diff --git a/api/@ohos.multimedia.mediaLibrary.d.ts b/api/@ohos.multimedia.mediaLibrary.d.ts
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+/*
+ * Copyright (C) 2022 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { AsyncCallback } from './basic';
+import Context from './@ohos.ability';
+import image from './@ohos.multimedia.image';
+
+/**
+ * @name mediaLibrary
+ * @since 6
+ * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+ * @import import media from '@ohos.multimedia.mediaLibrary'
+ */
+declare namespace mediaLibrary {
+  /**
+   * Obtains a MediaLibrary instance.
+   * @since 6
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @import import mediaLibrary from '@ohos.multimedia.mediaLibrary'
+   * @FAModelOnly
+   * @return Returns a MediaLibrary instance if the operation is successful; returns null otherwise.
+   */
+  function getMediaLibrary(): MediaLibrary;
+  /**
+   * Returns an instance of MediaLibrary
+   * @since 8
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @StageModelOnly
+   * @param Hap context information
+   * @return Instance of MediaLibrary
+   */
+  function getMediaLibrary(context: Context): MediaLibrary;
+
+  /**
+   * Enumeration types for different kind of Media Files
+   * @since 8
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   */
+  enum MediaType {
+    /**
+     * File media type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    FILE = 0,
+    /**
+     * Image media type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    IMAGE,
+    /**
+     * Video media type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    VIDEO,
+    /**
+     * Audio media type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    AUDIO
+  }
+
+  /**
+   * Describes media resource options.
+   * @since 6
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @import import mediaLibrary from '@ohos.multimedia.mediaLibrary'
+   */
+  interface MediaAssetOption {
+    /**
+     * URI of the media source.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    src: string;
+    /**
+     * Multipurpose Internet Mail Extensions (MIME) type of the media.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    mimeType: string;
+    /**
+     * Relative path for storing media resources.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    relativePath?: string;
+  }
+
+  /**
+   * Describes media selection options.
+   * @since 6
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @import import mediaLibrary from '@ohos.multimedia.mediaLibrary'
+   */
+  interface MediaSelectOption {
+    /**
+     * Media type, which can be image, video, or media (indicating both image and video).
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    type: 'image' | 'video' | 'media';
+    /**
+     * Maximum number of media items that can be selected
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    count: number;
+  }
+
+  /**
+   * Provides methods to encapsulate file attributes.
+   * @since 7
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @import import mediaLibrary from '@ohos.multimedia.mediaLibrary'
+   */
+  interface FileAsset {
+    /**
+     * File ID.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly id: number;
+    /**
+     * URI of the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly uri: string;
+    /**
+     * MIME type, for example, video/mp4, audio/mp4, or audio/amr-wb.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly mimeType: string;
+    /**
+     * Media type, for example, IMAGE, VIDEO, FILE, AUDIO 
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly mediaType: MediaType;
+    /**
+     * Display name (with a file name extension) of the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    displayName: string;
+    /**
+     * File name title (without the file name extension).
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    title: string;
+    /**
+     * Relative Path of the file.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    relativePath: string;
+    /**
+     * Parent folder's file_id of the file.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly parent: number;
+    /**
+     * Data size of the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly size: number;
+    /**
+     * Date (timestamp) when the file was added.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly dateAdded: number;
+    /**
+     * Date (timestamp) when the file was modified.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly dateModified: number;
+    /**
+     * Date (timestamp) when the file was taken.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly dateTaken: number;
+    /**
+     * Artist of the audio file.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly artist: string;
+    /**
+     * audioAlbum of the audio file.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly audioAlbum: string;
+    /**
+     * Display width of the file. This is valid only for videos and images.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly width: number;
+    /**
+     * Display height of the file. This is valid only for videos and images.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly height: number;
+    /**
+     * Rotation angle of the file, in degrees.
