diff --git a/static/player/mode.ts b/static/player/mode.ts
index 8e86dce..ecf37f4 100644
--- a/static/player/mode.ts
+++ b/static/player/mode.ts
@@ -3,17 +3,9 @@ import { showControls } from "./controls";
 import { updateSubtitleOptions } from "./subtitles";
 import { updateQualityOptions } from "./quality";
 import { safeLocalStorage } from "./storage";
+import { streamUrlForMode } from "./source";
 import { loadVideoSource } from "./video";
 
-// builds stream URL with mode, token, and optional quality param
-const streamUrlForMode = (mode: string, quality?: string): string => {
-  const src = state.modeSources[mode];
-  if (!src?.token) return "";
-  let url = `${state.streamURL}?mode=${encodeURIComponent(mode)}&token=${encodeURIComponent(src.token)}`;
-  if (quality && quality !== "best") url += `&quality=${encodeURIComponent(quality)}`;
-  return url;
-};
-
 /**
  * Switches between sub/dub mode.
  * Saves preference to localStorage, reloads video src.
diff --git a/static/player/quality.ts b/static/player/quality.ts
index 4e14fea..20befdc 100644
--- a/static/player/quality.ts
+++ b/static/player/quality.ts
@@ -1,16 +1,8 @@
 import { state } from "./state";
+import { streamUrlForMode } from "./source";
 import { safeLocalStorage } from "./storage";
 import { loadVideoSource } from "./video";
 
-// same as mode.ts - could be extracted to shared util
-const streamUrlForMode = (mode: string, quality?: string): string => {
-  const src = state.modeSources[mode];
-  if (!src?.token) return "";
-  let url = `${state.streamURL}?mode=${encodeURIComponent(mode)}&token=${encodeURIComponent(src.token)}`;
-  if (quality && quality !== "best") url += `&quality=${encodeURIComponent(quality)}`;
-  return url;
-};
-
 /**
  * Switches video quality (resolution).
  * Persists preference to localStorage.
diff --git a/static/player/source.ts b/static/player/source.ts
new file mode 100644
index 0000000..ec786ca
--- /dev/null
+++ b/static/player/source.ts
@@ -0,0 +1,13 @@
+import { state } from "./state";
+
+export const streamUrlForMode = (mode: string, quality?: string): string => {
+  const src = state.modeSources[mode];
+  if (!src?.token) return "";
+
+  let url = `${state.streamURL}?mode=${encodeURIComponent(mode)}&token=${encodeURIComponent(src.token)}`;
+  if (quality && quality !== "best") {
+    url += `&quality=${encodeURIComponent(quality)}`;
+  }
+
+  return url;
+};