Fake webcam chrome option when used with python selenium webdriver

Question

I did not get a specific chrome option to work fine, when started chrome per python selenium webdriver script.

The goal is to start chrome in a python selenium script with a fake webcam, which plays a video file.

The problematic options are "use-file-for-fake-video-capture" combined with "use-fake-device-for-media-stream":

options.add_argument("--use-fake-device-for-media-stream")
options.add_argument("--use-file-for-fake-video-capture=C:\Testfiles\videofiles\bus_cif.y4m")

Both Options are working totally fine used in a batch-file with chrome.exe. For example, the following batch is working fine and used fake webcam videofile: "C:\Program Files\Google\Chrome\Application\chrome.exe" --use-fake-device-for-media-stream --use-file-for-fake-video-capture=C:\Testfiles\videofiles\bus_cif.y4

Also, the rest of my python chrome webdriver script options are working fine, so the code itself should be correct. For example, the following options are working fine :

options.add_argument("--allow-file-access-from-files")
options.add_argument("--use-fake-ui-for-media-stream")
options.add_argument("--disable-infobars")

Chrome 97.x (with newest stable chromium webdriver files)

Is there something special about the option "use-file-for-fake-video-capture" when used in a python script with options? Or perhaps the path have to be in another format?

Thanks a lot!

Answer 1

Figured it out. Spent hours yesterday, but today shortly after posting to stackoverflow, I found the solution myself:

Problem is the path I used: Windows path in Python

When using the following, everything works fine and fake video is used even when chrome is started by python script:

options = Options()    
options.add_argument("--use-fake-ui-for-media-stream")
options.add_argument("--use-fake-device-for-media-stream")
options.add_argument(r'--use-file-for-fake-video-capture=C:\Testfiles\videofiles\bus_cif.y4m')
self.driver = webdriver.Chrome(options=options)

Important is the r' when using windows path with backslashes. I think the other solution would be using slash instead of backslash.