diff --git a/src/components/maincontroller.ts b/src/components/maincontroller.ts
index e269a159..484aa746 100644
--- a/src/components/maincontroller.ts
+++ b/src/components/maincontroller.ts
@@ -247,7 +247,7 @@ window.playerManager.addEventListener(
     () => {
         setTextTrack(
             window.playerManager.getMediaInformation()?.customData
-                .subtitleStreamIndex
+                ?.subtitleStreamIndex ?? null
         );
     }
 );
@@ -494,7 +494,7 @@ export async function changeStream(
     params: any = undefined // eslint-disable-line @typescript-eslint/no-explicit-any
 ): Promise<void> {
     if (
-        window.playerManager.getMediaInformation()?.customData.canClientSeek &&
+        window.playerManager.getMediaInformation()?.customData?.canClientSeek &&
         params == null
     ) {
         window.playerManager.seek(ticksToSeconds(ticks));
@@ -847,7 +847,6 @@ export function createMediaInformation(
 
     mediaInfo.contentId = streamInfo.url;
     mediaInfo.contentType = streamInfo.contentType;
-    // TODO make a type for this
     mediaInfo.customData = {
         audioStreamIndex: streamInfo.audioStreamIndex,
         canClientSeek: streamInfo.canClientSeek,
diff --git a/src/helpers.ts b/src/helpers.ts
index f6dfca0d..9003e704 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -22,7 +22,7 @@ export function getCurrentPositionTicks(state: PlaybackState): number {
         window.playerManager.getCurrentTimeSec() * TicksPerSecond;
     const mediaInformation = window.playerManager.getMediaInformation();
 
-    if (mediaInformation && !mediaInformation.customData.canClientSeek) {
+    if (mediaInformation && !mediaInformation.customData?.canClientSeek) {
         positionTicks += state.startPositionTicks || 0;
     }
 
diff --git a/src/types/global.d.ts b/src/types/global.d.ts
index 9268c09c..08239a1d 100644
--- a/src/types/global.d.ts
+++ b/src/types/global.d.ts
@@ -103,3 +103,19 @@ declare global {
         volume: SystemVolumeData;
     }
 }
+
+declare module 'chromecast-caf-receiver/cast.framework.messages' {
+    interface MediaInformationCustomData {
+        audioStreamIndex: string;
+        canClientSeek: boolean;
+        canSeek: boolean;
+        itemId: string | undefined;
+        liveStreamId: number;
+        mediaSourceId: number;
+        playMethod: 'DirectStream' | 'Transcode';
+        playSessionId: string;
+        runtimeTicks: number;
+        startPositionTicks: number;
+        subtitleStreamIndex: number;
+    }
+}