24 Sep
2007
24 Sep
'07
6:39 a.m.
On Monday 24 September 2007 00:43, david wrote:
Matthias Schönborn wrote:
> On Sunday 23 September 2007 15:05:56 Simon Williams wrote:
>> Does anyone know of a program which will convert audio to midi?
>> Maybe that's a little ambitious. What about something that will show
>> which notes are being played or what key the audio is in?
>>
>> I have some mp3s which I want to play along to, but I have no idea what
>> key they are in or what notes are being played. The tracks move too
>> quickly for me to pick out the notes.
Sonic Visualiser (http://www.sonicvisualiser.org) is very suitable for this
sort of thing. It allows you to loop sections and slow them down, there are
plugins (see http://www.vamp-plugins.org/download.html -- the ones using Paul
Brossier's aubio library are obvious candidates) to help with pitch and key
estimation, and you can look at the frequency content in a spectrogram. It
won't do very meaningful audio-to-MIDI though.
There are a lot of programs that can turn audio
recordings into MIDI
files. They all seem to be closed-source, proprietary, pay-money Windows
programs. My band leader and I tried out some of them (they can run
under WINE, typically, and my band leader uses Windows, anyway).
Not a single one produced anything usable! They were able to identify
notes, and output them as MIDIs, but the output was pretty useless:
every note of every instrument on the same staff.
That's not a bad result for such a tough problem. Even monophonic note
tracking is tricky, depending a great deal on the instrument. Note tracking
in a dense polyphonic mixture is much harder (if it's possible at all).
Chris