diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 1a8c1c6ee..76a22fb4c 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -159,6 +159,11 @@ interface BiquadFilterOptions extends AudioNodeOptions {
     type?: BiquadFilterType;
 }
 
+interface BlobEventInit {
+    data: Blob;
+    timecode?: number;
+}
+
 interface BlobPropertyBag {
     endings?: EndingType;
     type?: string;
@@ -692,6 +697,14 @@ interface MediaQueryListEventInit extends EventInit {
     media?: string;
 }
 
+interface MediaRecorderOptions {
+    audioBitrateMode?: BitrateMode;
+    audioBitsPerSecond?: number;
+    bitsPerSecond?: number;
+    mimeType?: string;
+    videoBitsPerSecond?: number;
+}
+
 interface MediaStreamAudioSourceOptions {
     mediaStream: MediaStream;
 }
@@ -2559,6 +2572,15 @@ declare var Blob: {
     new(blobParts?: BlobPart[], options?: BlobPropertyBag): Blob;
 };
 
+interface BlobEvent extends Event {
+    readonly data: Blob;
+}
+
+declare var BlobEvent: {
+    prototype: BlobEvent;
+    new(type: string, eventInitDict: BlobEventInit): BlobEvent;
+};
+
 interface Body {
     readonly body: ReadableStream<Uint8Array> | null;
     readonly bodyUsed: boolean;
@@ -4647,6 +4669,7 @@ interface Document extends Node, DocumentAndElementEventHandlers, DocumentOrShad
     createEvent(eventInterface: "AnimationPlaybackEvent"): AnimationPlaybackEvent;
     createEvent(eventInterface: "AudioProcessingEvent"): AudioProcessingEvent;
     createEvent(eventInterface: "BeforeUnloadEvent"): BeforeUnloadEvent;
+    createEvent(eventInterface: "BlobEvent"): BlobEvent;
     createEvent(eventInterface: "ClipboardEvent"): ClipboardEvent;
     createEvent(eventInterface: "CloseEvent"): CloseEvent;
     createEvent(eventInterface: "CompositionEvent"): CompositionEvent;
@@ -4891,6 +4914,7 @@ interface DocumentEvent {
     createEvent(eventInterface: "AnimationPlaybackEvent"): AnimationPlaybackEvent;
     createEvent(eventInterface: "AudioProcessingEvent"): AudioProcessingEvent;
     createEvent(eventInterface: "BeforeUnloadEvent"): BeforeUnloadEvent;
+    createEvent(eventInterface: "BlobEvent"): BlobEvent;
     createEvent(eventInterface: "ClipboardEvent"): ClipboardEvent;
     createEvent(eventInterface: "CloseEvent"): CloseEvent;
     createEvent(eventInterface: "CompositionEvent"): CompositionEvent;
@@ -10135,6 +10159,45 @@ declare var MediaQueryListEvent: {
     new(type: string, eventInitDict?: MediaQueryListEventInit): MediaQueryListEvent;
 };
 
