[Audacity-devel] Embedded drum sequencer

[Dave F. <dav...@at...>]

All,=20

Ok, it's become inevitable.  My drum sequencer sucks, but it's not becaus=
e=20
it's a bad sequencer.  The metaphor it uses is flawed, IMO, and I want=20
something better.  :)  Since it depends on GTK directly, and I haven't th=
e=20
foggiest how to program GTK, and I'd prefer something cross-platform anyw=
ay=20
(a matter of philosophy rather than practicality), I'd like to embed a dr=
um=20
sequencer into audacity as a composition tool.

So, first my questions.  :)

The drum sequencer should be able to play a sequence in realtime, but whe=
n it=20
comes time to lay down tracks it should export directly to audacity.  Sin=
ce=20
the nature of the thing is to create a stream, mix the sequence into it=20
(following whatever algorithm it follow, pretty well laid down already), =
then=20
what api does audacity have already for me to stream into a new track?

Second, the file format for a drum sequence will be xml, something like t=
his=20
(needs some work still):

<!-- define typical rock verse, 4/4 time with 2 bar phrases, 4 phrases to=
tal,=20
accent on upbeat with an upbeat bass drum -->

<verse name=3D"firstverse" time=3D"4/4" phraselength=3D"2" totalphrases=3D=
"4">
=09<snare hits=3D"2,4"/>
=09<bass hits=3D"1,3" style=3D"upbeat"/>
</verse>
<prechorus>
etc....

<fill type=3D"verse" length=3D"2">
fill stuff
</fill>

The idea is that the sequencer would either chose selected fills at the=20
appropriate times or it would randomly choose a fill in an attempt to=20
simulate a real drummer, but would only chose fills that are appropriate =
for=20
the section of music.  (additional function would be stuff like standard=20
beats and fills that you can use with the sequencer coming stock with as=20
complete a selection as possible, but allow custom fills, implemented in =
CSS)

XML is perfect for this sort of thing, isn't it?

Anyway, the question is this:  Should this be a separate file or integrat=
ed=20
into Audacity's project file under the assumption that a drum track would=
 be=20
associated with a project always?  (import/export ability implied)

Finally, is this sort of embedded sequencer something that Audacity shoul=
d=20
have natively (i.e. I write it and if you guys like it audacity gets it i=
n=20
the base distribution) or should it be a plugin?  If the latter, does=20
audacity have its own generic plugin architecture at this time, or should=
 I=20
make it a LADSPA plugin?  (I don't know if LADSPA plugins typically allow=
 a=20
gui to be associated with it)

In the end, it will be some time before I actually start working on it.  =
I=20
have to wait until the need is strong enough.  I only know that the need =
is=20
strong right now.  :)  Also, I have some details to work out, like the xm=
l=20
format.  (ultimately this format could be used to link to specific sectio=
ns=20
of music within audacity, or just within a wav file, and it could be used=
 to=20
include lyrics, tab, and so forth, and audacity could automatically displ=
ay=20
the appropriate section during playback to help the singer that can't=20
remember the lyrics, and could also provide an alternate composition-base=
d=20
interface rather than the typical sound editing/processing interface, and=
=20
would allow the first RSC (Rapid Song Composition) interface ever, near a=
s I=20
can tell)

Oh yeah, one more issue.  The sequencer as described would require a cert=
ain=20
minimum knowledge of music theory (specifically rhythm & timing) and may =
also=20
require a certain minimum knowledge of drumming (I have it, obviously). =20
Audacity targets, at least in part, those people lacking in certain techn=
ical=20
information.  Does this basic theory requirement violate this preferred=20
target?

Dave

--=20
"I slipped inside the oval office,
I slipped in oh so fast,
Grabbed the president by the necktie
And wiped my funky ass, hey"
                -Soulhat, "Bonecrusher"