OptionalchannelsOptionalgainmaster level, 0 to 1
Optionalmaxhard cap on rendered seconds; longer tails are cut
Optionalmissingwhat plays for a program the font lacks, as for parseSoundFont; 'piano' when omitted
Optionalsampleoutput sample rate in Hz
Optionalsoundraw SoundFont 2 bytes: parsed on this thread, voiced on the worker
Optionalsyntha MidiSynth request as for renderMidiToBuffer; a synth lives on this thread, so such a render does not go to the worker
voices only these channels (0 to 15), as for
renderMidiToBuffer