Sysex messages restricted to 39590 bytes in size

[eclab]

I am using Edisyn, which has long been a CoreMIDI4J editor. I'm building a new patch editor in Edisyn which targets the Kawai K5000. The K5000 has a very large sysex file, and CoreMIDI4J appears to truncate it to 39590 bytes. I can receive arbitrarily large sysex files. This is an unfortunate result.

I include an example sysex file and a simple uploader which uses CoreMIDI4J via a MIDI library.

example.zip

[eclab]

I do not believe this is an issue with my USB interface (presently a Roland UM-ONE) for two reasons. First, it can download huge messages without issue. Second, the message uploading is also truncated if it's sent to a MIDI Loopback. I will check in a day or two with another interface (a Tascam US2x2), but I'm not hopeful.

[eclab]

I'm on MacOS 12.6 on an M1, running Java 20.

[brunchboy]

I am hoping Derek will eventually find some time to weigh in on this, but have you tried looking at the source code if you see anywhere that a buffer size could be increased? You could then try running a custom build to see if it addresses your problem.

[eclab]

I have not: indeed I wouldn't even know where to start.

I can say that large sysex messages appear to be properly emitted in Windows, so this is probably not a top-level Java API issue; it's either a problem with CoreMidi4J or just above it in the Java Midi stack.

[DerekCook]

Sorry for delay. Life is as manic as ever...

To the best of my knowledge, and I've just had a quick check, there are no hard coded buffer sizes in the CoreMIDI native code. Memory for MIDI Packets is allocated based on the reported size of the packet.

Likewise on the Java side, I could not see any hard coded buffers

TBH, because the code is quite old and stable it means I barely look at it, so after ten years, I barely understand what it is doing any more!