+     * The rotation angle can be 0, 90, 180, or 270 degrees. This is valid only for videos.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    orientation: number;
+    /**
+     * duration of the audio and video file.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly duration: number;
+    /**
+     * ID of the album where the file is located.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly albumId: number;
+    /**
+     * URI of the album where the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly albumUri: string;
+    /**
+     * Name of the album where the file is located.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly albumName: string;
+
+    /**
+     * If it is a directory where the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback, Callback return the result of isDerectory.
+     */
+    isDirectory(callback: AsyncCallback<boolean>): void;
+    /**
+     * If it is a directory where the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    isDirectory():Promise<boolean>;
+    /**
+     * Modify meta data where the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback, no value will be returned.
+     */
+    commitModify(callback: AsyncCallback<void>): void;
+    /**
+     * Modify meta data where the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    commitModify(): Promise<void>;
+    /**
+     * Open the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param mode, mode for open, for example: rw, r, w.
+     * @param callback, Callback return the fd of the file.
+     */
+    open(mode: string, callback: AsyncCallback<number>): void;
+    /**
+     * Open the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param mode, mode for open, for example: rw, r, w.
+     */
+    open(mode: string): Promise<number>;
+    /**
+     * Close the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param fd, fd of the file which had been opened
+     * @param callback, no value will be returned.
+     */
+    close(fd: number, callback: AsyncCallback<void>): void;
+    /**
+     * Close the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param fd, fd of the file which had been opened
+     */
+    close(fd: number): Promise<void>;
+    /**
+     * Get thumbnail of the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return the thumbnail's pixelmap.
+     */
+    getThumbnail(callback: AsyncCallback<image.PixelMap>): void;
+    /**
+     * Get thumbnail of the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param size, thumbnail's size
+     * @param callback Callback used to return the thumbnail's pixelmap.
+     */
+    getThumbnail(size: Size, callback: AsyncCallback<image.PixelMap>): void;
+    /**
+     * Get thumbnail of the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param size, thumbnail's size
+     */
+    getThumbnail(size?: Size): Promise<image.PixelMap>;
+    /**
+     * Set favorite for the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param isFavorite ture is favorite file, false is not favorite file
+     * @param callback Callback used to return, No value is returned.
+     */
+    favorite(isFavorite: boolean, callback: AsyncCallback<void>): void;
+    /**
+     * Set favorite for the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param isFavorite ture is favorite file, false is not favorite file
+     */
+    favorite(isFavorite: boolean): Promise<void>;
+    /**
+     * If the file is favorite when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return true or false.
+     */
+    isFavorite(callback: AsyncCallback<boolean>): void;
+    /**
+     * If the file is favorite when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    isFavorite():Promise<boolean>;
+    /**
+     * Set trash for the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param isTrash true is trashed file, false is not trashed file
+     * @param callback Callback used to return, No value is returned. 
+     */
+    trash(isTrash: boolean, callback: AsyncCallback<void>): void;
+    /**
+     * Set trash for the file when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param isTrash true is trashed file, false is not trashed file
+     */
+    trash(isTrash: boolean,): Promise<void>;
+    /**
+     * If the file is in trash when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return true or false.
