MPATE-GE 2623 Music Information Retrieval - Assignment # 4
Instructor: Juan Pablo Bello
Please check the course’s website for detailed submission instructions.
Write a Matlab function that takes the name of any 16-bit wav file (if stereo, please simply
disregard the 2nd channel) sampled at fs= 44.1kHz , and performs the following operations:
•computes the sequence of Mel-frequency cepstral coefficients (MFCC).
•breaks the feature sequence into 1 second-long, non-overlapping subsequences, and
computes the average MFCC vector for each subsequence.
•uses a nearest neighbor classifier (using the Euclidean distance) to label each subse-
quence as belonging to one of a predefined set of 4 music instrument classes.
•plots the output of each operation as subplots in a single figure.
Please note that you will need to create both “training” and “testing” sets of manually-
labeled audio files evenly distributed across the 4 classes (e.g. 50 seconds each of violin,
flute, piano and trombone). It is recommended that you select instrument classes that can
be easily differentiated from each other. Train and test files should be recordings of a single
instrument (or a concatenation of excerpts featuring only one instrument at a time). Note
that recordings of the same instrument should be different for each set.
Please report the percentage of 1-second windows that are correctly classified, per in-
strument class and overall. Include graphs in your report as necessary. Comment on the
resulting plots, their differences and their relationship to the characteristics of the sounds,
and your choice of processing parameters.
Extra point: Experiment with increasing the number of nearest neighbors and of instrumental
classes. Discuss how these modifications impact classification.
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