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IDProjectCategoryView StatusLast Update
0001297OpenMPTPlugins / VSTpublic2020-03-07 10:02
ReporterAndreB Assigned To 
Status closedResolutionno change required 
PlatformoldOSWindows XPOS VersionSP3
Product VersionOpenMPT / libopenmpt 0.4.11 (upgrade first) 
Summary0001297: Midi-Out plug-in swallows SYSEX message

When my Midi-VST sends out a Sysex-Message to my Synthesizer, it doesn't go through.

Steps To Reproduce

Well, you need a VST that can send out a sysex message, send it to the midi-in/out-plugin, and see if it reaches your synthesizer.

TagsNo tags attached.
Has the bug occurred in previous versions?yes
Tested code revision (in case you know it)




2020-03-02 15:23

reporter   ~0004238

Any advice appreciated.

Saga Musix

Saga Musix

2020-03-02 15:42

administrator   ~0004239

  1. Which VST plugin is used to send the SysEx message?
  2. Is your synthesizer maybe configured to filter out certain messages? (e.g. check program memory protection if you are trying to modify programs)
Saga Musix

Saga Musix

2020-03-02 19:56

administrator   ~0004240

I just tested this with a SysEx message being routed through Kirnu Arp and then on to the MIDI I/O plugin, and the SysEx message arrived at the connected synthesizer. So it must be either the VST plugin you use doing something weird, or your synthesizer filtering the message.



2020-03-02 21:08

reporter   ~0004241

Dear Saga Musix
thank you very much for your swift service / investigating this!
To answer your question: It's a not yet published VST, but it worked as a stand-alone exe file. And no, the synthesizer is good with it. It's really something in connection with the midi-i/o of OpenMPT, but we'll checkwhere it could be on our end. I wouldn't have had another chance to test it, so I am thankful you could do that, so I know that the midi-i/o does usually take them. (I read something about sysex in the version history, but I wasn't sure if it pertained to this)
Can I contact you in case I stumble over someting else?
Kind regards,



2020-03-02 21:15

reporter   ~0004242

I had the midi-VST loaded as a vst from the same category as the midi-i/o-plugin. Then, I connected its output to the midi-i/o by way of the output select thing under 'General'. Everything else (notes, volume, etc) worked, except for the sysex messages. what format do the messages have to be written in, all hex? Sorry for asking strange things, I'm not the programmer. :D

Saga Musix

Saga Musix

2020-03-02 21:33

administrator   ~0004243

If you are not the programmer but it is an unpublished plugin, then please ask the programmer how they are sending SysEx messages in the plugin. OpenMPT can only process SysEx events if they arrive via the audioMasterProcessEvents opcode as a VstMidiSysexEvent (and I cannot think of any other way OpenMPT could be receiving those events from the plugin).

what format do the messages have to be written in, all hex?

That entirely depends on your plugin. OpenMPT does not receive a hex string from the plugin, it receives the actual raw bytes.



2020-03-07 07:30

reporter   ~0004250

Dear Saga Musix,
The programmer made it in SynthMaker, and he found out by now, that when compiling the program into VST, the Sysex-messages get sent the wrong way. I'm sorry for having bothered you, and I thank you for your help. The thread can be closed. Best regards - Andre

Issue History

Date Modified Username Field Change
2020-03-02 15:16 AndreB New Issue
2020-03-02 15:23 AndreB Note Added: 0004238
2020-03-02 15:42 Saga Musix Severity block => minor
2020-03-02 15:42 Saga Musix Note Added: 0004239
2020-03-02 19:56 Saga Musix Note Added: 0004240
2020-03-02 21:08 AndreB Note Added: 0004241
2020-03-02 21:15 AndreB Note Added: 0004242
2020-03-02 21:33 Saga Musix Note Added: 0004243
2020-03-07 07:30 AndreB Note Added: 0004250
2020-03-07 10:02 Saga Musix Status new => closed
2020-03-07 10:02 Saga Musix Resolution open => no change required