diff --git a/web-ui/src/playback-engine/render/renderer.test.ts b/web-ui/src/playback-engine/render/renderer.test.ts
new file mode 100644
index 00000000..d80a4f73
--- /dev/null
+++ b/web-ui/src/playback-engine/render/renderer.test.ts
@@ -0,0 +1,167 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { createVideoRenderPipeline, type VideoRenderPipeline } from ".";
+
+const { present, upload } = vi.hoisted(() => ({ present: vi.fn(), upload: vi.fn() }));
+
+// Exercise the real pipeline and frame scheduling; GPU output is checked in a browser.
+vi.mock("./presenters", () => ({
+  PassthroughPresenter: class {
+    init() {}
+    present = present;
+    destroy() {}
+  },
+}));
+vi.mock("./fsr", () => ({
+  FsrPresenter: class {
+    init() {}
+    present = present;
+    releaseTransientResources() {}
+    destroy() {}
+  },
+}));
+vi.mock("./denoise", () => ({
+  TemporalDenoiser: class {
+    init() {}
+    render(_gl: unknown, texture: unknown) {
+      return texture;
+    }
+    reset() {}
+    releaseTransientResources() {}
+    destroy() {}
+  },
+}));
+vi.mock("./filters/bwdif", () => ({}));
+vi.mock("./filters/types", () => ({
+  createFilter: (name: string) => ({ name, historyFrames: 2, init() {}, render() {}, destroy() {} }),
+}));
+
+class TestVideo extends EventTarget {
+  videoWidth = 768;
+  videoHeight = 576;
+  readyState = 1;
+  paused = true;
+  private nextHandle = 0;
+  private callbacks = new Map<number, VideoFrameRequestCallback>();
+
+  requestVideoFrameCallback(callback: VideoFrameRequestCallback): number {
+    const handle = ++this.nextHandle;
+    this.callbacks.set(handle, callback);
+    return handle;
+  }
+
+  cancelVideoFrameCallback(handle: number): void {
+    this.callbacks.delete(handle);
+  }
+
+  deliverFrame(mediaTime = 0): void {
+    const callbacks = [...this.callbacks.values()];
+    this.callbacks.clear();
+    const now = mediaTime * 1000;
+    for (const callback of callbacks) {
+      callback(now, {
+        width: 720,
+        height: 576,
+        mediaTime,
+        presentationTime: now,
+        expectedDisplayTime: now,
+        presentedFrames: Math.round(mediaTime * 25) + 1,
+        processingDuration: 0,
+      });
+    }
+  }
+}
+
+function createCanvas(): HTMLCanvasElement {
+  const gl = {
+    getParameter: () => 4096,
+    createTexture: () => ({}),
+    createFramebuffer: () => ({}),
+    checkFramebufferStatus: () => 0x8cd5,
+    FRAMEBUFFER_COMPLETE: 0x8cd5,
+    texSubImage2D: upload,
+    bindTexture() {},
+    texStorage2D() {},
+    texImage2D() {},
+    texParameteri() {},
+    activeTexture() {},
+    bindFramebuffer() {},
+    framebufferTexture2D() {},
+    viewport() {},
+    deleteTexture() {},
+    deleteFramebuffer() {},
+  };
+  return Object.assign(new EventTarget(), {
+    width: 300,
+    height: 150,
+    parentElement: null,
+    getContext: () => gl,
+  }) as unknown as HTMLCanvasElement;
+}
+
+describe("first decoded video frame", () => {
+  let pipeline: VideoRenderPipeline;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.stubGlobal("HTMLVideoElement", TestVideo);
+    vi.stubGlobal("HTMLMediaElement", { HAVE_CURRENT_DATA: 2 });
+    vi.stubGlobal("window", { requestAnimationFrame: vi.fn(() => 1), cancelAnimationFrame: vi.fn() });
+  });
+
+  afterEach(() => {
+    pipeline?.destroy();
+    vi.unstubAllGlobals();
+  });
+
+  it.each([
+    { enhancement: true, deinterlace: false },
+    { enhancement: false, deinterlace: true },
+    { enhancement: true, deinterlace: true },
+  ])("presents without waiting for a second frame: %o", ({ enhancement, deinterlace }) => {
+    const video = new TestVideo();
+    const canvas = createCanvas();
+    pipeline = createVideoRenderPipeline(video as unknown as HTMLVideoElement, canvas);
+    pipeline.setPictureEnhancementEnabled(enhancement);
+    pipeline.setAutoDeinterlaceEnabled(deinterlace);
+    pipeline.setScanType("interlaced");
+
+    // Chromium can deliver rVFC before it advances readyState to HAVE_CURRENT_DATA.
+    video.deliverFrame();
+
+    expect(pipeline.active).toBe(true);
+    expect(upload).toHaveBeenCalledTimes(1);
+    expect(present).toHaveBeenCalledTimes(1);
+    expect(present.mock.calls[0].slice(2, 6)).toEqual([720, 576, 768, 576]);
+    expect([canvas.width, canvas.height]).toEqual([768, 576]);
+  });
+
+  it("does not upload or filter the first frame twice when it was already primed", () => {
+    const video = new TestVideo();
+    video.readyState = 2;
+    pipeline = createVideoRenderPipeline(video as unknown as HTMLVideoElement, createCanvas());
+
+    video.deliverFrame();
+
+    expect(upload).toHaveBeenCalledTimes(1);
+    expect(present).toHaveBeenCalledTimes(1);
+
+    video.deliverFrame(0.04);
+
+    expect(upload).toHaveBeenCalledTimes(2);
+    expect(present).toHaveBeenCalledTimes(2);
+  });
+
+  it("keeps raw video when both processing features are disabled", () => {
+    const video = new TestVideo();
+    pipeline = createVideoRenderPipeline(video as unknown as HTMLVideoElement, createCanvas());
+    pipeline.setPictureEnhancementEnabled(false);
+    pipeline.setAutoDeinterlaceEnabled(false);
+    pipeline.setScanType("interlaced");
+
+    video.deliverFrame();
+
+    expect(pipeline.active).toBe(false);
+    expect(upload).not.toHaveBeenCalled();
+    expect(present).not.toHaveBeenCalled();
+  });
+});
diff --git a/web-ui/src/playback-engine/render/renderer.ts b/web-ui/src/playback-engine/render/renderer.ts
index 054001fe..991e14ca 100644
--- a/web-ui/src/playback-engine/render/renderer.ts
+++ b/web-ui/src/playback-engine/render/renderer.ts
@@ -603,8 +603,11 @@ export class VideoRenderer {
       this.frameHeight = metadata.height;
       if (sizeChanged) this.onFrameSizeChange?.();
       if (!this.running) return;
-      // Starting from the size notification already primes this same frame.
-      if (wasRunning) this.processFrame(now, metadata);
+      // Starting from the size notification may have primed this frame, but
+      // rVFC can arrive before HAVE_CURRENT_DATA and make primeCanvas skip it.
+      // Render that decoded frame now instead of showing an empty canvas until
+      // the next callback; do not upload/filter a successfully primed frame twice.
+      if (wasRunning || this.textures.length === 0) this.processFrame(now, metadata);
       if (this.running) this.scheduleFrame();
     });
   }