diff --git a/aegisub/src/ass_exporter.cpp b/aegisub/src/ass_exporter.cpp
index e74d69c14..b9087db35 100644
--- a/aegisub/src/ass_exporter.cpp
+++ b/aegisub/src/ass_exporter.cpp
@@ -131,9 +131,9 @@ wxArrayString AssExporter::GetAllFilterNames() {
 /// @param export_dialog 
 /// @return 
 ///
-AssFile *AssExporter::ExportTransform(wxWindow *export_dialog) {
+AssFile *AssExporter::ExportTransform(wxWindow *export_dialog,bool copy) {
 	// Copy
-	AssFile *Subs = new AssFile(*OriginalSubs);
+	AssFile *Subs = copy ? new AssFile(*OriginalSubs) : OriginalSubs;
 
 	// Run filters
 	for (FilterList::iterator cur=Filters.begin();cur!=Filters.end();cur++) {
@@ -151,7 +151,7 @@ AssFile *AssExporter::ExportTransform(wxWindow *export_dialog) {
 /// @param export_dialog 
 ///
 void AssExporter::Export(wxString filename, wxString charset, wxWindow *export_dialog) {
-	std::auto_ptr<AssFile> Subs(ExportTransform(export_dialog));
+	std::auto_ptr<AssFile> Subs(ExportTransform(export_dialog,true));
 	Subs->Save(filename,false,false,charset);
 }
 
diff --git a/aegisub/src/ass_exporter.h b/aegisub/src/ass_exporter.h
index d254ba810..d6c270a82 100644
--- a/aegisub/src/ass_exporter.h
+++ b/aegisub/src/ass_exporter.h
@@ -93,7 +93,7 @@ public:
 	void AddAutoFilters();
 	void DrawSettings(wxWindow *parent,wxSizer *AddTo);
 	void Export(wxString file, wxString charset, wxWindow *export_dialog=NULL);
-	AssFile *ExportTransform(wxWindow *export_dialog=NULL);
+	AssFile *ExportTransform(wxWindow *export_dialog=NULL,bool copy=false);
 	wxSizer *GetSettingsSizer(wxString name);
 
 	/// @brief DOCME
diff --git a/aegisub/src/threaded_frame_source.cpp b/aegisub/src/threaded_frame_source.cpp
index 0a3d1761a..437def4cf 100644
--- a/aegisub/src/threaded_frame_source.cpp
+++ b/aegisub/src/threaded_frame_source.cpp
@@ -86,6 +86,10 @@ std::tr1::shared_ptr<AegiVideoFrame> ThreadedFrameSource::ProcFrame(int frameNum
 				// other lines will probably not be viewed before the file changes
 				// again), and if it's a different frame, export the entire file.
 				if (singleFrame == -1) {
+					AssExporter exporter(subs.get());
+					exporter.AddAutoFilters();
+					exporter.ExportTransform();
+
 					singleFrame = frameNum;
 					// Copying a nontrivially sized AssFile is fairly slow, so
 					// instead muck around with its innards to just temporarily
@@ -173,14 +177,12 @@ ThreadedFrameSource::~ThreadedFrameSource() {
 }
 
 void ThreadedFrameSource::LoadSubtitles(AssFile *subs) throw() {
-	AssExporter exporter(subs);
-	exporter.AddAutoFilters();
-	AssFile *exported = exporter.ExportTransform();
+	subs = new AssFile(*subs);
 	wxMutexLocker locker(jobMutex);
 	// Set nextSubs and let the worker thread move it to subs so that we don't
 	// have to lock fileMutex on the GUI thread, as that can be locked for
 	// extended periods of time with slow-rendering subtitles
-	nextSubs.reset(exported);
+	nextSubs.reset(subs);
 }
 
 void ThreadedFrameSource::RequestFrame(int frame, double time) throw() {