Fix Attack Command Number; Add Chorus & Portamento Time

[deckerego]

• Fixed ATTACK_TIME value
• Added CHORUS value
• Added PORTAMENTO_TIME to match the PORTAMENTO on/off value

[tekktrik]

I know very little about MIDI so I don't know if I'm qualified approve this or not, but a quick search about it lead to the above comments. Thanks for submitting!

[tekktrik]

Okay, coming back to this after doing a little more digging. So it looks like 5 is the MSB for the coarse adjustment, and 37 is the LSB for fine adjustment. In that case, it might be more future proof to label 37 as PORTAMENTO_TIME_FINE so that PORTAMENTO_TIME can be 5. I'm basing this off the way that the same thing could happen to FOOT_PEDAL if 36 is ever added. What do you think about that?

[rimwolf-redux]

The putative norms and actual practice of which CCs should be used for which controls diverges widely, and this file by and large defines just the most commonly implemented assignments; many synthesizers won't even implement all of them thus. (It might be wise to add a comment to the file to this effect.) My comments address these common usages.

PORTAMENTO_TIME should be 5, not 37. Theoretically CCs 32--63 are reserved for LSB (7 bits) of the MSB (7 bits) of the controller values for 0--32, but in practice very few synthesizers implement LSB for any of these values. (CC37 would be the LSB of CC5.) I certainly don't think it's worthwhile defining names for any of them.

Another relatively common controller is BANK SELECT, CC 0. This is used to select which bank of patches a Program Change message references.

The assigments for CCs 75--78 are not common -- they're normatively just Sound Controller 6--9 -- and I'd be happy to see them removed from this file.

(These comments are based on my having studied, owned, and used a wide variety of synthesizers, hardware and software, since the 1980s, with particular attention to CC implementation.)

[deckerego]

...it looks like 5 is the MSB for the coarse adjustment, and 37 is the LSB for fine adjustment. In that case, it might be more future proof to label 37 as PORTAMENTO_TIME_FINE so that PORTAMENTO_TIME can be 5.

Updated to coarse adjustment

[tekktrik]

So based off everything here, I think this is good to go. If we ever want to clean this up by removing things, we can do so knowing that it is (I would say) a breaking change for the library. Thanks y'all!