[LAU] A2J-MIDI Bridge error

[Len Ovens]

On Sat, 21 Dec 2013, Kevin Utter wrote:

> The uname -a shows:
> Linux StudioLinux 3.5.0-42-generic #65~precise1-Ubuntu SMP Wed Oct 2 20:57:18 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
> Studio is just its name reflecting location, it isn't a special blend of Linux.

I would sugest that installing linux-lowlatency would make a difference as 
many of the settings depend on having the access provided in the 
lowlatency or RT kernel.

Lowlatency vs. RT:

RT is a patched kernel. It does provide better latency performance, but 
there may be some problems with those code chunks needed for video or 
wireless etc. On a Ubuntu system you would have to roll you own.

Lowlatency is the same as the generic kernel with one or two config 
changes when compiling that allow some preemptive operations like setting 
interupt priorities for example. It is precompiled and can be installed 
with apt-get, synaptic, The kde variants... who knows, maybe even USC

I have only one audio IF (at least I only use one at a time) and use the 
lowlatency kernel. I am able to get less than 1ms latency with no xruns 
when I turn off hyperthreading.... of course the audio card itself has 1ms 
delay internally that is not included in that :)  Anyway, in my case the 
RT kernel would not add anything. This is also true for most USB audio IF 
as their lowest latency is around 5ms as determined by their smallest 
buffer settings. RT kernels might help when using more than one audio card 
at a time. Note that a MIDI IF is not an audio card and is treated 
separately even if it is a aprt of the same card as the audio IF. The MIDI 
port is just a serial port that is treated specially. It is not even that 
fast.

--
Len Ovens
www.ovenwerks.net