+     */
+    isTrash(callback: AsyncCallback<boolean>): void;
+    /**
+     * If the file is in trash when the file is located.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    isTrash():Promise<boolean>;
+  }
+
+  /**
+   * Describes MediaFetchOptions's selection
+   * @since 8
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   */
+  enum FileKey {
+    /**
+     * File ID
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    ID = "file_id",
+    /**
+     * Relative Path
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    RELATIVE_PATH = "relative_path",
+    /**
+     * File name
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DISPLAY_NAME = "display_name",
+    /**
+     * Parent folder file id
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    PARENT = "parent",
+    /**
+     * Mime type of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    MIME_TYPE = "mime_type",
+    /**
+     * Media type of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    MEDIA_TYPE = "media_type",
+    /**
+     * Size of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    SIZE = "size",
+    /**
+     * Date of the file creation
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DATE_ADDED = "date_added",
+    /**
+     * Modify date of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DATE_MODIFIED = "date_modified",
+    /**
+     * Date taken of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DATE_TAKEN = "date_taken",
+    /**
+     * Title of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    TITLE = "title",
+    /**
+     * Artist of the audio file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    ARTIST = "artist",
+    /**
+     * Audio album of the audio file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    AUDIOALBUM = "audio_album",
+    /**
+     * Duration of the audio and video file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DURATION = "duration",
+    /**
+     * Width of the image file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    WIDTH = "width",
+    /**
+     * Height of the image file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    HEIGHT = "height",
+    /**
+     * Orientation of the image file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    ORIENTATION = "orientation",
+    /**
+     * Album id of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    ALBUM_ID = "bucket_id",
+    /**
+     * Album name of the file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    ALBUM_NAME = "bucket_display_name",
+  }
+
+  /**
+   * Fetch parameters applicable on images, videos, audios, albums and other media
+   * @since 7
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   */
+  interface MediaFetchOptions {
+    /**
+     * Fields to retrieve, for example, selections: "media_type =? OR media_type =?".
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    selections: string;
+    /**
+     * Conditions for retrieval, for example, selectionArgs: [IMAGE, VIDEO].
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    selectionArgs: Array<string>;
+    /**
+     * Sorting criterion of the retrieval results, for example, order: "datetaken DESC,_display_name DESC, _id DESC".
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    order?: string;
+    /**
+     * uri for retrieval
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    uri?: string;
+    /**
+     * networkId for retrieval
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    networkId?: string;
+    /**
+     * extendArgs for retrieval
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    extendArgs?: string;
+  }
+
+  /**
+   * Implements file retrieval.
+   * @since 7
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @import import mediaLibrary from '@ohos.multimedia.mediaLibrary'
+   */
+  interface FetchFileResult {
+    /**
+     * Obtains the total number of files in the file retrieval result.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @return Total number of files.
+     */
+    getCount(): number;
+    /**
+     * Checks whether the result set points to the last row.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @return Whether the file is the last one.
+     * You need to check whether the file is the last one before calling getNextObject,
+     * which returns the next file only when True is returned for this method.
+     */
+    isAfterLast(): boolean;
+    /**
+     * Releases the FetchFileResult instance and invalidates it. Other methods cannot be called.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    close(): void;
+    /**
+     * Obtains the first FileAsset in the file retrieval result. This method uses a callback to return the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return the file in the format of a FileAsset instance.
+     */
+    getFirstObject(callback: AsyncCallback<FileAsset>): void;
+    /**
+     * Obtains the first FileAsset in the file retrieval result. This method uses a promise to return the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @return A Promise instance used to return the file in the format of a FileAsset instance.
+     */
+    getFirstObject(): Promise<FileAsset>;
+    /**
+     * Obtains the next FileAsset in the file retrieval result.
+     * This method uses a callback to return the file.
+     * Before calling this method, you must use isAfterLast() to check whether the result set points to the last row.
+     * This method returns the next file only when True is returned for isAfterLast().
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return the file in the format of a FileAsset instance.
+     */
+    getNextObject(callback: AsyncCallback<FileAsset>): void;
+    /**
+     * Obtains the next FileAsset in the file retrieval result.
+     * This method uses a promise to return the file.
+     * Before calling this method, you must use isAfterLast() to check whether the result set points to the last row.
+     * This method returns the next file only when True is returned for isAfterLast().
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @return A Promise instance used to return the file in the format of a FileAsset instance.
+     */
+    getNextObject(): Promise<FileAsset>;
+    /**
+     * Obtains the last FileAsset in the file retrieval result. This method uses a callback to return the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return the file in the format of a FileAsset instance.
+     */
+    getLastObject(callback: AsyncCallback<FileAsset>): void;
+    /**
+     * Obtains the last FileAsset in the file retrieval result. This method uses a promise to return the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @return A Promise instance used to return the file in the format of a FileAsset instance.
