diff --git a/src/pixels.c b/src/pixels.c
index 15457c5..7df0624 100644
--- a/src/pixels.c
+++ b/src/pixels.c
@@ -32,7 +32,7 @@ void pixel32_to_cpixel(uint8_t *restrict dst,
 	assert(dst_fmt->true_colour_flag);
 	assert(dst_fmt->bits_per_pixel <= 32);
 	assert(dst_fmt->depth <= 24);
-	assert(bytes_per_cpixel <= 3 && bytes_per_cpixel >= 1);
+	assert(bytes_per_cpixel <= 4 && bytes_per_cpixel >= 1);
 
 	uint32_t src_red_shift = src_fmt->red_shift;
 	uint32_t src_green_shift = src_fmt->green_shift;
@@ -86,6 +86,8 @@ void pixel32_to_cpixel(uint8_t *restrict dst,
 			dst_blue_shift -= min_dst_shift;
 		}
 
+		/* fallthrough */
+	case 4:
 		dst_endian_correction = dst_fmt->big_endian_flag ? 16 : 0;
 
 		while (len--) {
diff --git a/src/raw-encoding.c b/src/raw-encoding.c
index f43be85..74136b8 100644
--- a/src/raw-encoding.c
+++ b/src/raw-encoding.c
@@ -2,6 +2,7 @@
 #include "rfb-proto.h"
 #include "vec.h"
 #include "fb.h"
+#include "pixels.h"
 
 #include <pixman.h>
 
@@ -26,9 +27,11 @@ int raw_encode_box(struct vec *dst, const struct rfb_pixel_format *dst_fmt,
 
 	uint32_t* b = fb->addr;
 
+	int bytes_per_pixel = dst_fmt->depth / 8;
+
 	for (int y = y_start; y < y_start + height; ++y)
-		for (int x = x_start; x < x_start + width; ++x)
-			vec_fast_append_32(dst, b[x + y * stride]);
+		pixel32_to_cpixel(dst->data, dst_fmt, b + y * stride, src_fmt,
+				  bytes_per_pixel, width);
 
 	return 0;
 }