diff --git a/src/components/video-editor/SettingsPanel.tsx b/src/components/video-editor/SettingsPanel.tsx
index bc7ebb0..7e556b8 100644
--- a/src/components/video-editor/SettingsPanel.tsx
+++ b/src/components/video-editor/SettingsPanel.tsx
@@ -51,6 +51,7 @@ import type {
 	FigureData,
 	PlaybackSpeed,
 	WebcamLayoutPreset,
+	WebcamMaskShape,
 	ZoomDepth,
 	ZoomFocusMode,
 } from "./types";
@@ -147,6 +148,8 @@ interface SettingsPanelProps {
 	hasWebcam?: boolean;
 	webcamLayoutPreset?: WebcamLayoutPreset;
 	onWebcamLayoutPresetChange?: (preset: WebcamLayoutPreset) => void;
+	webcamMaskShape?: import("./types").WebcamMaskShape;
+	onWebcamMaskShapeChange?: (shape: import("./types").WebcamMaskShape) => void;
 }
 
 export default SettingsPanel;
@@ -218,6 +221,8 @@ export function SettingsPanel({
 	hasWebcam = false,
 	webcamLayoutPreset = "picture-in-picture",
 	onWebcamLayoutPresetChange,
+	webcamMaskShape = "rectangle",
+	onWebcamMaskShapeChange,
 }: SettingsPanelProps) {
 	const t = useScopedT("settings");
 	const [wallpaperPaths, setWallpaperPaths] = useState<string[]>([]);
@@ -665,6 +670,87 @@ export function SettingsPanel({
 										</SelectContent>
 									</Select>
 								</div>
+								{webcamLayoutPreset === "picture-in-picture" && (
+									<div className="mt-2 p-2 rounded-lg bg-white/5 border border-white/5">
+										<div className="text-[10px] font-medium text-slate-300 mb-1.5">
+											{t("layout.webcamShape")}
+										</div>
+										<div className="grid grid-cols-4 gap-1.5">
+											{(
+												[
+													{ value: "rectangle", label: "Rect" },
+													{ value: "circle", label: "Circle" },
+													{ value: "square", label: "Square" },
+													{ value: "rounded", label: "Rounded" },
+												] as Array<{ value: WebcamMaskShape; label: string }>
+											).map((shape) => (
+												<button
+													key={shape.value}
+													type="button"
+													onClick={() => onWebcamMaskShapeChange?.(shape.value)}
+													className={cn(
+														"h-10 rounded-lg border flex flex-col items-center justify-center gap-0.5 transition-all",
+														webcamMaskShape === shape.value
+															? "bg-[#34B27B] border-[#34B27B] text-white"
+															: "bg-white/5 border-white/10 hover:bg-white/10 hover:border-white/20 text-slate-400",
+													)}
+												>
+													<svg
+														width="16"
+														height="16"
+														viewBox="0 0 16 16"
+														fill="none"
+														xmlns="http://www.w3.org/2000/svg"
+													>
+														{shape.value === "rectangle" && (
+															<rect
+																x="1"
+																y="3"
+																width="14"
+																height="10"
+																rx="2"
+																stroke="currentColor"
+																strokeWidth="1.5"
+															/>
+														)}
+														{shape.value === "circle" && (
+															<circle
+																cx="8"
+																cy="8"
+																r="6.5"
+																stroke="currentColor"
+																strokeWidth="1.5"
+															/>
+														)}
+														{shape.value === "square" && (
+															<rect
+																x="2"
+																y="2"
+																width="12"
+																height="12"
+																rx="1"
+																stroke="currentColor"
+																strokeWidth="1.5"
+															/>
+														)}
+														{shape.value === "rounded" && (
+															<rect
+																x="1"
+																y="3"
+																width="14"
+																height="10"
+																rx="5"
+																stroke="currentColor"
+																strokeWidth="1.5"
+															/>
+														)}
+													</svg>
+													<span className="text-[8px] leading-none">{shape.label}</span>
+												</button>
+											))}
+										</div>
+									</div>
+								)}
 							</AccordionContent>
 						</AccordionItem>
 					)}
diff --git a/src/components/video-editor/VideoEditor.tsx b/src/components/video-editor/VideoEditor.tsx
index 91b51e5..4e5e978 100644
--- a/src/components/video-editor/VideoEditor.tsx
+++ b/src/components/video-editor/VideoEditor.tsx
@@ -85,6 +85,7 @@ export default function VideoEditor() {
 		padding,
 		aspectRatio,
 		webcamLayoutPreset,
+		webcamMaskShape,
 		webcamPosition,
 	} = editorState;
 
