How this website extract chords of any song?

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music143
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Joined: Mon Mar 18, 2019 6:20 am

How this website extract chords of any song?

Post by music143 »

"Would like to know a little bit about the mechanism?

Check it Out: https://www.guitaa.com/chords/jayda-hap ... usic-video

Select any song, It'll extract the chords. But How?"
tippie53
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Re: How this website extract chords of any song?

Post by tippie53 »

looks interesting
do you know anything about this site? I gave it a quick looksee.
thanks
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robinsonb5
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Re: How this website extract chords of any song?

Post by robinsonb5 »

music143 wrote:Select any song, It'll extract the chords. But How?
If it's anything like RiffStation (software I bought a few years ago, sadly no longer available) then it's basically a polyphonic equivalent of the pitch detection in electronic guitar tuners, coupled with some heuristics to help guide the algorithm.

I've not used the site you've linked, but RiffStation does a pretty good of identifying chords in simple songs that don't stray beyond the I IV V + relative minors - but doesn't cope well with key changes, modulations and songs that use both minor and major versions of the same chord.
MaineGeezer
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Re: How this website extract chords of any song?

Post by MaineGeezer »

I don't know if this is what it does, but one way of doing it would be to do a Fourier transform of the sound wave, which would give you the individual frequencies that add together to produce the sound you hear. For example, a C chord is made up of a 261.63 Hz wave (C), a 326.63 Hz wave (E). and a 392.00 Hz wave (G). If the output of the Fourier transform was those three frequencies, you would know you have a C chord.

Now, what that program does is considerably messier than that. The melody is constantly changing, so it must do a sample every x milliseconds, for some x. At any instant, the chord may be incomplete or ambiguous. Somehow or other it has to average all that out and get some sort of general trend, which becomes a "best guess" for a chord.
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