+     */
+    getLastObject(): Promise<FileAsset>;
+    /**
+     * Obtains the FileAsset with the specified index in the file retrieval result.
+     * This method uses a callback to return the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param index Index of the file to obtain.
+     * @param callback Callback used to return the file in the format of a FileAsset instance.
+     */
+    getPositionObject(index: number, callback: AsyncCallback<FileAsset>): void;
+    /**
+     * Obtains the FileAsset with the specified index in the file retrieval result.
+     * This method uses a promise to return the file.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param index Index of the file to obtain.
+     * @return A Promise instance used to return the file in the format of a FileAsset instance.
+     */
+    getPositionObject(index: number): Promise<FileAsset>;
+     /**
+     * Obtains all FileAssets in the file retrieval result.
+     * This method uses a callback to return the result. After this method is called, 
+     * close() is automatically called to release the FetchFileResult instance and invalidate it.
+     * In this case, other methods cannot be called.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return a FileAsset array.
+     */
+    getAllObject(callback: AsyncCallback<Array<FileAsset>>): void;
+    /**
+     * Obtains all FileAssets in the file retrieval result.
+     * This method uses a promise to return the result. that store the selected media resources.
+     * close() is automatically called to release the FetchFileResult instance and invalidate it.
+     * In this case, other methods cannot be called.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @return A Promise instance used to return a FileAsset array.
+     */
+    getAllObject(): Promise<Array<FileAsset>>;
+  }
+
+  /**
+   * Defines the album.
+   *
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @since 7
+   */
+  interface Album {
+    /**
+     * Album ID.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly albumId: number;
+    /**
+     * Album name.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    albumName: string;
+    /**
+     * Album uri.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly albumUri: string;
+    /**
+     * Date (timestamp) when the album was last modified.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly dateModified: number;
+    /**
+     * File count for the album
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly count: number;
+    /**
+     * Relative path for the album
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly relativePath: string;
+    /**
+     * coverUri for the album
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    readonly coverUri: string;
+
+    /**
+     * Modify the meta data for the album
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback, no value will be returned.
+     */
+    commitModify(callback: AsyncCallback<void>): void;
+    /**
+     * Modify the meta data for the album
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    commitModify(): Promise<void>;
+    /**
+     * SObtains files in an album. This method uses an asynchronous callback to return the files.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback Callback used to return the files in the format of a FetchFileResult instance.
+     */
+    getFileAssets(callback: AsyncCallback<FetchFileResult>): void;
+    /**
+     * SObtains files in an album. This method uses an asynchronous callback to return the files.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media retrieval options.
+     * @param callback Callback used to return the files in the format of a FetchFileResult instance.
+     */
+    getFileAssets(options: MediaFetchOptions, callback: AsyncCallback<FetchFileResult>): void;
+    /**
+     * Obtains files in an album. This method uses a promise to return the files.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media retrieval options.
+     * @return A Promise instance used to return the files in the format of a FetchFileResult instance.
+     */
+    getFileAssets(options?: MediaFetchOptions): Promise<FetchFileResult>;
+  }
+
+  /**
+   * Enumeration public directory that predefined
+   * @since 8
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   */
+  enum DirectoryType {
+    /**
+     * predefined public directory for files token by Camera.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DIR_CAMERA = 0,
+    /**
+     * predefined public directory for VIDEO files.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DIR_VIDEO,
+    /**
+     * predefined public directory for IMAGE files.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DIR_IMAGE,
+    /**
+     * predefined public directory for AUDIO files.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DIR_AUDIO,
+    /**
+     * predefined public directory for DOCUMENTS files.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DIR_DOCUMENTS,
+    /**
+     * predefined public directory for DOWNLOAD files.
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    DIR_DOWNLOAD
+  }
+
+  /**
+   * Defines the MediaLibrary class and provides functions to access the data in media storage.
+   *
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @since 6
+   */
+  interface MediaLibrary {
+    /**
+     * get system predefined root dir, use to create file asset by relative path
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param type, public directory predefined in DirectoryType.