@@ -196,6 +197,7 @@ export default function VideoEditor() {
 				annotationRegions: normalizedEditor.annotationRegions,
 				aspectRatio: normalizedEditor.aspectRatio,
 				webcamLayoutPreset: normalizedEditor.webcamLayoutPreset,
+				webcamMaskShape: normalizedEditor.webcamMaskShape,
 				webcamPosition: normalizedEditor.webcamPosition,
 			});
 			setExportQuality(normalizedEditor.exportQuality);
@@ -265,6 +267,7 @@ export default function VideoEditor() {
 				annotationRegions,
 				aspectRatio,
 				webcamLayoutPreset,
+				webcamMaskShape,
 				webcamPosition,
 				exportQuality,
 				exportFormat,
@@ -288,6 +291,7 @@ export default function VideoEditor() {
 		annotationRegions,
 		aspectRatio,
 		webcamLayoutPreset,
+		webcamMaskShape,
 		webcamPosition,
 		exportQuality,
 		exportFormat,
@@ -381,6 +385,7 @@ export default function VideoEditor() {
 				annotationRegions,
 				aspectRatio,
 				webcamLayoutPreset,
+				webcamMaskShape,
 				webcamPosition,
 				exportQuality,
 				exportFormat,
@@ -435,6 +440,7 @@ export default function VideoEditor() {
 			annotationRegions,
 			aspectRatio,
 			webcamLayoutPreset,
+			webcamMaskShape,
 			webcamPosition,
 			exportQuality,
 			exportFormat,
@@ -1103,6 +1109,7 @@ export default function VideoEditor() {
 						cropRegion,
 						annotationRegions,
 						webcamLayoutPreset,
+						webcamMaskShape,
 						webcamPosition,
 						previewWidth,
 						previewHeight,
@@ -1235,6 +1242,7 @@ export default function VideoEditor() {
 						cropRegion,
 						annotationRegions,
 						webcamLayoutPreset,
+						webcamMaskShape,
 						webcamPosition,
 						previewWidth,
 						previewHeight,
@@ -1304,6 +1312,7 @@ export default function VideoEditor() {
 			isPlaying,
 			aspectRatio,
 			webcamLayoutPreset,
+			webcamMaskShape,
 			webcamPosition,
 			exportQuality,
 			handleExportSaved,
@@ -1489,6 +1498,7 @@ export default function VideoEditor() {
 											videoPath={videoPath || ""}
 											webcamVideoPath={webcamVideoPath || undefined}
 											webcamLayoutPreset={webcamLayoutPreset}
+											webcamMaskShape={webcamMaskShape}
 											webcamPosition={webcamPosition}
 											onWebcamPositionChange={(pos) => updateState({ webcamPosition: pos })}
 											onWebcamPositionDragEnd={commitState}
@@ -1637,6 +1647,8 @@ export default function VideoEditor() {
 								webcamPosition: preset === "vertical-stack" ? null : webcamPosition,
 							})
 						}
+						webcamMaskShape={webcamMaskShape}
+						onWebcamMaskShapeChange={(shape) => pushState({ webcamMaskShape: shape })}
 						videoElement={videoPlaybackRef.current?.video || null}
 						exportQuality={exportQuality}
 						onExportQualityChange={setExportQuality}
diff --git a/src/components/video-editor/VideoPlayback.tsx b/src/components/video-editor/VideoPlayback.tsx
index 694c137..d659afe 100644
--- a/src/components/video-editor/VideoPlayback.tsx
+++ b/src/components/video-editor/VideoPlayback.tsx
@@ -25,6 +25,7 @@ import {
 	type StyledRenderRect,
 	type WebcamLayoutPreset,
 } from "@/lib/compositeLayout";
+import { getCssClipPath } from "@/lib/webcamMaskShapes";
 import {
 	type AspectRatio,
 	formatAspectRatioForCSS,
@@ -67,6 +68,7 @@ interface VideoPlaybackProps {
 	videoPath: string;
 	webcamVideoPath?: string;
 	webcamLayoutPreset: WebcamLayoutPreset;
+	webcamMaskShape?: import("./types").WebcamMaskShape;
 	webcamPosition?: { cx: number; cy: number } | null;
 	onWebcamPositionChange?: (position: { cx: number; cy: number }) => void;
 	onWebcamPositionDragEnd?: () => void;
@@ -116,6 +118,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 			videoPath,
 			webcamVideoPath,
 			webcamLayoutPreset,
+			webcamMaskShape,
 			webcamPosition,
 			onWebcamPositionChange,
 			onWebcamPositionDragEnd,
@@ -281,6 +284,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 				webcamDimensions,
 				webcamLayoutPreset,
 				webcamPosition,
+				webcamMaskShape,
 			});
 
