/** @format */
import { MemoryImage } from '../image/image.js';
import { Decoder, DecoderDecodeOptions } from './decoder.js';
import { ImageFormat } from './image-format.js';
import { WebPInfo } from './webp/webp-info.js';
/**
 * Decode a WebP formatted image. This supports lossless (vp8l), lossy (vp8),
 * lossy+alpha, and animated WebP images.
 */
export declare class WebPDecoder implements Decoder {
    /**
     * Input buffer for the WebPDecoder.
     * @private
     */
    private _input;
    /**
     * Internal WebP information.
     * @private
     */
    private _info;
    /**
     * Get the WebP information.
     * @returns {WebPInfo | undefined} The WebP information.
     */
    get info(): WebPInfo | undefined;
    /**
     * Get the image format.
     * @returns {ImageFormat} The image format.
     */
    get format(): ImageFormat;
    /**
     * Get the number of frames available to decode.
     * @returns {number} The number of frames.
     */
    get numFrames(): number;
    /**
     * Constructor for WebPDecoder.
     * @param {Uint8Array} [bytes] - Optional bytes to start decoding.
     */
    constructor(bytes?: Uint8Array);
    /**
     * Decode a frame internally.
     * @private
     * @param {InputBuffer<Uint8Array>} input - The input buffer.
     * @param {number} [frameIndex=0] - The frame index.
     * @returns {MemoryImage | undefined} The decoded image.
     */
    private decodeFrameInternal;
    /**
     * Validate the WebP format header.
     * @private
     * @param {InputBuffer<Uint8Array>} input - The input buffer.
     * @returns {boolean} True if valid, false otherwise.
     */
    private getHeader;
    /**
     * Get information about the WebP image.
     * @private
     * @param {InputBuffer<Uint8Array>} input - The input buffer.
     * @param {WebPInfoInternal} webp - The WebP information.
     * @returns {boolean} True if successful, false otherwise.
     */
    private getInfo;
    /**
     * Get VP8X information.
     * @private
     * @param {InputBuffer<Uint8Array>} input - The input buffer.
     * @param {WebPInfo} [webp] - The WebP information.
     * @returns {boolean} True if successful, false otherwise.
     */
    private getVp8xInfo;
    /**
     * Get animation information.
     * @private
     * @param {InputBuffer<Uint8Array>} input - The input buffer.
     * @param {WebPInfo} webp - The WebP information.
     * @returns {boolean} True if successful, false otherwise.
     */
    private getAnimInfo;
    /**
     * Get animation frame information.
     * @private
     * @param {InputBuffer<Uint8Array>} input - The input buffer.
     * @param {WebPInfo} webp - The WebP information.
     * @param {number} size - The size of the frame.
     * @returns {boolean} True if successful, false otherwise.
     */
    private getAnimFrameInfo;
    /**
     * Is the given file a valid WebP image?
     * @param {Uint8Array} bytes - The file bytes.
     * @returns {boolean} True if valid, false otherwise.
     */
    isValidFile(bytes: Uint8Array): boolean;
    /**
     * Validate the file is a WebP image and get information about it.
     * If the file is not a valid WebP image, undefined is returned.
     * @param {Uint8Array} bytes - The file bytes.
     * @returns {WebPInfo | undefined} The WebP information.
     */
    startDecode(bytes: Uint8Array): WebPInfo | undefined;
    /**
     * Decode a WebP formatted file stored in **bytes** into an Image.
     * If it's not a valid WebP file, undefined is returned.
     * @param {DecoderDecodeOptions} opt - The decode options.
     * @param {Uint8Array} opt.bytes - The file bytes.
     * @param {number} [opt.frameIndex] - The frame index to decode.
     * @returns {MemoryImage | undefined} The decoded image.
     */
    decode(opt: DecoderDecodeOptions): MemoryImage | undefined;
    /**
     * Decode a specific frame.
     * @param {number} frameIndex - The frame index.
     * @returns {MemoryImage | undefined} The decoded image.
     */
    decodeFrame(frameIndex: number): MemoryImage | undefined;
}