Melcepstral

Melcepstral is a term used in the field of speech processing and audio analysis to describe a set of features derived from the Mel-frequency cepstral coefficients (MFCCs). These features are commonly used in various applications such as speech recognition, speaker identification, and music information retrieval. The Melcepstral features are obtained by applying a cepstral analysis to the Mel-frequency spectrum of an audio signal.

The Mel-frequency scale is a perceptual scale of pitches judged by listeners to be equal in distance from one another. It is based on the human auditory system's response to different frequencies, which is not linear but rather logarithmic. The Mel-frequency spectrum is computed by applying a filter bank to the short-time Fourier transform (STFT) of the audio signal, where the filters are spaced according to the Mel scale.

The cepstral analysis involves taking the logarithm of the Mel-frequency spectrum and then applying the inverse discrete Fourier transform (IDFT) to obtain the cepstral coefficients. These coefficients represent the power spectrum of the audio signal in a compact form, capturing the spectral envelope and removing the fine structure of the spectrum.

The Melcepstral features are typically used in conjunction with other features such as the delta and delta-delta coefficients to capture the dynamic aspects of the audio signal. They have been shown to be effective in various speech and audio processing tasks due to their ability to capture the spectral envelope and remove the fine structure of the spectrum.