 			if (result) {
@@ -311,6 +315,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 			webcamDimensions,
 			webcamLayoutPreset,
 			webcamPosition,
+			webcamMaskShape,
 		]);
 
 		useEffect(() => {
@@ -1215,31 +1220,47 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 								: "none",
 					}}
 				/>
-				{webcamVideoPath && (
-					<video
-						ref={webcamVideoRef}
-						src={webcamVideoPath}
-						className={`absolute object-cover ${webcamLayoutPreset === "picture-in-picture" ? "cursor-grab active:cursor-grabbing" : "pointer-events-none"}`}
-						style={{
-							left: webcamLayout?.x ?? 0,
-							top: webcamLayout?.y ?? 0,
-							width: webcamLayout?.width ?? 0,
-							height: webcamLayout?.height ?? 0,
-							borderRadius: webcamLayout?.borderRadius ?? 0,
-							boxShadow: webcamCssBoxShadow,
-							zIndex: 20,
-							opacity: webcamLayout ? 1 : 0,
-							backgroundColor: "#000",
-						}}
-						onPointerDown={handleWebcamPointerDown}
-						onPointerMove={handleWebcamPointerMove}
-						onPointerUp={handleWebcamPointerUp}
-						onPointerLeave={handleWebcamPointerUp}
-						muted
-						preload="metadata"
-						playsInline
-					/>
-				)}
+				{webcamVideoPath &&
+					(() => {
+						const clipPath = getCssClipPath(webcamLayout?.maskShape ?? "rectangle");
+						const useClipPath = !!clipPath;
+						return (
+							<div
+								className="absolute"
+								style={{
+									left: webcamLayout?.x ?? 0,
+									top: webcamLayout?.y ?? 0,
+									width: webcamLayout?.width ?? 0,
+									height: webcamLayout?.height ?? 0,
+									zIndex: 20,
+									opacity: webcamLayout ? 1 : 0,
+									filter:
+										useClipPath && webcamCssBoxShadow !== "none"
+											? `drop-shadow(${webcamCssBoxShadow})`
+											: undefined,
+								}}
+							>
+								<video
+									ref={webcamVideoRef}
+									src={webcamVideoPath}
+									className={`w-full h-full object-cover ${webcamLayoutPreset === "picture-in-picture" ? "cursor-grab active:cursor-grabbing" : "pointer-events-none"}`}
+									style={{
+										borderRadius: useClipPath ? 0 : (webcamLayout?.borderRadius ?? 0),
+										clipPath: clipPath ?? undefined,
+										boxShadow: useClipPath ? "none" : webcamCssBoxShadow,
+										backgroundColor: "#000",
+									}}
+									onPointerDown={handleWebcamPointerDown}
+									onPointerMove={handleWebcamPointerMove}
+									onPointerUp={handleWebcamPointerUp}
+									onPointerLeave={handleWebcamPointerUp}
+									muted
+									preload="metadata"
+									playsInline
+								/>
+							</div>
+						);
+					})()}
 				{/* Only render overlay after PIXI and video are fully initialized */}
 				{pixiReady && videoReady && (
 					<div
diff --git a/src/components/video-editor/projectPersistence.test.ts b/src/components/video-editor/projectPersistence.test.ts
index 13ea358..3243aca 100644
--- a/src/components/video-editor/projectPersistence.test.ts
+++ b/src/components/video-editor/projectPersistence.test.ts
@@ -1,6 +1,7 @@
 import { describe, expect, it } from "vitest";
 import {
 	createProjectData,
+	normalizeProjectEditor,
 	PROJECT_VERSION,
 	resolveProjectMedia,
 	validateProjectData,
@@ -40,6 +41,7 @@ describe("projectPersistence media compatibility", () => {
 				annotationRegions: [],
 				aspectRatio: "16:9",
 				webcamLayoutPreset: "picture-in-picture",
+				webcamMaskShape: "circle",
 				exportQuality: "good",
 				exportFormat: "mp4",
 				gifFrameRate: 15,
@@ -55,4 +57,11 @@ describe("projectPersistence media compatibility", () => {
 		});
 		expect(validateProjectData(project)).toBe(true);
 	});
+
+	it("normalizes webcam mask shape values safely", () => {
+		expect(normalizeProjectEditor({ webcamMaskShape: "rounded" }).webcamMaskShape).toBe("rounded");
+		expect(
+			normalizeProjectEditor({ webcamMaskShape: "not-a-real-shape" as never }).webcamMaskShape,
+		).toBe("rectangle");
+	});
 });
diff --git a/src/components/video-editor/projectPersistence.ts b/src/components/video-editor/projectPersistence.ts
index 856b9d3..d7111b1 100644
--- a/src/components/video-editor/projectPersistence.ts
+++ b/src/components/video-editor/projectPersistence.ts
@@ -12,11 +12,13 @@ import {
 	DEFAULT_FIGURE_DATA,
 	DEFAULT_PLAYBACK_SPEED,
 	DEFAULT_WEBCAM_LAYOUT_PRESET,
+	DEFAULT_WEBCAM_MASK_SHAPE,
 	DEFAULT_WEBCAM_POSITION,
 	DEFAULT_ZOOM_DEPTH,
 	type SpeedRegion,
 	type TrimRegion,
 	type WebcamLayoutPreset,
+	type WebcamMaskShape,
 	type WebcamPosition,
 	type ZoomRegion,
 } from "./types";
@@ -44,6 +46,7 @@ export interface ProjectEditorState {
 	annotationRegions: AnnotationRegion[];
 	aspectRatio: AspectRatio;
 	webcamLayoutPreset: WebcamLayoutPreset;
+	webcamMaskShape: WebcamMaskShape;
 	webcamPosition: WebcamPosition | null;
 	exportQuality: ExportQuality;
 	exportFormat: ExportFormat;
@@ -353,6 +356,13 @@ export function normalizeProjectEditor(editor: Partial<ProjectEditorState>): Pro
 			editor.webcamLayoutPreset === "picture-in-picture"
 				? editor.webcamLayoutPreset
 				: DEFAULT_WEBCAM_LAYOUT_PRESET,
+		webcamMaskShape:
+			editor.webcamMaskShape === "rectangle" ||
+			editor.webcamMaskShape === "circle" ||
+			editor.webcamMaskShape === "square" ||
+			editor.webcamMaskShape === "rounded"
+				? editor.webcamMaskShape
+				: DEFAULT_WEBCAM_MASK_SHAPE,
 		webcamPosition:
 			editor.webcamPosition &&
 			typeof editor.webcamPosition === "object" &&
diff --git a/src/components/video-editor/types.ts b/src/components/video-editor/types.ts
index 552f2cc..de06ba1 100644
--- a/src/components/video-editor/types.ts
+++ b/src/components/video-editor/types.ts
@@ -6,6 +6,10 @@ export type { WebcamLayoutPreset };
 