+interface MediaRecorderEventMap {
+    "dataavailable": Event;
+    "error": ErrorEvent;
+    "pause": Event;
+    "resume": SpeechSynthesisEvent;
+    "start": Event;
+    "stop": Event;
+}
+
+interface MediaRecorder extends EventTarget {
+    readonly audioBitrateMode: BitrateMode;
+    readonly audioBitsPerSecond: number;
+    readonly mimeType: string;
+    ondataavailable: ((this: MediaRecorder, ev: Event) => any) | null;
+    onerror: ((this: MediaRecorder, ev: ErrorEvent) => any) | null;
+    onpause: ((this: MediaRecorder, ev: Event) => any) | null;
+    onresume: ((this: MediaRecorder, ev: SpeechSynthesisEvent) => any) | null;
+    onstart: ((this: MediaRecorder, ev: Event) => any) | null;
+    onstop: ((this: MediaRecorder, ev: Event) => any) | null;
+    readonly state: RecordingState;
+    readonly stream: MediaStream;
+    readonly videoBitsPerSecond: number;
+    pause(): void;
+    requestData(): void;
+    resume(): void;
+    start(timeslice?: number): void;
+    stop(): void;
+    addEventListener<K extends keyof MediaRecorderEventMap>(type: K, listener: (this: MediaRecorder, ev: MediaRecorderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MediaRecorderEventMap>(type: K, listener: (this: MediaRecorder, ev: MediaRecorderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
+}
+
+declare var MediaRecorder: {
+    prototype: MediaRecorder;
+    new(stream: MediaStream, options?: MediaRecorderOptions): MediaRecorder;
+    isTypeSupported(type: string): boolean;
+};
+
 interface MediaSourceEventMap {
     "sourceclose": Event;
     "sourceended": Event;
@@ -19725,6 +19788,7 @@ type AutoKeyword = "auto";
 type AutomationRate = "a-rate" | "k-rate";
 type BinaryType = "arraybuffer" | "blob";
 type BiquadFilterType = "allpass" | "bandpass" | "highpass" | "highshelf" | "lowpass" | "lowshelf" | "notch" | "peaking";
+type BitrateMode = "constant" | "variable";
 type CanPlayTypeResult = "" | "maybe" | "probably";
 type CanvasDirection = "inherit" | "ltr" | "rtl";
 type CanvasFillRule = "evenodd" | "nonzero";
@@ -19819,6 +19883,7 @@ type RTCStatsIceCandidatePairState = "failed" | "frozen" | "in-progress" | "succ
 type RTCStatsIceCandidateType = "host" | "peerreflexive" | "relayed" | "serverreflexive";
 type RTCStatsType = "candidate-pair" | "certificate" | "codec" | "csrc" | "data-channel" | "ice-server" | "inbound-rtp" | "local-candidate" | "media-source" | "outbound-rtp" | "peer-connection" | "receiver" | "remote-candidate" | "remote-inbound-rtp" | "remote-outbound-rtp" | "sctp-transport" | "sender" | "stream" | "track" | "transceiver" | "transport";
 type ReadyState = "closed" | "ended" | "open";
+type RecordingState = "inactive" | "paused" | "recording";
 type ReferrerPolicy = "" | "no-referrer" | "no-referrer-when-downgrade" | "origin" | "origin-when-cross-origin" | "same-origin" | "strict-origin" | "strict-origin-when-cross-origin" | "unsafe-url";
 type RequestCache = "default" | "force-cache" | "no-cache" | "no-store" | "only-if-cached" | "reload";
 type RequestCredentials = "include" | "omit" | "same-origin";
diff --git a/inputfiles/idl/MediaStream Recording.commentmap.json b/inputfiles/idl/MediaStream Recording.commentmap.json
new file mode 100644
index 000000000..f1476bcd1
--- /dev/null
+++ b/inputfiles/idl/MediaStream Recording.commentmap.json	
@@ -0,0 +1,3 @@
+{
+    "domhighrestimestamp": "The difference between the timestamp of the first chunk in data and the timestamp of the first chunk in the first BlobEvent produced by this recorder as a DOMHighResTimeStamp [HR-TIME]. Note that the timecode in the first produced BlobEvent does not need to be zero."
+}
diff --git a/inputfiles/idl/MediaStream Recording.widl b/inputfiles/idl/MediaStream Recording.widl
new file mode 100644
index 000000000..f3f7288bc
--- /dev/null
+++ b/inputfiles/idl/MediaStream Recording.widl	
@@ -0,0 +1,65 @@
+[Exposed=Window]
+interface MediaRecorder : EventTarget {
+  constructor(MediaStream stream, optional MediaRecorderOptions options = {});
+  readonly attribute MediaStream stream;
+  readonly attribute DOMString mimeType;
+  readonly attribute RecordingState state;
+  attribute EventHandler onstart;
+  attribute EventHandler onstop;
+  attribute EventHandler ondataavailable;
+  attribute EventHandler onpause;
+  attribute EventHandler onresume;
+  attribute EventHandler onerror;
+  readonly attribute unsigned long videoBitsPerSecond;
+  readonly attribute unsigned long audioBitsPerSecond;
+  readonly attribute BitrateMode audioBitrateMode;
+
+  undefined start(optional unsigned long timeslice);
+  undefined stop();
+  undefined pause();
+  undefined resume();
+  undefined requestData();
+
+  static boolean isTypeSupported(DOMString type);
+};
+
+dictionary MediaRecorderOptions {
+  DOMString mimeType = "";
+  unsigned long audioBitsPerSecond;
+  unsigned long videoBitsPerSecond;
+  unsigned long bitsPerSecond;
+  BitrateMode audioBitrateMode = "variable";
+};
+
+enum BitrateMode {
+  "constant",
+  "variable"
+};
+
+enum RecordingState {
+  "inactive",
+  "recording",
+  "paused"
+};
+
+[Exposed=Window]
+interface BlobEvent : Event {
+  constructor(DOMString type, BlobEventInit eventInitDict);
+  [SameObject] readonly attribute Blob data;
+  readonly attribute DOMHighResTimeStamp timecode;
+};
+
+dictionary BlobEventInit {
+  required Blob data;
+  DOMHighResTimeStamp timecode;
+};
+
+dictionary MediaRecorderErrorEventInit : EventInit {
+  required DOMException error;
+};
+
+[Exposed=Window]
+interface MediaRecorderErrorEvent : Event {
+  constructor(DOMString type, MediaRecorderErrorEventInit eventInitDict);
+  [SameObject] readonly attribute DOMException error;
+};
diff --git a/inputfiles/idlSources.json b/inputfiles/idlSources.json
index cbf9d88f8..9848d5a63 100644
--- a/inputfiles/idlSources.json
+++ b/inputfiles/idlSources.json
@@ -402,6 +402,10 @@
         "url": "https://www.w3.org/TR/media-source/",
         "title": "Media Source Extensions"
     },
+    {
+        "url": "https://w3c.github.io/mediacapture-record/",
+        "title": "MediaStream Recording"
+    },
     {
         "url": "https://w3c.github.io/navigation-timing/",
         "title": "Navigation Timing"