diff --git a/types/Demuxer.d.ts b/types/Demuxer.d.ts
index 6bcb223..937aad6 100644
--- a/types/Demuxer.d.ts
+++ b/types/Demuxer.d.ts
@@ -75,7 +75,7 @@ export interface Demuxer extends Omit<FormatContext,
 	/**
 	 * Abandon the demuxing process and forcibly close the file or stream without waiting for it to finish
 	 */
-	forceClose(): undefined
+	forceClose(): number
 }
 
 /**
diff --git a/types/Muxer.d.ts b/types/Muxer.d.ts
index 81cec39..b0ed2ab 100644
--- a/types/Muxer.d.ts
+++ b/types/Muxer.d.ts
@@ -93,7 +93,7 @@ export interface Muxer extends Omit<FormatContext,
 	/**
 	 * Abandon the muxing process and forcibly close the file or stream without completing it
 	 */
-	forceClose(): undefined
+	forceClose(): number
 }
 
 /**