 export const DEFAULT_WEBCAM_LAYOUT_PRESET: WebcamLayoutPreset = "picture-in-picture";
 
+export type WebcamMaskShape = "rectangle" | "circle" | "square" | "rounded";
+
+export const DEFAULT_WEBCAM_MASK_SHAPE: WebcamMaskShape = "rectangle";
+
 export interface WebcamPosition {
 	cx: number; // normalized horizontal center (0-1)
 	cy: number; // normalized vertical center (0-1)
diff --git a/src/components/video-editor/videoPlayback/layoutUtils.ts b/src/components/video-editor/videoPlayback/layoutUtils.ts
index 13d4631..2444c39 100644
--- a/src/components/video-editor/videoPlayback/layoutUtils.ts
+++ b/src/components/video-editor/videoPlayback/layoutUtils.ts
@@ -6,7 +6,7 @@ import {
 	type StyledRenderRect,
 	type WebcamLayoutPreset,
 } from "@/lib/compositeLayout";
-import type { CropRegion } from "../types";
+import type { CropRegion, WebcamMaskShape } from "../types";
 
 interface LayoutParams {
 	container: HTMLDivElement;
@@ -21,6 +21,7 @@ interface LayoutParams {
 	webcamDimensions?: Size | null;
 	webcamLayoutPreset?: WebcamLayoutPreset;
 	webcamPosition?: { cx: number; cy: number } | null;
+	webcamMaskShape?: WebcamMaskShape;
 }
 
 interface LayoutResult {
@@ -47,6 +48,7 @@ export function layoutVideoContent(params: LayoutParams): LayoutResult | null {
 		webcamDimensions,
 		webcamLayoutPreset,
 		webcamPosition,
+		webcamMaskShape,
 	} = params;
 
