diff --git a/aegisub/src/video_display.cpp b/aegisub/src/video_display.cpp
index 3ea91506b..a0ed718ce 100644
--- a/aegisub/src/video_display.cpp
+++ b/aegisub/src/video_display.cpp
@@ -152,6 +152,7 @@ void VideoDisplay::ShowCursor(bool show) {
 }
 
 void VideoDisplay::SetFrame(int frameNumber) {
+	VideoContext *context = VideoContext::Get();
 	ControlSlider->SetValue(frameNumber);
 
 	// Get time for frame
@@ -163,7 +164,7 @@ void VideoDisplay::SetFrame(int frameNumber) {
 
 	// Set the text box for frame number and time
 	PositionDisplay->SetValue(wxString::Format(_T("%01i:%02i:%02i.%03i - %i"), h, m, s, ms, frameNumber));
-	if (VideoContext::Get()->GetKeyFrames().Index(frameNumber) != wxNOT_FOUND) {
+	if (context->GetKeyFrames().Index(frameNumber) != wxNOT_FOUND) {
 		// Set the background color to indicate this is a keyframe
 		PositionDisplay->SetBackgroundColour(Options.AsColour(_T("Grid selection background")));
 		PositionDisplay->SetForegroundColour(Options.AsColour(_T("Grid selection foreground")));
@@ -178,7 +179,7 @@ void VideoDisplay::SetFrame(int frameNumber) {
 	int startOff = 0;
 	int endOff = 0;
 
-	if (AssDialogue *curLine = VideoContext::Get()->curLine) {
+	if (AssDialogue *curLine = context->curLine) {
 		startOff = time - curLine->Start.GetMS();
 		endOff = time - curLine->End.GetMS();
 	}
@@ -193,8 +194,11 @@ void VideoDisplay::SetFrame(int frameNumber) {
 	if (IsShownOnScreen() && visual) visual->Refresh();
 
 	// Render the new frame
-	videoOut->InvalidateFrame();
-	Render(frameNumber);
+	if (context->IsLoaded()) {
+		AegiVideoFrame frame = context->GetFrame(frameNumber);
+		videoOut->UploadFrameData(frame);
+	}
+	Render();
 
 	currentFrame = frameNumber;
 }
@@ -205,7 +209,7 @@ void VideoDisplay::SetFrameRange(int from, int to) {
 
 
 /// @brief Render the currently visible frame
-void VideoDisplay::Render(int frameNumber) try {
+void VideoDisplay::Render() try {
 	if (!IsShownOnScreen()) return;
 	if (!wxIsMainThread()) throw _T("Error: trying to render from non-primary thread");
 
@@ -275,7 +279,7 @@ void VideoDisplay::Render(int frameNumber) try {
 	glDisable(GL_BLEND);
 	if (glGetError()) throw _T("Error disabling blending.");
 
-	videoOut->DisplayFrame(context->GetFrame(frameNumber), frameNumber, sw, sh);
+	videoOut->Render(sw, sh);
 
 	DrawTVEffects();
 
diff --git a/aegisub/src/video_display.h b/aegisub/src/video_display.h
index d5d3913b6..9563a07fd 100644
--- a/aegisub/src/video_display.h
+++ b/aegisub/src/video_display.h
@@ -145,7 +145,7 @@ public:
 	int GetFrame() const { return currentFrame; }
 	void SetFrameRange(int from, int to);
 
-	void Render(int frameNumber = -1);
+	void Render();
 
 	void ShowCursor(bool show);
 	void ConvertMouseCoords(int &x,int &y);
diff --git a/aegisub/src/video_out_gl.cpp b/aegisub/src/video_out_gl.cpp
index 1eeb21c81..47dbec387 100644
--- a/aegisub/src/video_out_gl.cpp
+++ b/aegisub/src/video_out_gl.cpp
@@ -111,8 +111,7 @@ VideoOutGL::VideoOutGL()
 	textureList(),
 	textureCount(0),
 	textureRows(0),
-	textureCols(0),
-	lastFrame(-1)
+	textureCols(0)
 { }
 
 /// @brief Runtime detection of required OpenGL capabilities
@@ -152,7 +151,7 @@ void VideoOutGL::DetectOpenGLCapabilities() {
 /// @param height The frame's height
 /// @param format The frame's format
 /// @param bpp The frame's bytes per pixel
-void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
+void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp, bool flipped) {
 	// Do nothing if the frame size and format are unchanged
 	if (width == frameWidth && height == frameHeight && format == frameFormat) return;
 	wxLogDebug("VideoOutGL::InitTextures: Video size: %dx%d\n", width, height);
@@ -222,6 +221,12 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
 			ti.texRight = 1.0f - ti.texLeft;
 			ti.texBottom = 1.0f - ti.texTop;
 
+			if (flipped) {
+				float t = ti.texTop;
+				ti.texTop = ti.texBottom;
+				ti.texBottom = ti.texTop;
+			}
+
 			// destW/H is the percent of the output which this texture covers
 			ti.destW = float(w) / width;
 			ti.destH = float(h) / height;
@@ -258,22 +263,34 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
 	frameHeight = height;
 	frameFormat = format;
 }
-
-void VideoOutGL::DisplayFrame(const AegiVideoFrame& frame, int frameNumber, int sw, int sh) {
+void VideoOutGL::UploadFrameData(const AegiVideoFrame& frame) {
 	if (frame.h == 0 || frame.w == 0) return;
 
