[mythtv-users] PVR250 or HD3000?

[Fred Squires]

On Mon, 20 Dec 2004 14:24:18 -0600, Michael J. Lynch <mlynch at gcom.com> wrote:
> Preston Crow wrote:
> 
> >On Mon, 2004-12-20 at 14:56, Michael J. Lynch wrote:
> >
> >
> >>Other than cost, is there any reason to choose a PVR250 over a pchdtv
> >>hd3000 since the latter can MPEG2 encode both NTSC and ATSC?
> >>
> >>
> >
> >You need to go back and do some more research, as the HD-3000 doesn't
> >MPEG encode anything.  (ATSC is broadcast as MPEG, so no encoding is
> >required by the recipient.)  Most HD-3000 users also use a PVR-250 card
> >for NTSC.
> >
> >Check the list archives.
> >
> >
> >
> That's not what the pcHDTV website says.  It specifically states that
> the card
> MPEG2 encoding.  See the second line of paragraph 2 of the following link:
> 
> HD-3000 at pcHDTV <http://www.pchdtv.com/hd_3000.html>
> 
> The line I'm referencing is:
> 
> "The card receives NTSC and ATSC Signals and converts them to
> digital streams which are transported across the PCI bus."
> 
> I know that ATSC is already MPEG2, does this possibly mean that
> NTSC is converted to some digital format that is something other
> than MPEG2?
> 
> Further reading on the page suggests NTSC is, in fact, MPEG2 encoded.

It converts them to a digital stream but it doesn't encode them as
mpeg.  ATSC is fm modulated mpeg2 video, it's simply demodulated by
the hd3000, but NTSC is modulated analog video.  The hd3000 simply
samples the demodulated signal at whatever resolution and bitrate it
does and sends that info over the pci bus.  Your computer can either
save this raw video directly to disk or transcode it  into another
format, such as mpeg2 or mpeg4.It basically works just like an ati tv
wonder or similar card.


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