import { CobraOptions } from './types';
/**
 * Node.js binding for Cobra voice activity detection engine
 *
 * Performs the calls to the Cobra node library. Does some basic parameter validation to prevent
 * errors occurring in the library layer. Provides clearer error messages in native JavaScript.
 */
export default class Cobra {
    private _pvCobra;
    private _handle;
    private readonly _version;
    private readonly _frameLength;
    private readonly _sampleRate;
    /**
     * Creates an instance of Cobra.
     * @param {string} accessKey AccessKey obtained from Picovoice Console (https://console.picovoice.ai/).
     * @param options Optional configuration arguments.
     * @param {string} options.device String representation of the device (e.g., CPU or GPU) to use.
     *   If set to `best`, the most suitable device is selected automatically.
     *   If set to `gpu`, the engine uses the first available GPU device.
     *   To select a specific GPU device, set this argument to `gpu:${GPU_INDEX}`.
     *   If set to `cpu`, the engine will run on the CPU with the default number of threads.
     *   To specify the number of threads, set this argument to `cpu:${NUM_THREADS}`.
     * @param {string} options.libraryPath the path to the Cobra library (.node extension)
     */
    constructor(accessKey: string, options?: CobraOptions);
    /**
     * @returns number of audio samples per frame (i.e. the length of the array provided to the process function)
     * @see {@link process}
     */
    get frameLength(): number;
    /**
     * @returns the audio sampling rate accepted by the process function
     * @see {@link process}
     */
    get sampleRate(): number;
    /**
     * @returns the version of the Cobra engine
     */
    get version(): string;
    /**
     * Processes a frame of audio and returns the voice probability result.
     *
     * @param {Int16Array} pcm Audio data. The audio needs to have a sample rate equal to `Cobra.sampleRate` and be 16-bit linearly-encoded.
     * The specific array length can be attained by calling `Cobra.frameLength`. This function operates on single-channel audio.
     * @returns {number} Probability of voice activity. It is a floating-point number within [0, 1].
     */
    process(pcm: Int16Array): number;
    /**
     * Releases the resources acquired by Cobra.
     *
     * Be sure to call this when finished with the instance
     * to reclaim the memory that was allocated by the C library.
     */
    release(): void;
    /**
     * Lists all available devices that Cobra can use for inference.
     * Each entry in the list can be used as the `device` argument when initializing Cobra.
     *
     * @returns {string[]} Array of all available devices that Cobra can use for inference.
     */
    static listAvailableDevices(options?: CobraOptions): string[];
    private handlePvStatus;
}
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