diff --git a/aegisub/video_provider_ffmpegsource.cpp b/aegisub/video_provider_ffmpegsource.cpp
index 5578e620b79f2380fb201613aae4f243fdeaf30e..823292af695e4c7a15c9d1277b560417606f0b4f 100644
--- a/aegisub/video_provider_ffmpegsource.cpp
+++ b/aegisub/video_provider_ffmpegsource.cpp
@@ -219,7 +219,7 @@ const AegiVideoFrame FFmpegSourceVideoProvider::GetFrame(int _n, int FormatType)
 	// this is what we'll return eventually
 	AegiVideoFrame &DstFrame = CurFrame;
 	
-	bool big_endian = Endian::BigToMachine((int)1)==(int)1;
+	bool big_endian = Endian::BigToMachine((unsigned int)1)==(unsigned int)1;
 
 	// choose output format
 	if (FormatType & FORMAT_RGB32 && big_endian) {