I have an idea, I can't divulge (the already mostly public)
MFi info, ARGH, but I can tell everyone how to do it
with a SMAF file since Yamaha made those specs public.
Its actually quite obvious to me. Just listen.
There is a place in the SMAF file where it controls how
long each "tick" or "dt" essentially each point of time is
worth. You change that value and a 1 second song can last
1 minute or something close to that. I've done it already and
tested it. It works. Its annoyingly long.
Next inside SMAF files as it says in the public specs you
can change the volume in the middle of a song for a certain
channel and voice (as I call them). These commands are each
about 4 bytes long in SMAF (if I remember right).
So you can make a song of 10 or 20 second value notes increasing
or decreasing from a certain volume. This song will be less
than 1 k due to its simplicity.
I don't know the details of the DOJA specs, but some of the
i-appli programmers here at layer-8 have been able to play back
MFi files from the phones with a very small delay between songs.
There that's it. Now just apply what I told you about SMAF files
to MFi files (which are different but the same) since they are both
as we all know close to Midi files in many respects.
Note: The smoother you make the volume transition the longer
the file will be. The more choppy you change the volume, the
smaller the song will be. A constant volume song's length is limited
by the "timebase" setting of the SMAF file.
Michael Turner wrote:
> Thank to Manish Prabhune and David Cotter (and even
> Paul Lester, sort of) for their feedback on my questions.
>
SNIP
>
>
> Having half a dozen 20 second loops, differing only by volume,
> each repeated a few times, would probably be gradual enough.
> Anyway, 10 minutes was just a guess....experimentation is
> required.
>
> Paul <paul_lester@lincmedia.co.jp> begs to differ about
> memory requirements:
>
> > I am almost positive a 10 minute piece could be much
> > smaller than 10k, I'd go as far to say it could be less
> > than 1k. And I have clear ideas how volume can be
> > controlled, in a hacky but effective way for this application....
>
> ...but in an ultimately unhelpful manner:
>
> > Also I'm not giving away the answer on how. That would
> > involve divulging too much about MFi.
>
> Can't have that, now can we. :-/
SNIP
--
-Paul Lester
pbl1@cornell.edu
http://members.tripod.com/~pbl1/
"Don't Forget to Try in Mind"
"May the Force be with you"
"Ketchup is Good"
-"Ketchup, natto and kimchee, that`s what Wogis are made of"
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Received on Sat Aug 18 03:20:32 2001