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Subject: Re: Metronome enhancements?

Re: Metronome enhancements?

From: Matthias Wientapper <>
Date: Sun, 15 Aug 2004 17:44:33 +0200

Stefan Hahn wrote:
> Some questions:
> - how did you create the values for the static
> unsigned char sound[]?

It is the byte representation of the mp3.
Using Unix I did something like "od -t u1 tick.mp3" and re-formatted the
output a little.

> --> reason for this question is that I have access to
> one of those high-end metronomes (see:
> where I
> could record the sounds from.
> Also a talking (one two three four....) one is around
> ...

That could be interesting. The sounds have to be short enough to match
the fastest playback speed.

>>..... Triplets might become tricky to implement.
> No. You just need to look at the logic of the BPMs -
> quarter gives the base BPM, eighths are 2*BPM,
> eighth-note triplets are 3*BPM , sixteenth-note are
> 4*BPM

I know ;-) The thing is: Triplets will become pretty fast and there is a
limit in terms of playback speed, depending on the lenght of the sound.
On the other side the sound has to have the length of one mp3 frame at
least. And it should not sound too chopped off IMHO. Nevertheless it is
also worth a try.

> Well, I can imagine percentages of volume per
> quarter/eigthth/eighth triplet/sixteenth of a main
> volume


> As I said above, I'd be happy to join in and do some
> programming here (yes, once upon a time I finished my
> computer science studies), but as I don't want to
> destroy anything I'd be pleased and all of us would be
> on the safe side if we could go for a shared action
> here. Let me know what you prefer.

Unfortunately I have to travel a lot currently. So I will definitively
not be doing the hacking I wanted to for the next weeks. Simply check
out the CVS tree, play around with the code and submit a patch if it
works. You can't destroy anything! If you have questions regarding
technical stuff do not hesitate to contact people via IRC (normally I
hang around in #rockbox, but currently I am too busy).

When I have a little more time again I will look into the code again.


                          Matthias Wientapper
                  I'll get you yet, you kwazy wabbit!
Received on 2004-08-15

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