angular 10.0.8(ionic)でMediaRecorederが使えない

angularで開発中のアプリで動画撮影機能を実装しています。

MediaRecorderを使用しているのですが、あるタイミングから以下のエラーが出てしまいます。

zsh
1ERROR in src/app/pages/shooting/shooting.component.ts:20:18 - error TS2304: Cannot find name 'MediaRecorder'.
2[ng]     
3[ng]     20   mediaRecorder: MediaRecorder
4[ng]                         ~~~~~~~~~~~~~
5[ng]     src/app/pages/shooting/shooting.component.ts:91:34 - error TS2304: Cannot find name 'MediaRecorder'.
6[ng]     
7[ng]     91         this.mediaRecorder = new MediaRecorder(stream)

npm installはしているのでMediaRecorderは定義されています。

ts
1declare class MediaRecorder extends EventTarget {
2    readonly stream: MediaStream;
3    readonly mimeType: string;
4    readonly state: RecordingState;
5    readonly videoBitsPerSecond: number;
6    readonly audioBitsPerSecond: number;
7    readonly audioBitrateMode: BitrateMode;
8
9    ondataavailable: ((event: BlobEvent) => void) | null;
10    onerror: ((event: MediaRecorderErrorEvent) => void) | null;
11    onpause: EventListener | null;
12    onresume: EventListener | null;
13    onstart: EventListener | null;
14    onstop: EventListener | null;
15
16    constructor(stream: MediaStream, options?: MediaRecorderOptions);
17
18    addEventListener<K extends keyof MediaRecorderEventMap>(type: K, listener: (this: MediaRecorder, ev: MediaRecorderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
19    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
20    removeEventListener<K extends keyof MediaRecorderEventMap>(type: K, listener: (this: MediaRecorder, ev: MediaRecorderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
21    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
22
23    start(timeslice?: number): void;
24    stop(): void;
25    resume(): void;
26    pause(): void;
27    requestData(): void;
28
29    static isTypeSupported(type: string): boolean;
30}