Shifting pitch in a MIDI file?

[Hartmut Noack]

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Hello Angel,

Am 13.12.2010 13:59, schrieb Angel de Vicente:
> Hi all,
> 
> yesterday I was trying to find a way to shift the pitch in a MIDI file 

You need to tune the instrument, that plays the MIDI-file.

Since MIDI-files contain only abstract desriptions of what should be
played (e.g. notes) they do not know anything about pitch. Notes can be
transposed, which is quite a different thing. Rosegarden offers
transposing so you could load your MIDI-file in RG and say: transpose
this piece 3 halfnotes up/down until it sounds the way you wish.

But I guess, this is not what you want and it would be only but a crude
workaround for the problem in question.

Better you tune the instrument. First step would be, to leave the easy
world of automagic and enter the grim realm of "find out yourself, what
is really happening." . ;-)

Some program plays you file using a soundfont. If this one is timidity I
would yield in your place and switch to a soundfondplayer with a
convenient GUI. Qsynth is one but there are others, that allow graphical
handling of fluidsynth also.
Find the knob/slider that allows you to set the basic tuning(will be set
to 440) and fiddle with it until it sounds as you wish.

BUT: this also is, in some way, a workaround.

Others have already mentioned the samplerate-kind-of-thing. Most cheap
soundchips only run at 48KHz and leave the job to adjust the samplerate
of 44.1-samples to the software, that plays the these.

But alas: some programs dont resample (for the sake of better
performance). So in this case you have 2 choices:

1.) try to resample the soundfont itself to 48KHz
2.) start jack with 48 KHz and use  a soundfont-player that actually
does resampling to jacks rate if needed.

The latter is warmly recommended....

best regards

HZN



> but couldn't figure out a way to do it, so I'm looking for advice here...
> 
> My situation is as follows. I have a MIDI file of a piece (for four 
> guitars), and I just want to mute one of the tracks and play along with 
> my real guitar (a sort of virtual quartet...). But the problem is that 
> the tuning of my computer is wrong (I read somewhere that DELL laptops 
> had this problem. I'm not sure, but in any case the standard A at 440Hz 
> sounds actually like a C).
> 
> I could tune up my guitar, but that is quite inconvenient, specially if 
> later I want to play with more instruments, so I was hoping that I could 
> find a way to tune up or down the whole MIDI output. The Virtual 
> Keyboard has a pitch wheel, which it would be exactly what I'm looking 
> for if it could be applied to the whole MIDI output... In Rosegarden I 
> didn't find anything... In Qtractor I could load up plugins that seemed 
> promising (if I remember correctly I could find four plugins with names 
> like pitchshift, but I couldn't make them to work, plus they applied to 
> individual tracks, and not to the whole MIDI output).
> 
> Any pointers?
> 
> Thanks,
> Ángel de Vicente

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