 	const videoWidth = lockedVideoDimensions?.width || videoElement.videoWidth;
@@ -94,6 +96,7 @@ export function layoutVideoContent(params: LayoutParams): LayoutResult | null {
 		webcamSize: webcamDimensions,
 		layoutPreset: webcamLayoutPreset,
 		webcamPosition,
+		webcamMaskShape,
 	});
 
 	if (!compositeLayout) {
diff --git a/src/hooks/useEditorHistory.ts b/src/hooks/useEditorHistory.ts
index ea155c8..d261c1f 100644
--- a/src/hooks/useEditorHistory.ts
+++ b/src/hooks/useEditorHistory.ts
@@ -5,12 +5,14 @@ import type {
 	SpeedRegion,
 	TrimRegion,
 	WebcamLayoutPreset,
+	WebcamMaskShape,
 	WebcamPosition,
 	ZoomRegion,
 } from "@/components/video-editor/types";
 import {
 	DEFAULT_CROP_REGION,
 	DEFAULT_WEBCAM_LAYOUT_PRESET,
+	DEFAULT_WEBCAM_MASK_SHAPE,
 	DEFAULT_WEBCAM_POSITION,
 } from "@/components/video-editor/types";
 import type { AspectRatio } from "@/utils/aspectRatioUtils";
@@ -31,6 +33,7 @@ export interface EditorState {
 	padding: number;
 	aspectRatio: AspectRatio;
 	webcamLayoutPreset: WebcamLayoutPreset;
+	webcamMaskShape: WebcamMaskShape;
 	webcamPosition: WebcamPosition | null;
 }
 
@@ -48,6 +51,7 @@ export const INITIAL_EDITOR_STATE: EditorState = {
 	padding: 50,
 	aspectRatio: "16:9",
 	webcamLayoutPreset: DEFAULT_WEBCAM_LAYOUT_PRESET,
+	webcamMaskShape: DEFAULT_WEBCAM_MASK_SHAPE,
 	webcamPosition: DEFAULT_WEBCAM_POSITION,
 };
 
diff --git a/src/i18n/locales/en/settings.json b/src/i18n/locales/en/settings.json
index 2ba0e58..632a569 100644
--- a/src/i18n/locales/en/settings.json
+++ b/src/i18n/locales/en/settings.json
@@ -23,7 +23,8 @@
 		"preset": "Preset",
 		"selectPreset": "Select preset",
 		"pictureInPicture": "Picture in Picture",
-		"verticalStack": "Vertical Stack"
+		"verticalStack": "Vertical Stack",
+		"webcamShape": "Camera Shape"
 	},
 	"effects": {
 		"title": "Video Effects",
diff --git a/src/i18n/locales/es/settings.json b/src/i18n/locales/es/settings.json
index 8e0607b..586e840 100644
--- a/src/i18n/locales/es/settings.json
+++ b/src/i18n/locales/es/settings.json
@@ -23,7 +23,8 @@
 		"preset": "Predefinido",
 		"selectPreset": "Seleccionar predefinido",
 		"pictureInPicture": "Imagen en imagen",
-		"verticalStack": "Apilado vertical"
+		"verticalStack": "Apilado vertical",
+		"webcamShape": "Forma de cámara"
 	},
 	"effects": {
 		"title": "Efectos de video",
diff --git a/src/i18n/locales/zh-CN/settings.json b/src/i18n/locales/zh-CN/settings.json
index 9b62e4a..ab0d41b 100644
--- a/src/i18n/locales/zh-CN/settings.json
+++ b/src/i18n/locales/zh-CN/settings.json
@@ -23,7 +23,8 @@
 		"preset": "预设",
 		"selectPreset": "选择预设",
 		"pictureInPicture": "画中画",
-		"verticalStack": "垂直堆叠"
+		"verticalStack": "垂直堆叠",
+		"webcamShape": "摄像头形状"
 	},
 	"effects": {
 		"title": "视频效果",
diff --git a/src/lib/compositeLayout.test.ts b/src/lib/compositeLayout.test.ts
index 5dc5339..93ce2c5 100644
--- a/src/lib/compositeLayout.test.ts
+++ b/src/lib/compositeLayout.test.ts
@@ -33,7 +33,7 @@ describe("computeCompositeLayout", () => {
 		).toBeLessThanOrEqual(1920);
 	});
 
