Recurring Crash Issue

[NetNomad]

Hey guys! Sorry if this has already been answered somewhere, I lurked for a bit and didn't have any luck searching my error code. I use OpenMPT to MIDI control my Yamaha PortaSound PSS-680 with a mio uSB MIDI cable and I've been experiencing frequent crashes, usually within 10 minutes of starting the program. The error reads like this:

>Unhandled exception 0xC0000005 at the address 736C0B1D

>Debug information has been saved to [a pathway I can't seem to get to, but that's probably another problem altogether]

>1 modified file has been rescued, but it cannot be guaranteed that it is still intact

>OpenMPT 1.26.0700 32 bit ( (clean))

After that it prompts me to open a file, and if I don't I have to force quit the program, and if I do open the new file, it immediately crashes and generates an identical report. Has anyone ever encountered an issue like this or has any advice? Thank you for reading!

[Saga Musix]

Since you mention MIDI specifically, do the crashes only occur while using MIDI? The MIDI I/O library we are currently using (PortMidi) seems to crash sometimes, so I have been looking into replacing it.

>Debug information has been saved to [a pathway I can't seem to get to, but that's probably another problem altogether]

That's weird, since this is just a subfolder of your temporary folder. You should be able to find it by typing %TEMP% into Explorer's address bar and then find the "OpenMPT Crash Files" folder in there. Please compress and upload the .dmp file associated with the crash from that folder so that I can have a look at it.

[NetNomad]

Explorer wasn't playing nice, but I managed to get there typing %TEMP% in like you said, thank you! The .dmp is zipped and attached. All of the crashes have been when I was using MIDI, usually directly after I enter a note but sometimes during playback.

[Saga Musix]

Thanks, I can confirm that the crash is related to PortMidi. For what it's worth, this problem is already being tracked here: https://bugs.openmpt.org/view.php?id=843
I'll see if I can provide an alternative test version for you to try out in the next few days.

[NetNomad]

Thank you, I appreciate it!

[Saga Musix]

Here is something for you to test:
https://sagagames.de/stuff/mptrack.exe
This version no longer uses PortMidi for MIDI I/O but RtMidi instead. The transition is not finished yet, so some things do not work as intended yet. In particular, latency compensation is currently not implemented, so compared to previous versions, notes might be played too early on the MIDI device. However, this will be fixed before the official release of OpenMPT 1.27.

Please try this version and report how it works for you. Hopefully, the crashes should be a thing of the past now, but I cannot know for sure.

[NetNomad]

Just used it for the better part of an hour, no crashes to speak of with RtMidi. Thank you again! I'll be sure to post any .dmps if it starts misbehaving again but it seems really stable to me.

[Saga Musix]

I'm glad it's working well for you so far. Windows MIDI has quite a few gotchas which PortMidi doesn't seem to take care of, while RtMidi seems to be much more mature in that regard.

[Saga Musix]

RtMidi is now fully integrated as of r7573. Latency compensation is now also implemented, with the improvement that the user can now add a (negative or positive) latency to OpenMPT's own output latency to cater for any additional latency in the system.
https://buildbot.openmpt.org/ will contain the new version in a few hours.