Plug'n Script MIDI Timing Problems.

[Eine Alte Oma]

Hello,

it's me again with a timing problem, lol. This time it's regarding MIDI. So i made this VSTi which transforms incoming MIDI-Data and sends it out in realtime, at least that's the plan. But for some reason it seems to have a bit of latency. In my DAW this latency is so small that i'd just not care about it, but i sent the plugin to a friend who said that the latency was so bad that he couldn't use the plugin on more than 50bpm. How can i ensure that it works the same on every machine?

Here's how the code in the processBlock-method is structured atm (sry if it's a bit too much, but maybe some of it is the problem, so better show everything i guess):

/* inputParameters */
uint8 microtonal;

/* midi */
uint8 eventChannel,sourceChannel,destChannel,note,rootVal;
int pitchWheelValue,noteModInt;
float noteMod,bendRangeDevide;
MidiEvent noteEvent,pichWheelEvent;
bool isPlaying=false;

void processBlock(BlockData& data){
for(uint m=0;m<data.inputMidiEvents.length;m++){
eventChannel=sourceChannel=0;
if(eventChannel==sourceChannel or sourceChannel==0){
noteEvent=data.inputMidiEvents[m];
if(MidiEventUtils::getType(noteEvent)==kMidiNoteOn){
note=MidiEventUtils::getNote(noteEvent);
if(isPlaying){
MidiEventUtils::setType(noteEvent,kMidiNoteOff);
MidiEventUtils::setNote(noteEvent,noteModInt);
data.outputMidiEvents.push(noteEvent);
MidiEventUtils::setType(noteEvent,kMidiNoteOn);
}
isPlaying=true;
if(note>rootVal)
noteMod=rootVal+(12.0/microtonal)*(note-rootVal);
else
noteMod=rootVal-(12.0/microtonal)*(rootVal-note);
pitchWheelValue=rint(fraction(noteMod)*8192*bendRangeDevide);
noteModInt=int(noteMod);
MidiEventUtils::setNote(noteEvent,noteModInt);
MidiEventUtils::setChannel(noteEvent,destChannel);
data.outputMidiEvents.push(noteEvent);
} else if (MidiEventUtils::getType(noteEvent)==kMidiNoteOff){
if(note==MidiEventUtils::getNote(noteEvent)){
isPlaying=false;
MidiEventUtils::setType(noteEvent,kMidiNoteOff);
MidiEventUtils::setNote(noteEvent,noteModInt);
data.outputMidiEvents.push(noteEvent);
}
}
MidiEventUtils::setPitchWheelValue(pichWheelEvent,pitchWheelValue);
data.outputMidiEvents.push(pichWheelEvent);
}
}
}

[Eine Alte Oma]

here's a pastebin link to the same code so it's displayed more accurately:

https://pastebin.com/186ff20a

[Eine Alte Oma]

and here's the current state of the plugin (64bit vst2), in case it's needed:

https://we.tl/t-cmGCUwfQIS

[akeia]

I think that the delay depends on the block size configured in your DAW. My understanding is that all you do in the loop will be sent out at the next block border. Meaning after the time in milliseconds that you have configured in the DAW as block size.

[Eine Alte Oma]

I think that the delay depends on the block size configured in your DAW. My understanding is that all you do in the loop will be sent out at the next block border. Meaning after the time in milliseconds that you have configured in the DAW as block size.

first of all thanks for helping me with this tricky issue
but i think it can't be the blocksize this time. my cubase is configured to have a blocksize of around 800 samples so if anyone had terrible latency due to the blocksize it would be me, lol. or does midi have a different block from audio?

[Blue Cat Audio]

Your code looks fine from here, so I guess it is an issue with the host latency. The buffer size is not the only parameter here: the number of buffers and the driver also make a difference. Also, are you sending these events to an external MIDI device or are they processed by a plug-in inside the DAW?