+     * @param callback, Callback return the FetchFileResult.
+     */
+    getPublicDirectory(type: DirectoryType, callback: AsyncCallback<string>): void;
+    /**
+     * get system predefined root dir, use to create file asset by relative path
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param type, public directory predefined in DirectoryType.
+     * @param return A promise instance used to return the public directory in the format of string
+     */
+    getPublicDirectory(type: DirectoryType): Promise<string>;
+    /**
+     * query all assets just for count & first cover
+     * if need all data, getAllObject from FetchFileResult
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param options, Media retrieval options.
+     * @param callback, Callback return the FetchFileResult.
+     */
+    getFileAssets(options: MediaFetchOptions, callback: AsyncCallback<FetchFileResult>): void;
+    /**
+     * query all assets just for count & first cover
+     * if need all data, getAllObject from FetchFileResult
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param options, Media retrieval options.
+     * @return A promise instance used to return the files in the format of a FetchFileResult instance
+     */
+    getFileAssets(options: MediaFetchOptions): Promise<FetchFileResult>;
+    /**
+     * Trun on mornitor the data changes by media type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param type, mediaType
+     * @param callback no value returned
+     */
+    on(type: 'Device'|'Album'|'Image'|'Audio'|'Video'|'File'| 'Remote file', callback: () => {}): void;
+    /**
+     * Trun off Mornitor the data changes by media type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param type, mediaType
+     * @param callback no value returned
+     */
+     off(type: 'Device'|'Album'|'Image'|'Audio'|'Video'|'File'| 'Remote file', callback?: () => {}): void;
+    /**
+     * Create File Asset
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param mediaType, mediaType for example:IMAGE, VIDEO, AUDIO, FILE
+     * @param displayName, file name
+     * @param relativePath, relative path
+     * @param callback Callback used to return the FileAsset
+     */
+    createAsset(mediaType: MediaType, displayName: string, relativePath: string, callback: AsyncCallback<FileAsset>): void;
+    /**
+     * Create File Asset
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param mediaType, mediaType for example:IMAGE, VIDEO, AUDIO, FILE
+     * @param displayName, file name
+     * @param relativePath, relative path
+     * @return A Promise instance used to return the FileAsset
+     */
+    createAsset(mediaType: MediaType, displayName: string, relativePath: string): Promise<FileAsset>;
+    /**
+     * Delete File Asset
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param uri, FileAsset's URI
+     * @param callback no value returned
+     */
+    deleteAsset(uri: string, callback: AsyncCallback<void>): void;
+    /**
+     * Delete File Asset
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param uri, FileAsset's URI
+     * @return A Promise instance, no value returned
+     */
+    deleteAsset(uri: string): Promise<void>;
+    /**
+     * Obtains albums based on the media retrieval options. This method uses an asynchronous callback to return.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media retrieval options.
+     * @param callback Callback used to return an album array.
+     */
+    getAlbums(options: MediaFetchOptions, callback: AsyncCallback<Array<Album>>): void;
+    /**
+     * Obtains albums based on the media retrieval options. This method uses a promise to return the albums.
+     * @since 7
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media retrieval options.
+     * @return A Promise instance used to return an album array.
+     */
+    getAlbums(options: MediaFetchOptions): Promise<Array<Album>>;
+    /**
+     * Stores media resources. This method uses an asynchronous callback to return the URI that stores
+     * the media resources.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media resource option.
+     * @param callback Callback used to return the URI that stores the media resources.
+     */
+    storeMediaAsset(option: MediaAssetOption, callback: AsyncCallback<string>): void;
+    /**
+     * Stores media resources. This method uses a promise to return the URI that stores the media resources.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media resource option.
+     * @return Promise used to return the URI that stores the media resources.
+     */
+    storeMediaAsset(option: MediaAssetOption): Promise<string>;
+    /**
+     * Starts image preview, with the first image to preview specified. This method uses an asynchronous callback
+     * to receive the execution result.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param images List of images to preview.
