diff --git a/aegisub/gl_wrap.cpp b/aegisub/gl_wrap.cpp
index 9369ebadb..d230acc25 100644
--- a/aegisub/gl_wrap.cpp
+++ b/aegisub/gl_wrap.cpp
@@ -408,7 +408,7 @@ GLuint OpenGLWrapper::CreateYV12PixelShader() {
 
 /////////////////////////////////////
 // Create YV12->RGB32 Shader Program
-GLuint OpenGLWrapper::CreateYV12Shader(float tw,float th) {
+GLuint OpenGLWrapper::CreateYV12Shader(float tw,float th,float tws) {
 	// Create vertex shader
 	GLuint ver = OpenGLWrapper::CreateStandardVertexShader();
 	if (glGetError() != 0) throw _T("Error creating generic vertex shader");
@@ -431,7 +431,7 @@ GLuint OpenGLWrapper::CreateYV12Shader(float tw,float th) {
 	address = glGetUniformLocationARB(program,"off1");
 	glUniform2fARB(address, 0.0f, th);
 	address = glGetUniformLocationARB(program,"off2");
-	glUniform2fARB(address, tw*0.5f, th);
+	glUniform2fARB(address, tws, th);
 
 	// Return shader
 	return program;
diff --git a/aegisub/gl_wrap.h b/aegisub/gl_wrap.h
index 8daa998de..121fc8b40 100644
--- a/aegisub/gl_wrap.h
+++ b/aegisub/gl_wrap.h
@@ -66,5 +66,5 @@ public:
 	static bool ShadersAvailable();
 	static void SetShader(GLuint i);
 	static void DestroyShaderProgram(GLuint i);
-	static GLuint CreateYV12Shader(float tw,float th);
+	static GLuint CreateYV12Shader(float tw,float th,float tws);
 };
diff --git a/aegisub/video_context.cpp b/aegisub/video_context.cpp
index a014cef0d..8dc224b6f 100644
--- a/aegisub/video_context.cpp
+++ b/aegisub/video_context.cpp
@@ -452,7 +452,7 @@ GLuint VideoContext::GetFrameAsTexture(int n) {
 		// Load image data into texture
 		int height = frame.h;
 		if (frame.format == FORMAT_YV12) height = height * 3 / 2;
-		int tw = SmallestPowerOf2(frame.w);
+		int tw = SmallestPowerOf2(MAX(frame.pitch[0],frame.pitch[1]+frame.pitch[2]));
 		int th = SmallestPowerOf2(height);
 		texW = float(frame.w)/float(tw);
 		texH = float(frame.h)/float(th);
@@ -469,12 +469,12 @@ GLuint VideoContext::GetFrameAsTexture(int n) {
 
 		// Create shader if necessary
 		if (frame.format == FORMAT_YV12 && yv12shader == 0) {
-			yv12shader = OpenGLWrapper::CreateYV12Shader(texW,texH);
+			yv12shader = OpenGLWrapper::CreateYV12Shader(texW,texH,float(frame.pitch[1])/float(tw));
 		}
 	}
 	
 	// Load texture data
-	glTexSubImage2D(GL_TEXTURE_2D,0,0,0,frame.w,frame.h,format,GL_UNSIGNED_BYTE,frame.data[0]);
+	glTexSubImage2D(GL_TEXTURE_2D,0,0,0,frame.pitch[0],frame.h,format,GL_UNSIGNED_BYTE,frame.data[0]);
 	if (glGetError() != 0) throw _T("Error uploading primary plane");
 
 	// UV planes for YV12
@@ -485,9 +485,9 @@ GLuint VideoContext::GetFrameAsTexture(int n) {
 			u = 2;
 			v = 1;
 		}
-		glTexSubImage2D(GL_TEXTURE_2D,0,0,frame.h,frame.w/2,frame.h/2,format,GL_UNSIGNED_BYTE,frame.data[u]);
+		glTexSubImage2D(GL_TEXTURE_2D,0,0,frame.h,frame.pitch[1],frame.h/2,format,GL_UNSIGNED_BYTE,frame.data[u]);
 		if (glGetError() != 0) throw _T("Error uploading U plane.");
-		glTexSubImage2D(GL_TEXTURE_2D,0,frame.w/2,frame.h,frame.w/2,frame.h/2,format,GL_UNSIGNED_BYTE,frame.data[v]);
+		glTexSubImage2D(GL_TEXTURE_2D,0,frame.pitch[1],frame.h,frame.pitch[2],frame.h/2,format,GL_UNSIGNED_BYTE,frame.data[v]);
 		if (glGetError() != 0) throw _T("Error uploadinv V plane.");
 	}
 
diff --git a/aegisub/video_frame.cpp b/aegisub/video_frame.cpp
index 282558c57..95161511a 100644
--- a/aegisub/video_frame.cpp
+++ b/aegisub/video_frame.cpp
@@ -49,7 +49,7 @@ void AegiVideoFrame::Reset() {
 	memSize = 0;
 	w = 0;
 	h = 0;
-	format = FORMAT_RGB24;
+	format = FORMAT_NONE;
 	flipped = false;
 	cppAlloc = true;
 	invertChannels = true;
@@ -85,10 +85,20 @@ AegiVideoFrame::AegiVideoFrame(int width,int height,VideoFrameFormat fmt) {
 ////////////
 // Allocate
 void AegiVideoFrame::Allocate() {
+	// Check consistency
+	wxASSERT(pitch[0] > 0 && pitch[0] < 10000);
+	wxASSERT(w > 0 && w < 10000);
+	wxASSERT(h > 0 && h < 10000);
+	wxASSERT(format != FORMAT_NONE);
+
 	// Get size
 	int height = h;
 	unsigned int size;
-	if (format == FORMAT_YV12) size = pitch[0] * height * 3 / 2;
+	if (format == FORMAT_YV12) {
+		wxASSERT(pitch[1] > 0 && pitch[1] < 10000);
+		wxASSERT(pitch[2] > 0 && pitch[2] < 10000);
+		size = pitch[0]*height + (pitch[1]+pitch[2])*height/2;
+	}
 	else size = pitch[0] * height;
 
