[LAU] Sysex with Jack MIDI

Alexandre DENIS contact at alexandredenis.net
Thu Nov 5 00:51:58 CET 2020


On Tue, 3 Nov 2020 23:45:24 +0100
Alexandre DENIS <contact at alexandredenis.net> wrote:

> On Tue, 3 Nov 2020 09:56:36 -0800 (PST)
> Len Ovens <len at ovenwerks.net> wrote:
> 
> > The one question I do have is the buffer size (128/2 ?) and if you
> > tested at more than one buffer size. I would expect that the two
> > would be tied together.   
> 
> Even with a buffer size of 2048, a sysex message of 139 bytes cannot
> be sent (but can be received).
> 
> -a.
> 

Somme follow-up.

I upgraded jackd from 1.9.12 to 1.9.16. It didn't change the result.

Then I tried to use the MIDI subsystem of the ALSA backend, instead of
a2jmidid. It works correctly. So the bug is actually in a2jmidid.

I had the habit to use a2jmidid, because I had previously a soundcard
supported only by FFADO, but now that my main soundcard is supported by
ALSA, I can switch.

However, what is annoying with MIDI through the ALSA backend is port
naming scheme. It doesn't follow ALSA naming scheme, so port grouping
is broken in Catia. It replaces spaces in names with dashes. And funny
thing, 'capture' and 'playback' are reversed in the aliases! Example,
from jack_lsp -A:
system:midi_playback_21
   alsa_pcm:Prophet-12-Keyboard/midi_capture_1
   Prophet-12-Keyboard:midi/capture_1

The main name here is *playback*, aliases are *capture*. WTF?

-a.

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