fix(preview): stop leaking video sources on layout changes

src/components/video-editor/VideoPlayback.tsx

@@ -1,4 +1,4 @@
-import { Application, Container, Graphics, Rectangle, Sprite, Texture, VideoSource } from "pixi.js";
+import { Application, Container, Graphics, Rectangle, Sprite, Texture } from "pixi.js";
 import { MotionBlurFilter } from "pixi-filters/motion-blur";
 import { ZoomBlurFilter } from "pixi-filters/zoom-blur";
 import type React from "react";
@@ -111,6 +111,7 @@ import {
 	stepSpringValue,
 } from "./videoPlayback/motionSmoothing";
 import { updateOverlayIndicator } from "./videoPlayback/overlayUtils";
+import { PreviewVideoSource } from "./videoPlayback/previewVideoSource";
 import { createVideoEventHandlers } from "./videoPlayback/videoEventHandlers";
 import {
 	getWebcamMediaTargetTimeSeconds,
@@ -381,6 +382,13 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 		ref,
 	) => {
 		const videoRef = useRef<HTMLVideoElement | null>(null);
+		const previewVideoSourceRef = useRef(new PreviewVideoSource());
+		const attachVideo = useCallback((video: HTMLVideoElement | null) => {
+			// VideoSource.destroy() clears the media URL, so only destroy it when
+			// React detaches the element, never during a layout effect cleanup.
+			previewVideoSourceRef.current.setVideo(video);
+			videoRef.current = video;
+		}, []);
 		const previewFrameRef = useRef<HTMLDivElement | null>(null);
 		const containerRef = useRef<HTMLDivElement | null>(null);
 		const appRef = useRef<Application | null>(null);
@@ -1944,13 +1952,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 				return;
 			if (video.videoWidth === 0 || video.videoHeight === 0) return;
 
-			const source = VideoSource.from(video);
-			if ("autoPlay" in source) {
-				(source as { autoPlay?: boolean }).autoPlay = false;
-			}
-			if ("autoUpdate" in source) {
-				(source as { autoUpdate?: boolean }).autoUpdate = true;
-			}
+			const source = previewVideoSourceRef.current.getSource();
 			const videoTexture = Texture.from(source);
 
 			const videoSprite = new Sprite(videoTexture);
@@ -1967,7 +1969,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 
 			animationStateRef.current = createPlaybackAnimationState();
 
-			layoutVideoContent();
+			layoutVideoContentRef.current?.();
 			video.pause();
 
 			const { handlePlay, handlePause, handleSeeked, handleSeeking, dispose } =
@@ -2004,10 +2006,11 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 				destroyPixiContainer(maskGraphics);
 				maskGraphicsRef.current = null;
 				if (!videoTexture.destroyed) videoTexture.destroy(false);
+				previewVideoSourceRef.current.suspend();
 
 				videoSpriteRef.current = null;
 			};
-		}, [layoutVideoContent, onPlayStateChange, onTimeUpdate, pixiReady, videoReady]);
+		}, [onPlayStateChange, onTimeUpdate, pixiReady, videoReady]);
 
 		useEffect(() => {
 			if (!pixiReady || !videoReady) return;
@@ -2885,7 +2888,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 				{/* Keep the source video off-screen instead of display:none so the
 					browser continues producing presented frames for Pixi and preview sync. */}
 				<video
-					ref={videoRef}
+					ref={attachVideo}
 					src={videoPath}
 					className={fallbackVideoClassName}
 					preload="metadata"

