diff --git a/aegisub/audio_provider_ffmpegsource.cpp b/aegisub/audio_provider_ffmpegsource.cpp
index c143582b5..4889791fd 100644
--- a/aegisub/audio_provider_ffmpegsource.cpp
+++ b/aegisub/audio_provider_ffmpegsource.cpp
@@ -65,10 +65,10 @@ void FFmpegSourceAudioProvider::LoadAudio(Aegisub::String filename) {
 	// clean up
 	Close();
 
-	wxString FileNameWX(filename.c_str(), wxConvUTF8);
+	wxString FileNameWX(filename.c_str(), wxConvFile);
 
 	// generate a default name for the cache file
-	wxString CacheName(filename.c_str());
+	wxString CacheName(filename.c_str(), wxConvFile);
 	CacheName.append(_T(".ffindex"));
 
 	FrameIndex *Index;
diff --git a/aegisub/video_provider_ffmpegsource.cpp b/aegisub/video_provider_ffmpegsource.cpp
index f1a7337f5..ab6230b99 100644
--- a/aegisub/video_provider_ffmpegsource.cpp
+++ b/aegisub/video_provider_ffmpegsource.cpp
@@ -78,10 +78,10 @@ void FFmpegSourceVideoProvider::LoadVideo(Aegisub::String filename, double fps)
 	// make sure we don't have anything messy lying around
 	Close();
 
-	wxString FileNameWX(filename.c_str(), wxConvUTF8);
+	wxString FileNameWX(filename.c_str(), wxConvFile);
 
 	// generate a name for the cache file
-	wxString CacheName(filename.c_str());
+	wxString CacheName(filename.c_str(), wxConvFile);
 	CacheName.append(_T(".ffindex"));
 
 	// try to read index