Export as midi channel issue

KingWolf · February 03, 2019, 01:40:27

I've tried to export an MPTM sequence as midi, using several different combinations of manually setting each instrument (the ones on a single channel) to a dedicated channel, and making sure the option to "allow instruments to overlap" unchecked, but I am still getting two instruments overlapping on channel 1. I've also ensured to not export any instruments not used in that particular sequence. The sequence has 16 channels. Channel 10 and 11 are used as percussion, but both will be mapped to channel 10. Channel 7, 8, 9, and 12 are unused. I am trying to preserve channel mapping for note panning, and other effects but for some reason, it's just not working out for me. Is this a known issue? Channels 14, 15, and 16 are a melody, using one instrument (which is why I want to map those as [any]). It seems like Channel 14, 15, and 16 get bumped up by one, causing channel 16 to be wrapped back to channel 1.

I hope this post made sense, and if you need mptm find it attached.

Sequence 5 is the one I am currently working with. There are no actual samples used, since I am using purely midi.
I should also mention that I use a specific soundfont, that isn't exactly in line with General MIDI... So weird midi patch choices are weird.

Sorry if this is an actual bug to report and in the wrong section, I am unable to access the issue tracker, due to "application errors"...

Saga Musix · February 03, 2019, 11:44:38

Channel 1 and 16 will overlap because in MIDI Export, "mapped" channels will avoid channel 10, so if a mapped instrument is on channel 10, it will play on MIDI channel 11, and a mapped instrument on channel 16 will play on MIDI channel 1. I would suggest to put melodic instruments on channels 1-15 and percussions on channels 16+.
The discrepancy between mapped channels in the MIDI I/O plugin and MIDI export is because the MIDI I/O plugin does not care about General MIDI (many MIDI devices are not General MIDI devices), so channel 10 has no special meaning to it.

KingWolf · February 03, 2019, 13:56:08

Excellent! I've moved percussion to 16 and 17 and the problem is solved! Thank you for the suggestion, I didn't know that's how it worked.

Saga Musix · February 03, 2019, 14:14:51

I've also updated the manual a bit - it wasn't up-to-date for OpenMPT 1.28 regarding mapped MIDI channels the "allow instruments to overlap" feature, hopefully it's a bit more self-explanatory now.

KingWolf · February 03, 2019, 17:15:01

One more question, Since I've moved all percussion, is there a way that I can prevent channel 10 from playing as drums in the editor, or is this something I'd have to look for changing through the synthesizer?

Saga Musix · February 03, 2019, 17:38:04

Right now you will have to avoid channel 10 entirely, I'm afraid, or just move channels around before MIDI export. The MIDI I/O plugin is not made with General MIDI in mind (more than half of my MIDI gear is not even General MIDI compatible for example, so not being able to use channel 10 in "mapped" mode would waste a channel on that gear), so there is a bit of an incompatibility between MIDI Export and the plugin. I suppose I could make MIDI export use the same mapping logic as OpenMPT uses for plugins when the original instrument was also controlling a plugin, but that would also assume that the musician used GM-compatible plugins / synths. Maybe having "mapped" and "mapped (with channel 10)" as export options would be a better idea, as it would allow for both scenarios during export.

KingWolf · February 03, 2019, 17:46:55

That would be a cool feature addition as I am using a GM config by default, but I'm also looking at re-mapping the soundfonts to better handle the editor, to see if I can work around the issue, but then again, Im not sure how export will behave there... Wish me luck on that.
Update: Apparently I was able to move drums to channel 16, but channel 10 was still treated as drums which just muted it. Nice... Ahh well, I figured it was worth a shot.