diff --git a/effects/boxblur.frag b/effects/boxblur.frag
index 626cc1f7e..3da0380bc 100644
--- a/effects/boxblur.frag
+++ b/effects/boxblur.frag
@@ -6,24 +6,28 @@ uniform float radius;
 uniform vec2 resolution;
 uniform bool horiz_blur;
 uniform bool vert_blur;
+uniform int iteration;
+
+varying vec2 vTexCoord;
 
 void main(void) {
 	float rad = ceil(radius);
-	float x_rad = (horiz_blur) ? rad : 0.5;
-	float y_rad = (vert_blur) ? rad : 0.5;
-	vec2 texCoord = gl_FragCoord.xy/resolution;
-	if (radius == 0.0 || (!horiz_blur && !vert_blur)) {
-		gl_FragColor = texture2D(image, texCoord);
-	} else {
-		float divider = 1.0;
-		if (horiz_blur) divider /= rad;
-		if (vert_blur) divider /= rad;
-		vec4 color = vec4(0.0);
-		for (float x=-x_rad+0.5;x<=x_rad;x+=2.0) {					
-			for (float y=-y_rad+0.5;y<=y_rad;y+=2.0) {
-				color += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y+y))/resolution)*(divider);
-			}
+	
+	float divider = 1.0 / rad;		
+	vec4 color = vec4(0.0);
+	bool radius_is_zero = (rad == 0.0);
+
+	if (iteration == 0 && horiz_blur && !radius_is_zero) {
+		for (float x=-rad+0.5;x<=rad;x+=2.0) {					
+			color += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y))/resolution)*(divider);
 		}
 		gl_FragColor = color;
+	} else if (iteration == 1 && vert_blur && !radius_is_zero) {
+		for (float x=-rad+0.5;x<=rad;x+=2.0) {					
+			color += texture2D(image, (vec2(gl_FragCoord.x, gl_FragCoord.y+x))/resolution)*(divider);
+		}
+		gl_FragColor = color;
+	} else {
+		gl_FragColor = texture2D(image, vTexCoord);
 	}
 }
\ No newline at end of file
diff --git a/effects/boxblur.xml b/effects/boxblur.xml
index 1dd4cb45e..a6c0cb491 100644
--- a/effects/boxblur.xml
+++ b/effects/boxblur.xml
@@ -9,5 +9,5 @@
 	<row name="Vertical">
 		<field type="bool" default="1" id="vert_blur"/>
 	</row>
-	<shader vert="common.vert" frag="boxblur.frag"/>
+	<shader vert="common.vert" frag="boxblur.frag" iterations="2"/>
 </effect>
\ No newline at end of file
diff --git a/effects/gaussianblur.frag b/effects/gaussianblur.frag
index b5dd4e8c9..80aaedb18 100644
--- a/effects/gaussianblur.frag
+++ b/effects/gaussianblur.frag
@@ -4,13 +4,14 @@
 
 uniform sampler2D image;
 
-uniform float radius;
+// uniform float radius;
 uniform float sigma;
 uniform vec2 resolution;
 uniform bool horiz_blur;
 uniform bool vert_blur;
+uniform int iteration;
 
-uniform bool opt;
+varying vec2 vTexCoord;
 
 float gaussian(float x, float sigma) {
 	return (1.0/(sigma*sqrt(2.0*M_PI)))*exp(-0.5*pow(x/sigma, 2.0));
@@ -21,28 +22,33 @@ float gaussian2(float x, float y, float sigma) {
 }
 
 void main(void) {
-	if (radius == 0.0 || sigma == 0.0 || (!horiz_blur && !vert_blur)) {
-		gl_FragColor = texture2D(image, gl_FragCoord.xy/resolution);
-	} else {
-		float rad = ceil(radius);
-		float x_rad = horiz_blur ? rad : 0.5;
-		float y_rad = vert_blur ? rad : 0.5;
+	float rad = ceil(sigma);
 
-		float sum = 0.0;
+	float sum = 0.0;
 
-		for (float x=-x_rad+0.5;x<=x_rad;x+=2.0) {
-			for (float y=-y_rad+0.5;y<=y_rad;y+=2.0) {
-				sum += gaussian2(x, y, sigma);
-			}
+	vec4 color = vec4(0.0);
+
+	bool radius_is_zero = (rad == 0.0);
+
+	if (!radius_is_zero) {
+		for (float x=-rad+0.5;x<=rad;x+=2.0) {
+			sum += gaussian2(x, 0.0, sigma);
 		}
+	}
 
