diff --git a/src/renderer/src/components/emulator-pane/use-emulator-video-stream.test.tsx b/src/renderer/src/components/emulator-pane/use-emulator-video-stream.test.tsx
new file mode 100644
index 00000000000..fadaf1abf07
--- /dev/null
+++ b/src/renderer/src/components/emulator-pane/use-emulator-video-stream.test.tsx
@@ -0,0 +1,98 @@
+// @vitest-environment happy-dom
+
+import { act } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { useEmulatorVideoStream } from './use-emulator-video-stream'
+import type { StreamSize } from './emulator-device-frame-layout'
+
+type Frame = { displayWidth: number; displayHeight: number; close: () => void }
+type Meta = {
+  streamId: string
+  deviceId: string
+  meta: { codecId: string; width: number; height: number }
+}
+
+let output: (frame: Frame) => void
+let metaListener: (meta: Meta) => void
+let streamId: string
+let reports: StreamSize[]
+let root: Root
+let contextDescriptor: PropertyDescriptor | undefined
+
+function Screen() {
+  const { canvasRef } = useEmulatorVideoStream('device', 'stream', true, (size) =>
+    reports.push(size)
+  )
+  return <canvas ref={canvasRef} />
+}
+
+beforeEach(() => {
+  Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true })
+  reports = []
+  vi.stubGlobal(
+    'VideoDecoder',
+    class {
+      state = 'unconfigured'
+      constructor(init: { output: (frame: Frame) => void }) {
+        output = init.output
+      }
+      close(): void {}
+    }
+  )
+  vi.stubGlobal('EncodedVideoChunk', class {})
+  contextDescriptor = Object.getOwnPropertyDescriptor(HTMLCanvasElement.prototype, 'getContext')
+  Object.defineProperty(HTMLCanvasElement.prototype, 'getContext', {
+    configurable: true,
+    value: () => ({ clearRect: () => {}, drawImage: () => {} })
+  })
+  Object.defineProperty(window, 'api', {
+    configurable: true,
+    value: {
+      emulator: {
+        startVideoStream: async (args: { streamId: string }) => {
+          streamId = args.streamId
+          return args
+        },
+        stopVideoStream: async () => {},
+        onVideoStreamMeta: (cb: (meta: Meta) => void) => {
+          metaListener = cb
+          return () => {}
+        }
+      }
+    }
+  })
+  root = createRoot(document.createElement('div'))
+})
+
+afterEach(() => {
+  act(() => root.unmount())
+  if (contextDescriptor) {
+    Object.defineProperty(HTMLCanvasElement.prototype, 'getContext', contextDescriptor)
+  } else {
+    Reflect.deleteProperty(HTMLCanvasElement.prototype, 'getContext')
+  }
+  Reflect.deleteProperty(window, 'api')
+  vi.unstubAllGlobals()
+})
+
+describe('useEmulatorVideoStream decoded size', () => {
+  it('reports decoded frame size changes once after codec metadata', async () => {
+    await act(async () => root.render(<Screen />))
+    const frame = (): void => output({ displayWidth: 480, displayHeight: 240, close: () => {} })
+    act(() => {
+      metaListener({
+        streamId,
+        deviceId: 'device',
+        meta: { codecId: 'h264', width: 240, height: 480 }
+      })
+      frame()
+      frame()
+      frame()
+    })
+    expect(reports).toEqual([
+      { width: 240, height: 480 },
+      { width: 480, height: 240 }
+    ])
+  })
+})
diff --git a/src/renderer/src/components/emulator-pane/use-emulator-video-stream.ts b/src/renderer/src/components/emulator-pane/use-emulator-video-stream.ts
index b0fdf11c961..5ba4fe622d6 100644
--- a/src/renderer/src/components/emulator-pane/use-emulator-video-stream.ts
+++ b/src/renderer/src/components/emulator-pane/use-emulator-video-stream.ts
@@ -43,6 +43,7 @@ export function useEmulatorVideoStream(
   const onSizeRef = useRef(onSize)
   onSizeRef.current = onSize
 
+  // oxlint-disable-next-line react-doctor/effect-needs-cleanup -- cleanup() clears the first-frame timeout.
   useEffect(() => {
     const api = (window as { api?: { emulator?: EmulatorVideoApi } }).api?.emulator
     if (!enabled || !deviceId) {
@@ -65,6 +66,14 @@ export function useEmulatorVideoStream(
     let configured = false
     let timestamp = 0
     let configBytes: Uint8Array | null = null
+    let reportedSize: StreamSize | null = null
+    const reportSize = (width: number, height: number): void => {
+      if (reportedSize?.width === width && reportedSize.height === height) {
+        return
+      }
+      reportedSize = { width, height }
+      onSizeRef.current?.(reportedSize)
+    }
     const currentStreamId = newVideoStreamId()
     let streamId: string | null = currentStreamId
     let unsubMeta: (() => void) | undefined
@@ -84,6 +93,7 @@ export function useEmulatorVideoStream(
             canvas.width = frame.displayWidth
             canvas.height = frame.displayHeight
           }
+          reportSize(frame.displayWidth, frame.displayHeight)
           ctx.drawImage(frame, 0, 0)
         }
         frame.close()
@@ -135,7 +145,7 @@ export function useEmulatorVideoStream(
 
     unsubMeta = api.onVideoStreamMeta?.((msg) => {
       if (!disposed && msg.streamId === streamId && msg.deviceId === deviceId) {
-        onSizeRef.current?.({ width: msg.meta.width, height: msg.meta.height })
+        reportSize(msg.meta.width, msg.meta.height)
       }
     })