[ecasound] Re: [linux-audio-dev] Re: [Jackit-devel] Maybe I'm going at this wrong...?

Kai Vehmanen kai.vehmanen at wakkanet.fi
Thu Sep 9 19:41:34 UTC 2004


to avoid too heavy cross-posting, I dropped jackit-devel from the 

On Thu, 9 Sep 2004, Eric Dantan Rzewnicki wrote:
> seeing aren't reported by jackd at all. I only see them from the 
> ecasound instance that is hosting the analogueOsc LADSPA plugins and 
> only when it exits. The rtnull input object reports them when this 
> ecasound instance exits. Every ecasound chain has to have an input and
> an output. Since I just want the audio from the plugin, which in
> ecasound's world is an effect attached to a chain between an input and
> an output, the rtnull input object serves as a place holder virtual 
> audio device/file/thing.
> Maybe these xruns are red herring? Kai?

Definitely! You should use "null" instead of "rtnull" if you have any 
JACK, ALSA, or other real-time objects in the same setup.

Rtnull, or realtime null, consumes or produces data at real-time speed 
(unlike plain "null" that does the same as fast as it can). This is useful 
feature in some circumstances, for example when writing audio to a pipe 
and from there with netcat to network. Without rtnull, you'd overflow the 
network interface (and the receiving end).

But if you have both rtnull and jack/alsa devices in the same setup, you 
will get xruns, as rtnull is driven by the system clock while jack/alsa 
are driven by the soundcard clock. Sooner or later the clocks will drift 
enough and you'll start to get constant xruns.

 Audio software for Linux!

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