Harmonix: replaying a MIDI sequence | Unreal Source | Page 1

remote pecan Mar 15, 2026, 5:24 PM

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This is my current setup

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(‘Trigger To Midi Note’ node courtesy of @distant swan: https://github.com/Amir-BK/MidiDeviceMetasoundWrapper)

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The idea is that the player should be able to trigger playback of the song, or of the extra note, at any moment, no matter how many times, and it should be sampled by the same “instrument”. Currently this works for note on/off events just fine, but not for the PlaySong trigger. I’ve tried every combination of transport signals I can imagine, but no dice— it seems like, once the sequence has been played, it’s “spent” until I restart the audio component that this MetaSound source is part of.

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If I didn’t need the extra note on/off events, I could just plug ‘On Play (UE Source)’ to ‘Play’ directly and tell the Blueprint to play the audio component again (what I mean above by “restart”), but since there’s this case of a potential extra note being played at the same time, I don’t want there to be a cut.

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My intuition tells me this should be easy, but I have no idea how to achieve it, and I would be so grateful if anyone could steer me in the right direction— thanks in advance! 🤗

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Harmonix: replaying a MIDI sequence

sonic patrol Mar 15, 2026, 6:00 PM

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What happens if you Seek to a Seek Target of Bar 1, Beat 1?

remote pecan Mar 15, 2026, 7:00 PM

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Nothing 🤷

distant swan Mar 15, 2026, 7:06 PM

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Did you try activating the simple loop bool?

remote pecan Mar 15, 2026, 7:22 PM

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Yes, if I activate the one in the clock generator nothing happens, and if I activate the one in the sequence player, it loops endlessly

distant swan Mar 15, 2026, 7:34 PM

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Just to verify, the same behavior reproduces even if you remove the questionable third party node (my node! some self deprecating humor) from the the chain, right?

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I am also relatively convinced that my node merges the input stream correctly as I think I just copied the code from the 'merge streams' node but might be also worth checking if using the official merge midi streams node has an affect.

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I don't have a ton of experience with the sequence player itself, but I think it might be that you have to send 'stop' via the transport to actually reset the clock, I assume you tried that?

remote pecan Mar 15, 2026, 8:07 PM

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I think this recording will help 🙂

distant swan Mar 15, 2026, 9:25 PM

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From that video is looks like a bug, but I'm starting unreal up to give it a try myself.

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ok, I'm rather sure this is a bug in the sequence player node, the midi player node works just fine with all the transport commands, starts stops pauses, etc.

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I think there's something weird with the way the sequencer node relies on an external clock node.

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Forget what I just wrote I forgot how to read a switch statement, apparently.

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(I deleted what I wrote so, you probably won't see it)

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I can't spot anything obvious in the code, but it still looks like a bug to me

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Well, according to Claude Opus 4.6 the thing I thought might be the bug might actually be buggy, but I'll need to compile the engine to see if it's actually the case, can't just trust LLMs without trying. One way or another, I think it's a bug in the engine.

remote pecan Mar 15, 2026, 10:51 PM

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Oh wow, thanks for the massive effort! 🙏🙏

#Harmonix: replaying a MIDI sequence