export type SoundDetectorOptions = {
    /**
     * Defines how often the detector should check whether a sound is present.
     * Defaults to 500ms.
     */
    detectionFrequencyInMs?: number;
    /**
     * Defines the audio level threshold before a "change" is emitted.
     * Defaults to 150. This value should be in the range of 0-255.
     */
    audioLevelThreshold?: number;
    /**
     * See https://developer.mozilla.org/en-US/docs/web/api/analysernode/fftsize
     *
     * Defaults to 128.
     */
    fftSize?: number;
    /**
     * Defines whether the provided audio stream should be stopped (destroyed)
     * when the sound detector is stopped.
     *
     * Defaults to `true`.
     */
    destroyStreamOnStop?: boolean;
};
export type SoundDetectorState = {
    isSoundDetected: boolean;
    /**
     * Represented as percentage (0-100) where 100% is defined by `audioLevelThreshold` property.
     * Decrease time between samples (to 50-100ms) with `detectionFrequencyInMs` property.
     */
    audioLevel: number;
};
export type SoundStateChangeHandler = (state: SoundDetectorState) => void;
/**
 * Creates a new sound detector.
 *
 * @param audioStream the audio stream to observe. Depending on the provided configuration, this stream might be destroyed when the sound detector is stopped.
 * @param onSoundDetectedStateChanged a callback which is called when the sound state changes.
 * @param options custom options for the sound detector.
 * @returns a clean-up function which once invoked stops the sound detector.
 */
export declare const createSoundDetector: (audioStream: MediaStream, onSoundDetectedStateChanged: SoundStateChangeHandler, options?: SoundDetectorOptions) => () => Promise<void>;