[mythtv-users] Building a system from scratch

Brandon Beattie bbeattie-maillist at linkexplorer.com
Tue Nov 18 17:12:24 EST 2003


On Tue, Nov 18, 2003 at 03:10:51PM -0500, D Banerjee wrote:
> > I was also looking at the WinTV-HD card.  I figure down the road, as
> > HDTV catches on, it would be ideal to have this (though I'm also far
> > from an hdtv expert).  FWIW, I have an HDTV ready tv, so think I'm good
> > there.  Looks like HDTV is already broadcast as mpeg2, so hdtv doesn't
> > need an encoder?  Looks like this card has an mpeg-2 decoder, but not an
> > mpeg-2 encoder(?)...  Also, looks like it has the tv out (obviously) to
> > connect to the hdtv itself.  For non-HDTV signals, I'm guessing with
> > this card it needs to encode in software?  Is this card (well) supported
> > in MythTV (is this the pcHDTV card noted on the MythTV homepage as being
> > better supported in .12)?
> 
> If you plan on using hdtv, don't waste the money on a 350. You will
> want/need an nvidia card (because it has hardware decoding acceleration
> under linux) take a look at www.pchdtv.com Also your tv-out will not be a
> "tv-out" you will split your regular monitor video output into your hdtv.
> Google for hooking up your computer to hdtv. HDTV is broadcast as an mpeg-2
> stream, you just save it to disk, no cpu involved, but you will need a good
> processor and a good video card with acceleration to play it back.
> 
> btw, it seems the current crop of hdtv cards have both the hd-mpeg capture,
> and a regular analog input. Afaik this isn't work _yet_ on the pchdtv, but
> it's just an issue of someone fixing the drivers. This _is_ bleeding edge,

The NTSC tuner on the pchdtv card does work with Myth.  The known issue
is that Myth does not support having different tuner types in a system.
(ie, in myth setup you have to pick if your system will get NTSC, ATSC
(HDTV), PAL, NTSC-JP, etc.  If he/you are planning on using NTSC for
now, and then using ATSC/HDTV in the future, the pchdtv card and MythTV
will work just fine -- But don't try to use ATSC and NTSC modes at the
same time (It won't work anyway).  There is also another known problem
that the pchdtv card does not play nice with other tuner cards (any ntsc
card, like the 250, 350, or any generic tuner card).  This is because
the pchdtv card uses a custom bttv driver that broke a non-pchdtv
specific tuners -- People are working to fix this already.

> > My end goal would be to put a large box with multiple encoders in a
> > central location, connected to the hdtv, later creating smaller mythtv
> > frontend boxes for around the house.
> >
> 
> This is ok if you know what you are doing with properly designing a system
> for sound and air-flow. i.e. 5400rpm FDB drives, soft-mounted, sound-proofed
> case, etc. I have 7 5400 rpm FDB drives in a system with soft-mounts, it's
> hard to hear them idling/reading even with your ear next to them.

I personally used an AMD 2600+ system with 2 hdtv cards.  I'm working on
finishing a PIII 450 system to hold the 2 hdtv cards, a 30gb drive for
the OS, a 180 drive for my movies that are ripped, and a 200 GB drive
for HDTV content.  This will work because HDTV requires no encoding, as
it's already mpeg2 data.  (But I do transcode to a smaller res).  I'll
post the results of this test, but it should work on this older
computer.  (Unless we add to much to the hdtv recorder source that
requires a fast processor, but right now recording HDTV is simply
dumping data to disk and that's it -- All IO.

My 2600+ will become my frontend as you need about an AMD 3Ghz or P4
2.6Ghz system to decoding/de-interlace all types of HD data in realtime.

I'll buy a shuttle with a prescot (P5) CPU when they come out, as the
frontend will require more CPU than the backend for HDTV multi-frontend
setups.  (Unless you transcode all HD content down to smaller res, then
the backend would require more CPU and less on the frontend.. but you
get my point.

--Brandon



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