[mythtv-users] Re: Large-scale myth farm

[Stephen Boddy]

Just a quick note that, depending on your system and set-up, the transcoding 
may take longer than you expect. I have an Athlon 64, and the cool-n-quiet 
means that when idle it roughly halves the processor speed. Niced processes 
(i.e. the transcoding) do not cause the processor to ramp up to full speed. I 
found this out when I niced the MythTV compile and wondered why it was taking 
so long.

On Monday 03 October 2005 18:06, Derek Meek wrote:
> one quad opteron system could easily commflag and transcode four at
> once - and probably capture at least one and display one at the same
> time
>
> trancoding is niced at 17 so if something like capture and/or display
> is going on it looses CPU to the more important process and simply
> takes longer to complete.
>
> Trancoding 640x480 29.97 fps RTJpeg .nuv to MPEG4 runs at about 1/2 to
> 1 hr of time for each 1hr of video when no other tasks are running on
> my Athlon XP 2500+ with 1GB of RAM.  my MPEG settings are something
> like 1200bps with all three settings recommended for internlaced and
> mp3 quality at like 6
>
> comm flagging happens in about 1/2 the time
>
> On 10/3/05, Illtud Daniel <illtud.daniel at llgc.org.uk> wrote:
> > 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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-- 
Steve Boddy