diff --git a/utils/kmstest.py b/utils/kmstest.py
index b7c976a..2d61d5d 100755
--- a/utils/kmstest.py
+++ b/utils/kmstest.py
@@ -6,6 +6,7 @@
 
 import numpy as np
 
+from kms.framebuffer import Framebuffer
 from pixutils.dmaheap import DMAHeap
 
 import kms
@@ -36,6 +37,141 @@ def draw_test_pattern(fb):
     d1[0::fb.width+1] = 0xffffff
     d1[fb.width-1::fb.width-1] = 0xffffff
 
+def draw_pixel_xv15(fmt: kms.PixelFormat, buf_y, buf_uv, x, y, color: tuple):
+    MASK10 = (1 << 10) - 1
+
+    color_Y, color_Cb, color_Cr = color
+
+    pos = (x, y)
+
+    Y_pos = (pos[0] // fmt.planes[0].hsub, pos[1] // fmt.planes[0].vsub)
+    UV_pos = (pos[0] // fmt.planes[1].hsub, pos[1] // fmt.planes[1].vsub)
+
+    Y_offset = Y_pos[0] // 3
+    Y_mod = Y_pos[0] % 3
+
+    UV_offset = UV_pos[0] // 3
+    UV_mod = UV_pos[0] % 3
+
+    Y_pos_unit = (Y_offset, Y_pos[1])
+    UV_pos_unit = (UV_offset, UV_pos[1])
+
+
+    #print('pos:', pos, Y_pos, UV_pos)
+    #print('Y offset ', Y_offset, 'mod', Y_mod)
+    #print('UV offset ', UV_offset, 'mod', UV_mod)
+
+
+    shift_Y = 10 * Y_mod
+
+    v = buf_y[Y_pos_unit[1], Y_pos_unit[0]]
+    v &= ~(MASK10 << shift_Y)
+    v |= color_Y << shift_Y
+    buf_y[Y_pos_unit[1], Y_pos_unit[0]] = v
+
+
+    if UV_mod == 0:
+        shift_Cb = 0
+        shift_Cr = 10
+    elif UV_mod == 1:
+        shift_Cb = 20
+        shift_Cr = 32
+    elif UV_mod == 2:
+        shift_Cb = 32 + 10
+        shift_Cr = 32 + 20
+    else:
+        assert False
+
+    v = buf_uv[UV_pos_unit[1], UV_pos_unit[0]]
+    v &= ~((np.uint64(MASK10) << np.uint64(shift_Cb)) | (np.uint64(MASK10) << np.uint64(shift_Cr)))
+    v |= (np.uint64(color_Cb) << np.uint64(shift_Cb)) | (np.uint64(color_Cr) << np.uint64(shift_Cr))
+    buf_uv[UV_pos_unit[1], UV_pos_unit[0]] = v
+
+def draw_test_pattern_xv15(fb: Framebuffer):
+    fmt = fb.format
+
+    buf_y = np.frombuffer(fb.map(0), dtype=np.dtype('<u4'))
+    buf_y = buf_y.reshape(fb.height, fb.planes[0].pitch // 4)
+
+    buf_uv = np.frombuffer(fb.map(1), dtype=np.dtype('<u8'))
+    buf_uv = buf_uv.reshape(fb.height // 2, fb.planes[1].pitch // 8)
+
+    # Draw single pixel
+
+    draw_pixel_xv15(fmt, buf_y, buf_uv, 400, 100, (255 << 2, 255 << 2, 255 << 2))
+
+    # Draw Diagonal
+
+    for y in range(0, fb.height):
+        draw_pixel_xv15(fmt, buf_y, buf_uv, y, y, (255 << 2, 255 << 2, 255 << 2))
+
+    # Draw red, green, blue boxes
+
+    red = (76 << 2, 84 << 2, 255 << 2)
+    green = (149 << 2, 43 << 2, 21 << 2)
+    blue = (29 << 2, 255 << 2, 107 << 2)
+
+    for y in range(100, 150):
+        for x in range(100, 150):
+            draw_pixel_xv15(fmt, buf_y, buf_uv, x, y, red)
+
+    for y in range(100, 150):
+        for x in range(150, 200):
+            draw_pixel_xv15(fmt, buf_y, buf_uv, x, y, green)
+
+    for y in range(100, 150):
+        for x in range(200, 250):
+            draw_pixel_xv15(fmt, buf_y, buf_uv, x, y, blue)
+
+
+def draw_pixel_nv12(buf_y, buf_uv, x, y, color):
+    color_Y, color_Cb, color_Cr = color
+
+    macro_x = x
+    macro_y = y
+    buf_y[macro_y, macro_x] = color_Y
+
+    macro_x = x // 2
+    macro_y = y // 2
+
+    shift_Cb = 0
+    shift_Cr = 8
+
+    buf_uv[macro_y, macro_x] = (color_Cb << shift_Cb) | (color_Cr << shift_Cr)
+
+
+def draw_test_pattern_nv12(fb):
+    buf_y = np.frombuffer(fb.map(0), dtype=np.dtype('<u1')).reshape(fb.height, fb.planes[0].pitch)
+    buf_uv = np.frombuffer(fb.map(1), dtype=np.dtype('<u2')).reshape(fb.height // 2, fb.planes[1].pitch // 2)
+
+    # Draw single pixel
+
+    draw_pixel_nv12(buf_y, buf_uv, 400, 100, (255, 255, 255))
+
+    # Draw Diagonal
+
+    for y in range(0, fb.height):
+        draw_pixel_nv12(buf_y, buf_uv, y, y, (255, 255, 255))
+
+    # Draw red, green, blue boxes
+
+    red = (76, 84, 255)
+    green = (149, 43, 21)
+    blue = (29, 255, 107)
+
+    for y in range(100, 150):
+        for x in range(100, 150):
+            draw_pixel_nv12(buf_y, buf_uv, x, y, red)
+
+    for y in range(100, 150):
+        for x in range(150, 200):
+            draw_pixel_nv12(buf_y, buf_uv, x, y, green)
+
+    for y in range(100, 150):
+        for x in range(200, 250):
+            draw_pixel_nv12(buf_y, buf_uv, x, y, blue)
+
+
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('-c', '--connector', default='')
@@ -51,7 +187,7 @@ def main():
     plane = res.reserve_generic_plane(crtc)
     mode = conn.get_default_mode()
 
-    print(mode)
+    mode = next(m for m in conn.modes if m.hdisplay == 720)
 
     modeb = mode.to_blob(card)
 
@@ -79,6 +215,10 @@ def main():
         fb.end_cpu_access()
         ts2 = time.perf_counter()
         print(f'Drawing took {(ts2 - ts1) * 1000:.4f} ms')
+    elif fmt == kms.PixelFormats.XV15:
+        draw_test_pattern_xv15(fb)
+    elif fmt == kms.PixelFormats.NV12:
+        draw_test_pattern_nv12(fb)
 
     req = kms.AtomicReq(card)