+     * @param index Sequence number of the first image to preview.
+     * @param callback Callback used for image preview. No value is returned.
+     */
+    startImagePreview(images: Array<string>, index: number, callback: AsyncCallback<void>): void;
+    /**
+     * Starts image preview. This method uses an asynchronous callback to receive the execution result.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param images List of images to preview.
+     * @param callback Callback used for image preview. No value is returned.
+     */
+    startImagePreview(images: Array<string>, callback: AsyncCallback<void>): void;
+    /**
+     * Starts image preview, with the first image to preview specified.
+     * This method uses a promise to return the execution result.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param images List of images to preview.
+     * @param index Sequence number of the first image to preview.
+     * @return Promise used to return whether the operation is successful.
+     */
+    startImagePreview(images: Array<string>, index?: number): Promise<void>;
+    /**
+     * Starts media selection. This method uses an asynchronous callback to
+     * return the list of URIs that store the selected media resources.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media selection option.
+     * @param callback Callback used to return the list of URIs that store the selected media resources.
+     */
+    startMediaSelect(option: MediaSelectOption, callback: AsyncCallback<Array<string>>): void;
+    /**
+     * Starts media selection. This method uses a promise to return the list of URIs
+     * that store the selected media resources.
+     * @since 6
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param option Media selection option.
+     * @return Promise used to return the list of URIs that store the selected media resources.
+     */
+    startMediaSelect(option: MediaSelectOption): Promise<Array<string>>;
+    /**
+     * Get Active Peer device information
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     * @param callback, Callback return the list of the active peer devices' information
+     */
+    getActivePeers(callback: AsyncCallback<Array<PeerInfo>>): void;
+    /**
+     * Get Active Peer device information
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     * @return Promise used to return the list of the active peer devices' information
+     */
+    getActivePeers(): Promise<Array<PeerInfo>>;
+    /**
+     * Get all the peer devices' information
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     * @param callback, Callback return the list of the all the peer devices' information
+     */
+    getAllPeers(callback: AsyncCallback<Array<PeerInfo>>): void;
+    /**
+     * Get all the peer devices' information
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     * @return Promise used to return the list of the all the peer devices' information
+     */
+    getAllPeers(): Promise<Array<PeerInfo>>;
+    /**
+     * Release MediaLibrary instance
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     * @param callback, no value returned
+     */
+    release(callback: AsyncCallback<void>): void;
+    /**
+     * Release MediaLibrary instance
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    release(): Promise<void>;
+  }
+
+  /**
+   * thumbnail's size which have width and heigh
+   * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+   * @since 8
+   */
+  interface Size {
+    /**
+     * Width of image file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    width: number;
+    /**
+     * Height of image file
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.Core
+     */
+    height: number;
+  }
+  
+  /**
+   * peer devices' information
+   * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+   * @systemapi
+   * @since 8
+   */
+  interface PeerInfo {
+    /**
+     * Peer device name
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    readonly deviceName: string;
+    /**
+     * Peer device network id
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    readonly networkId: string;
+    /**
+     * Peer device type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    readonly deviceType: DeviceType;
+    /**
+     * Peer device online status
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    readonly isOnline: boolean;
+  }
+
+  /**
+   * peer device type
+   * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+   * @systemapi
+   * @since 8
+   */
+  enum DeviceType {
+    /**
+     * Unknow device type
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_UNKNOWN = 0,
+    /**
+     * Laptop device
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_LAPTOP,
+    /**
+     * Phone device
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_PHONE,
+    /**
+     * Tablet device
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_TABLET,
+    /**
+     * Watch device
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_WATCH,
+    /**
+     * Car device
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_CAR,
+    /**
+     * TV device
+     * @since 8
+     * @syscap SystemCapability.Multimedia.MediaLibrary.DistributedCore
+     * @systemapi
+     */
+    TYPE_TV
+  }
+}
+
+export default mediaLibrary;