Color coding

Steve ST-Pierre's Avatar

Steve ST-Pierre

18 Apr, 2013 06:05 PM

Hello,

I would like to know how the color coding is calculated. What each color mean?

Thank you,

Steve ST-Pierre

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  • beaTunes : 3.5.11
  • JVM : Java HotSpot(TM) 64-Bit Server VM
  • Version : 20.14-b01-447
  • Vendor : Apple Inc.
  • OS : Mac OS X 10.8.3, x86_64
  • Library: iTunes
  • Registered as : Student Needs.ca - Besoins particuliers Steve ST-Pierre
  1. Support Staff 1 Posted by Hendrik Schreib... on 19 Apr, 2013 12:00 PM

    Hendrik Schreiber's Avatar

    Hi,

    when two songs in your collection have the same color, it simply means that they are similar with respect to their frequency spectrum.

    E.g. "red" itself does not have meaning whatsoever. But when two songs are red, it means that they share some properties.

    Does this help?

    -hendrik

  2. 2 Posted by Steve ST-Pierre on 19 Apr, 2013 06:44 PM

    Steve ST-Pierre's Avatar

    Do you have more informations? Is it a mind of matrix? Do you have the formula for that? I am doing a psychological research using your software and I would like to use it as a measurement tools.

    Could you help me to find the information ?

    Steve ST-Pierre

  3. Support Staff 3 Posted by Hendrik Schreib... on 21 Apr, 2013 11:40 AM

    Hendrik Schreiber's Avatar

    Hi,

    I'm sorry, but there is no documentation on this.

    -hendrik

  4. 4 Posted by Martin on 27 Jun, 2013 07:41 AM

    Martin's Avatar

    I'd also like to know this. Spectral centroid maybe?

  5. Support Staff 5 Posted by Hendrik Schreib... on 28 Jun, 2013 08:21 AM

    Hendrik Schreiber's Avatar

    Martin,

    spectral centroid is one-dimensional and therefore hard to project into a 3D space (RGB). It's more like multi-dimensional, bark scaled intensities, projected into 3D space using PCA. As such it has some shortcomings, as PCA requires all values of the set to do its projection. If the set changes (a song is added/deleted), all values have to be re-computed. This is why "color" will probably be re-implemented in a future version of beaTunes.

    -hendrik

  6. 6 Posted by Martin Weiss Ha... on 28 Jun, 2013 09:11 AM

    Martin Weiss Hansen's Avatar

    Hi henrik,

    Thanks for you reply.

    Regards,
    Martin

    On Jun 28, 2013, at 10:21 , "hendrik" <[email blocked]> wrote:

  7. Support Staff 7 Posted by Hendrik Schreib... on 28 Jun, 2013 09:18 AM

    Hendrik Schreiber's Avatar

    You're welcome...

    Out of curiosity—since "spectral centroid" certainly isn't in everybody's vocabulary—what sparked the interest?

    -hendrik

  8. 8 Posted by Martin Weiss Ha... on 28 Jun, 2013 09:40 AM

    Martin Weiss Hansen's Avatar

    I've been using beaTunes lately, for organizing my DJ mixes. I'm doing a monthly radio show on Sense.FM (https://soundcloud.com/the-marsbar).

    And I'm quite interested in signal processing. I've done an MSc in Digital Music Processing at Queen Mary, University of London.

    Regards,
    Martin

  9. Support Staff 9 Posted by Hendrik Schreib... on 28 Jun, 2013 10:25 AM

    Hendrik Schreiber's Avatar

    Very cool!

    Queen Mary seems to be the European epicenter of MIR—I run into Queen Mary folks pretty much at every ISMIR.

    If you ever find yourself wanting to write your own analyzer for beaTunes (key, BPM, ..) - take a look at http://www.beatunes.com/beatlet-songpropertyanalyzer.html It's easier than it seems at first. :-)

    Cheers,

    -hendrik

  10. 10 Posted by Martin Weiss Ha... on 28 Jun, 2013 07:07 PM

    Martin Weiss Hansen's Avatar

    Ah cool :) Thank you.

