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Package at.ofai.music.beatroot

Class Agent

  • java.lang.Object
    • at.ofai.music.beatroot.Agent

  • public class Agent
extends java.lang.Object
    Agent is the central class for beat tracking. Each Agent object has a tempo hypothesis, a history of tracked beats, and a score evaluating the continuity, regularity and salience of its beat track.

    • Field Summary

      Fields 
      Modifier and Type Field and Description
      int beatCount
      The number of beats found by this Agent, including interpolated beats.
      double beatInterval
      The current tempo hypothesis of the Agent, expressed as the beat period in seconds.
      double beatTime
      The time of the most recent beat accepted by this Agent.
      static double CONF_FACTOR
      The slope of the penalty function for onsets which do not coincide precisely with predicted beat times.
      protected static double correctionFactor
      Controls the reactiveness/inertia balance, i.e.
      static boolean debug
      Print debugging information
      protected static double decayFactor
      For scoring Agents in a (non-existent) real-time version (otherwise not used).
      static double DEFAULT_CORRECTION_FACTOR
      The reactiveness/inertia balance, i.e.
      static double DEFAULT_EXPIRY_TIME
      The default value of expiryTime, which is the time (in seconds) after which an Agent that has no Event matching its beat predictions will be destroyed.
      EventList events
      The list of Events (onsets) accepted by this Agent as beats, plus interpolated beats.
      protected static double expiryTime
      The time (in seconds) after which an Agent that has no Event matching its beat predictions will be destroyed.
      protected static int idCounter
      The identity number of the next created Agent
      protected int idNumber
      The Agent's unique identity number.
      double initialBeatInterval
      The initial tempo hypothesis of the Agent, expressed as the beat period in seconds.
      static double INNER_MARGIN
      The default value of innerMargin, which is the maximum time (in seconds) that a beat can deviate from the predicted beat time without a fork occurring.
      protected static double innerMargin
      The maximum time (in seconds) that a beat can deviate from the predicted beat time without a fork occurring (i.e.
      static double MAX_CHANGE
      The maximum allowed deviation from the initial tempo, expressed as a fraction of the initial beat period.
      double phaseScore
      Sum of salience values of the Events which have been interpreted as beats by this Agent, weighted by their nearness to the predicted beat times.
      static double POST_MARGIN_FACTOR
      The maximum amount by which a beat can be later than the predicted beat time, expressed as a fraction of the beat period.
      double postMargin
      The size of the outer half-window after the predicted beat time.
      static double PRE_MARGIN_FACTOR
      The maximum amount by which a beat can be earlier than the predicted beat time, expressed as a fraction of the beat period.
      double preMargin
      The size of the outer half-window before the predicted beat time.
      double tempoScore
      To be used in real-time version??
      double topScoreTime
      How long has this agent been the best? For real-time version; otherwise not used.

    • Constructor Summary

      Constructors 
      Constructor and Description
      Agent(double ibi)
      Constructor: the work is performed by init()
      Agent(Agent clone)
      Copy constructor.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      protected void accept(Event e, double err, int beats)
      Accept a new Event as a beat time, and update the state of the Agent accordingly.
      boolean considerAsBeat(Event e, AgentList a)
      The given Event is tested for a possible beat time.
      protected void fillBeats()
      Interpolates missing beats in the Agent's beat track, starting from the beginning of the piece.
      protected void fillBeats(double start)
      Interpolates missing beats in the Agent's beat track.
      protected void init(double ibi)
      Initialise all the fields of this Agent.
      void print()
      Output debugging information about this Agent, at the default (highest) level of detail.
      void print(int level)
      Output debugging information about this Agent.
      void showTracking(EventList allEvents)
      Show detailed debugging output describing the beat tracking behaviour of this agent.
      void showTracking(EventList allEvents, double level)
      Show detailed debugging output describing the beat tracking behaviour of this agent.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • beatCount

        public int beatCount
        The number of beats found by this Agent, including interpolated beats.

      • beatInterval

        public double beatInterval
        The current tempo hypothesis of the Agent, expressed as the beat period in seconds.

      • beatTime

        public double beatTime
        The time of the most recent beat accepted by this Agent.

      • CONF_FACTOR

        public static double CONF_FACTOR
        The slope of the penalty function for onsets which do not coincide precisely with predicted beat times.

      • correctionFactor

        protected static double correctionFactor
        Controls the reactiveness/inertia balance, i.e. degree of change in the tempo. The beat period is updated by the reciprocal of the correctionFactor multiplied by the difference between the predicted beat time and matching onset.

      • debug

        public static boolean debug
        Print debugging information

      • decayFactor

        protected static double decayFactor
        For scoring Agents in a (non-existent) real-time version (otherwise not used).

