test_checksum_video

generated using ffmpeg: ``` ffmpeg -y -f lavfi -i "color=c=gray:s=1920x1080:d=300:r=25,format=rgba,\ drawbox=x=0:y=0:w=50:h=50:color=red@1.0:t=fill,\ drawbox=x=200:y=100:w=50:h=50:color=green@1.0:t=fill,\ drawbox=x=350:y=200:w=50:h=50:color=blue@1.0:t=fill,\ drawbox=x=580:y=300:w=50:h=50:color=yellow@1.0:t=fill,\ drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf:\ text='F\: %{frame_num} T\: %{eif\:t\:d.2}s':\ x=(w-tw)/2:y=h-th-50:fontsize=40:fontcolor=white:\ box=1:boxcolor=black@0.5:boxborderw=5" \ -c:v libx264 -preset medium -pix_fmt yuv420p test_checksum_video.mp4 ```