[mythtv-users] pcHDTV w/ MythTV

[Doug Larrick]

>> 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).

> 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.

-Doug
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