diff --git a/decode.py b/decode.py
index 610359a..e1c88ec 100644
--- a/decode.py
+++ b/decode.py
@@ -89,8 +89,8 @@ for i, img in enumerate(tqdm(images)):
 # frame = b''.join(df.iloc[:32]['data'])
 # Image.frombytes('RGB', (288, 256), frame).show()
 start_len = len(b'T=(-1.665884e-08)*X^4+(1.347094e-05)*X^3+(-4.396264e-03)*X^2+(9.506939e-01)*X+(-6.353247e+01)\r\n')
-# 250 bytes at start of frame
 
+# 250 bytes at start of frame
 equations = {x[:250].decode().strip() for x in df[df.part == 0]['data']}
 # seen only a single equation on all packets
 assert len(equations) == 1
@@ -101,5 +101,5 @@ assert list(equations)[0] == 'T=(-1.665884e-08)*X^4+(1.347094e-05)*X^3+(-4.39626
 assert df.shape[0] == 6372
 
 # produce a video
-system('ffmpeg -f image2 -framerate 25 -i %04d.png -s 288x384 thermal.mp4')
+system('ffmpeg -f image2 -framerate 25 -i %04d.png -vf "transpose=1" -s 384x288 -vcodec libx264 -pix_fmt yuv420p thermal.mp4')
 print('to play: ffplay thermal.mp4')