Pushing Messages onto an Array?

[clevername27]

I'm trying to store MIDI notes as they come in. Does anyone please know why this code isn't valid?

Thank you.

[ustk]

@clevername27 Message is a class name, you need to mention what value you want to store...

Also, a MidiList is more adapted to store Midi messages than a simple array which is slower
https://docs.hise.audio/scripting/scripting-api/midilist/index.html

[clevername27]

@ustk Thank you - if I could ask two more questioned, pls -

• Would I create a new instance of Message for each note, and store that in the array?
• How would I best use MidiList, as it's limited to 128 items?

Thank you.

[d.healey]

@clevername27

You probably want myArray.push(Message.getNoteNumber());

If you're storing event IDs and you want to store one for each note then a MIDI list is the way to go.

[clevername27]

@clevername27 Thank you for your reply. As a follow up, pls —

• if I'm storing multiple members of the Message class, wouldn't it be more efficient to simply create an array of Messages? That would seem to be the store method (i.e, Message.store(var messageEventHolder)?
• The MIDI list only seems to hold 128 elements; I'm not clear how this would be useful?

Thank you

[ustk]

@clevername27 In the end it depends on what you want to do with your stored messages, and what you want to store exactly (note nb? vel?)

You could, for instance, use the midi list index as note number, and use the value at that index for the velocity MidiList.setValue(noteNb, noteVel)

[clevername27]

@ustk I wish to store all the event data.

[d.healey]

@clevername27

if I'm storing multiple members of the Message class, wouldn't it be more efficient to simply create an array of Messages?

You'd have to create message holders I think and there things might get interesting. I've not played with them for years so have fun :)

The MIDI list only seems to hold 128 elements; I'm not clear how this would be useful?

The MIDI list is useful if you want to store one value per note. A common scenario is storing the velocity for each note.

[clevername27]

| The MIDI list is useful if you wan to store one value per note. A common scenario is storing the velocity for each note.

Isn't that only useful if I want to store less than 129 notes?

[ustk]

@clevername27 I follow Dave, in this case you need a message holder, which is in fact a midi sequence. But I haven't played with it for a while too :)

[ustk]

@clevername27 I'd say a midlist is useful when you want to hold a value during a time or until something happens so you reset the value until the next instance, or at the next instance of that note.
A message holder is more a sequence where you store the timestamp as well so it can be played back or batch modified, etc...

So if you want to record all events and keep them in a sequence -> message holder

[d.healey]

@clevername27 said in Pushing Messages onto an Array?:

| The MIDI list is useful if you wan to store one value per note. A common scenario is storing the velocity for each note.

Isn't that only useful if I want to store less than 129 notes?

Each real note (that comes from a keyboard press or DAW) can only have one velocity at a time. If you play MIDI note 60 its velocity would go in slot 59 of the MIDI list. If you play MIDI note 60 again it would overwrite the previous value. Unless you have a keyboard with two middle Cs there wouldn't be an issue.

[clevername27]

@d-healey Thank you for answering my question; I'm still a little confused. Let's say I want to record 1,000 notes. But if the MIDIList can only be 128 elements long, wouldn't that mean I can only store 128 notes?

[d.healey]

@clevername27 The MIDI list isn't for that purpose. It's not like an event list in a DAW.

Christoph explains it in this post - https://forum.hise.audio/topic/79/scripting-best-practices

[clevername27]

@d-healey Thank you for the reference - I guess I'm still not seeing how this object would be useful here. Off the cuff, this object has a performance advantage because it allocates all 128 slots at once, allowing pointer mathematics to access individual slots (instead of pulling them individually off the heap or from the stack). In @Christoph-Hart 's example for an array of notes, he simply uses a regular array (i.e., traditional linked list).

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[Christoph Hart]

There is another container class called unordered stack which can hold the full event data but I think it‘s also limited to 256 slots.

[clevername27]

@Christoph-Hart Thank you - I'm also realizing you explicitly wrote in the documentation that the performance advantage of the MIDI List is not gained from pre-allocating the memory, so I'm not correct there.

[Christoph Hart]

With a bit more context of your use case I might help you out. Your initial approach is not recommended, the array will allocate in the audio thread (and the AudioThreadGuard should complain).

[clevername27]

@Christoph-Hart Thank you, kindly. I'm looking to:

1. Capture all incoming MIDI notes in real-time.

2. Offline, I will adjust the Note-On and Note-Off timestamps.

3. Finally, pipe the resulting note list into a MIDI Player, and play it back in time with the host DAW.

Cheers, mate. I would post and comment my code for the community.

[Christoph Hart]

Before you reinvent the wheel, you are aware that the MIDI player has a record function that does exactly this? You can even supply it a post processing function that will give you an array of all new events that you then can process (eg. for quantization).

I'm using this in a current product I'm working on, so I would consider it stable but under documented - like everything in HISE that comes fresh out of the oven :)

These MIDIPlayer functions are useful in this case:

• setUseTimestampInTicks() - calling this in onInit is highly recommended as it will use ticks instead of samples as unit which makes sample rate agnostic operations much more simple (960 ticks = 1 quarter).
• record() / stop(): obvious...
• setRecordEventCallback() - supply it with a function that modifies the array of MessageHolders before it gets written into the MIDI sequence
• setSyncToMasterClock() hooks the MIDI player to be controlled by the master clock (and then use the TransportHandler for DAW syncing).