 	// Reallocate, if necessary
@@ -104,11 +114,12 @@ void AegiVideoFrame::Allocate() {
 		// Planar
 		if (format == FORMAT_YV12) {
 			data[1] = data[0] + (pitch[0]*height);
-			data[2] = data[0] + (pitch[0]*height*5/4);
+			data[2] = data[0] + (pitch[0]*height+pitch[1]*height/2);
 		}
-	}
 
-	cppAlloc = true;
+		// Flag as allocated by C++
+		cppAlloc = true;
+	}
 }
 
 
diff --git a/aegisub/video_frame.h b/aegisub/video_frame.h
index a33603b69..e0c3dea84 100644
--- a/aegisub/video_frame.h
+++ b/aegisub/video_frame.h
@@ -40,6 +40,7 @@
 //////////////////////
 // Video Frame format
 enum VideoFrameFormat {
+	FORMAT_NONE,
 	FORMAT_RGB24,
 	FORMAT_RGB32,
 	FORMAT_YUY2,
diff --git a/aegisub/video_provider_dshow.cpp b/aegisub/video_provider_dshow.cpp
index 7b4107ae3..1fc7a7edc 100644
--- a/aegisub/video_provider_dshow.cpp
+++ b/aegisub/video_provider_dshow.cpp
@@ -419,34 +419,25 @@ void DirectShowVideoProvider::ReadFrame(long long timestamp, unsigned format, un
 	df->frame.w = width;
 	df->frame.h = height;
 	df->frame.pitch[0] = stride;
+	if (format == IVS_YV12) {
+		df->frame.pitch[1] = stride/2;
+		df->frame.pitch[2] = stride/2;
+	}
 	df->frame.cppAlloc = false;
 	df->frame.invertChannels = true;
 
-	// Planar
-	if (format == IVS_YUY2) {
-		df->frame.format = FORMAT_YUY2;
+	// Set format
+	if (format == IVS_RGB24) df->frame.format = FORMAT_RGB24;
+	else if (format == IVS_RGB32) df->frame.format = FORMAT_RGB32;
+	else if (format == IVS_YV12) {
+		df->frame.format = FORMAT_YV12;
+		df->frame.invertChannels = true;
 	}
+	else if (format == IVS_YUY2) df->frame.format = FORMAT_YUY2;
 
-	// Interleaved
-	else {
-		// Set format
-		if (format == IVS_RGB24) df->frame.format = FORMAT_RGB24;
-		else if (format == IVS_RGB32) df->frame.format = FORMAT_RGB32;
-		else if (format == IVS_YV12) df->frame.format = FORMAT_YV12;
-
-		// Allocate
-		unsigned int datalen = stride*height;
-		df->frame.Allocate();
-
-		// Prepare data for YV12
-		if (format == IVS_YV12) {
-			datalen = datalen * 3 / 2;
-			df->frame.invertChannels = true;
-		}
-
-		// Copy
-		memcpy(df->frame.data[0],src,datalen);
-	}
+	// Allocate and copy data
+	df->frame.Allocate();
+	memcpy(df->frame.data[0],src,df->frame.pitch[0]*height + (df->frame.pitch[1]+df->frame.pitch[2])*height/2);
 }
 
 
diff --git a/aegisub/video_provider_lavc.cpp b/aegisub/video_provider_lavc.cpp
index eea6ffcc9..c9b42a611 100644
--- a/aegisub/video_provider_lavc.cpp
+++ b/aegisub/video_provider_lavc.cpp
@@ -85,6 +85,7 @@ LAVCVideoProvider::LAVCVideoProvider(wxString filename,double fps) {
 	validFrame = false;
 
 	// Load
+	SetCacheMax(8);
 	LoadVideo(filename,fps);
 }
 
@@ -389,21 +390,24 @@ const AegiVideoFrame LAVCVideoProvider::DoGetFrame(int n) {
 		switch (format) {
 			case PIX_FMT_BGR24: final.invertChannels = true;
 			case PIX_FMT_RGB24: final.format = FORMAT_RGB24; break;
+			#ifdef __WINDOWS__
 			case PIX_FMT_BGR32: final.invertChannels = true;
+			#endif
 			case PIX_FMT_RGB32: final.format = FORMAT_RGB32; break;
 			case PIX_FMT_YUYV422: final.format = FORMAT_YUY2; break;
 			case PIX_FMT_YUV420P: final.format = FORMAT_YV12; break;
+			default: throw _T("ffmpeg returned an unknown frame format.");
 		}
 
 		// Allocate
-		final.pitch[0] = final.w * final.GetBpp();
+		for (int i=0;i<4;i++) final.pitch[i] = frame->linesize[i];
 		final.Allocate();
 
 		// Copy data
 		if (final.format == FORMAT_YV12) {
-			memcpy(final.data[0],frame->data[0],final.w * final.h);
-			memcpy(final.data[1],frame->data[1],final.w * final.h / 4);
-			memcpy(final.data[2],frame->data[2],final.w * final.h / 4);
+			memcpy(final.data[0],frame->data[0],frame->linesize[0] * final.h);
+			memcpy(final.data[1],frame->data[1],frame->linesize[1] * final.h / 2);
+			memcpy(final.data[2],frame->data[2],frame->linesize[2] * final.h / 2);
 		}
 		else memcpy(final.data[0],frame->data[0],size);
 	}