noise blur experiment based on https://www.shadertoy.com/view/XtGGzz

blur.glsl

#define SPREAD 10.0
#define OFFSET 1.0

vec2 hash23(vec3 p3) {
	p3 = fract(p3 * vec3(443.897, 441.423, 437.195));
	p3 += dot(p3, p3.yzx+19.19);
	return fract(vec2((p3.x + p3.y)*p3.z, (p3.x+p3.z)*p3.y))*2.0-1.0;
}

vec4 sample(vec2 uv, float offset, float n, bool dancing) {
	float z_offset = 0.0;
	if (dancing)
		z_offset = mod(iGlobalTime, 1.0);
	vec2 p0 = uv+hash23(vec3(uv,z_offset+offset))/iResolution.xy*(SPREAD+OFFSET*n);

	return texture2D(iChannel0, p0);
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
	vec2 uv = fragCoord.xy / iResolution.xy;
	bool dancing = uv.y < 0.5;

	// 1, 2 and 4 samples respectively.
	if (uv.x <= 1.0/3.0) {
		fragColor = sample(uv, 0.0, 0.0, dancing);
	}
	else if (uv.x > 1.0/3.0 && uv.x < 2.0/3.0) {
		fragColor  = sample(uv, 0.0, 0.0, dancing);
		fragColor += sample(uv, 0.5, 1.0, dancing);
		fragColor /= 2.0;
	}
	else {
		fragColor  = sample(uv, 0.0, 0.0, dancing);
		fragColor += sample(uv, 0.5, 1.0, dancing);
		fragColor += sample(uv, 1.0, 2.0, dancing);
		fragColor += sample(uv, 1.5, 3.0, dancing);
		fragColor /= 4.0;
	}
}