However, I don't know if you got a
> > useful answer yet ;-).
> >
> > To record mpeg4 at 640x480 without dropping frames generally
> > takes a little less then the equivalent of 1GHz of AMD cycles.
> > Your Duron may work but only at disappointing resolutions.
> > The Athlon should easily handle the MythTV default (480x480)
> > and should be able to record and playback at 640x480 with
> > little or no jitter.
> >
> > For playback, decode is surprisingly lightweight and uses
> > only a fraction of the CPU time that it takes to record.
> >
> > Hope this helps,
> >
> > --  bjm
> >
> >
> > _______________________________________________
> > mythtv-dev mailing list
> > mythtv-dev at snowman.net
> > http://www.snowman.net/mailman/listinfo/mythtv-dev
> >
> 
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev at snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-dev
> 
> 



More information about the mythtv-dev mailing list