[LAD] latency issues (practical aid needed on a practical example) (fwd)

[Nedko Arnaudov]

Julien Claassen <julien at c-lab.de> writes:

> Hi everyone!
>    (this was first posted on Linux-Audio-Users, but is probably really more 
> suited to this list.)
>    I just compiled a sound generator, which can be controlled vai MIDI, it uses 
> simpe raw-midi and jack as output, via bio2jack.
>    Now I have horrible latency 0.2-0.5sec (rough estimate). Where should I start 
> looking in my setupt. I know others had the software running without problems.
>    Sorry for being so abstract, but I'm not allowed to mention the software. :-(
>    I already tried setting internal audio-buffer to 128 samples and reducing 
> message queues for the tonegenerator and MIDI. Still it's much too much 
> latency. Does bio2jack have some settings for reducing latency? Does bio2jack 
> do samplerate conversion, is it costly? The sound-engines samplerate is set to 
> 44100 or 22050 and my JACKd runs at 48000.
>
>    But I could post parts of the source if necessary.
>    My setup is:
> Debian Lenny with custom built kernel 2.6.24-rt1
>    JACK subversion 0.109.0
>    jack-commandline:
> jackd --timeout 4500 -R -d alsa -d hw:1 -r 48000 -p 128 -H -M -z shaped
>    ALSA version 1.0.15
>    Any idea where to optimise?
>    Kindest regards
>           Julien

Realtime addicted people tend to use JACK with realtime kernel and JACK
MIDI ;) No bio2jack eresy :P

-- 
Nedko Arnaudov <GnuPG KeyID: DE1716B0>
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