src/components/video-editor/videoPlayback/previewVideoSource.test.ts

@@ -0,0 +1,125 @@
+import { DOMAdapter, Texture } from "pixi.js";
+import { afterAll, beforeAll, describe, expect, it, vi } from "vitest";
+import { PreviewVideoSource } from "./previewVideoSource";
+
+class TestVideo extends EventTarget {
+	videoWidth = 5120;
+	videoHeight = 2880;
+	width = 5120;
+	height = 2880;
+	readyState = 4;
+	HAVE_ENOUGH_DATA = 4;
+	HAVE_FUTURE_DATA = 3;
+	paused = true;
+	ended = false;
+	src = "recording.mp4";
+	currentTime = 5;
+	playbackRate = 1;
+	play = vi.fn();
+	pause = vi.fn();
+	load = vi.fn();
+	requestVideoFrameCallback = vi.fn(() => 1);
+	cancelVideoFrameCallback = vi.fn();
+	listeners = new Map<string, Set<EventListenerOrEventListenerObject>>();
+
+	override addEventListener(type: string, listener: EventListenerOrEventListenerObject) {
+		const listeners = this.listeners.get(type) ?? new Set();
+		listeners.add(listener);
+		this.listeners.set(type, listeners);
+		super.addEventListener(type, listener);
+	}
+
+	override removeEventListener(type: string, listener: EventListenerOrEventListenerObject) {
+		this.listeners.get(type)?.delete(listener);
+		super.removeEventListener(type, listener);
+	}
+
+	asElement() {
+		return this as unknown as HTMLVideoElement;
+	}
+}
+
+const originalAdapter = DOMAdapter.get();
+beforeAll(() => {
+	DOMAdapter.set({
+		...originalAdapter,
+		createCanvas: () => ({ getContext: () => null }) as unknown as HTMLCanvasElement,
+	});
+});
+afterAll(() => DOMAdapter.set(originalAdapter));
+
+describe("PreviewVideoSource", () => {
+	it("reuses a single source and listener set across repeated texture lifecycles", async () => {
+		const video = new TestVideo();
+		const owner = new PreviewVideoSource();
+		owner.setVideo(video.asElement());
+		const source = owner.getSource();
+		await source.load();
+		const unload = vi.fn();
+		source.on("unload", unload);
+
+		for (let i = 0; i < 100; i++) {
+			expect(owner.getSource()).toBe(source);
+			const texture = new Texture({ source });
+			texture.destroy(false);
+			owner.suspend();
+		}
+
+		expect(source.destroyed).toBe(false);
+		expect(unload).toHaveBeenCalledTimes(100);
+		for (const type of ["play", "pause", "seeked"]) {
+			expect(video.listeners.get(type)?.size).toBe(1);
+		}
+		expect(video.src).toBe("recording.mp4");
+		expect(video.currentTime).toBe(5);
+		expect(video.play).not.toHaveBeenCalled();
+		expect(video.load).not.toHaveBeenCalled();
+
+		owner.setVideo(null);
+		expect(source.destroyed).toBe(true);
+		for (const listeners of video.listeners.values()) expect(listeners.size).toBe(0);
+	});
+
+	it("updates paused seeks and new media dimensions after resuming", async () => {
+		const video = new TestVideo();
+		const owner = new PreviewVideoSource();
+		owner.setVideo(video.asElement());
+		const source = owner.getSource();
+		await source.load();
+		const update = vi.fn();
+		source.on("update", update);
+		video.dispatchEvent(new Event("seeked"));
+		expect(update).toHaveBeenCalledTimes(1);
+		owner.suspend();
+		video.dispatchEvent(new Event("seeked"));
+		expect(update).toHaveBeenCalledTimes(1);
+		video.videoWidth = 1920;
+		video.videoHeight = 1080;
+		owner.getSource();
+		expect(source.pixelWidth).toBe(1920);
+		expect(source.pixelHeight).toBe(1080);
+		owner.setVideo(null);
+	});
+
+	it("cancels frame callbacks and releases the source when the element detaches", async () => {
+		const video = new TestVideo();
+		const owner = new PreviewVideoSource();
+		owner.setVideo(video.asElement());
+		const source = owner.getSource();
+		await source.load();
+		video.paused = false;
+		video.dispatchEvent(new Event("play"));
+		expect(video.requestVideoFrameCallback).toHaveBeenCalledTimes(1);
+		owner.setVideo(null);
+		expect(video.cancelVideoFrameCallback).toHaveBeenCalledWith(1);
+		expect(source.destroyed).toBe(true);
+		owner.setVideo(null);
+		expect(video.load).toHaveBeenCalledTimes(1);
+		expect(() => owner.getSource()).toThrow("not attached");
+		const nextVideo = new TestVideo();
+		owner.setVideo(nextVideo.asElement());
+		expect(owner.getSource()).not.toBe(source);
+		await owner.getSource().load();
+		owner.setVideo(null);
+	});
+});

src/components/video-editor/videoPlayback/previewVideoSource.ts

@@ -0,0 +1,33 @@
+import { VideoSource } from "pixi.js";
+
+/** Own the GPU source for the lifetime of React's persistent video element. */
+export class PreviewVideoSource {
+	private video: HTMLVideoElement | null = null;
+	private source: VideoSource | null = null;
+
+	setVideo(video: HTMLVideoElement | null): void {
+		if (video === this.video) return;
+
+		if (this.source) {
+			this.source.autoUpdate = false;
+			this.source.destroy();
+			this.source = null;
+		}
+		this.video = video;
+	}
+
+	getSource(): VideoSource {
+		if (!this.video) throw new Error("Preview video element is not attached");
+		this.source ??= new VideoSource({ resource: this.video, autoPlay: false });
+		this.source.autoUpdate = true;
+		// React can load another media URL into the same element.
+		this.source.update();
+		return this.source;
+	}
+
+	suspend(): void {
+		if (!this.source) return;
+		this.source.autoUpdate = false;
+		this.source.unload();
+	}
+}