Re: Percussion and delta-time?

At 10:58 AM 2001-05-18 +0100, Lee Goddard wrote:
>[...]The documentation doesn't make much sense to me, though, specifically:

Yup.  The MIDI data format is wide and strange, and so the file format is a
mess, and so anything predicated on it is a mess.  I try to pull away from
the more aggregious parts, like the whole awful ticks-interval=96 things,
and things like:

>2. what is MIDI::Event's *dtime* or delta-time ?

It's something that I meant to abstract completely away from in
MIDI::Simple, because it's good at the data-representation level, but
hurtful at the level of composition.

MIDI::Filespec says:
"<delta-time> is stored as a variable-length quantity. It represents the
amount of time before the following [actually, current] event."

...which is not clear.

When you have an event A, and then an another event B with delta-time X,
this means: "Play A, wait X ticks, and then play B".


As I say in the preface to MIDI::Filespec:
"The file below is not everything you need to know about MIDI -- not by a
long shot. If you know MIDI-on-the-wire, this document tells you how to
encapsulate that data into files -- and that's about all it tells you. If
you need to know the semantics (or even syntax) of, for example,
key_after_touch, it's not in here."

Maybe I should add something about how it's neither complete NOR clear.


Man, I wish /Musician's Guide to MIDI/ were still in print:
  http://www.amazon.com/exec/obidos/ASIN/0782112854


--
Sean M. Burke  [email protected]  http://www.spinn.net/~sburke/