updateMatchedPairs not doing what it's supposed to do?

General JUCE discussion
1

Hi everyone,

Perhaps I completely misunderstand the purpose of MidiMessageSequence::updateMatchedPairs but my assumption was that this function is supposed to “fix” note-on messages that do not have a matching note-off and therefore will cause a hanging note when played back in a sequencer.

I wrote this example piece of code below. After calling updateMatchedPairs, nothing really changes in the sequence object even though I expected it to either remove the note-on or append a note-off (both could be reasonable solutions for fixing a hanging note).

juce::MidiMessageSequence sequence;
sequence.addEvent(juce::MidiMessage::noteOn(1, 60, 1.0f), 0);
DBG(sequence.getNumEvents()); // 1
sequence.updateMatchedPairs();
DBG(sequence.getNumEvents()); // 1

Could anyone explain to me what is going on here?

Thank you very much,
Jelle

2

No, but with only one event in your sequence, stepping into ‘updateMatchedPairs’ with the debugger should be simple, and the problem made obvious. :nerd_face:

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3

From the docs, it looks like the main purpose of updateMatchedPairs is to update MidiEventHolder::noteOffObject for each note-on event. Extra note-offs will only be inserted if there are two note-ons in a row on the same note + channel.

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