diff --git a/src/hls/hls-misc.ts b/src/hls/hls-misc.ts
index d34beeb..209df3a 100644
--- a/src/hls/hls-misc.ts
+++ b/src/hls/hls-misc.ts
@@ -57,7 +57,7 @@ export class AttributeList {
 		}
 
 		if (key) {
-			this._attributes[key.toLowerCase()] = value;
+			this._attributes[key.trim().toLowerCase()] = value;
 		}
 	}