-	if (frameNumber == -1) frameNumber = lastFrame;
-
-	glEnable(GL_TEXTURE_2D);
-	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glEnable(GL_TEXTURE_2d)", err);
-
 	GLuint format = frame.invertChannels ? GL_BGRA_EXT : GL_RGBA;
-	InitTextures(frame.w, frame.h, format, frame.GetBpp(0));
+	InitTextures(frame.w, frame.h, format, frame.GetBpp(0), frame.flipped);
 
 	// Set the row length, needed to be able to upload partial rows
 	glPixelStorei(GL_UNPACK_ROW_LENGTH, frame.w);
 	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glPixelStorei(GL_UNPACK_ROW_LENGTH, FrameWidth)", err);
 
+	for (unsigned i = 0; i < textureList.size(); i++) {
+		TextureInfo& ti = textureList[i];
+
+		glBindTexture(GL_TEXTURE_2D, ti.textureID);
+		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glBindTexture", err);
+
+		glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, ti.sourceW, ti.sourceH, format, GL_UNSIGNED_BYTE, frame.data[0] + ti.dataOffset);
+		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexSubImage2D", err);
+	}
+
+	glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glPixelStorei(GL_UNPACK_ROW_LENGTH, default)", err);
+}
+
+void VideoOutGL::Render(int sw, int sh) {
+	glEnable(GL_TEXTURE_2D);
+	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glEnable(GL_TEXTURE_2d)", err);
+
 	for (unsigned i = 0; i < textureList.size(); i++) {
 		TextureInfo& ti = textureList[i];
 
@@ -285,40 +302,19 @@ void VideoOutGL::DisplayFrame(const AegiVideoFrame& frame, int frameNumber, int
 		glBindTexture(GL_TEXTURE_2D, ti.textureID);
 		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glBindTexture", err);
 
-		if (lastFrame != frameNumber) {
-			glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, ti.sourceW, ti.sourceH, format, GL_UNSIGNED_BYTE, frame.data[0] + ti.dataOffset);
-			if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexSubImage2D", err);
-		}
-
 		glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glColor4f", err);
 
-		float top, bottom;
-		if (frame.flipped) {
-			top = ti.texBottom;
-			bottom = ti.texTop;
-		}
-		else {
-			top = ti.texTop;
-			bottom = ti.texBottom;
-		}
-
 		glBegin(GL_QUADS);
-			glTexCoord2f(ti.texLeft,  top);     glVertex2f(destX, destY);
-			glTexCoord2f(ti.texRight, top);     glVertex2f(destX + destW, destY);
-			glTexCoord2f(ti.texRight, bottom);  glVertex2f(destX + destW, destY + destH);
-			glTexCoord2f(ti.texLeft,  bottom);  glVertex2f(destX, destY + destH);
+			glTexCoord2f(ti.texLeft,  ti.texTop);     glVertex2f(destX, destY);
+			glTexCoord2f(ti.texRight, ti.texTop);     glVertex2f(destX + destW, destY);
+			glTexCoord2f(ti.texRight, ti.texBottom);  glVertex2f(destX + destW, destY + destH);
+			glTexCoord2f(ti.texLeft,  ti.texBottom);  glVertex2f(destX, destY + destH);
 		glEnd();
 		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"GL_QUADS", err);
 	}
-
-	glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
-	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glPixelStorei(GL_UNPACK_ROW_LENGTH, default)", err);
-
 	glDisable(GL_TEXTURE_2D);
 	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glDisable(GL_TEXTURE_2d)", err);
-
-	lastFrame = frameNumber;
 }
 
 VideoOutGL::~VideoOutGL() {
diff --git a/aegisub/src/video_out_gl.h b/aegisub/src/video_out_gl.h
index 17ece0649..24dca22fb 100644
--- a/aegisub/src/video_out_gl.h
+++ b/aegisub/src/video_out_gl.h
@@ -74,24 +74,20 @@ private:
 	int textureRows;
 	/// The number of columns of textures
 	int textureCols;
-	/// The frame currently displayed
-	int lastFrame;
 
 	void DetectOpenGLCapabilities();
-	void InitTextures(int width, int height, GLenum format, int bpp);
+	void InitTextures(int width, int height, GLenum format, int bpp, bool flipped);
 
 	VideoOutGL(const VideoOutGL &);
 	VideoOutGL& operator=(const VideoOutGL&);
 public:
-	/// @brief Render a frame
+	/// @brief Set the frame to be displayed when Render() is called
 	/// @param frame The frame to be displayed
-	/// @param frameNumber The frame number of the frame to be displayed
+	void UploadFrameData(const AegiVideoFrame& frame);
+	/// @brief Render a frame
 	/// @param sw The current script width
 	/// @param sh The current script height
-	void DisplayFrame(const AegiVideoFrame& frame, int frameNumber, int sw, int sh);
-
-	/// @brief Force the redisplay of the frame the next time DisplayFrame is called even if the frame number has not changed
-	void InvalidateFrame() { lastFrame = -1; }
+	void Render(int sw, int sh);
 
 	/// @brief Constructor
 	VideoOutGL();