diff --git a/Outputs/CRT/CRT.cpp b/Outputs/CRT/CRT.cpp
index 0943c596d..09a10a954 100644
--- a/Outputs/CRT/CRT.cpp
+++ b/Outputs/CRT/CRT.cpp
@@ -302,13 +302,24 @@ void CRT::output_blank(unsigned int number_of_cycles)
 void CRT::output_level(unsigned int number_of_cycles)
 {
 	_openGL_output_builder->lock_output();
-	Scan scan {
-		.type = Scan::Type::Level,
-		.number_of_cycles = number_of_cycles,
-		.tex_x = _openGL_output_builder->get_last_write_x_posititon(),
-		.tex_y = _openGL_output_builder->get_last_write_y_posititon()
-	};
-	output_scan(&scan);
+	if(!_openGL_output_builder->input_buffer_is_full())
+	{
+		Scan scan {
+			.type = Scan::Type::Level,
+			.number_of_cycles = number_of_cycles,
+			.tex_x = _openGL_output_builder->get_last_write_x_posititon(),
+			.tex_y = _openGL_output_builder->get_last_write_y_posititon()
+		};
+		output_scan(&scan);
+	}
+	else
+	{
+		Scan scan {
+			.type = Scan::Type::Blank,
+			.number_of_cycles = number_of_cycles
+		};
+		output_scan(&scan);
+	}
 	_openGL_output_builder->unlock_output();
 }
 
@@ -328,8 +339,9 @@ void CRT::output_colour_burst(unsigned int number_of_cycles, uint8_t phase, uint
 void CRT::output_data(unsigned int number_of_cycles, unsigned int source_divider)
 {
 	_openGL_output_builder->lock_output();
-	if(_openGL_output_builder->reduce_previous_allocation_to(number_of_cycles / source_divider))
+	if(!_openGL_output_builder->input_buffer_is_full())
 	{
+		_openGL_output_builder->reduce_previous_allocation_to(number_of_cycles / source_divider);
 		Scan scan {
 			.type = Scan::Type::Data,
 			.number_of_cycles = number_of_cycles,
@@ -341,7 +353,11 @@ void CRT::output_data(unsigned int number_of_cycles, unsigned int source_divider
 	}
 	else
 	{
-		output_blank(number_of_cycles);
+		Scan scan {
+			.type = Scan::Type::Blank,
+			.number_of_cycles = number_of_cycles
+		};
+		output_scan(&scan);
 	}
 	_openGL_output_builder->unlock_output();
 }
diff --git a/Outputs/CRT/Internals/CRTInputBufferBuilder.cpp b/Outputs/CRT/Internals/CRTInputBufferBuilder.cpp
index eecae0ee3..9cc3eae84 100644
--- a/Outputs/CRT/Internals/CRTInputBufferBuilder.cpp
+++ b/Outputs/CRT/Internals/CRTInputBufferBuilder.cpp
@@ -41,9 +41,14 @@ void CRTInputBufferBuilder::allocate_write_area(size_t required_length)
 	}
 }
 
-bool CRTInputBufferBuilder::reduce_previous_allocation_to(size_t actual_length)
+bool CRTInputBufferBuilder::is_full()
 {
-	if(_next_write_y_position == InputBufferBuilderHeight) return false;
+	return (_next_write_y_position == InputBufferBuilderHeight);
+}
+
+void CRTInputBufferBuilder::reduce_previous_allocation_to(size_t actual_length)
+{
+	if(_next_write_y_position == InputBufferBuilderHeight) return;
 
 	uint8_t *const image_pointer = _image.get();
 
@@ -68,8 +73,6 @@ bool CRTInputBufferBuilder::reduce_previous_allocation_to(size_t actual_length)
 
 	// return any allocated length that wasn't actually used to the available pool
 	_next_write_x_position -= (_last_allocation_amount - actual_length);
-
-	return true;
 }
 
 uint8_t *CRTInputBufferBuilder::get_image_pointer()
diff --git a/Outputs/CRT/Internals/CRTInputBufferBuilder.hpp b/Outputs/CRT/Internals/CRTInputBufferBuilder.hpp
index 55d3ea792..39afba9d0 100644
--- a/Outputs/CRT/Internals/CRTInputBufferBuilder.hpp
+++ b/Outputs/CRT/Internals/CRTInputBufferBuilder.hpp
@@ -23,7 +23,7 @@ struct CRTInputBufferBuilder {
 	CRTInputBufferBuilder(size_t bytes_per_pixel);
 
 	void allocate_write_area(size_t required_length);
-	bool reduce_previous_allocation_to(size_t actual_length);
+	void reduce_previous_allocation_to(size_t actual_length);
 
 	uint16_t get_and_finalise_current_line();
 	uint8_t *get_image_pointer();
@@ -36,6 +36,8 @@ struct CRTInputBufferBuilder {
 
 	size_t get_bytes_per_pixel();
 
+	bool is_full();
+
 	private:
 		// where pixel data will be put to the next time a write is requested
 		uint16_t _next_write_x_position, _next_write_y_position;
diff --git a/Outputs/CRT/Internals/CRTOpenGL.hpp b/Outputs/CRT/Internals/CRTOpenGL.hpp
index c4cc534d3..7c72cf909 100644
--- a/Outputs/CRT/Internals/CRTOpenGL.hpp
+++ b/Outputs/CRT/Internals/CRTOpenGL.hpp
@@ -173,9 +173,14 @@ class OpenGLOutputBuilder {
 			return _buffer_builder->get_write_target();
 		}
 
-		inline bool reduce_previous_allocation_to(size_t actual_length)
+		inline void reduce_previous_allocation_to(size_t actual_length)
 		{
-			return _buffer_builder->reduce_previous_allocation_to(actual_length);
+			_buffer_builder->reduce_previous_allocation_to(actual_length);
+		}
+
+		inline bool input_buffer_is_full()
+		{
+			return _buffer_builder->is_full();
 		}
 
 		inline uint16_t get_last_write_x_posititon()