How to access builtin webcam from a docker container using ffmpeg?

问题

I have wrote my code that captures videos by my builtin webcam of my MAC using ffmpeg.
On local machine, the code works fine. However, I built a docker container of my code, and tried to run it, but I got the following error:

error: Command failed: ffmpeg -f avfoundation -framerate 30 -i "0" -target pal-vcd -vf scale=640x480 -flags +global_header -f segment -segment_time 10 -segment_list ../out.csv -segment_format_options movflags=+faststart -reset_timestamps 1 -strftime 1 %Y%m%d-%H%M%S.mp4
ffmpeg version git-2016-05-25-9591ca7 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  configuration: --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-openssl
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 43.100 / 57. 43.100
  libavformat    57. 37.100 / 57. 37.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.100 /  6. 46.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Unknown input format: 'avfoundation'

as far as what I understood from this log, is that the docker container doesn't have access to local devices.
According to this discussion Docker - a way to give access to a host USB or serial device? , I need to use the --device flag to pass my device's location.
However, according to this answer, that is not possible?
In addition to what I've mentioned above, I couldn't get my webcam's path at the first place. what is a correct path for macbook webcam

My question is: How to access my MAC's builtin camera to record from a docker container?

回答1:

I'm not a docker expert, but there are a bunch of problems I can see:

Docker on Mac runs a virtual machine (hyperkit/xhyve) running Linux, which then uses containers. This means containers aren't running on the bare metal kernel, and their kernel doesn't have direct access to hardware. You can of course also use Parallels or VMWare Fusion or VirtualBox to run the Linux system instead.
It depends on the specific model of Mac, but many of the more recent models use PCIe based cameras, not USB.

So to make it work, you would need to:

Unload the macOS driver for your camera.
Pass through the raw USB device to the virtual machine running Linux, if it is indeed a USB model.
Get Linux to load the driver for the camera.
Pass the camera from the host Linux system through to the container.

PCIe passthrough is currently not possible on macOS hosts at all, so depending on your hardware, it might be completely infeasible.

If it's working without Docker, trying to force it into a container seems far more complicated and error prone than necessary.

回答2:

I think this comment would answer your question: https://stackoverflow.com/a/64634921/838712

This explains how to make the macOS camera available inside a linux docker container. ffmpeg should then be able to use this device without any problem.

来源：https://stackoverflow.com/questions/62556566/how-to-access-builtin-webcam-from-a-docker-container-using-ffmpeg

标签

macos

Docker

ffmpeg

usb

avfoundation