Fix locale-dependent default device detection

The previous check used label.startsWith('Default') to detect if a
track is using the system default device, but this only works when
the browser locale is English. On other locales the label is
translated (e.g. 'Standard' in German).

Replaced with getSettings().deviceId === 'default' which is
locale-independent and directly checks what we actually care about.

Fixes #1194

Author: Charlie Tonneslan

packages/core/src/components/mediaDeviceSelect.ts

@@ -19,6 +19,19 @@ export type SetMediaDeviceOptions = {
   exact?: boolean;
 };
 
+/**
+ * Check if a MediaStreamTrack is using the system default device.
+ * Uses the deviceId from getSettings() instead of the label string,
+ * since labels are locale-dependent and can't be reliably matched.
+ */
+function isDefaultDevice(track: MediaStreamTrack): boolean {
+  try {
+    return track.getSettings().deviceId === 'default';
+  } catch {
+    return false;
+  }
+}
+
 export function setupDeviceSelector(
   kind: MediaDeviceKind,
   room: Room,
@@ -33,7 +46,7 @@ export function setupDeviceSelector(
       await localTrack.setDeviceId(options.exact ? { exact: id } : id);
       const actualId = await localTrack.getDeviceId(false);
       activeDeviceSubject.next(
-        id === 'default' && localTrack.mediaStreamTrack.label.startsWith('Default') ? id : actualId,
+        id === 'default' && isDefaultDevice(localTrack.mediaStreamTrack) ? id : actualId,
       );
     } else if (room) {
       const browser = getBrowser();
@@ -57,7 +70,7 @@ export function setupDeviceSelector(
       }
       const useDefault =
         (id === 'default' && !targetTrack) ||
-        (id === 'default' && targetTrack?.mediaStreamTrack.label.startsWith('Default'));
+        (id === 'default' && targetTrack && isDefaultDevice(targetTrack.mediaStreamTrack));
       activeDeviceSubject.next(useDefault ? id : actualDeviceId);
     }
   };