diff --git a/src/components/CallFooterViewModel.test.ts b/src/components/CallFooterViewModel.test.ts
index ed0ffe8ed..6f353e540 100644
--- a/src/components/CallFooterViewModel.test.ts
+++ b/src/components/CallFooterViewModel.test.ts
@@ -13,7 +13,10 @@ import type { CallViewModel } from "../state/CallViewModel/CallViewModel";
 import type { Layout } from "../state/layout-types";
 import type { SpotlightTileViewModel } from "../state/TileViewModel";
 import type { DeviceLabel } from "../state/MediaDevices";
-import { createCallFooterViewModel } from "./CallFooterViewModel";
+import {
+  createCallFooterViewModel,
+  createLobbyFooterViewModel,
+} from "./CallFooterViewModel";
 import { HeaderStyle } from "../UrlParams";
 
 const platformMock = vi.hoisted(() => vi.fn(() => "desktop"));
@@ -23,10 +26,10 @@ vi.mock("../Platform", () => ({
   },
 }));
 
-// Prevent supportsBackgroundProcessors from throwing in jsdom – it is not
-// exercised by these tests (only used in `videoToggles`, not `videoOptions`).
+// The SDK's own check needs WebGL and canvas APIs jsdom does not have.
+const sdkSupportMock = vi.hoisted(() => vi.fn(() => false));
 vi.mock("@livekit/track-processors", () => ({
-  supportsBackgroundProcessors: (): boolean => false,
+  supportsBackgroundProcessors: (): boolean => sdkSupportMock(),
 }));
 
 const outputSelectionMock = vi.hoisted(() => vi.fn(() => true));
@@ -217,4 +220,55 @@ describe("createCallFooterViewModel", () => {
       ]);
     });
   });
+
+  describe("background effects", () => {
+    // The lobby, because in a call the whole device switcher is already
+    // withheld on a phone, whatever the verdict says.
+    function lobbyOn(
+      platform: string,
+    ): ReturnType<typeof createLobbyFooterViewModel> {
+      platformMock.mockReturnValue(platform);
+      return createLobbyFooterViewModel(
+        testScope(),
+        mockMuteStates(),
+        twoMicsAndOneCamMediaDevices,
+        /* openSettings */ undefined,
+        /* hangup */ undefined,
+        /* showLogo */ false,
+      );
+    }
+
+    it("offers nothing on a phone, where the pipeline would refuse them", () => {
+      sdkSupportMock.mockReturnValue(true);
+      expect(lobbyOn("ios").toggleBlur$.value).toBeUndefined();
+    });
+
+    it("offers them where the pipeline will honour them", () => {
+      sdkSupportMock.mockReturnValue(true);
+      expect(lobbyOn("desktop").toggleBlur$.value).toBeDefined();
+    });
+
+    it("offers nothing where the browser itself cannot run them", () => {
+      sdkSupportMock.mockReturnValue(false);
+      expect(lobbyOn("desktop").toggleBlur$.value).toBeUndefined();
+    });
+
+    it("availability is the same before and during a call", () => {
+      for (const supported of [true, false]) {
+        sdkSupportMock.mockReturnValue(supported);
+        const lobby = lobbyOn("desktop");
+        const inCall = createCallFooterViewModel(
+          testScope(),
+          buildMinimalCallViewModel(gridLayout),
+          mockMuteStates(),
+          twoMicsAndOneCamMediaDevices,
+          /* reactionIdentifier */ undefined,
+          { showControls: true, header: HeaderStyle.Standard },
+        );
+        const offeredInLobby = lobby.toggleBlur$.value !== undefined;
+        expect(inCall.toggleBlur$.value !== undefined).toBe(offeredInLobby);
+        expect(offeredInLobby).toBe(supported);
+      }
+    });
+  });
 });
diff --git a/src/components/CallFooterViewModel.tsx b/src/components/CallFooterViewModel.tsx
index 50efb42f9..9a110c370 100644
--- a/src/components/CallFooterViewModel.tsx
+++ b/src/components/CallFooterViewModel.tsx
@@ -6,9 +6,10 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { combineLatest, map, type Observable, switchMap } from "rxjs";
-import { supportsBackgroundProcessors } from "@livekit/track-processors";
 import { supportsAudioOutputSelection } from "livekit-client";
 
+import { supportsBackgroundProcessors } from "../tracks/backgroundProcessing";
+
 import { type CallViewModel } from "../state/CallViewModel/CallViewModel";
 import { type MenuOptions } from "./MediaMuteAndSwitchButton";
 import { type MediaDevices } from "../state/MediaDevices";
diff --git a/src/tracks/BackgroundEffectsContext.tsx b/src/tracks/BackgroundEffectsContext.tsx
index f1b384e0a..c5ae575fd 100644
--- a/src/tracks/BackgroundEffectsContext.tsx
+++ b/src/tracks/BackgroundEffectsContext.tsx
@@ -5,17 +5,14 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import {
-  BackgroundProcessorWrapper,
-  supportsBackgroundProcessors as supportsBackgroundProcessorsLivekitSdk,
-} from "@livekit/track-processors";
+import { BackgroundProcessorWrapper } from "@livekit/track-processors";
 import { createContext, type FC, type JSX, use } from "react";
 
 import { backgroundBlur as backgroundBlurSettings } from "../settings/settings";
 import { BackgroundEffectTransformer } from "./BackgroundEffectTransformer";
+import { supportsBackgroundProcessors } from "./backgroundProcessing";
 import { type Behavior } from "../state/Behavior";
 import { type ObservableScope } from "../state/ObservableScope";
-import { platform } from "../Platform";
 import {
   type BackgroundEffects,
   type BackgroundEffectsState,
@@ -40,10 +37,6 @@ export function useBackgroundEffectsState$(): Behavior<BackgroundEffectsState> {
   return effects.state$;
 }
 
-function supportsBackgroundProcessors(): boolean {
-  return supportsBackgroundProcessorsLivekitSdk() && platform === "desktop";
-}
-
 /**
  * The app's one pipeline, shared by every camera track it opens. Its builds
  * and teardowns take their turns through the SDK, which runs one operation
diff --git a/src/tracks/backgroundProcessing.ts b/src/tracks/backgroundProcessing.ts
new file mode 100644
index 000000000..8b6168dad
--- /dev/null
+++ b/src/tracks/backgroundProcessing.ts
@@ -0,0 +1,15 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { supportsBackgroundProcessors as supportsBackgroundProcessorsLivekitSdk } from "@livekit/track-processors";
+
+import { platform } from "../Platform";
+
+/** One answer for the controls and the pipeline, so neither offers what the other refuses. */
+export function supportsBackgroundProcessors(): boolean {
+  return supportsBackgroundProcessorsLivekitSdk() && platform === "desktop";
+}