diff --git a/Components/6560/6560.hpp b/Components/6560/6560.hpp
index 7ab74c41a..395047d9a 100644
--- a/Components/6560/6560.hpp
+++ b/Components/6560/6560.hpp
@@ -54,14 +54,15 @@ template <class T> class MOS6560 {
 				audio_generator_(audio_queue_),
 				speaker_(audio_generator_)
 		{
-			crt_->set_composite_sampling_function(
-				"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)"
+			crt_->set_svideo_sampling_function(
+				"vec2 svideo_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase)"
 				"{"
 					"vec2 yc = texture(texID, coordinate).rg / vec2(255.0);"
-					"float phaseOffset = 6.283185308 * 2.0 * yc.y;"
 
-					"float chroma = cos(phase + phaseOffset);"
-					"return mix(yc.x, step(yc.y, 0.75) * chroma, amplitude);"
+					"float phaseOffset = 6.283185308 * 2.0 * yc.y;"
+					"float chroma = step(yc.y, 0.75) * cos(phase + phaseOffset);"
+
+					"return vec2(yc.x, chroma);"
 				"}");
 
 			// default to NTSC
diff --git a/Machines/Atari2600/TIA.cpp b/Machines/Atari2600/TIA.cpp
index 63d637bf6..f1f8b1437 100644
--- a/Machines/Atari2600/TIA.cpp
+++ b/Machines/Atari2600/TIA.cpp
@@ -123,20 +123,20 @@ void TIA::set_output_mode(Atari2600::TIA::OutputMode output_mode) {
 	Outputs::CRT::DisplayType display_type;
 
 	if(output_mode == OutputMode::NTSC) {
-		crt_->set_composite_sampling_function(
-			"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)"
+		crt_->set_svideo_sampling_function(
+			"vec2 svideo_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase)"
 			"{"
 				"uint c = texture(texID, coordinate).r;"
 				"uint y = c & 14u;"
 				"uint iPhase = (c >> 4);"
 
 				"float phaseOffset = 6.283185308 * float(iPhase) / 13.0 + 5.074880441076923;"
-				"return mix(float(y) / 14.0, step(1, iPhase) * cos(phase + phaseOffset), amplitude);"
+				"return vec2(float(y) / 14.0, step(1, iPhase) * cos(phase + phaseOffset));"
 			"}");
 		display_type = Outputs::CRT::DisplayType::NTSC60;
 	} else {
-		crt_->set_composite_sampling_function(
-			"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)"
+		crt_->set_svideo_sampling_function(
+			"vec2 svideo_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase)"
 			"{"
 				"uint c = texture(texID, coordinate).r;"
 				"uint y = c & 14u;"
@@ -145,7 +145,7 @@ void TIA::set_output_mode(Atari2600::TIA::OutputMode output_mode) {
 				"uint direction = iPhase & 1u;"
 				"float phaseOffset = float(7u - direction) + (float(direction) - 0.5) * 2.0 * float(iPhase >> 1);"
 				"phaseOffset *= 6.283185308 / 12.0;"
-				"return mix(float(y) / 14.0, step(4, (iPhase + 2u) & 15u) * cos(phase + phaseOffset), amplitude);"
+				"return vec2(float(y) / 14.0, step(4, (iPhase + 2u) & 15u) * cos(phase + phaseOffset));"
 			"}");
 		display_type = Outputs::CRT::DisplayType::PAL50;
 	}
diff --git a/Outputs/CRT/Internals/Shaders/IntermediateShader.cpp b/Outputs/CRT/Internals/Shaders/IntermediateShader.cpp
index f989d725f..8bb35bbe2 100644
--- a/Outputs/CRT/Internals/Shaders/IntermediateShader.cpp
+++ b/Outputs/CRT/Internals/Shaders/IntermediateShader.cpp
@@ -180,7 +180,7 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_svideo_source_shade
 		fragment_shader
 			<< rgb_shader <<
 			"uniform mat3 rgbToLumaChroma;"
-			"float svideo_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase)"
+			"vec2 svideo_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase)"
 			"{"
 				"vec3 rgbColour = clamp(rgb_sample(texID, coordinate, iCoordinate), vec3(0.0), vec3(1.0));"
 				"vec3 lumaChromaColour = rgbToLumaChroma * rgbColour;"
@@ -194,7 +194,7 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_svideo_source_shade
 		"{"
 			"vec2 sample = svideo_sample(texID, inputPositionsVarying[5], iInputPositionVarying, phaseAndAmplitudeVarying.x);"
 			"vec2 quadrature = vec2(cos(phaseAndAmplitudeVarying.x), -sin(phaseAndAmplitudeVarying.x));"
-			"fragColour = vec3(luminance, vec2(0.5) + (chrominance * quadrature));"
+			"fragColour = vec3(sample.x, vec2(0.5) + (sample.y * quadrature));"
 		"}";
 
 	return make_shader(fragment_shader.str(), true, true);