[mythtv-users] Looking for initial advice.

Dewey Smolka dsmolka at gmail.com
Sun Jan 14 19:10:22 UTC 2007

On 1/14/07, Steve <mythtv at birniefamily.net> wrote:
> Hello mythtv-users.
> I currently do not have a mythtv system, but I am in the process of
> deciding what pieces of hardware I need to create one.  I am making a
> bunch of assumptions throughout here because I am VERY unfamiliar with the
> technologies and terms of video and audio (MPEG-2, SDIFF, etc).
> I live in the US, currently use cable service, have an HD TV, subscribe to
> their HD-tier, and send the audio output through digital out into my
> stereo receiver for 5.1 surround.  I'd like to be able to build a system
> where I don't lose any of that functionality.  I realize that some of the
> HD channels that are in the HD tier may be unavailable if it's encrypted.
> (1) CPU.  I have several pc's that aren't in use right now, but I am
> assuming this will be decided AFTER I pick some of the other pieces of
> hardware on how beefy a CPU I will need.

CPU strength and speed is more critical to playback than to recording,
particularly with HD content.

> (2) Video input cards.  The HOWTO lists several different HD tuner cards,
> but says none of them do any encoding.  Does that mean that when it's
> recording the input from the cable that it will have to encode using
> software when writing to disk?

For SD cards, the Hauppage PVR series are golden as they do the
encoding on the card hardware.

Although I don't have any experience with HD (yet), the HD cards
mentioned often on this list (eg the pcHDTV series) will not require
much in terms of processing power while encoding since the task is
much simpler -- a PVR card needs to turn an analog signal into an MPEG
stream while unencrypted HD is already an MPEG stream. The capture
card is basically just dumping the stream to disc.

> (3) Video output card.  ATI, NVIDIA?  Is one choice better than the other?
>  I've read some things about drivers, etc.  Also, Do they have models that
> will output to 1080i or 720p?

Nvidia. People have got ATI cards working, but nvidia cards are more
common and better supported, particularly when a setup requuires Xvmc
acceleration for HD playback.

The gold standard is the fx5200, based on its low cost and solid
performance. This card can easily be found with VGA and DVI outputs,
and in fanless configurations. I believe some of the 6x00 series
nvidia cards have component out but I'm not sure. If your HD display
supports VGA or DVI inputs, this is probably the way top go. All the
nvidia cards (AFAIK) support S-video out, which can drive an SD

> (4) Audio input card.  Is one needed or will the video card be all I need?
>  Will the pcHDTV cards record in mono, stereo, or 5.1?

The PVR series cards hve audio on the card. Not sure about the pcHDTV
cards or surround passthrough, but I believe it is supported.

> (5) Audio output card.  What cards are available that will output so I
> will be able to listen to the shows that record in 5.1?

There are options, but I've had very good experience with Turtle Beach
cards. They are well supported under Linux, support various surround
modes, AC3 passthrough, and S/PDIF. Plus they're very reasonably
priced. I use a Riviera, which supports S/PDIF optical, 7.1 surround,
is very clean sounding over the analog outputs, and runs around $30

> After hardware, I have a few questions regarding the general setup:
> It sounds like it's a good idea to go with a 2 machine setup.  One as the
> backend that records, stores, and manipulates all the shows and one that
> will pipe the recordings/live-tv to the television/receiver.  Is that
> correct?  Would it be better to put both video input cards on the backend
> machine, or put one on the backend and one on the frontend?

Just to clarify things a bit: a mythbackend is a machine with a tuner
on it. A mythfrontend is a machine that runs mythfrontend. Whichever
machine runs the MySQL server is the master backend. These roles can
all be on one machine or spread across however many you want.

But any machine with a tuner/capture card is by definition a backend.

The most common setup, and the easiest way to begin is with a combined
FE/BE. This will reduce the amount of time it takes to get the system
up and running, and reduce the expense until you've had a chance to
work with the system a while a figure out more specifically what you
need for expansion.

The requirements for FEs and BEs are a little different as well. For
the BE, a powerful processor helps but is not essential. What is
essential is expansion capacity -- you will want plenty of PCI slots
and plenty of drive bays. The more storage the better.

On the FE, CPU performance is much more important, especially the
horsepower to decode HD content. Many people want small, quiet, and
attractive FEs. But if you load a small machine with heat-producing
components like capture cards and HDDs, and combine that with the
small-size fans in small cases, you'll end up with a fairly noisy

I'd recommend you start with a combined BE/FE box in the system you've
already got. Tower or mid-tower cases that support ATX motherboards
are better for this type of system -- they can support lots of cards
and HDDs, as well as larger fans (a small fan has to spin faster than
a large fan to move the same amount of air; higher fan speed means
more noise).

Once you've got your combined box working to your satisfaction, then
you can set up a FE machine in a small, attractive case, since your FE
will only require a small HDD for OS (or no HDD if you use
netbooting), and a video card. Less heat means less noise.

> To get familiar with everything, I used one of my existing PC's without any
> input card.  I figure this is just throwaway work, but my hope is to get a
> better understanding of MythTV.  I found a great article for installing with
> Ubuntu, so I went that route.  I set up for a backend/frontend combo and
> installed the plugins.  I obviously couldn't add an input card during the setup,
> but I was able to set up downloading of content, etc.
> I can use the mythweb, but I can't figure out how to use the weather one.
> Is the mythweb the main interface to the frontend?

I think the Mythweather module is undergoing repair at the moment and
is not entirely functional.

Mythweb is very useful for setting up and administering recordings but
is more of an interface for the backend than the frontend. Each FE can
perform the same scheduling and administation tasks as mythweb, as
well as being set up individually -- i.e. a FE hooked up to an HD
display will be configured differently than one hooked up to an SD

Hope this helps, and good luck.

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