Download BigBlueButton recordings as videos

Oct 19, 2021 by Thibault Debatty | 160 views

Teaching

https://cylab.be/blog/179/download-bigbluebutton-recordings-as-videos

BigBlueButton is a great platform for online teaching. It has many features like built-in drawing tools (even supports multi-user drawing), breakout rooms, chat, shared notes, polling, screen sharing, session recording etc. But, the recorded sessions are no actual videos.

bigbluebutton-polling-typed-response.png

How BigBlueButton works

During the meeting, the different "streams" are recorded separately: presentation pages, chat messages, drawings, audio stream and webcams. On the playback interface, the different streams are "played" separately from each other, maintaining the synchronization. This allows to spare a lot of bandwidth as only the webcam streams have to be recorded as videos.

But if you want to share or archive the session, you might some time prefer a video recording...

TLDR : use Docker

You can use our Docker image to capture the recorded session into a video. By default, videos are saved to the /video directory of the container, so you must use a mounted volume to get the video on your host machine:

docker run --rm -v `pwd`:/video cylab/bbb-recorder <URL>

Where <URL> is the URL of the recording. E.g.

docker run --rm -v `pwd`:/video cylab/bbb-recorder https://meet.cylab.be/playback/presentation/2.3/e9edba52669216dab8a3a0314033c11ffc21c6e6-1634497463561

bbb-recorder.png

How it works

Under the hood, this image contains an X virtual framebuffer (xvfb) and a node script that:

  • launches an instance of Google Chrome in full screen, using xvfb as a virtual display, and with screen capture activated
  • open the provided URL
  • start the video
  • wait for the end of the video (so it will take some time...)
  • save the recorded screen capture

The source of the image is available at https://gitlab.cylab.be/cylab/bbb-recorder