4 ms·

I want to prank my students. During class, I want to play a video as my video-background, in which a pre-recorded version of me is doing things behind me. Any

I want to prank my students. During class, I want to play a video as my video-background, in which a pre-recorded version of me is doing things behind me. Any ideas how I can do this on linux?

Anunayj 5y ago
well the easiest way I can think of is just using the OBS virtual camera thing (Unsure if they released it officially on Linux, but there is a plugin for that [1]). Use chroma key to remove the background and add a video there, possibly on a loop. [1]. https://github.com/CatxFish/obs-v4l2sink https://github.com/CatxFish/obs-v4l2sink
- rombert 5y ago
  It is present for Linux in recent releases.
jabl 5y ago
I've been using https://github.com/allo-/virtual_webcam_background https://github.com/allo-/virtual_webcam_background There are many others similar to the above. They all basically work by using the v4l2loopback driver to create a loopback video device. Then you have the program consume video from the real webcam video device, apply a deep learning model that subtracts the background (leaving your face and torso) and replaces it with an image or video of your choice, and outputs the video to the loopback device. Then you configure your video conferencing software (zoom, teams, webex, whatever) to use the loopback device instead of the real one.
orbital-decay 5y ago
It's "easily" done with OBS and a green screen, however having sufficient quality for the prank to work is trickier than it sounds (matching the lighting, getting the good keying quality, avoiding the green cast, calibrating and matching the color etc).
- abdullahkhalids 5y ago
  I am not looking for perfection. Just want to get a laugh out of them. I also just realized that if I place my laptop camera in the exact same spot, while recording the background video and during class, all I need to do is sit on the left of the camera pane during class, and only stay on the right for the background video, then I just need to stitch the two videos side-by-side in OBS and it should work well enough. I think I achieved my purpose here. Ask a question from a bunch of smart people. Either they give a great answer, or their response forces you to rethink and figure out a simple solution. Thank you HN for being my AI enabled rubber duck.
  - soylentcola 5y ago
    Yeah, if you don't have a "real" green screen, you can probably shoot a video from the same angle where you come in from one side and stay on that side. Then use OBS's crop filter and keep your live video on the other side. I just said to hell with it and bought a bright green sheet early on last year since I was spending so much time in meetings and assisting professors with running their classes. That sheet and a couple of cheap clamp lights (plus a decent tabletop mic) made a huge difference in the quality and entertainment value of my telepresence work.

I want to prank my students. During class, I want to play a video as my video-background, in which a pre-recorded version of me is doing things behind me. Any ideas how I can do this on linux?

Anunayj 5y ago

well the easiest way I can think of is just using the OBS virtual camera thing (Unsure if they released it officially on Linux, but there is a plugin for that [1]). Use chroma key to remove the background and add a video there, possibly on a loop. [1]. https://github.com/CatxFish/obs-v4l2sink https://github.com/CatxFish/obs-v4l2sink

rombert 5y ago
It is present for Linux in recent releases.

jabl 5y ago

I've been using https://github.com/allo-/virtual_webcam_background https://github.com/allo-/virtual_webcam_background There are many others similar to the above. They all basically work by using the v4l2loopback driver to create a loopback video device. Then you have the program consume video from the real webcam video device, apply a deep learning model that subtracts the background (leaving your face and torso) and replaces it with an image or video of your choice, and outputs the video to the loopback device. Then you configure your video conferencing software (zoom, teams, webex, whatever) to use the loopback device instead of the real one.

orbital-decay 5y ago

It's "easily" done with OBS and a green screen, however having sufficient quality for the prank to work is trickier than it sounds (matching the lighting, getting the good keying quality, avoiding the green cast, calibrating and matching the color etc).

abdullahkhalids 5y ago
I am not looking for perfection. Just want to get a laugh out of them. I also just realized that if I place my laptop camera in the exact same spot, while recording the background video and during class, all I need to do is sit on the left of the camera pane during class, and only stay on the right for the background video, then I just need to stitch the two videos side-by-side in OBS and it should work well enough. I think I achieved my purpose here. Ask a question from a bunch of smart people. Either they give a great answer, or their response forces you to rethink and figure out a simple solution. Thank you HN for being my AI enabled rubber duck.
- soylentcola 5y ago
  Yeah, if you don't have a "real" green screen, you can probably shoot a video from the same angle where you come in from one side and stay on that side. Then use OBS's crop filter and keep your live video on the other side. I just said to hell with it and bought a bright green sheet early on last year since I was spending so much time in meetings and assisting professors with running their classes. That sheet and a couple of cheap clamp lights (plus a decent tabletop mic) made a huge difference in the quality and entertainment value of my telepresence work.