diff --git a/Machines/ZX8081/Video.cpp b/Machines/ZX8081/Video.cpp
index 703086c01..0d127ae2d 100644
--- a/Machines/ZX8081/Video.cpp
+++ b/Machines/ZX8081/Video.cpp
@@ -13,12 +13,13 @@ using namespace ZX8081;
 Video::Video() :
 	crt_(new Outputs::CRT::CRT(207 * 2, 1, Outputs::CRT::DisplayType::PAL50, 1)) {
 
-	// Set a composite sampling function that assumes 8bpp input grayscale.
-	// TODO: lessen this to 1bpp.
+	// Set a composite sampling function that assumes 1bpp input.
 	crt_->set_composite_sampling_function(
 		"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
 		"{"
-			"return float(texture(texID, coordinate).r) / 255.0;"
+			"uint texValue = texture(sampler, coordinate).r;"
+			"texValue <<= int(icoordinate.x * 8) & 7;"
+			"return float(texValue & 128u);"
 		"}");
 
 	// Show only the centre 80% of the TV frame.
@@ -45,10 +46,10 @@ void Video::flush(bool next_sync) {
 		if(line_data_) {
 			// If there is output data queued, output it either if it's being interrupted by
 			// sync, or if we're past its end anyway. Otherwise let it be.
-			unsigned int data_length = static_cast<unsigned int>(line_data_pointer_ - line_data_);
+			unsigned int data_length = static_cast<unsigned int>(line_data_pointer_ - line_data_) * 8;
 			if(data_length < cycles_since_update_ || next_sync) {
 				unsigned int output_length = std::min(data_length, cycles_since_update_);
-				crt_->output_data(output_length, 1);
+				crt_->output_data(output_length, 8);
 				line_data_pointer_ = line_data_ = nullptr;
 				cycles_since_update_ -= output_length;
 			} else return;
@@ -79,25 +80,21 @@ void Video::output_byte(uint8_t byte) {
 
 	// Grab a buffer if one isn't already available.
 	if(!line_data_) {
-		line_data_pointer_ = line_data_ = crt_->allocate_write_area(320);
+		line_data_pointer_ = line_data_ = crt_->allocate_write_area(40);
 	}
 
 	// If a buffer was obtained, serialise the new pixels.
 	if(line_data_) {
 		// If the buffer is full, output it now and obtain a new one
-		if(line_data_pointer_ - line_data_ == 320) {
-			crt_->output_data(320, 1);
+		if(line_data_pointer_ - line_data_ == 40) {
+			crt_->output_data(40, 8);
 			cycles_since_update_ -= 320;
-			line_data_pointer_ = line_data_ = crt_->allocate_write_area(320);
+			line_data_pointer_ = line_data_ = crt_->allocate_write_area(40);
 			if(!line_data_) return;
 		}
 
-		uint8_t mask = 0x80;
-		for(int c = 0; c < 8; c++) {
-			line_data_pointer_[c] = (byte & mask) ? 0xff : 0x00;
-			mask >>= 1;
-		}
-		line_data_pointer_ += 8;
+		line_data_pointer_[0] = byte;
+		line_data_pointer_ ++;
 	}
 }