Android : Android: Read from internal camera via /dev/video0

I have a rooted „LG E430 Optimus L3 II“ with Android 4.1.2. Parallel there is Debian running via DebianKit.

I want to read from the internal camera from the command line. When I try to take a photo like this:

sudo streamer -c /dev/video0 -o test.jpeg

then I get the following output:

files / video: JPEG (JFIF) / audio: none
ioctl: VIDIOC_ENUMINPUT(index=0;name="";type=unknown;audioset=0;tuner=0; std=0x0 [];status=0x0 []): Inappropriate ioctl for device
ioctl: VIDIOC_ENUMSTD(index=0;id=0x0 [];name="";frameperiod.numerator=0; frameperiod.denominator=0;framelines=0): Inappropriate ioctl for device
no way to get: 320x240 JPEG (JFIF)
movie writer initialisation failed

I don't understand this error message and I can't find any android specific solutions on google. Do you have an idea?

Is my approach correct or is there a better way? I don't want to use the Java-API or adb for various reasons.

Thank you :)