improving music mood classification using lyrics, audio and social tags

6.2.3 Text Stylistic Features
Text stylistic features often refer to interjection words (e.g., “ooh,” “ah”), special
punctuations (e.g., “!,” “?”) and text statistics (e.g., number of unique words, length of words,
etc.). They have been used effectively in text stylometric analyses dealing with authorship
attribution, text genre identification, and authority classification (Argamon et al., 2003).
In the music domain, text stylistic features on lyrics were successfully used in a study in
music genre classification (Mayer et al., 2008). In particular, Mayer et al. (2008) demonstrated
interesting distribution patterns of some exemplar lyric features across different genres. For
example, the word “nuh” and “fi” mostly occurred in reggae and hip-hop songs. Their
experiment results showed that the combination of text stylistic features, part-of-speech features
and audio spectral features significantly outperformed the classifier using audio spectral features
only as well as the classifier combining audio and bag-of-words lyric features.
In the task of mood classification, the usefulness of text stylistic features has not been
formally evaluated, and thus this dissertation research includes text stylistic features. In
particular, the text stylistic features evaluated in this study are defined in Table 6.2, which
includes 25 dimensions: six interjection words, two special punctuation marks and 17 text
statistics (also see Section 6.4.3).
Table 6.3 summarizes the aforementioned linguistic features and text stylistic features with
their numbers of dimensions and numbers of representation models.
77