If those timing variations were intentional, then I agree they represent information. If they are just sloppy playing, they are noise. And if the performer is just applying a stylistic form ("swing these bars"), then it's an inefficient encoding of the musical intent.
And yet notating any of that information in every bar as, say, three-quarters to one-and-a-half hemidemisemiquavers early or late to each offbeat defeats the purpose of having a readable score.
The score is a reduction that's intentionally lacking tons of information that defines the essence of a performance. That's not a bug, but a feature.
This is precisely part of my point, or would be if you corrected it. The score contains, either implicitly or explicitly, global performance clues that will tell the performer what to do about timing (and if it doesn't that's because it is expected to come from a conductor or other similar source). It's a highly efficient mechanism precisely because it is a global property of the score (or perhaps locally scoped to sections). Much better than providing timing information for every note (as MIDI would do). The MIDI version is an inefficient means of information transfer.
BTW, things do not get even crazier with "world music styles like samba". Samba is an extremely regular groove that is very easy to understand. This is true of most Afro-Cuban derived rhythmic structures - the complexities come from layering a set of very simple patterns. Things do get "even crazier" with rhythmic traditions from Indian, Balinese and some parts of Africa, places where conventional western ways of describing things really don't do a good job at all.
And I'm sorry, but regarding samba, you have absolutely no idea what you're talking about. I assume you're referring only to the surdo's backbeat, but the essence of the samba rhythm is the sixteenth-note groove played by the pandeiro, and that sound is pretty much as far from "extremely regular" as you can get while still maintaining a consistent pulse. I found the style relevant to bring up, as it's a commonly given basic example of a groove featuring microrhythmic variation.
and yet ... in almost all the musical forms where this happens, it isn't notated.
I've played samba (surdo and tamborim parts, mostly). I have many friends who play Brasilian music in general. I think we have a problem with definitions, because the pandeiro part precisely fits my definition of "extremely regular timing". When playing samba, unlike various jazz influenced forms, you do not play ahead or behind the groove. The variation still uses a 16th note grid, albeit with lots of freedom of which parts of the grid to play or not play.
Regardless, the context of this discussion was determining whether MIDI data can hold "extra information" that the score does not, and I can't agree with most of your statements about that.
> technically, that would be a case of the MIDI data having noise in it, not extra information.
> and yet ... in almost all the musical forms where this happens, it isn't notated.
There's a term for this type of thinking, and it's called "notational centricity."
> "musicological methods tend to foreground those musical parameters which can be easily notated" such as pitch relationships or the relationship between words and music. On the other hand, historical musicology tends to "neglect or have difficulty with parameters which are not easily notated", such as tone colour or non-Western rhythms.
So any given parameter not being notated with ease or in detail doesn't prove anything about its role as an intentional, stylistic element of the music. That is, not being notated doesn't make a parameter any more likely to be "noise," because what does get notated is not a "core representation" of the musical text. In fact, the distinction between the two mostly comes down to historical coincidence or other non-musical factors.
MIDI or other more granulous performance capture standards have plenty of "extra information" to offer that is not noise, and I'd even say it's mostly the case that you'll see a robust SNR there.
Samba isn’t Afro-Cuban derived, whether in its rhythmic structures or otherwise.