----- Original Message -----
> From: "Alessio Elmi" <[email protected]>

> Here's the scenario:
> Client A with RDAirPlay and playout system, server B with MySQL and
> audio
> share (NFS exported). On the client we use a special keyboard like
> this
> http://www.tipro.net/ecatalogue/64-programmable-keys. Every key is
> associated to a key-shortcut (like CTRL+SHIFT+E or whatever). Ubuntu
> catches the combo and execute a .sh file, containing a rmlsend
> command.
> Most of them are sound panel start/stop or Next command. A bit
> complicated
> but works.
> 
> From the moment we press NEXT button (on our keyboard) to the moment
> we actually hear sound, *sometimes* it takes like 3-500ms...
> 
> But (!) if we pre-listen the song (double click on the left side of
> RDAirPlay), then when we will press NEXT it will start almost immediately,
> as it were moved in cache and got ready to be played.

It's partially the caching of the media, and partially the caching of 
your shellscript.  It takes a finite amount of time for a program to start
running, and you're launching them off a button.  If I were you,
I'd merge all your scripts so it's one script with an argument; I know
that deprives you of a little administrative flexibility, but it will
increase the odds that script hasn't been pushed out of cache when you
need to run it.

Past that point, you're going to need to instrument your script and
run wireshark on your network to see if you *also* have a delay problem
in your NFS.  If you want to get below 250ms, you're in soft-realtime
territory, and you need to take special measures, yes.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       [email protected]
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274
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