control the PTZ function of OBSBOT camera using a python script (pySerial or pyusb ….)

Question

DEARS,

I want to control the OBSBOT Tiny camera movements which is a usb camera (not an IP camera). I don’t know what is the protocol used by the manufacturer. The only thing I know is that it is feasible in Ubuntu since I can control it with the OBS-studio.

I tried to use pyusb and I was dealing with giving permissions to python in order to access the usb device. In addition, I was receiving this error usb.core.USBError: [Errno 16] Resource busy all the time. I tried dev.detach_kernel_driver(0) but this was stopping the device and I had to unplug and re-plug it.

THANKS

Asked By: Seif eddine Seghiri

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Answer 1

Controlling a USB camera using pyusb requires a good understanding of the USB protocol and the device’s vendor-specific commands. Since you do not have the protocol information, it may be challenging to control the camera using pyusb.

The "Resource busy" error suggests that another process is using the camera. You can use the lsusb command in the terminal to list all connected USB devices and check if the camera is in use by another process. If it is, you need to stop that process before accessing the camera.

As for the dev.detach_kernel_driver(0) command, it detaches the default kernel driver of the USB device. However, if the device does not have a default kernel driver or if the driver is already detached, this command will not work.

One possible solution is to use the v4l2 (Video for Linux 2) interface to control the camera. v4l2 is a standard Linux kernel interface for video devices, including USB cameras. You can use the v4l2-ctl command in the terminal to get information about the camera and to control its settings.

To install v4l2-ctl, run the following command in the terminal

sudo apt-get install v4l-utils

Once installed, you can use the v4l2-ctl command to get information about the camera

v4l2-ctl --all -d /dev/video0

Replace /dev/video0 with the correct device path of your camera.

You can also use v4l2-ctl to control the camera’s settings, such as brightness, contrast, and zoom

v4l2-ctl -d /dev/video0 -c brightness=128
v4l2-ctl -d /dev/video0 -c contrast=64
v4l2-ctl -d /dev/video0 -c zoom_absolute=200

Again, replace /dev/video0 with the correct device path of your camera.

You can use the subprocess module in Python to run the v4l2-ctl command and get its output. Here is an example

import subprocess

def run_v4l2_ctl(args):
    cmd = ['v4l2-ctl'] + args
    process = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = process.communicate()
    return stdout.decode(), stderr.decode()

# Get camera information
stdout, stderr = run_v4l2_ctl(['--all', '-d', '/dev/video0'])
print(stdout)

# Set camera brightness
stdout, stderr = run_v4l2_ctl(['-c', 'brightness=128', '-d', '/dev/video0'])
print(stderr)

Try this once, probably this works!!

Answered By: Bharadwaj

control the PTZ function of OBSBOT camera using a python script (pySerial or pyusb ….)

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