MMIR Framework

Class: MicLevelsAnalysis

MicLevelsAnalysis

new MicLevelsAnalysis()

env/media/webMicLevels.js, line 83

Members

_audioAnalyzerAnalyserNode

See:

_audioContextAudioContext

_currentInputStreamLocalMediaStream

See:

_isAnalysisActive

internal flag: is/should mic-levels analysis be active?

_isAnalysisCanceled

internal flag: is/should mic-levels analysis be active?

html5Navigatornavigator

isMicLevelsEnabled

Switch for generally disabling "microphone-level changed" calculations (otherwise calculation becomes active/inactive depending on whether or not a listener is registered to event MIC_CHANGED_EVT_NAME)

TODO make this configurable?...

constantLEVEL_CHANGED_THRESHOLD

MIC-LEVELS: threshold for calculating level changes

private,constantMIC_CHANGED_EVT_NAME

MIC-LEVELS: Name for the event that is emitted, when the input-mircophone's level change.
Default Value:
  • "miclevelchanged"

constantMIC_MAX_NORM_VAL

MIC-LEVELS: the maximal value for level changes (used for normalizing change-values)

MIC_MAX_VAL

MIC-LEVELS: the maximal value to occurs in the input data

FIXME verify / check if this is really the maximal possible value...

constantMIC_NORMALIZATION_FACTOR

MIC-LEVELS: normalization factor for values: adjust value, so that is more similar to the results from the other input-modules

constantMIC_QUERY_INTERVALL

MIC-LEVELS: time interval / pauses between calculating level changes

recording

state-flag that indicates, if the process (e.g. ASR, recording) is actually active right now, i.e. if analysis calculations should be done or not.

private,constantSTREAM_STARTED_EVT_NAME

STREAM_STARTED: Name for the event that is emitted, when the audio input stream for analysis becomes available.
Default Value:
  • "webaudioinputstarted"

Methods

_startAudioAnalysis()

env/media/webMicLevels.js, line 415
HELPER start-up mic-levels analysis (and fire events for registered listeners)

_startUserMedia(inputstream)

env/media/webMicLevels.js, line 263
HELPER callback for getUserMedia: creates the microphone-levels-changed "analyzer" and fires mic-levels-changed events for registered listeners
Name Type Description
inputstream LocalMediaStream

_stopAudioAnalysis()

env/media/webMicLevels.js, line 439
HELPER stop mic-levels analysis

_updateMicLevelAnalysis()

env/media/webMicLevels.js, line 485
HELPER determine whether to start/stop audio-analysis based on listeners getting added/removed on the MediaManager

active(active){Boolean}

env/media/webMicLevels.js, line 598
Getter/Setter for ASR-/recording-active state. This function should be called with true when ASR starts and with false when ASR stops. NOTE setting the active state allows the analyzer to start processing when a listener for miclevelchanged is added while ASR/recording is already active (otherwise the processing would not start immediately, but when the ASR/recording is started the next time).
Name Type Description
active Boolean optional if active is provided, then the mic-level-analysis' (recording) active-state is set to this value.
Returns:
Type Description
Boolean the mic-level-analysis' (recording) active-state. If argument active was supplied, then the return value will be the same as this input value.

createAudioContext()

env/media/webMicLevels.js, line 99

enabled(enable){Boolean}

env/media/webMicLevels.js, line 563
Get/set the mic-level-analysis' enabled-state: If the analysis is disabled, then start will not active the analysis (and currently running analysis will be stopped). This function is getter and setter: if an argument enable is provided, then the mic-level-analysis' enabled-state will be set, before returning the current value of the enabled-state (if omitted, just the enabled-state will be returned)
Name Type Description
enable Boolean optional OPTIONAL if enable is provided, then the mic-level-analysis' enabled-state is set to this value.
Returns:
Type Description
Boolean the mic-level-analysis' enabled-state

getDb()

env/media/webMicLevels.js, line 225
HELPER calculate the dezible value for PCM value
Deprecated
  • currently un-used

    getRms()

    env/media/webMicLevels.js, line 200
    HELPER calculate the RMS value for list of audio values
    Deprecated
    • currently un-used

      hasChanged()

      env/media/webMicLevels.js, line 233
      HELPER determine if a value has change in comparison with a previous value (taking the LEVEL_CHANGED_THRESHOLD into account)

      normalize()

      env/media/webMicLevels.js, line 192
      HELPER normalize the levels-changed value to MIC_MAX_NORM_VAL
      Deprecated
      • currently un-used

        start(audioInputData)

        env/media/webMicLevels.js, line 530
        Start the audio analysis for generating "microphone levels changed" events. This functions should be called, when ASR is starting / receiving the audio audio stream. When the analysis has started, listeners of the MediaManager for event miclevelchanged will get notified, when the mic-levels analysis detects changes in the microphone audio input levels.
        Name Type Description
        audioInputData AudioInputData optional If provided, the analysis will use these audio input objects instead of creating its own audio-input via getUserMedia. The AudioInputData object must have 2 properties: { inputSource: MediaStreamAudioSourceNode (HTML5 Web Audio API) audioContext: AudioContext (HTML5 Web Audio API) } If this argument is omitted, then the analysis will create its own audio input stream via getUserMedia

        stop()

        env/media/webMicLevels.js, line 543
        Stops the audio analysis for "microphone levels changed" events. This functions should be called, when ASR has stopped / closed the audio input stream.