[mythtv-users] Processor Requirements for different HDTV formats?

Joe Barnhart joebarnhart at yahoo.com
Tue Oct 19 16:25:39 UTC 2004

--- Jason <potuncle at enjoyingeugene.com> wrote:

> I currently have a Pundit PIII 2.4Mhz with a PVR-350
> and now have a 
> pcHDTV HD-3000 on order. I have read that my 2.4Mhz
> is going to have 
> some problems decoding the HDTV signal without frame
> drops, but I want 
> to know if this applies to decoding all HDTV formats
> or just 1080l 
> and/or 1080P.

Broadcasters typically use either 1080i or 720p
resolutions.  When a network chooses one or the other,
they convert all of their material to that format --
they don't change back and forth.  One exception is
that they change between non-HD and HD resolutions all
the time (i.e. 480i and 480p) depending on whether
they have anything high-def to broadcast.

> Also, can the PVR-350 be of any assistance in
> decoding HDTV recordings 
> since HDTV is encoded using MPEG2 and the PVR-350
> has a hardware MPEG2 
> decoder?

Decoding in hardware is your only hope with a P3.  I
found XvMC to be too problematic to use on either
Athlon or P4 systems.  It hangs the frontend if you
just press the skip forward or backward button. 
Perhaps it works better with non-nVidia cards, but
with the nVidia 6111 driver it's just plain broken. 
The good news is that Xv works very well.  On a P4
(530, 3GHz) it takes about 60% cpu to play a 1080i
stream vs. 40% for XvMC, so it's not such an enormous
difference.  I have no idea if the MPEG decoder on the
350 will help or not -- I'll be watching replies

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