Capture Card Resolution -- was: Re: [mythtv-users] 2 Capturecard questions

Edward Wildgoose edward.wildgoose at
Sun Mar 23 08:40:55 UTC 2003

> Well, I have some interesting (yet frustrating) results.  It seems the
> for me is the height.  I can record at 720x240 using mpeg4 at only like
33% cpu,
> rtjpeg works great too.  However, if I select 480 for the height, the
quality is
> terrible no matter what the width is and the cpu usuage is very high.  I
have a
> P4 1.5Ghz using a WinTV Go for capture and NVidia 440MX for TV out (3123

Define "quality is terrible"?  Do you mean lost frames, ie jerky video or
that the picture is grainy and horrible?

Lost frames would seem to imply a performance problem.  Check for DMA on the
hard disk (hdparm /dev/hda) first.  Does switching to rtjpeg help?

The other thing that I have found is that adding a "gbuffers=lots" option to
the bttv module options helps quite a bit, although this seems to be against
the general advice that I have seen elsewhere (this file is usually
/etc/modules.conf - google on gbuffers= for more documentation)

Did you find it fairly easy getting tv out on your NVidia?  Is the 440MX
fast enough for myth game and general video duties?  I am assuming that it
runs cool enough to air cool?  I am thinking about getting a cheap one to
replace my ATI Radeon which I have so far failed to get TVout working...

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