#1: Formal proposal sent to the Amarok developers

This proposal intends to use the algorithms in this suite to solve the problem of duplicate songs with inconsistent ratings.

Hello, gents.

Let's make this quick, since it's a long writeup. First of all, Amarok rocks. Second, the purpose of this message is to put a proposal forward for a long-overdue Amarok improvement, one that will give Amarok a series of features no other player has.

I'm talking about integrating Butterscotch into Amarok, and (in the medium-term future) replacing features powered by MusicBrainz using a service that could, very conceivably, be integrated with Last.FM (this is technically possible).

So, what it is: Butterscotch is an algorithm to fingerprint songs which is not designed to provide an unique ID for a file (technically, it can as long as the file has not been transcoded or you have the first 2 minutes of audio, but that's not the point). Read again: it is NOT like MB or liblastfm or Soren's patch.

Butterscotch's unique property -- what makes Butterscotch interesting -- is that it lets you identify "duplicates". Let me illustrate by example: let's assume you have a track named "What hurts the most" in MP3 format 128 kbps, from an album you ripped that is called "Perfect day", and that you have another track "What hurts the most (radio mix U.S.)" from an album called "What hurts the most CD maxi" that you ripped in FLAC lossless. Now, upon listening, you will discover that those are the exact same tracks, maybe one of them starts half a second later, but they sound exactly the same (except for the maxi cut being in perfect CD quality). Butterscotch will tell you beyond a doubt that those songs are the same using simple math (correlation coefficient averages).

Several interesting possibilities follow from that (stage 1):

• Amarok can auto-identify duplicates and normalize ratings, play counts and scores) for the duplicates. This is useful for those of us who prefer full albums. Also, no duplicates and normalized statistics mean that the true favorites really bubble up this time.
• Amarok can avoid putting duplicates in your portable devices, where space is a concern.
• You can now make UI to weed duplicates out easily. This is useful for those who prefer single tracks and no duplicates.
• Amarok could tell you "this track is already in your collection under a different album" upon UI actions, such as "copy to collection".
• (In the future, with another *really cheap* music analysis algorithm) Amarok can automatically select / visually identify the highest-quality versions of duplicate tracks for playback or portable devices.

How, how is this better than using MusicBrainz and the like? Simple, you don't need a central server or unique IDs for tracks (MusicDNS which is the partner of MusicBrainz works that way, it has a series of technical problems that make it less reliable than Butterscotch). All you need is computation power, which your computer has aplenty. MusicBrainz also has problems with false positives and the like. And you can decode any format, not just the formats that a closed source library can.

But if you throw a central server into the mix (stage 2), this gets much better:

• Amarok can auto-submit tags+fingerprints+amarokuniqueid to the server.
• Amarok can avoid computing the fingerprint by asking the server for the fingerprint corresponding to an uniqueid.
• Amarok can auto-tag songs based on exact matches of the fingerprints, AND it can also show the user alternatives in case of non-exact matches (correlations > 0.9 in the current definition of the algorithm) which should be very few. Imagine being able to complete incomplete tags from a database vetted by majority "vote" (submission, see below).
• We can build the definitive music encyclopedia all by ourselves (okay, technically others can play too). We can use that data to provide very accurate tagging since our service would know, mathematically, which tags correspond to which fingerprints. We can also make it very user-participative, allowing user submissions to grow the database and letting the user say "no, this info is wrong" so we get a self-correcting encyclopedia with minimal user or admin intervention. The web page could also be wiki-like and allow others (even artists and producers themselves) to complete information that is not available from the ID3 tags. *- We can make the service *completely anonymous* for Amarok users.

There are a few technical roadblocks I still have to cross (the biggest one being that identical songs that are sung by the same performer but in different languages correlate too highly), but the technology should be sufficiently solid for me to write an amarok2 extension that actually makes stage 1 a reality. In the following days.

So, before you commit yourselves exclusively to a MusicBrainz or Last.FM type of thing, maybe you'd like to give me a shot and perhaps help me along?