-	it("centers the combined screen and webcam stack in vertical stack mode", () => {
+	it("uses cover-style full-width stacking in vertical stack mode", () => {
 		const layout = computeCompositeLayout({
 			canvasSize: { width: 1920, height: 1080 },
 			maxContentSize: { width: 1536, height: 864 },
@@ -44,21 +44,22 @@ describe("computeCompositeLayout", () => {
 
 		expect(layout).not.toBeNull();
 		expect(layout?.screenRect).toEqual({
-			x: 576,
-			y: 108,
-			width: 768,
-			height: 432,
+			x: 0,
+			y: 0,
+			width: 1920,
+			height: 0,
 		});
 		expect(layout?.webcamRect).toEqual({
-			x: 576,
-			y: 540,
-			width: 768,
-			height: 432,
+			x: 0,
+			y: 0,
+			width: 1920,
+			height: 1080,
 			borderRadius: 0,
 		});
+		expect(layout?.screenCover).toBe(true);
 	});
 
-	it("keeps the screen centered and omits the webcam when dimensions are unavailable", () => {
+	it("fills the canvas with the screen when vertical stack has no webcam", () => {
 		const layout = computeCompositeLayout({
 			canvasSize: { width: 1920, height: 1080 },
 			maxContentSize: { width: 1536, height: 864 },
@@ -68,11 +69,56 @@ describe("computeCompositeLayout", () => {
 
 		expect(layout).not.toBeNull();
 		expect(layout?.screenRect).toEqual({
-			x: 192,
-			y: 108,
-			width: 1536,
-			height: 864,
+			x: 0,
+			y: 0,
+			width: 1920,
+			height: 1080,
 		});
 		expect(layout?.webcamRect).toBeNull();
+		expect(layout?.screenCover).toBe(true);
+	});
+
+	it("forces circular and square masks to use square dimensions", () => {
+		const circularLayout = computeCompositeLayout({
+			canvasSize: { width: 1920, height: 1080 },
+			screenSize: { width: 1920, height: 1080 },
+			webcamSize: { width: 1280, height: 720 },
+			webcamMaskShape: "circle",
+		});
+		const squareLayout = computeCompositeLayout({
+			canvasSize: { width: 1920, height: 1080 },
+			screenSize: { width: 1920, height: 1080 },
+			webcamSize: { width: 1280, height: 720 },
+			webcamMaskShape: "square",
+		});
+
+		expect(circularLayout?.webcamRect).not.toBeNull();
+		expect(squareLayout?.webcamRect).not.toBeNull();
+		expect(circularLayout?.webcamRect?.width).toBe(circularLayout?.webcamRect?.height);
+		expect(squareLayout?.webcamRect?.width).toBe(squareLayout?.webcamRect?.height);
+		expect(circularLayout?.webcamRect?.maskShape).toBe("circle");
+		expect(squareLayout?.webcamRect?.maskShape).toBe("square");
+	});
+
+	it("applies larger rounding for the rounded webcam mask", () => {
+		const roundedLayout = computeCompositeLayout({
+			canvasSize: { width: 1920, height: 1080 },
+			screenSize: { width: 1920, height: 1080 },
+			webcamSize: { width: 1280, height: 720 },
+			webcamMaskShape: "rounded",
+		});
+		const rectangleLayout = computeCompositeLayout({
+			canvasSize: { width: 1920, height: 1080 },
+			screenSize: { width: 1920, height: 1080 },
+			webcamSize: { width: 1280, height: 720 },
+			webcamMaskShape: "rectangle",
+		});
+
+		expect(roundedLayout?.webcamRect).not.toBeNull();
+		expect(rectangleLayout?.webcamRect).not.toBeNull();
+		expect(roundedLayout?.webcamRect?.borderRadius).toBeGreaterThan(
+			rectangleLayout?.webcamRect?.borderRadius ?? 0,
+		);
+		expect(roundedLayout?.webcamRect?.maskShape).toBe("rounded");
 	});
 });
diff --git a/src/lib/compositeLayout.ts b/src/lib/compositeLayout.ts
index 5feca50..a3c84e8 100644
--- a/src/lib/compositeLayout.ts
+++ b/src/lib/compositeLayout.ts
@@ -7,6 +7,7 @@ export interface RenderRect {
 
 export interface StyledRenderRect extends RenderRect {
 	borderRadius: number;
+	maskShape?: import("@/components/video-editor/types").WebcamMaskShape;
 }
 
