For a large amount of musical audio tracks I am doing the following with every single track:

I am slicing the track into very small pieces whereas each piece represents a note onset event. So the piece begins at a note onset event and ends before the next event starts. The result is having hundreds of very small, typically sub-2-second slices for each track.

Now I want to take one of these slices - a totally random pick - and search through all the remaining slices to find the slice that is most similar to the picked one.

Most similar means that it "sounds" like the picked one. More specific this means that it is having the same **key, pitch** - **not timbre** and **not rhythmically** (since rhythm is cut off by slicing at note onsets)

**The Problems**

To find the slice that is most similar to / that most "sounds-like" a randomly chosen slice I have to determine its "sound". I have been reading about MFCCs but I am not sure if this will help determine the sound, which in this case will be key, pitch.

Next, when having a way to determine the "sound" in numerical way I need to find a way how to compare these results. There are things like **euclidian distance** or **consine-similarity**.

Last but not least the slices are of different length.

**What I have done so far**

Slicing based on note onset-events is done with the help of the onset-feature extraction methods of the [`librosa` python library][1]. This function returns a list of onset-events represented as time-stamps. Each time-stamp is used as a "cut-mark" to slice the audio tracks.

I have been playing with the fastDTW python library which does a dynamic time warping analyzation, compares the result with using an euclidian distance function and fed it with slices. But I am not sure if the result is the distance in MFCCs

**The question**

To summarize the above into a single question:

How to match a piece of very short audio based on key and pitch to find a piece in a large database that is most similar to it?


  [1]: http://librosa.github.io/librosa/onset.html