diff --git a/Makefile b/Makefile
index 427b63b..2916fd0 100644
--- a/Makefile
+++ b/Makefile
@@ -20,7 +20,7 @@ test: all
 clean:
 	rm -f encode decode *.o {8000,11025,40000,44100,48000}.{ppm,wav}
 
-encode: encode.o mmap_file.o
+encode: encode.o mmap_file.o yuv.o
 
-decode: decode.o mmap_file.o pcm.o wav.o alsa.o window.o ddc.o delay.o yuv.c
+decode: decode.o mmap_file.o pcm.o wav.o alsa.o window.o ddc.o delay.o yuv.o
 
diff --git a/decode.c b/decode.c
index 6671a69..1457633 100644
--- a/decode.c
+++ b/decode.c
@@ -11,30 +11,7 @@
 #include "ddc.h"
 #include "delay.h"
 #include "yuv.h"
-
-int64_t gcd(int64_t a, int64_t b)
-{
-	int64_t c;
-	while ((c = a % b)) {
-		a = b;
-		b = c;
-	}
-	return b;
-}
-
-float fclampf(float x, float min, float max)
-{
-	float tmp = x < min ? min : x;
-	return tmp > max ? max : tmp;
-}
-
-char *string_time(char *fmt)
-{
-	static char s[64];
-	time_t now = time(0);
-	strftime(s, sizeof(s), fmt, localtime(&now));
-	return s;
-}
+#include "utils.h"
 
 void process_line(uint8_t *pixel, uint8_t *y_pixel, uint8_t *uv_pixel, int y_width, int uv_width, int width, int height, int n)
 {
diff --git a/encode.c b/encode.c
index 6dec237..41ef1de 100644
--- a/encode.c
+++ b/encode.c
@@ -7,43 +7,8 @@
 #include <complex.h> 
 #include <limits.h>
 #include "mmap_file.h"
-
-float limit(float min, float max, float x)
-{
-	float tmp = x < min ? min : x;
-	return tmp > max ? max : tmp;
-}
-float lerp(float a, float b, float x)
-{
-	return a - a * x + b * x;
-}
-uint8_t R_YUV(uint8_t Y, uint8_t U, uint8_t V)
-{
-	(void)U;
-	return limit(0.0, 255.0, 0.003906 * ((298.082 * (Y - 16.0)) + (408.583 * (V - 128.0))));
-}
-uint8_t G_YUV(uint8_t Y, uint8_t U, uint8_t V)
-{
-	return limit(0.0, 255.0, 0.003906 * ((298.082 * (Y - 16.0)) + (-100.291 * (U - 128.0)) + (-208.12 * (V - 128.0))));
-}
-uint8_t B_YUV(uint8_t Y, uint8_t U, uint8_t V)
-{
-	(void)V;
-	return limit(0.0, 255.0, 0.003906 * ((298.082 * (Y - 16.0)) + (516.411 * (U - 128.0))));
-}
-
-uint8_t Y_RGB(uint8_t R, uint8_t G, uint8_t B)
-{
-	return limit(0.0, 255.0, 16.0 + (0.003906 * ((65.738 * R) + (129.057 * G) + (25.064 * B))));
-}
-uint8_t V_RGB(uint8_t R, uint8_t G, uint8_t B)
-{
-	return limit(0.0, 255.0, 128.0 + (0.003906 * ((112.439 * R) + (-94.154 * G) + (-18.285 * B))));
-}
-uint8_t U_RGB(uint8_t R, uint8_t G, uint8_t B)
-{
-	return limit(0.0, 255.0, 128.0 + (0.003906 * ((-37.945 * R) + (-74.494 * G) + (112.439 * B))));
-}
+#include "yuv.h"
+#include "utils.h"
 
