[mythtv-users] pcHDTV w/ MythTV
curtis at penguinbrat.com
Tue Feb 17 10:14:05 EST 2004
Thanx for all the info - it really helps..
On Tuesday 17 February 2004 07:35 am, Doug Larrick wrote:
> >> I saw in one of the other threads about needing a P 3g-HT machine to
> >> do this on? Is this true?
> > With hardware assistance (nVidia XvMC), you can get by with less (like
> > 2.4GHz, IIRC), but the quality is somewhat diminished. Otherwise, yes,
> > 3.0GHz. :-\
> FWIW, I think more recent ffmpeg versions have done some performance
> work in this area. It also helps significantly to add a '-mpentium4' to
> the compiler flags in the libavcodec directory (assuming you have a P4
> :-) ). My P4 2.8 GHz (w/ HT) is ticking along at 40-60% CPU decoding &
> displaying 1080i now, with normal Xv (not even XvMC).
Just as an FYI on the speed issue - I received a reply from pcHDTV sales about
a few things, and one that they mentioned was that the 2.6 kernel improved
performance signaficantly. The first driver works (2.6.0-test4) but something
about the drivers being broke on the latest kernel - they are suppose to get
new version out in a week or so that does work :-)
-- "With the early versions of 2.6.0 there was a significant improvement in
performance over the 2.4 kernels."
> > At the moment, nVidia's Linux drivers don't support interlaced modes, so
> > no 1920x1080i. Supposedly, the next release, due by the end of March,
> > will feature interlaced mode support.
> I'll believe it when I see it, but this would be nice. I actually run
> at 1920x540, and have inserted relevant calls to 'xrandr' to switch back
> to 960x540 for the GUI. If I could think of a clean, general way to do
> this, I'd submit a patch.
> >>>> I currently have the PVR250 card and it seems to work pretty well,
> >>>> it would be very nice to be able to get that kind of quality from the
> >>>> pcHDTV - is that even possible?
> >>> What exactly do you mean by "that kind of quality"? The quality of the
> >>> video captured by a pcHDTV card BLOWS AWAY the video captured by a
> >>> PVR-250. If you mean quality as far as stability, it isn't quite as
> >>> good, but steadily improving.
> >> That is kind of a bad question - what I meant was the smoothness of
> >> the 250, it has the encoder on baord, so its not a capture card - does
> >> the pcHDTV stream mpeg2 or capture like a normal tv card? It seems that
> >> from some of the responces I've seen and on the pcHDTV site, it streams
> >> mpeg2 like the 250 does...
> If by 'smoothness' you mean smoothness of motion, no, we're not there
> yet. This issue is most noticeable when the image pans -- the frame
> cadence is not even enough to appear smooth. I believe this problem can
> be tuned out of the various video sync methods. I am making slow
> progress here, but haven't had a lot of time recently.
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