Mainly for piping videos to dash-player over websockets.
Dash-player implements it.
Notes on DASH DRM (digital copy write)
Essentially you have a DRM platform, Widevine, that encrypts the content and stores the keys.
VideoJS supports it.
Assuming here VideoJS extracts the cenc key for you.
Encoding with DRM
Remember iframe interval to match dash segmentation
https://www.axinom.com/creating-multi-drm-protected-videos-with-free-tools/ "@samelie/chewb-redis": "git://github.com/samradical/chewb-redis.git",