 typedef struct {
 	uint32_t ChunkID;
@@ -145,9 +110,9 @@ int main(int argc, char **argv)
 		}
 		// Y
 		for (int ticks = 0; ticks < (int)(0.088 * rate); ticks++) {
-			float xf = limit(0.0, 319.0, (320.0 * (float)ticks) / (0.088 * rate));
+			float xf = fclampf((320.0 * (float)ticks) / (0.088 * rate), 0.0, 319.0);
 			int x0 = xf;
-			int x1 = limit(0.0, 319.0, x0 + 1);
+			int x1 = fclampf(x0 + 1, 0.0, 319.0);
 			int off0 = 3 * y * width + 3 * x0;
 			int off1 = 3 * y * width + 3 * x1;
 			uint8_t R0 = pixel[off0 + 0];
@@ -156,9 +121,9 @@ int main(int argc, char **argv)
 			uint8_t R1 = pixel[off1 + 0];
 			uint8_t G1 = pixel[off1 + 1];
 			uint8_t B1 = pixel[off1 + 2];
-			uint8_t R = lerp(R0, R1, xf - (float)x0);
-			uint8_t G = lerp(G0, G1, xf - (float)x0);
-			uint8_t B = lerp(B0, B1, xf - (float)x0);
+			uint8_t R = flerpf(R0, R1, xf - (float)x0);
+			uint8_t G = flerpf(G0, G1, xf - (float)x0);
+			uint8_t B = flerpf(B0, B1, xf - (float)x0);
 			add_freq(1500.0 + 800.0 * Y_RGB(R, G, B) / 255.0);
 		}
 		// EVEN
@@ -171,9 +136,9 @@ int main(int argc, char **argv)
 		}
 		// V
 		for (int ticks = 0; ticks < (int)(0.044 * rate); ticks++) {
-			float xf = limit(0.0, 159.0, (160.0 * (float)ticks) / (0.044 * rate));
+			float xf = fclampf((160.0 * (float)ticks) / (0.044 * rate), 0.0, 159.0);
 			int x0 = xf;
-			int x1 = limit(0.0, 159.0, x0 + 1);
+			int x1 = fclampf(x0 + 1, 0.0, 159.0);
 			int evn0 = 3 * y * width + 6 * x0;
 			int evn1 = 3 * y * width + 6 * x1;
 			int odd0 = 3 * (y + 1) * width + 6 * x0;
@@ -184,9 +149,9 @@ int main(int argc, char **argv)
 			uint8_t R1 = (pixel[evn1 + 0] + pixel[odd1 + 0] + pixel[evn1 + 3] + pixel[odd1 + 3]) / 4;
 			uint8_t G1 = (pixel[evn1 + 1] + pixel[odd1 + 1] + pixel[evn1 + 4] + pixel[odd1 + 4]) / 4;
 			uint8_t B1 = (pixel[evn1 + 2] + pixel[odd1 + 2] + pixel[evn1 + 5] + pixel[odd1 + 5]) / 4;
-			uint8_t R = lerp(R0, R1, xf - (float)x0);
-			uint8_t G = lerp(G0, G1, xf - (float)x0);
-			uint8_t B = lerp(B0, B1, xf - (float)x0);
+			uint8_t R = flerpf(R0, R1, xf - (float)x0);
+			uint8_t G = flerpf(G0, G1, xf - (float)x0);
+			uint8_t B = flerpf(B0, B1, xf - (float)x0);
 			add_freq(1500.0 + 800.0 * V_RGB(R, G, B) / 255.0);
 		}
 		// ODD LINES
@@ -201,9 +166,9 @@ int main(int argc, char **argv)
 		}
 		// Y
 		for (int ticks = 0; ticks < (int)(0.088 * rate); ticks++) {
-			float xf = limit(0.0, 319.0, (320.0 * (float)ticks) / (0.088 * rate));
+			float xf = fclampf((320.0 * (float)ticks) / (0.088 * rate), 0.0, 319.0);
 			int x0 = xf;
-			int x1 = limit(0.0, 319.0, x0 + 1);
+			int x1 = fclampf(x0 + 1, 0.0, 319.0);
 			int off0 = 3 * y * width + 3 * x0;
 			int off1 = 3 * y * width + 3 * x1;
 			uint8_t R0 = pixel[off0 + 0];
@@ -212,9 +177,9 @@ int main(int argc, char **argv)
 			uint8_t R1 = pixel[off1 + 0];
 			uint8_t G1 = pixel[off1 + 1];
 			uint8_t B1 = pixel[off1 + 2];
-			uint8_t R = lerp(R0, R1, xf - (float)x0);
-			uint8_t G = lerp(G0, G1, xf - (float)x0);
-			uint8_t B = lerp(B0, B1, xf - (float)x0);
+			uint8_t R = flerpf(R0, R1, xf - (float)x0);
+			uint8_t G = flerpf(G0, G1, xf - (float)x0);
+			uint8_t B = flerpf(B0, B1, xf - (float)x0);
 			add_freq(1500.0 + 800.0 * Y_RGB(R, G, B) / 255.0);
 		}
 		// ODD
@@ -227,9 +192,9 @@ int main(int argc, char **argv)
 		}
 		// U
 		for (int ticks = 0; ticks < (int)(0.044 * rate); ticks++) {
-			float xf = limit(0.0, 159.0, (160.0 * (float)ticks) / (0.044 * rate));
+			float xf = fclampf((160.0 * (float)ticks) / (0.044 * rate), 0.0, 159.0);
 			int x0 = xf;
-			int x1 = limit(0.0, 159.0, x0 + 1);
+			int x1 = fclampf(x0 + 1, 0.0, 159.0);
 			int evn0 = 3 * (y - 1) * width + 6 * x0;
 			int evn1 = 3 * (y - 1) * width + 6 * x1;
 			int odd0 = 3 * y * width + 6 * x0;
@@ -240,9 +205,9 @@ int main(int argc, char **argv)
 			uint8_t R1 = (pixel[evn1 + 0] + pixel[odd1 + 0] + pixel[evn1 + 3] + pixel[odd1 + 3]) / 4;
 			uint8_t G1 = (pixel[evn1 + 1] + pixel[odd1 + 1] + pixel[evn1 + 4] + pixel[odd1 + 4]) / 4;
 			uint8_t B1 = (pixel[evn1 + 2] + pixel[odd1 + 2] + pixel[evn1 + 5] + pixel[odd1 + 5]) / 4;
-			uint8_t R = lerp(R0, R1, xf - (float)x0);
-			uint8_t G = lerp(G0, G1, xf - (float)x0);
-			uint8_t B = lerp(B0, B1, xf - (float)x0);
+			uint8_t R = flerpf(R0, R1, xf - (float)x0);
+			uint8_t G = flerpf(G0, G1, xf - (float)x0);
+			uint8_t B = flerpf(B0, B1, xf - (float)x0);
 			add_freq(1500.0 + 800.0 * U_RGB(R, G, B) / 255.0);
 		}
 	}
diff --git a/utils.h b/utils.h
new file mode 100644
index 0000000..767bb1c
--- /dev/null
+++ b/utils.h
@@ -0,0 +1,36 @@
+
+#ifndef UTILS_H
+#define UTILS_H
+#include <stdint.h>
+#include <time.h>
+
+int64_t gcd(int64_t a, int64_t b)
+{
+	int64_t c;
+	while ((c = a % b)) {
+		a = b;
+		b = c;
+	}
+	return b;
+}
+
+float fclampf(float x, float min, float max)
+{
+	float tmp = x < min ? min : x;
+	return tmp > max ? max : tmp;
+}
+
+float flerpf(float a, float b, float x)
+{
+	return a - a * x + b * x;
+}
+
+char *string_time(char *fmt)
+{
+	static char s[64];
+	time_t now = time(0);
+	strftime(s, sizeof(s), fmt, localtime(&now));
+	return s;
+}
+#endif
+
diff --git a/yuv.c b/yuv.c
index cb8934e..89eea09 100644
--- a/yuv.c
+++ b/yuv.c
@@ -1,7 +1,7 @@
 
