Audio To MIDI Conversion, Scientists Have It Sorted

Geoff3

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Thought this may interest some Of You,

Extracts from New Scientist Article "Ivory Encore For Dead Piano Greats"

"The breakthrough that zenph has achieved is to extract the sounds from audio recordings and convert them into a high resolution version of MIDI... To do this they had to tackle the problem of polyphonic transcription - distinguishing several notes played simultaneously as seperate entities... While researchers have been trying to achieve this for years, previous attempt have managed to identify at best 80 to 90 percent of notes correctly, with about 10 percent missing or wrong. "We have only begun to see excellent results in the last few weeks, the results are note perfect" says John Walker, Before founding zenoph in 2002 John Walker was the leading developer of VoIP.

The enginners then playback a stereo version of the music, one channel has the original recording, and the other has there midi derived audio version "if there even a few miliseconds out, the ear can immediately hear there something wrong"
This technique could be used to clean up old recordings by deleting unwanted parts of the midi info etc...."

Surely this has large potential for Remix work where the original parts or lost, but also opens up a whole new realm of ripoffs!!
 

ichabod

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I think this is only for piano... and even that has taken years of research. I guess the algorithm will do a mixture of transient analysis to determine key press timing with frequency analysis to try to fit the peaks in the frequency spectrum to known harmonic spacings and powers for different notes. This works well for a piano as the distribution and power of the harmonics for each note are similar. A piano is also an easy choice as you do not get pitchbend or tonal variation in the same way as you get with most other instruments... the player only interfaces via the keys. This also means it is simple to perfectly describe a piano solo using MIDI - something which is not possilbe for most other instruments. Not sure if its ready for transcribing psytrance yet!
 

soliptic

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Ichabod said:
I think this is only for piano... and even that has taken years of research. I guess the algorithm will do a mixture of transient analysis to determine key press timing with frequency analysis to try to fit the peaks in the frequency spectrum to known harmonic spacings and powers for different notes. This works well for a piano as the distribution and power of the harmonics for each note are similar. A piano is also an easy choice as you do not get pitchbend or tonal variation in the same way as you get with most other instruments... the player only interfaces via the keys. This also means it is simple to perfectly describe a piano solo using MIDI - something which is not possilbe for most other instruments. Not sure if its ready for transcribing psytrance yet!

wow. that's covered all the issues that immediately sprang to mind, except 20 times better

no need for me to post at all then really... :Smile3:

oops... i think i just did
 

AEON

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A piano is also an easy choice as you do not get pitchbend or tonal variation in the same way as you get with most other instruments... the player only interfaces via the keys.

don't forget the foot pedals - they affect timbre, and sustain. you can mute the string's sounds & you can allow them to ring for ages.
 
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