An Analysis of the Effect of Data Augmentation Methods: Experiments for a Musical Genre Classification Task

Abstract

Supervised machine learning relies on the accessibility of large datasets of annotated data. This is essential since small datasets generally lead to overfitting when training high-dimensional machine-learning models. Since the manual annotation of such large datasets is a long, tedious and expensive process, another possibility is to artificially increase the size of the dataset. This is known as data augmentation. In this paper we provide an in-depth analysis of two data augmentation methods: sound transformations and sound segmentation. The first transforms a music track to a set of new music tracks by applying processes such as pitch-shifting, time-stretching or filtering. The second one splits a long sound signal into a set of shorter time segments. We study the effect of these two techniques (and the parameters of those) for a genre classification task using public datasets. The main contribution of this work is to detail by experimentation the benefit of these methods, used alone or together, during training and/or testing. We also demonstrate their use in improving the robustness of potentially unknown sound degradations. By analyzing these results, good practice recommendations are provided.