    Have a nice weekend.

    Regards,
    Martin

  11. 11 Posted by Brian Santell on 29 Aug, 2013 02:32 PM

    Brian Santell's Avatar

    can the colors be imported into itunes? I analyzed my songs against my itunes library and I see things like bpm being updated in itunes, but I don't know where in itunes the color coding is stored.

    thank you

  12. Support Staff 12 Posted by Hendrik Schreib... on 30 Aug, 2013 08:05 AM

    Hendrik Schreiber's Avatar

    Hi Brian,

    unfortunately, iTunes does not support the color concept.

    -hendrik

  13. 13 Posted by Tom on 10 Oct, 2014 09:45 AM

    Tom's Avatar

    @ Hendrk,

    Maybe I misunderstood, but based on the PCA theory, I understand the RGB values are filled with 3 different values? Where does this different values come from insectly?

    I am making a data visualization of my music library and the color data could be a very interesting addition!

    Thanks in advance!

    -Tom

  14. Support Staff 14 Posted by Hendrik Schreib... on 10 Oct, 2014 10:01 AM

    Hendrik Schreiber's Avatar

    Where does this different values come from insectly?

    The color values are computed differently in beaTunes 4 compared to beaTunes 3.

    In beaTunes 4 we first compute a mel-spaced power spectrum which is then projected into a another space of which only the strongest 3 dimensions are considered. The projection happens via a matrix multiplication. In beaTunes 4 this matrix is constant and has been computed using PCA for a variety of songs from different genres.

    Hope this helps.

  15. 15 Posted by Tom on 10 Oct, 2014 10:56 AM

    Tom's Avatar

    Thanks for the quick answer!
     
    I googled a bit about power spectrums, but I can't get an idea of where it's based on. Can you rephrase your answer, I am not an sound expert haha

    Is it possible to make some kind of legenda based on the colors? Where different colors are linked to specific music related categories?

  16. Support Staff 16 Posted by Hendrik Schreib... on 10 Oct, 2014 04:01 PM

    Hendrik Schreiber's Avatar

    Basically you calculate the STFT over a number of signal windows, calculate their power spectra and transform them to mel bins (aka bark scale) and average them per bin. Then project the result into another space of which you take the top three dimensions as RGB.

    Why SFTF? It let's you determine how "strong" a frequency in the signal is. And when applying the SFTF you end up with a complex result. The magnitude of the (complex) value x is it's absolute value, i.e. |x|, the power is |x|^2. In other words it lets you determine how much energy/power is in a given frequency bin => Power spectrum.

    Is it possible to make some kind of legenda based on the colors? Where different colors are linked to specific music related categories?

    No.

    Color is not the same as genre or mood. It's merely an indicator for similarity in frequency distribution.

    Say, e.g. some piece of music is vocal only. It will most likely have a different frequency distribution than a piece that features piano only. Since some genres feature specific instruments, it's natural that they also have a certain frequency distribution. So there is a connection, but I wouldn't use it to guess a genre. As I said - it's an indicator of a certain kind of fairly low level similarity.

  17. 17 Posted by Sol Rosenberg on 16 Oct, 2014 01:54 AM

    Sol Rosenberg's Avatar

    Hendrik,
    So basically how would somebody use the color system for their advantage? How can it help you. I understand that it groups songs that are similar in frequency and it's "low level", but how does that help "joe listener" like me?
    Do people use colors to make playlists for example?
    Thank you!!

  18. Support Staff 18 Posted by Hendrik Schreib... on 16 Oct, 2014 08:53 AM

    Hendrik Schreiber's Avatar

    Color similarity does not predict musical similarity for sure, but it is an indicator for it.
    Just like genre does not for sure say that two songs match each other.
    It is helpful to create playlists with matching songs or simply find songs that have a higher probability to match one another.

    The best use for the color feature is to create matchlists or find matching songs in that panel right below the main table. Both use rulesets defined in the preferences that allow for a mixture of multiple rules (one of the color, if you're interested in that kind of match).

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