      • DEFAULT_CORRECTION_FACTOR

        public static final double DEFAULT_CORRECTION_FACTOR
        The reactiveness/inertia balance, i.e. degree of change in the tempo, is controlled by the correctionFactor variable. This constant defines its default value, which currently is not subsequently changed. The beat period is updated by the reciprocal of the correctionFactor multiplied by the difference between the predicted beat time and matching onset.
        See Also:
        Constant Field Values

      • DEFAULT_EXPIRY_TIME

        public static final double DEFAULT_EXPIRY_TIME
        The default value of expiryTime, which is the time (in seconds) after which an Agent that has no Event matching its beat predictions will be destroyed.
        See Also:
        Constant Field Values

      • events

        public EventList events
        The list of Events (onsets) accepted by this Agent as beats, plus interpolated beats.

      • expiryTime

        protected static double expiryTime
        The time (in seconds) after which an Agent that has no Event matching its beat predictions will be destroyed.

      • idCounter

        protected static int idCounter
        The identity number of the next created Agent

      • idNumber

        protected int idNumber
        The Agent's unique identity number.

      • initialBeatInterval

        public double initialBeatInterval
        The initial tempo hypothesis of the Agent, expressed as the beat period in seconds.

      • INNER_MARGIN

        public static final double INNER_MARGIN
        The default value of innerMargin, which is the maximum time (in seconds) that a beat can deviate from the predicted beat time without a fork occurring.
        See Also:
        Constant Field Values

      • innerMargin

        protected static double innerMargin
        The maximum time (in seconds) that a beat can deviate from the predicted beat time without a fork occurring (i.e. a 2nd Agent being created).

      • MAX_CHANGE

        public static double MAX_CHANGE
        The maximum allowed deviation from the initial tempo, expressed as a fraction of the initial beat period.

      • phaseScore

        public double phaseScore
        Sum of salience values of the Events which have been interpreted as beats by this Agent, weighted by their nearness to the predicted beat times.

      • POST_MARGIN_FACTOR

        public static double POST_MARGIN_FACTOR
        The maximum amount by which a beat can be later than the predicted beat time, expressed as a fraction of the beat period.

      • postMargin

        public double postMargin
        The size of the outer half-window after the predicted beat time.

      • PRE_MARGIN_FACTOR

        public static double PRE_MARGIN_FACTOR
        The maximum amount by which a beat can be earlier than the predicted beat time, expressed as a fraction of the beat period.

      • preMargin

        public double preMargin
        The size of the outer half-window before the predicted beat time.

      • tempoScore

        public double tempoScore
        To be used in real-time version??

      • topScoreTime

        public double topScoreTime
        How long has this agent been the best? For real-time version; otherwise not used.

    • Constructor Detail

      • Agent

        public Agent(double ibi)
        Constructor: the work is performed by init()
        Parameters:
        ibi - The beat period (inter-beat interval) of the Agent's tempo hypothesis.

      • Agent

        public Agent(Agent clone)
        Copy constructor.
        Parameters:
        clone - The Agent to duplicate.

    • Method Detail

      • init

        protected void init(double ibi)
        Initialise all the fields of this Agent.
        Parameters:
        ibi - The initial tempo hypothesis of the Agent.

      • print

        public void print()
        Output debugging information about this Agent, at the default (highest) level of detail.

      • print

        public void print(int level)
        Output debugging information about this Agent.
        Parameters:
        level - The level of detail in debugging

      • accept

        protected void accept(Event e,
                      double err,
                      int beats)
        Accept a new Event as a beat time, and update the state of the Agent accordingly.
        Parameters:
        e - The Event which is accepted as being on the beat.
        err - The difference between the predicted and actual beat times.
        beats - The number of beats since the last beat that matched an Event.

      • considerAsBeat

        public boolean considerAsBeat(Event e,
                              AgentList a)
        The given Event is tested for a possible beat time. The following situations can occur: 1) The Agent has no beats yet; the Event is accepted as the first beat. 2) The Event is beyond expiryTime seconds after the Agent's last 'confirming' beat; the Agent is terminated. 3) The Event is within the innerMargin of the beat prediction; it is accepted as a beat. 4) The Event is within the outerMargin's of the beat prediction; it is accepted as a beat by this Agent, and a new Agent is created which doesn't accept it as a beat. 5) The Event is ignored because it is outside the windows around the Agent's predicted beat time.
        Parameters:
        e - The Event to be tested
        a - The list of all agents, which is updated if a new agent is created.
        Returns:
        Indicate whether the given Event was accepted as a beat by this Agent.

      • fillBeats

        protected void fillBeats()
        Interpolates missing beats in the Agent's beat track, starting from the beginning of the piece.

      • fillBeats

        protected void fillBeats(double start)
        Interpolates missing beats in the Agent's beat track.
        Parameters:
        start - Ignore beats earlier than this start time

      • showTracking

        public void showTracking(EventList allEvents)
        Show detailed debugging output describing the beat tracking behaviour of this agent. Calls showTracking()/1 with a default metrical level of 1.
        Parameters:
        allEvents - An EventList of all onsets

      • showTracking

        public void showTracking(EventList allEvents,
                         double level)
        Show detailed debugging output describing the beat tracking behaviour of this agent.
        Parameters:
        allEvents - An EventList of all onsets
        level - The metrical level of beat tracking relative to the notated beat (used to count beats)
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