[LAD] Maximum size of SysEx messages in JACK MIDI and ALSA sequencer

[Dominic Sacré]

Hi,

I'm wondering what the size limit is for SysEx messages in the JACK MIDI 
and ALSA sequencer APIs. My observations so far:

In JACK MIDI, a SysEx message can be as large as the MIDI port buffer, 
which in turn has the same size as an audio buffer for one period. This 
is assuming that there are no other events transmitted on the same port 
during the same period.
Is this correct? Or are applications somehow expected to handle larger 
SysEx messages split over multiple periods?

In the documentation of the ALSA sequencer API, I couldn't find any 
mention of an upper limit. Some sources suggest that ALSA splits SysEx 
messages into chunks of 256 bytes, but from my own attempts at sending 
larger messages, it seems the limit is actually somewhere around 5500 
bytes. Unfortunately ALSA doesn't seem to report an error when I try to 
send larger chunks, instead the messages just disappear. Can anyone shed 
some light on how to handle larger SysEx messages correctly?


Thanks,

Dominic