diff --git a/src/controller/buffer-controller.ts b/src/controller/buffer-controller.ts
index f2c3341eda2..4060903f695 100755
--- a/src/controller/buffer-controller.ts
+++ b/src/controller/buffer-controller.ts
@@ -1197,5 +1197,5 @@ function addSource(media: HTMLMediaElement, url: string) {
 }
 
 function getSourceChild(media: HTMLMediaElement): HTMLSourceElement | null {
-  return media.querySelector('source');
+  return media.querySelector?.('source');
 }