[mythtv-users] Large-scale myth farm

Illtud Daniel illtud.daniel at llgc.org.uk
Mon Oct 3 14:31:01 UTC 2005


Rob Willett wrote:

> Intersting to see a UK government org taking an interest in MythTV.

...Welsh government org, if you please! We're doing this on
behalf of the National Screen & Sound Archive of Wales, who have
agreements with broadcasters about recording reference copies of
broadcast material pertaining to Wales.

>>>UK DVB cards/receivers - which would you recommend?

> I persoanlly use the Nebula DVB card, though other people report
 > success with the Avermedia 771 card.

Nebula have some linux pages on their website - can people
confirm that they're linux friendly?

> You can setup the system to record the EPG information provided by the DVB
> stream. This works pretty well, though only has a week in advance. I've never
> used Subtitiles so can't say if they work.

Anybody out there with experience of DVB subtitle capture on mythtv?
Does mythtv only do 'live' subtitle decoding from the stream as it
plays, or does it capture the subtitles to somewhere else (SMIL?
MPEG7?).

> Mythtv does not support FM radio nor does it easily support DVB radio e.g. BBC 7
> without a patch. This is because there is no video send with the audio. This is
> a majot pain in the butt and I wish they would change MythTv to properly support
> Radio.

We'll need audio-only capture, either from an internal tuner or
a simple audio-in. We currently have an audio digitization
application, so it's not essential that we build this into Myth,
but it'd make sense to have it all in one. The BBC (I think
we very rarely record non-BBC radio) have some radio listings
on: http://backstage.bbc.co.uk/feeds/tvradio/

> Since there are 30 or so channels you wou would need around 5-7 servers
> depending on the hardware specs.

We'd only be recording some programmes. We've enough experience of
enterprise systems to build a resilient backend (though we'd have
to look at how we'd do failover on the master backend - the SPoF
of the system). How many quad opterons (Sun do the nice v40z)
would it take to transcode say four programmes simultaneously?
Could one server handle 4 DVB capture cards? What's the first
bottleneck people hit - the PCI bus? hard drive speed?

-- 
Illtud Daniel                                 illtud.daniel at llgc.org.uk
Uwch Ddadansoddwr Systemau                       Senior Systems Analyst
Llyfrgell Genedlaethol Cymru                  National Library of Wales
Yn siarad drosof fy hun, nid LlGC   -  Speaking personally, not for NLW



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