Table 5 MIR extracted audio features provided by The Echo Nest API

duration_ms

The duration of the track in milliseconds.

key

The estimated overall key of the track. Integers map to pitches using standard Pitch Class notation. E.g. 0 = C, 1 = C♯/D♭, 2 = D, and so on. If no key was detected, the value is −1.

mode

Mode indicates the modality (major or minor) of a track. Major is represented by 1 and minor is 0.

time_signature

An estimated overall time signature of a track.

acousticness

A confidence measure from 0.0 to 1.0 of whether the track is acoustic. 1.0 represents high confidence the track is acoustic.

danceability

Danceability describes how suitable a track is for dancing based on a combination of musical elements.

energy

Energy is a measure from 0.0 to 1.0 and represents a perceptual measure of intensity and activity.

instrumentalness

Predicts whether a track contains no vocals. The closer the instrumentalness value is to 1.0, the greater likelihood the track contains no vocal content.

liveness

Higher liveness values represent an increased probability that the track was performed live.

loudness

The overall loudness of a track in decibels (dB).

speechiness

Speechiness detects the presence of spoken words in a track. The more exclusively speech-like the recording (e.g. talk show, audio book, poetry), the closer to 1.0 the attribute value.

valence

A measure from 0.0 to 1.0 describing the musical positiveness conveyed by a track.

tempo

The overall estimated tempo of a track in beats per minute (BPM).