How to send MIDI miessages independent of audio block size?


I’m writing a VST plugin that is supposed to process MIDI in as fast a manner as possible (<10 ms). How can I send MIDI notes in JUCE independent of the audio block size determined by the host?

One idea I had is to keep track of time stamps and at each processBlock call I would send multiple midi messages at one, each with different time stamp. Another idea I had is to run another timer that would send midi messages independent of the block size. The little intuition/knowledge I have about threads tells me that the latter solution is not ideal. What do you think?


Yes this is exactly what you want to be doing. For example, if you wanted to output a large midi buffer, you would do something like this (Warning: untested):

	void processBlock (AudioSampleBuffer& buffer, MidiBuffer& midiMessages)
		const int n = buffer.getNumSamples();
		MidiBuffer::Iterator it (*midiBufferToPlay);
		it.setNextSamplePosition (midiPosition);
		int position = midiPosition;
		MidiMessage msg;
		while (it.getNextEvent (msg, position) && position < (midiPosition + n))
			midiMessages.addEvent (msg, position - midiPosition);
		midiPosition += n;

	int midiPosition;
	MidiBuffer midiBufferToPlay;

…where the midi event time-stamps are assumed to be in samples.