Computer: Searching: Audio
Delta notation for music   (+7)  [vote for, against]
Store music in a delta format to facilitate searching for tunes

I think it would be useful to create a new format for music files built from the delta (number of semitones) between one note and the next. Since we are only storing differences between notes, the file format becomes essentially independent of the key. If we encode the duration of the note based on the ratio to the duration of the previous note as well we can also make it independent of tempo. This would make searching the files much easier. You could create a program to convert recorded humming, singing or whistling to this notation to help with searches for "What song was that? It goes kind of like this ..."
-- NoOneYouKnow, Dec 31 2005

Chord Progression http://en.wikipedia...i/Chord_progression
Here's an example of the roman numerals in use. [zigness, Jan 03 2006]

Music search system http://en.wikipedia.org/wiki/Parsons_code
similar stuff here... [zigness, Jan 03 2006]

Shazam - http://www.shazam.com/music/portal/
In the UK, dial 2580 from your mobile, and hold it up to the music source [Dub, Jan 03 2006]

No, I am Shazam ! http://www.antoniog...gio/anim/shazam.jpg
[normzone, Jan 03 2006]

Parson's Code http://www.musipedia.org/
a search engine for this [hazel, Jan 03 2006]

Yes and no - MIDI tones are essentially sheet music for computers, but actual recorded sound, WAV format, is not precisely that. This would be a great idea for an improvement to, if not recording, storage of MIDI format sound, though.
Only problem I forsee is data corruption, but this could be avioded fairly easily.
-- roleohibachi, Dec 31 2005


You suggest this as a file format alone, however as a learning musician I would like to see this in written form for performance. The vertical space taken by staves would be reduced. Every few bars you might explicitly state the starting note so you can start a performance halfway through easily, or recover the tune if you hit a wrong note. I find that I more-or-less read music as deltas anyway, finding the next note based on the movement from the previous one. Jumps of more than an octave could be abbreviated to the number of octaves plus a smaller jump.

I'm not sure if this would be good once you get beyond my level though, perhaps existing notation makes a lot of sense when you're very experienced.

I might try this with some music later. I'll post the result as an attachment.

[edit] - I've added this as a new idea, "Delta notation for sheet music"
-- ooooooooo, Jan 02 2006


The "keyless" part of this has been around for over 100 years... the typical notation is to use roman numerals to indicate which tone of the scale is used. For instance, I IV V for a little country music. (Make it minor (by adding 3 flats) and it's the same structure as Russian folk music.

A basic music theory text would be a good thing about now.

As far as a search mechanism goes... I'll have to think about that for a minute or two.
-- zigness, Jan 02 2006


I'm not sure I understand the Roman numeral thing. And "adding 3 flats" implies a key. The reason I suggest recording it as deltas (the difference between one note and the next) is that you can compare a melody to the same melody in a different key and the only thing different will be the initial note.
-- NoOneYouKnow, Jan 03 2006


First, in music, the "delta" you're talking about is referred to as an "interval". For instance, the interval between middle C and the E above it on a piano is a Major 3rd. Go to E flat, and it is a minor third.

I the key of C (no sharps or flats), I IV V would be C, F, G respectively. In the key of G (one sharp), I IV V would be G, C, D.

This kind of notation has been used in music for a long time. It's primary use is to show chords and chord progressions. In fact, a "chord progression" is just another term for "delta".

When I say add three flats, it's true. If you take any major key and do the equivalent of adding three flats, it becomes a minor key. Try it with a piano. If the key is G Major (F# is the key signature), just change the key signature to B flat and E flat. Play the song as written, but with a different key signature, and you'll be in G Minor.

There is really a lot to all of this, and I still recommend a basic music theory course. I like the idea -- especially as it relates to searching, but describing music as a series of intervals (or "deltas") has been around a long, long time. In fact, there is a kind of music notation that dates to the (help me out here bakers) 1600's I THINK... don't pin me down on the date... that involves a lot of flowing, wispy lines that describe ONLY the interval.

I'll look for some links...
-- zigness, Jan 03 2006


I wonder if that's how Shazam works [link]
-- Dub, Jan 03 2006


There's already a system called the Parsons Code which is used to identify tunes according to differences between consecutive notes. You just enter in whether the next note goes up, down or remains the same and search in this way [linky]
-- hazel, Jan 03 2006


OK, thanks for the link. The Musipedia site even has the search application already there. I'll have to play with it.
-- NoOneYouKnow, Jan 04 2006



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