FFmpeg only works in “terminal,” but is not working via “screen.”

I’m having a weird problem with FFmpeg.

I’m trying to stream video on a Raspberry Pi to a NodeJS server. When coecting via SSH directly, this command works great:

ffmpeg -s 320x240 -f video4linux2 -i /dev/video0 -f mpeg1video -vf "vflip,hflip" -b:v 800k -r 30 http://localhost:8082/camera/320/240/

However, when I try to run the command inside a screen, it doesn't work. I get the following error:

[video4linux2,v4l2 @ 0x21642a0] The device does not support the streaming I/O method.
/dev/video0: Function not implemented

I ran the command with the same user. I get the same error when ruing the command with sudo. It also doesn't work in a systemd service.

It looks like it doesn't like to run when not in an interactive shell? But I don't know why... Any ideas?