-		vec4 color = vec4(0.0);
-		for (float x=-x_rad+0.5;x<=x_rad;x+=2.0) {
-			for (float y=-y_rad+0.5;y<=y_rad;y+=2.0) {
-				float weight = (gaussian2(x, y, sigma)/sum);
-				color += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y+y))/resolution)*(weight);
-			}
+	if (iteration == 0 && horiz_blur && !radius_is_zero) {
+		for (float x=-rad+0.5;x<=rad;x+=2.0) {
+			float weight = (gaussian2(x, 0.0, sigma)/sum);
+			color += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y))/resolution)*(weight);
 		}
 		gl_FragColor = color;
-	}	
+	} else if (iteration == 1 && vert_blur && !radius_is_zero) {
+		for (float x=-rad+0.5;x<=rad;x+=2.0) {
+			float weight = (gaussian2(0.0, x, sigma)/sum);
+			color += texture2D(image, (vec2(gl_FragCoord.x, gl_FragCoord.y+x))/resolution)*(weight);
+		}
+		gl_FragColor = color;
+	} else {
+		gl_FragColor = texture2D(image, vTexCoord);
+	}
 }
\ No newline at end of file
diff --git a/effects/gaussianblur.xml b/effects/gaussianblur.xml
index 76a6bc82a..d0d669f6d 100644
--- a/effects/gaussianblur.xml
+++ b/effects/gaussianblur.xml
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <effect name="Gaussian Blur" category="Blur">
-	<row name="Radius">
+	<!-- <row name="Radius">
 		<field type="double" min="0" default="10" id="radius"/>
-	</row>
+	</row> -->
 	<row name="Sigma">
 		<field type="double" min="0" default="5.5" id="sigma"/>
 	</row>
@@ -12,8 +12,5 @@
 	<row name="Vertical">
 		<field type="bool" default="1" id="vert_blur"/>
 	</row>
-	<!-- <row name="Opt">
-		<field type="bool" default="0" id="opt"/>
-	</row> -->
-	<shader vert="common.vert" frag="gaussianblur.frag"/>
+	<shader vert="common.vert" frag="gaussianblur.frag" iterations="2"/>
 </effect>
\ No newline at end of file
diff --git a/project/effect.cpp b/project/effect.cpp
index 2beee31f7..7bb583bb4 100644
--- a/project/effect.cpp
+++ b/project/effect.cpp
@@ -102,7 +102,8 @@ Effect::Effect(Clip* c, const EffectMeta *em) :
 	texture(nullptr),
 	enable_always_update(false),
 	isOpen(false),
-	bound(false)
+	bound(false),
+	iterations(1)
 {
 	// set up base UI
 	container = new CollapsibleWidget();
@@ -276,6 +277,8 @@ Effect::Effect(Clip* c, const EffectMeta *em) :
 								vertPath = attr.value().toString();
 							} else if (attr.name() == "frag") {
 								fragPath = attr.value().toString();
+							} else if (attr.name() == "iterations") {
+								setIterations(attr.value().toInt());
 							}
 						}
 					}/* else if (reader.name() == "superimpose" && reader.isStartElement()) {
@@ -695,6 +698,14 @@ void Effect::endEffect() {
 	bound = false;
 }
 
+int Effect::getIterations() {
+	return iterations;
+}
+
+void Effect::setIterations(int i) {
+	iterations = i;
+}
+
 void Effect::process_image(double, uint8_t *, uint8_t *, int){}
 
 Effect* Effect::copy(Clip* c) {
@@ -704,9 +715,10 @@ Effect* Effect::copy(Clip* c) {
 	return copy;
 }
 
-void Effect::process_shader(double timecode, GLTextureCoords&) {
+void Effect::process_shader(double timecode, GLTextureCoords&, int iteration) {
 	glslProgram->setUniformValue("resolution", parent_clip->getWidth(), parent_clip->getHeight());
 	glslProgram->setUniformValue("time", GLfloat(timecode));
+	glslProgram->setUniformValue("iteration", iteration);
 
 	for (int i=0;i<rows.size();i++) {
 		EffectRow* row = rows.at(i);
diff --git a/project/effect.h b/project/effect.h
index dd681dc98..22a8213bd 100644
--- a/project/effect.h
+++ b/project/effect.h
@@ -193,7 +193,7 @@ public:
 	const char* ffmpeg_filter;
 
 	virtual void process_image(double timecode, uint8_t* input, uint8_t* output, int size);
-	virtual void process_shader(double timecode, GLTextureCoords&);
+	virtual void process_shader(double timecode, GLTextureCoords&, int iteration);
 	virtual void process_coords(double timecode, GLTextureCoords& coords, int data);
 	virtual GLuint process_superimpose(double timecode);
 	virtual void process_audio(double timecode_start, double timecode_end, quint8* samples, int nb_bytes, int channel_count);
@@ -231,6 +231,7 @@ private:
 	QGridLayout* ui_layout;
 	QWidget* ui;
 	bool bound;
+	int iterations;
 
 	// superimpose functions
 	virtual void redraw(double timecode);
diff --git a/ui/renderfunctions.cpp b/ui/renderfunctions.cpp
index 9180385d4..cead4ea51 100644
--- a/ui/renderfunctions.cpp
+++ b/ui/renderfunctions.cpp
@@ -97,9 +97,11 @@ void process_effect(Clip* c,
 		if (can_process_shaders || e->enable_superimpose) {
 			e->startEffect();
 			if (can_process_shaders && e->is_glsl_linked()) {
-				e->process_shader(timecode, coords);
-				composite_texture = draw_clip(c->fbo[fbo_switcher], composite_texture, true);
-				fbo_switcher = !fbo_switcher;
+				for (int i=0;i<e->getIterations();i++) {
+					e->process_shader(timecode, coords, i);
+					composite_texture = draw_clip(c->fbo[fbo_switcher], composite_texture, true);
+					fbo_switcher = !fbo_switcher;
+				}
 			}
 			if (e->enable_superimpose) {
 				GLuint superimpose_texture = e->process_superimpose(timecode);