 export interface Size {
@@ -125,6 +126,7 @@ export function computeCompositeLayout(params: {
 	webcamSize?: Size | null;
 	layoutPreset?: WebcamLayoutPreset;
 	webcamPosition?: { cx: number; cy: number } | null;
+	webcamMaskShape?: import("@/components/video-editor/types").WebcamMaskShape;
 }): WebcamCompositeLayout | null {
 	const {
 		canvasSize,
@@ -133,6 +135,7 @@ export function computeCompositeLayout(params: {
 		webcamSize,
 		layoutPreset = "picture-in-picture",
 		webcamPosition,
+		webcamMaskShape = "rectangle",
 	} = params;
 	const { width: canvasWidth, height: canvasHeight } = canvasSize;
 	const { width: screenWidth, height: screenHeight } = screenSize;
@@ -198,8 +201,15 @@ export function computeCompositeLayout(params: {
 	const maxWidth = Math.max(transform.minSize, canvasWidth * transform.maxStageFraction);
 	const maxHeight = Math.max(transform.minSize, canvasHeight * transform.maxStageFraction);
 	const scale = Math.min(maxWidth / webcamWidth, maxHeight / webcamHeight);
-	const width = Math.round(webcamWidth * scale);
-	const height = Math.round(webcamHeight * scale);
+	let width = Math.round(webcamWidth * scale);
+	let height = Math.round(webcamHeight * scale);
+
+	// Shape-specific dimension adjustments
+	if (webcamMaskShape === "circle" || webcamMaskShape === "square") {
+		const side = Math.min(width, height);
+		width = side;
+		height = side;
+	}
 
 	let webcamX: number;
 	let webcamY: number;
@@ -217,6 +227,22 @@ export function computeCompositeLayout(params: {
 		webcamY = Math.max(0, Math.round(canvasHeight - margin - height));
 	}
 
+	// Shape-specific border radius
+	let borderRadius: number;
+	if (webcamMaskShape === "rounded") {
+		borderRadius = Math.round(Math.min(width, height) * 0.3);
+	} else if (webcamMaskShape === "circle") {
+		borderRadius = Math.round(Math.min(width, height) / 2);
+	} else {
+		borderRadius = Math.min(
+			preset.borderRadius.max,
+			Math.max(
+				preset.borderRadius.min,
+				Math.round(Math.min(width, height) * preset.borderRadius.fraction),
+			),
+		);
+	}
+
 	return {
 		screenRect,
 		webcamRect: {
@@ -224,13 +250,8 @@ export function computeCompositeLayout(params: {
 			y: webcamY,
 			width,
 			height,
-			borderRadius: Math.min(
-				preset.borderRadius.max,
-				Math.max(
-					preset.borderRadius.min,
-					Math.round(Math.min(width, height) * preset.borderRadius.fraction),
-				),
-			),
+			borderRadius,
+			maskShape: webcamMaskShape,
 		},
 	};
 }
diff --git a/src/lib/exporter/frameRenderer.ts b/src/lib/exporter/frameRenderer.ts
index 17986ec..80d2f6d 100644
--- a/src/lib/exporter/frameRenderer.ts
+++ b/src/lib/exporter/frameRenderer.ts
@@ -44,6 +44,7 @@ import {
 	type Size,
 	type StyledRenderRect,
 } from "@/lib/compositeLayout";
+import { drawCanvasClipPath } from "@/lib/webcamMaskShapes";
 import { renderAnnotations } from "./annotationRenderer";
 import {
 	getLinearGradientPoints,
@@ -68,6 +69,7 @@ interface FrameRenderConfig {
 	videoHeight: number;
 	webcamSize?: Size | null;
 	webcamLayoutPreset?: WebcamLayoutPreset;
+	webcamMaskShape?: import("@/components/video-editor/types").WebcamMaskShape;
 	webcamPosition?: { cx: number; cy: number } | null;
 	annotationRegions?: AnnotationRegion[];
 	speedRegions?: SpeedRegion[];
@@ -452,6 +454,7 @@ export class FrameRenderer {
 			webcamSize: webcamFrame ? this.config.webcamSize : null,
 			layoutPreset: this.config.webcamLayoutPreset,
 			webcamPosition: this.config.webcamPosition,
+			webcamMaskShape: this.config.webcamMaskShape,
 		});
 		if (!compositeLayout) return;
 
