linux at thehobsons.co.uk
Fri Dec 2 08:24:51 UTC 2011
Jarl Friis wrote:
>I am new on the list. New to MythTV
Welcome - once you get it going, you'll wonder how you managed without it !
>I need a backend. Is that just a plain PC with some of the capture
>equipment mentioned on the wiki?
Yes. Just a regular PC or server, loads of disk space, and some
capture devices appropriate to your location/available services.
It's worth having a good trawl through the archives as there've been
some lengthy threads form time to time about "best" backend setups.
To summarise :
Ideally you want your storage on separate disk(s) to your OS and DB -
though many of us manage without. I/O transfer rates are fairly
meaningless, it is generally seek times that limit performance. If
you are writing and reading multiple recording streams on one disk,
eventually the seeks become the limiting factor and you start to get
Multiple recording disks will help with this, Myth will automatically
attempt to spread recording load across multiple disks.
Don't raid or stripe your recording disks together, you'll get better
performance with individual disks.
>I need a front end. Any good recommendation? It is probably going to
>be vissible in the TV room, so it would be nice with a reasonable
>design and low power consumption and low noise here, right?
That's as likely to get you a definitive answer as asking which is
the "best" position for sex ! Everyone has their own ideas about it.
One option is a low powered CPU with a capable (and supported) GPU.
You'll find plenty of references to Atom based systems with nVidia
graphics which are supported using VDPAU (an API for using the GPU).
Alternatively, you need enough CPU horsepower to do everything.
Whether you plan to do HD has a big impact on performance required as well.
>How are things supposed to be connected? Is video being transfered
>from backend to frontend over LAN/ethernet or by HDMI or something
>What about from frontend to TV? Is that going to be LAN as well or HDMI?
From backend to frontend is in compressed format. If you have
DVB-[CST] (or something else in the US) then the broadcast signal is
digital, and Myth stores it as it's been sent. here in the UK,
standard definition Freeview (DVB-T) runs to between 1 and
3GByte/hour depending on channel and program. HD is a lot more.
If you don't get a nice pre-compressed digital signal - analogue
transmissions, or an analogue capture card hung off a proprietary
satellite receiver for example, then your capture card will both
capture frames and compress it into a digital stream. In this case,
what you store and pass across the wire to your frontend is
determined by your capture card settings.
Use a wired LAN, 100Mbps is adequate. Wireless "works" but may not be
reliable all the time and you may get annoying pauses or stuttering
Between your frontend and the TV is whatever the TV supports. If your
frontend and DVI or HDMI out, and the TV has HDMI in, then that's
probably the best to use. But anything from composite video (yuck),
through RGB via SCART, and HD via component video can be done -
that's not something restricted by Myth.
Hope that helps.
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