import EE from 'eventemitter3';
export interface SpectrogramData {
    /**
     * The float32 data for the spectrogram.
     *
     * Stored frame by frame. For example, the first N elements
     * belong to the first time frame and the next N elements belong
     * to the second time frame, and so forth.
     */
    data: Float32Array;
    /**
     * Number of points per frame, i.e., FFT length per frame.
     */
    frameSize: number;
    /**
     * Duration of each frame in milliseconds.
     */
    frameDurationMillis?: number;
    /**
     * Index to the key frame (0-based).
     *
     * A key frame is a frame in the spectrogram that belongs to
     * the utterance of interest. It is used to distinguish the
     * utterance part from the background-noise part.
     *
     * A typical use of key frame index: when multiple training examples are
     * extracted from a spectroram, every example is guaranteed to include
     * the key frame.
     *
     * Key frame is not required. If it is missing, heuristics algorithms
     * (e.g., finding the highest-intensity frame) can be used to calculate
     * the key frame.
     */
    keyFrameIndex?: number;
}
export interface RawAudioData {
    /** Samples of the snippet. */
    data: Float32Array;
    /** Sampling rate, in Hz. */
    sampleRateHz: number;
}
export interface AudioExample {
    /** A label for the example. */
    label: string;
    /** Spectrogram data. */
    spectrogram: SpectrogramData;
    /**
     * A 224x224 heatmap image of this 1-second spectrogram example.
     */
    spectrogramCanvas?: HTMLCanvasElement;
    /**
     * Raw audio in PCM (pulse-code modulation) format.
     *
     * Optional.
     */
    rawAudio?: RawAudioData;
}
export interface RecordingProgress {
    progress: number;
    elapsedTimeMillis: number;
}
declare type SoundRecorderEvents = 'example' | 'update' | 'start' | 'stop' | 'error';
export interface RecordExampleOptions {
    /** The size of each frame in the spectrogram, i.e., the FFT length. */
    frameSize: number;
    /**
     * Whether to include raw audio data in the example.
     *
     * Default: false.
     */
    includeRawAudio?: boolean;
    durationMillis?: number;
    /** Sampling rate of the raw audio data, in Hz. */
    sampleRateHz: number;
    /**
     * Optional initial warmup period (ms).
     * During this period, no examples are emitted, but visualization continues.
     *
     * Default: 0.
     */
    warmupMillis?: number;
    columnTruncateLength?: number;
    overlapFactor?: number;
    includeCanvas?: boolean;
    deviceId?: string;
}
export default class SoundRecorder extends EE<SoundRecorderEvents> {
    canvas: HTMLCanvasElement | null;
    private stream;
    private audioContext;
    private analyser;
    private source;
    private frameIntervalTask;
    private audioElement;
    private isRecording;
    private stopRequested;
    private allFreqFrames;
    private lastRenderTime;
    private lastMainDrawWidth;
    private currentFrameDurationMillis;
    private currentSampleRateHz;
    private lastEmitTime;
    private startTime;
    private includeRawAudioCapture;
    private mediaRecorder;
    private sourceAudioBlob;
    private pendingExamples;
    private isFinishing;
    private startRawAudioCapture;
    private stopRawAudioCapture;
    private decodeBlobToMonoPcm;
    private sliceRawAudioAndPatchExamples;
    private finish;
    private emitOneSecondExample;
    private createFromStream;
    private createFromBlob;
    startRecording(word: string, options: RecordExampleOptions, blob?: Blob): Promise<void>;
    stopRecording(): void;
    private renderSpectrogram;
}
export {};