Using webcam connected to MacBook inside a Docker container
According to https://docs.docker.com/docker-for-mac/faqs/#what-is-the-benefit-of-hyperkit this is not possible.

Similar question is https://stackoverflow.com/questions/41023827/accessing-usb-webcam-hosted-on-os-x-from-a-docker-container

And possible answer is stream the camera into the container using ffmpeg according to a comment in https://stackoverflow.com/questions/37960828/webcam-streaming-from-mac-using-ffmpeg