[gst-devel] libgsttrm.so plugin

Tim Müller t.i.m at zen.co.uk
Thu Oct 14 01:32:14 CEST 2004

On Wednesday 13 October 2004 15:42, David I. Lehn wrote:

> The TRM code also uses the musicbrainz servers, and whatever magic 
> its closed source code does, to do the actual calculation which probably
> isn't something we want to depend on.

libmusicbrainz calculates an 'audio signature' that then gets sent to the 
server, which then uses its magic and returns a trmid.

The 'audio signature' contains data like this:

msratio,               /* fMeanSquare  */
fAverageZeroCrossing,  /* fZXing       */
f2Spec,                /* fSpectrum    */
specsum,               /* fSpectralSum */
estBPM,                /* fBeats       */
fAvgFFTDelta,          /* fAvgFFTDelta */
haar,                  /* fHaar        */
avgdiff,               /* fEnergyDiff  */
numsignchanges,        /* iEnergyZC    */
m_song_seconds, /* song_seconds */

I don't think the TRM ID itself is useful for regression testing either (not 
sensitive enough), but I wonder how hard it would be to determine the 
similarity between two 'audio signatures', and whether that would be useful 
at all for some of the tests.


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