[mythtv-users] Seeking Advice

[Michael T. Dean]

On 07/25/2007 12:23 PM, Joshua Gottlieb wrote:
> Ok, so I'm a noob at all this.  Now I have tried to do a good deal of
> reading on the forums and what not trying to get a feel for the
> recommended hardware etc.
>
> I'm trying to build a box from scratch, specifically for mythtv. 
> Originally I had planned on getting a Hauppauge PVR-350 so I could
> have the MPEG2 decryption on the card.

That's actually decoding.  Oh, and, IMHO, putting MPEG-2 decoding on an
external card is an anachronism.  Decoding standard-definition TV in
real-time has been an easy-enough task for general-purpose CPU's since
we hit the 800MHz mark or so.  Today, you can't really buy a CPU that
can't handle it.

And, in the event you get a "low-power" alternative processor (some of
the VIA's or whatever) and you want some "help" with decoding, you can
do so with XvMC--which is a function of the video card and its drivers.

>   This seemed like the ideal solution and I could get very low end
> hardware as all the work would be done by the card.  However, then I
> saw various comments about how the card is being phased out, soon to
> be not supported etc, etc...

And (again, IMHO) a complete and total waste of $50 to $100.  (Says
someone who wasted his money and bought a PVR-350 in 2003, on which he
used the video decoder for about 4 hours before deciding it was a
waste.  After then, I used the PVR-350 as if it were a PVR-150 or a
PVR-250.)

> So I started doing more research and noticed that there are a few
> small form factor motherboards that have TV-outs and built-in MPEG2
> decryption, so I thought maybe that would be a good path, but there
> didn't seem to be very many folks having used the newer hardware.

My recommendation is to get an NVIDIA video card and a PVR-150 (or
multiple PVR-150's).  The NVIDIA drivers work very well (for
proprietary, binary-only drivers, that is) and support XvMC on any
relatively recent GPU.  I'd recommend something from the GeForce 6000
series (i.e. GF6200) since the GeForce 4 series was end-of-lifed (no
longer supported by current drivers) within the last year and the
GeForce 5000 series is probably next on the chopping block, so the
oft-recommended GF5200 is likely to be EOL'ed "soon."  (Wouldn't it be
nice if NVIDIA published a "Linux driver support roadmap"?)

> Anyway, what I'm trying to do is get advice from the experienced folks
> on here to setup a good solid mythtv system.

Basically, the problem is that if you offload MPEG-2 decoding from the
CPU, it limits what you can do with video.  Using the PVR-350's built-in
decoder means you have to use the PVR-350's TV out--for video /and/ for
GUI.  It does not (and cannot) support OpenGL (which is the future of
the MythTV UI).  It also only supports 720x480 resolution and, IMHO, you
can get a much better result using a video card running at 800x600 or
1024x768 with the TV-out chip sampling from that picture.  (And, BTW,
regardless of what people may tell you, there's no equivalent of 1:1
pixel mapping for SDTV using a TV out.)

Mike