Bill Canty

If I want to process pitches in some way (e.g. sorting them in ascending order) I'd like the velocities to stay with the pitches they belong to.

- multiplying the pitch by 128 and adding the velocity

- multiplying the pitch by 128 and adding the velocity
- doing the processing
- [/ 128] = pitch, [% 128] = velocity

best-way-to-lock-a-notes-velocity-to-its-pitch

If efficiency is important, for powers of two there are better ways to handle multiply/divide/modulo:

[* 128] = [<< 7]
[/ 128] = [>> 7]
[% 128] = [& 127]


Multiplication and bitshifting are cool tricks for "packing" this data. If you find yourself needing to keep track of more than just MIDI note number and velocity (maybe duration and channel and whatever else is associated with a particular note/event), you might try tossing them all into a coll. I've used an arrangement where the note number is both the address of the data and part of the data itself. Like:

Then it's easy to sort the coll by address while retaining all the related information. These days SQL may provide an even more robust solution.

60, 60 101 3000 1 foo;
48, 48 68 2200 2 goo;
79, 79 ...

Then it's easy to sort the coll by address while retaining all the related information. These days SQL may provide an even more robust solution.


I'd forgotten about those objects because during my one and only cursory glance at them I thought "Binary maths? I'll *never* need that!"

Little did I know what the future held, eh? Still don't even pretend to understand the nitty-gritty of [& 127], but I can see that it works.

Quote: johnpitcairn wrote on Mon, 09 February 2009 15:07

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> If efficiency is important, for powers of two there are better ways to handle multiply/divide/modulo:

Quote: johnpitcairn wrote on Mon, 09 February 2009 15:07
----------------------------------------------------
> If efficiency is important, for powers of two there are better ways to handle multiply/divide/modulo:
>
> [* 128] = [<< 7]
> [/ 128] = [>> 7]
> [% 128] = [& 127]
----------------------------------------------------


Quote: Holland Hopson wrote on Tue, 10 February 2009 02:56

> If you find yourself needing to keep track of more than just MIDI note number and velocity (maybe duration and channel and whatever else is associated with a particular note/event), you might try tossing them all into a coll.

> Then it's easy to sort the coll by address while retaining all the related information.

At first I thought this might be either beyond what I need or limited by coll's processing capabilities, but while trying to figure out exactly what to ask you I've realized how incredibly useful your idea could be.

I'll play around with it and possibly get back to you with questions.

> These days SQL may provide an even more robust solution.

I was kinda hoping to avoid stuff like SQL in this lifetime!

Quote: Holland Hopson wrote on Tue, 10 February 2009 02:56
----------------------------------------------------
> If you find yourself needing to keep track of more than just MIDI note number and velocity (maybe duration and channel and whatever else is associated with a particular note/event), you might try tossing them all into a coll.
[snip]
> Then it's easy to sort the coll by address while retaining all the related information.

Best way to lock a note's velocity to its pitch?