 #include "yuv.h"
 
-uint8_t yuv_limit(float x)
+uint8_t yuv_clamp(float x)
 {
 	float tmp = x < 0.0 ? 0.0 : x;
 	return tmp > 255.0 ? 255.0 : tmp;
@@ -10,15 +10,28 @@ uint8_t yuv_limit(float x)
 uint8_t R_YUV(uint8_t Y, uint8_t U, uint8_t V)
 {
 	(void)U;
-	return yuv_limit(0.003906 * ((298.082 * (Y - 16.0)) + (408.583 * (V - 128))));
+	return yuv_clamp(0.003906 * ((298.082 * (Y - 16.0)) + (408.583 * (V - 128))));
 }
 uint8_t G_YUV(uint8_t Y, uint8_t U, uint8_t V)
 {
-	return yuv_limit(0.003906 * ((298.082 * (Y - 16.0)) + (-100.291 * (U - 128)) + (-208.12 * (V - 128))));
+	return yuv_clamp(0.003906 * ((298.082 * (Y - 16.0)) + (-100.291 * (U - 128)) + (-208.12 * (V - 128))));
 }
 uint8_t B_YUV(uint8_t Y, uint8_t U, uint8_t V)
 {
 	(void)V;
-	return yuv_limit(0.003906 * ((298.082 * (Y - 16.0)) + (516.411 * (U - 128))));
+	return yuv_clamp(0.003906 * ((298.082 * (Y - 16.0)) + (516.411 * (U - 128))));
+}
+
+uint8_t Y_RGB(uint8_t R, uint8_t G, uint8_t B)
+{
+	return yuv_clamp(16.0 + (0.003906 * ((65.738 * R) + (129.057 * G) + (25.064 * B))));
+}
+uint8_t V_RGB(uint8_t R, uint8_t G, uint8_t B)
+{
+	return yuv_clamp(128.0 + (0.003906 * ((112.439 * R) + (-94.154 * G) + (-18.285 * B))));
+}
+uint8_t U_RGB(uint8_t R, uint8_t G, uint8_t B)
+{
+	return yuv_clamp(128.0 + (0.003906 * ((-37.945 * R) + (-74.494 * G) + (112.439 * B))));
 }
 
diff --git a/yuv.h b/yuv.h
index 53c0629..feb2aca 100644
--- a/yuv.h
+++ b/yuv.h
@@ -6,4 +6,7 @@
 uint8_t R_YUV(uint8_t, uint8_t, uint8_t);
 uint8_t G_YUV(uint8_t, uint8_t, uint8_t);
 uint8_t B_YUV(uint8_t, uint8_t, uint8_t);
+uint8_t Y_RGB(uint8_t, uint8_t, uint8_t);
+uint8_t V_RGB(uint8_t, uint8_t, uint8_t);
+uint8_t U_RGB(uint8_t, uint8_t, uint8_t);
 #endif