In educational videos it is important that the teacher can mark special scenes in the video and explain important aspects. This is implemented by visible markers in the timeline and overlays that show some features when a marker appear.
The base implementation should be done by adding support for the official medialement marker plugin available at https://github.com/mediaelement/mediaelement-plugins/blob/master/docs/markers.md This adds support for rendering markers in different colors and width and fires a callback event.
- Add marker support to the timeline
- Add GUI to add / edit / delete markers in OpenOLAT
- In the editor, allow placing of a text as an overlay
- In the player, show the overlay when the marker appears
The size and location of the text should be scaled with the proportion of the video.