HarmTrace.Base.MusicTime

Summary: A set of types and classes for representing musical time, mainly (but not necessarily) in the context of recognising chords from an arbitrary audio source.

Datatypes

Types for representing Chords and their probabilities

type ChordAnnotation = [TimedData ProbChord]

A chord annotation consists of a list with chords and segment boundaries.

data ProbChordSeg

Clustering ProbChords in a collection of chords that share a key

Constructors

Segment

Fields

segKey :: Key

segChords :: [TimedData [ProbChord]]

Instances

Eq ProbChordSeg

Show ProbChordSeg

data ProbChord

Combines a ChordLabel with a probability.

Constructors

ProbChord

Fields

chordLab :: ChordLabel

prob :: NumData

Instances

Eq ProbChord

Show ProbChord

data ChordCand

A chord candidate: an intermediate datatype that matches shorthand, chord structure and root note (plus inversion)

Constructors

ChordCand

Fields

originalRootCC :: Root

inversionRootCC :: Root

shorthardCC :: Shorthand

chordStructCC :: ChordStruct

Instances

Eq ChordCand

Show ChordCand

Representing musical time

data TimedData a

A datatype that wraps around an (musical) datatype, adding information about the musical time to this datatype. Musical time is stored as a list of BarTime time stamps that can optionally be augmented with information about the Beat position of the particular time stamp inside the bar.

Constructors

TimedData

Fields

getData :: a

Returns the contained datatype

getTimeStamps :: [BarTime]

Returns the list of TimeStamps

Instances

Functor TimedData

Eq a => Eq (TimedData a)

Show a => Show (TimedData a)

data Beat

For now, we fix the number of available beats to four, because this is also hard-coded into the bar and beat-tracker.

Constructors

One

Two

Three

Four

NoBeat

Instances

Enum Beat

Eq Beat

Show Beat

data BarTime

Represents a musical time stamp, which is a NumData possibly augmented with a Beat denoting the position of the time stamp within a bar.

Constructors

BarTime NumData Beat

Time NumData

Instances

Eq BarTime

Ord BarTime

Show BarTime

type BarTimeTrackData = [BarTime]

type NumData = Double

A type synonym is defined for our main numerical representation, this allows us to easily change the precision.

Representing raw audio data

data AudioFeat

Groups the three types of VAMP plug-in data: ChordinoData, BarTimeTrackData, and KeyStrengthData. See for more information:

• http://www.vamp-plugins.org
• http://isophonics.net/nnls-chroma
• http://omras2.org/SonicAnnotator

Constructors

AudioFeat

Fields

getChroma :: ChordinoData

getBeats :: BarTimeTrackData

getKeys :: KeyStrengthData

getAudioFeatId :: FilePath

type ChordinoData = [ChordinoLine]

data ChordinoLine

Represents two chroma features and a time stamp.

Constructors

ChordinoLine

Fields

time :: NumData

Returns the time stamp of the chroma features

bass :: [NumData]

Returns the bass chroma feature

treb :: [NumData]

Returns the treble chroma feature

Instances

Eq ChordinoLine

Show ChordinoLine

type KeyStrengthData = ChordinoData

type BeatTrackerData = [NumData]

type BeatChroma = TimedData [ChordinoLine]

type ChordStruct = [NumData]

A chord template is list of NumDatas

Functions

Data access

timedData :: a -> NumData -> NumData -> TimedData a

alternative TimedData constructor

timedDataBT :: a -> BarTime -> BarTime -> TimedData a

alternative TimedData constructor

getBarTime :: TimedData a -> BarTime

Returns the start time stamp

getBeat :: TimedData a -> Beat

Returns the start Beat

onset :: TimedData a -> NumData

Returns the onset time stamp

offset :: TimedData a -> NumData

Returns the offset time stamp

setData :: TimedData a -> b -> TimedData b

wraps a datatype in TimedData

Type conversion and other utilities

getBeatTrack :: BarTimeTrackData -> BeatTrackerData

Converts BarTimeTrackData into BeatTrackerData

concatTimedData :: a -> TimedData a -> TimedData a -> TimedData a

concatenates the BarTime timestamps of two TimedDatas and creates a new TimedData that stores the first argument.

nextBeat :: Beat -> Beat

returns the next beat, e.g. nextBeat Two = Three . Following the (current) definition of Beat, we still assume 4/4, in the future this function should also have the meter as an argument.

prevBeat :: Beat -> Beat

returns the previous Beat, similar to prevBeat.

returns the next beat, e.g. nextBeat Two = Three . Following the (current) definition of Beat, we still assume 4/4, in the future this function should also have the meter as an argument.

updateTPChord :: (ChordLabel -> ChordLabel) -> TimedData ProbChord -> TimedData ProbChord

Updates transforms ChordLabel wrapped in a ProbChord and TimedData

dropProb :: [TimedData ProbChord] -> [TimedData ChordLabel]

drops the probabilties paired with chordlabels (in a list of ProbChords) and returns a list of ChordLabels

dropTimed :: [TimedData a] -> [a]

drops the time (with or without Beat) information of a list Timed data structure

timeStamp :: BarTime -> NumData

Returns the NumData timestamp, given a BarTime

beat :: BarTime -> Beat

Returns the NumData timestamp, given a BarTime

prettyPrint :: Show a => [TimedData a] -> String

Pretty prints a list of TimedDatas, one per line