[linux-audio-dev] XAP: a polemic

[David Olofson]

On Wednesday 18 December 2002 14.43, Tim Goetze wrote:
> David Olofson wrote:
>
> [TIMEBASE, aka ppq]
>
> >Either way, it's *still* floating point. Why use 1.0 when you can
> > use something else and get something slightly more logical
> > (maybe...) than 1.0 ticks/beat, and that allows you to express
> > *lots* of values in exact form?
>
> the only thing i object to is that you want to assign a fixed
> value. it is a severe limitation, but it gains us absolutely
> nothing. at least you don't give a reason why it needs to be
> fixed.

If it's not fixed, it's another parameter you have to get from the 
timeline, before you can do anything useful with a musical time 
value. That's all, basically.


> >> please, please, please, ask your favourite musician friends.
> >> read good books about it. listen to indian, jazz, techno,
> >> blues, classical western, classical indian, japanese, rap,
> >> whatever music: rhythmn is integral.
> >
> >Well, which ones qualify?
>
> all of them.

Well, you've already disqualified at least one on this list, I think. 
(And I don't count myself, of course.)


> rhythmn is always based on one integral periodic 'pulse'. if
> time is not divisible by this atom, there is no musical time.

>From a theoretical POV, I would agree, but that doesn't seem to be 
the best way to think of it at all times.


> the float meter proposal is like using floats to count your
> fingers.

Why not? Some people have half fingers. ;-)


> >If you really *want* a bar that's shortened by a fractional beat
> >(which is not all that unusual, even in pop music), what do you
> >do...? How do you ensure that plugins that beat sync don't freak
> > out when you multiply the meter to get integers?
>
> if you shorten, for example, 4/4 by 1/16, it's 15/16.

Yeah - but then your beat sync'ed effect suddently switches from 4ths 
to 16ths...


> if you
> shorten it by 1/32, it's 31/32 etc.

...or 32nds.


> if you want to shorten 4/4 by, say, 1/16 + 0.00212266328763,
> you're violating the very principle of the organization of
> musical time.

Well, I can't say for sure. All I know is that I do that kind of 
things by "abusing" the tempo map instead, since that's the only way 
you can do it in most sequencers.


> you're better off simply inserting a new meter
> where the shortened measure ends.

How would you do that? The meter just defines the subdivision of 
musical time. You can't just make a "skip" in musical time - unless 
you're seriously suggesting that this should be implemented as a 
transport "jump" to skip the last part of the shortened measure. 
(That would be rather nasty towards many kinds of plugins, especially 
direct-from-disk samplers, HDRs and the like.)


> and what seems to be the problem with beat sync? the relation
> of the meter to TIMEBASE is part of the tempo information, so
> all info you need, you have.

No. Where did the *real* beat value go?


> again, i strongly recommend you do some research on music and
> its theory and then round off your studies with some sequencer
> implementation reading, or even better, writing.
>
> please excuse the harsh word: your assumptions about these
> fields lack in realism.

*heh* Well, you seem to have all the right answers - so why do you 
tend to ignore the questions that cannot simply be disregarded as "in 
conflict with traditional theory"...?

I think fp arithmetics have more effect or accuracy than traditional 
ways of thinking about meters - but I must be wrong, then.


//David Olofson - Programmer, Composer, Open Source Advocate

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