λ yes | wf-recorder --muxer=v4l2 --codec=rawvideo --pixel-format=yuv420p --file=/dev/video0
Output file "/dev/video0" exists. Overwrite? Y/n: selected region 0,0 0x0
Using video filter: null
Output #0, video4linux2,v4l2, to '/dev/video0':
  Stream #0:0: Video: rawvideo (RGB[0] / 0x424752), rgb0(pc), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 49766400000 kb/s
[video4linux2,v4l2 @ 0x7fba24000d00] Unknown V4L2 pixel format equivalent for rgb0
Failed to write file header
Invalid argument

Output file "/dev/video0" exists. Overwrite? Y/n: selected region 0,0 0x0
Choosing pixel format yuv420p
Output #0, video4linux2,v4l2, to '/dev/video0':
  Stream #0:0: Unknown: none (rawvideo)
[video4linux2,v4l2 @ 0x7f0110000d00] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.