[FFmpeg-user] Ffmpeg doesn't recognize /dev/video0 when run as root?

[christina zou]

If I run my FFMPEG command as root, it does not recognize /dev/video0
properly:

16:17:22 E: Opening an input file: /dev/video0.

16:17:22 E: [video4linux2,v4l2 @ 0x2dff610] fd:4 capabilities:1000001

16:17:22 E: [video4linux2,v4l2 @ 0x2dff610] The device does not support the
streaming I/O method.

16:17:22 E: /dev/video0: Function not implemented

If I run as user, the FFMPEG command recognizes /dev/video0 and works
properly, no errors. Why?

Full command:

ffmpeg -loglevel debug \

    -thread_queue_size 1024 \

    -s 640x480 -c:v h264 -f v4l2 -framerate 10 -i /dev/video0 \

    -thread_queue_size 1024 \

    -i /tmp/temp.mp3 \

    -c:a copy \

    -c:v copy \

    -b:v 300K \

    -max_interleave_delta 2000000 \

    -report \

    -f flv rtmp://209.85.230.23/live2/KEY