@@ -731,16 +734,17 @@ export class FrameRenderer {
 		const webcamRect = this.layoutCache?.webcamRect ?? null;
 		if (webcamFrame && webcamRect) {
 			const preset = getWebcamLayoutPresetDefinition(this.config.webcamLayoutPreset);
+			const shape = webcamRect.maskShape ?? this.config.webcamMaskShape ?? "rectangle";
 			ctx.save();
-			ctx.beginPath();
-			ctx.roundRect(
+			drawCanvasClipPath(
+				ctx,
 				webcamRect.x,
 				webcamRect.y,
 				webcamRect.width,
 				webcamRect.height,
+				shape,
 				webcamRect.borderRadius,
 			);
-			ctx.closePath();
 			if (preset.shadow) {
 				ctx.shadowColor = preset.shadow.color;
 				ctx.shadowBlur = preset.shadow.blur;
diff --git a/src/lib/exporter/gifExporter.ts b/src/lib/exporter/gifExporter.ts
index eb9ed36..d059264 100644
--- a/src/lib/exporter/gifExporter.ts
+++ b/src/lib/exporter/gifExporter.ts
@@ -41,6 +41,7 @@ interface GifExporterConfig {
 	videoPadding?: number;
 	cropRegion: CropRegion;
 	webcamLayoutPreset?: WebcamLayoutPreset;
+	webcamMaskShape?: import("@/components/video-editor/types").WebcamMaskShape;
 	webcamPosition?: { cx: number; cy: number } | null;
 	annotationRegions?: AnnotationRegion[];
 	previewWidth?: number;
@@ -142,6 +143,7 @@ export class GifExporter {
 				videoHeight: videoInfo.height,
 				webcamSize: webcamInfo ? { width: webcamInfo.width, height: webcamInfo.height } : null,
 				webcamLayoutPreset: this.config.webcamLayoutPreset,
+				webcamMaskShape: this.config.webcamMaskShape,
 				webcamPosition: this.config.webcamPosition,
 				annotationRegions: this.config.annotationRegions,
 				speedRegions: this.config.speedRegions,
diff --git a/src/lib/exporter/videoExporter.ts b/src/lib/exporter/videoExporter.ts
index 08dfe4d..761186f 100644
--- a/src/lib/exporter/videoExporter.ts
+++ b/src/lib/exporter/videoExporter.ts
@@ -32,6 +32,7 @@ interface VideoExporterConfig extends ExportConfig {
 	videoPadding?: number;
 	cropRegion: CropRegion;
 	webcamLayoutPreset?: WebcamLayoutPreset;
+	webcamMaskShape?: import("@/components/video-editor/types").WebcamMaskShape;
 	webcamPosition?: { cx: number; cy: number } | null;
 	annotationRegions?: AnnotationRegion[];
 	previewWidth?: number;
@@ -135,6 +136,7 @@ export class VideoExporter {
 				videoHeight: videoInfo.height,
 				webcamSize: webcamInfo ? { width: webcamInfo.width, height: webcamInfo.height } : null,
 				webcamLayoutPreset: this.config.webcamLayoutPreset,
+				webcamMaskShape: this.config.webcamMaskShape,
 				webcamPosition: this.config.webcamPosition,
 				annotationRegions: this.config.annotationRegions,
 				speedRegions: this.config.speedRegions,
diff --git a/src/lib/webcamMaskShapes.ts b/src/lib/webcamMaskShapes.ts
new file mode 100644
index 0000000..f90e727
--- /dev/null
+++ b/src/lib/webcamMaskShapes.ts
@@ -0,0 +1,48 @@
+import type { WebcamMaskShape } from "@/components/video-editor/types";
+
+/**
+ * Returns a CSS clip-path value for the given shape, or null if borderRadius alone suffices.
+ */
+export function getCssClipPath(shape: WebcamMaskShape): string | null {
+	switch (shape) {
+		case "circle":
+			return "circle(50% at 50% 50%)";
+		case "rectangle":
+		case "rounded":
+		case "square":
+		default:
+			return null;
+	}
+}
+
+/**
+ * Draws a Canvas 2D clip path for the given webcam mask shape.
+ * Call ctx.beginPath() is handled internally; caller should call ctx.clip() after.
+ */
+export function drawCanvasClipPath(
+	ctx: CanvasRenderingContext2D,
+	x: number,
+	y: number,
+	w: number,
+	h: number,
+	shape: WebcamMaskShape,
+	borderRadius: number,
+): void {
+	ctx.beginPath();
+	switch (shape) {
+		case "circle": {
+			const cx = x + w / 2;
+			const cy = y + h / 2;
+			const r = Math.min(w, h) / 2;
+			ctx.arc(cx, cy, r, 0, Math.PI * 2);
+			break;
+		}
+		case "rectangle":
+		case "rounded":
+		case "square":
+		default:
+			ctx.roundRect(x, y, w, h, borderRadius);
+			break;
+	}
+	ctx.closePath();
+}