MIDI velocity rewriting

MIDI velocity rewriting

[Ryan Underwood]

Hi,

A problem that I have on some MIDI keyboards is that the velocity
information sent by the keyboard is just too low.  Banging on the
keyboard only results in a velocity of 90 for instance, instead of 127.
I can fix this in MIDI that I have captured by scanning for note-on
messages and adding either a fixed amount to them, or using a curve so
that notes closer to the max are only increased a little, where ones
that are very low get increased a lot.

The question is, does anyone know of any other way to make a MIDI louder
besides setting the master volume of the performer to highest, and doing
this rewriting of velocity information?  If not, I also had the idea
that perhaps this would be a useful thing to do in the ALSA MIDI layer.
For example, if the user specified to do so, the ALSA layer would
automatically increase velocity in the desired way for each note-on
message that comes from a given channel into the computer.

Of course there are probably things I haven't thought about, but
comments would be appreciated.

-- 
Ryan Underwood, <nemesis at icequake.net>, icq=10317253


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Re: MIDI velocity rewriting

[Manuel Jander]

Hi Ryan,

I encountered this same problem time ago on Windows using CakeWalk
Proaudio. But in this case, CakeWalk Proaudio provides a function to add
a offset to all MIDI notes on a given track. This isn't the best
solution since you loose dynamic range. Scaling would be better.
Having a solution like this in the library level, common for all
applications sounds reasonable to me. Many keyboards don't use the full
7 bit scale, so that could be considered as a "Hardware configuration
parameter".

I suggest: write a patch, and show it to Takashi and Jaroslav. They are
the boss around here :D 

Best Regards

Manuel

On Wed, 2003-10-08 at 00:21, Ryan Underwood wrote:
> Hi,
> 
> A problem that I have on some MIDI keyboards is that the velocity
> information sent by the keyboard is just too low.  Banging on the
> keyboard only results in a velocity of 90 for instance, instead of 127.
> I can fix this in MIDI that I have captured by scanning for note-on
> messages and adding either a fixed amount to them, or using a curve so
> that notes closer to the max are only increased a little, where ones
> that are very low get increased a lot.
> 
> The question is, does anyone know of any other way to make a MIDI louder
> besides setting the master volume of the performer to highest, and doing
> this rewriting of velocity information?  If not, I also had the idea
> that perhaps this would be a useful thing to do in the ALSA MIDI layer.
> For example, if the user specified to do so, the ALSA layer would
> automatically increase velocity in the desired way for each note-on
> message that comes from a given channel into the computer.
> 
> Of course there are probably things I haven't thought about, but
> comments would be appreciated.



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Re: MIDI velocity rewriting

[Takashi Iwai]

At Wed, 08 Oct 2003 08:44:59 -0400,
Manuel Jander wrote:
> 
> Hi Ryan,
> 
> I encountered this same problem time ago on Windows using CakeWalk
> Proaudio. But in this case, CakeWalk Proaudio provides a function to add
> a offset to all MIDI notes on a given track. This isn't the best
> solution since you loose dynamic range. Scaling would be better.
> Having a solution like this in the library level, common for all
> applications sounds reasonable to me. Many keyboards don't use the full
> 7 bit scale, so that could be considered as a "Hardware configuration
> parameter".
 
an easy way is to write a program working as an ALSA sequencer client,
which just does as described above.  running it with SCHED_FIFO, you
don't have delay.  if you need a MIDI device to access, you can
connect it/from the virmidi device.

although....

> I suggest: write a patch, and show it to Takashi and Jaroslav. They are
> the boss around here :D 

... a patch is always welcome :)


Takashi


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Re: MIDI velocity rewriting

[Ryan Underwood]

Mark,

On Wed, Oct 15, 2003 at 09:16:52AM -0700, Mark Knecht wrote:
> Note the end of the description. Possibly something like this would work?
> 
> http://tse3.sourceforge.net/doc/api/TSE3__MidiFilter.html
> 
> Or possibly
> 
> http://www.musickit.org/MusicKitConcepts/waveshapingparameters.html
> 
> I just googled on MIDI velocity scaling. There's lots of info out there. I
> believe there are some Windows key switch tools that will do this also. I've
> seen people talk about them in the Northern Sounds forums.

Excellent.  I was looking for a good term to describe what I was trying
to do, and the best I could come up with was "rewriting".  "Velocity
scaling", however, produces tons of results to sift through.  I'm sure
at least one of these will produce a satisfactory solution.

Thanks much!

-- 
Ryan Underwood, <nemesis at icequake.net>, icq=10317253


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