streaming mode | Music Similarity category


  • inputArray (vector_real) - a 2D binary cross similarity matrix of two audio chroma vectors (refer CrossSimilarityMatrix algorithm’).


  • scoreMatrix (matrix_real) - a 2D smith-waterman alignment score matrix from the input binary cross-similarity matrix as described in [2].

  • distance (real) - cover song similarity distance between the query and reference song from the input similarity. Either ‘asymmetric’ (as described in [2]) or ‘symmetric’ (maximum score in the alignment score matrix).


  • disExtension (real ∈ [0, ∞), default = 0.5) :

    penalty for disruption extension

  • disOnset (real ∈ [0, ∞), default = 0.5) :

    penalty for disruption onset

  • distanceType (string ∈ {asymmetric, symmetric}, default = asymmetric) :

    choose the type of distance. By default the algorithm outputs a asymmetric distance which is obtained by normalising the maximum score in the alignment score matrix with length of reference song

  • pipeDistance (bool ∈ {true, false}, default = false) :

    whether to pipe-out the computed cover song similarity distance for each stream of input similarity matrix


This algorithm computes a cover song similiarity measure from a binary cross similarity matrix input between two chroma vectors of a query and reference song using various alignment constraints of smith-waterman local-alignment algorithm.

This algorithm expects to recieve the binary similarity matrix input from essentia ‘ChromaCrossSimilarity’ algorithm or essentia ‘CrossSimilarityMatrix’ with parameter ‘binarize=True’.

The algorithm provides two different allignment contraints for computing the smith-waterman score matrix (check references).

Exceptions are thrown if the input similarity matrix is not binary or empty.


[1] Smith-Waterman algorithm (Wikipedia,

[2] Serra, J., Serra, X., & Andrzejak, R. G. (2009). Cross recurrence quantification for cover song identification.New Journal of Physics.

[3] Chen, N., Li, W., & Xiao, H. (2017). Fusing similarity functions for cover song identification. Multimedia Tools and Applications.

Source code

See also

ChromaCrossSimilarity (standard) ChromaCrossSimilarity (streaming) CoverSongSimilarity (standard) CrossSimilarityMatrix (standard)