Uploading video doesn't work - high priority

[uklomp]

Two of my colleagues experience problems with recording a video to add with new signs (within the Oefenproject dataset). One of them tried to record a video (so: add a new sign to the dataset, and then record a video on the laptop with the integrated camera) and the image appeared but froze. Then they tried again, and recording and seeing it again works, but with uploading, the screen remains black. The other colleague experienced this as well.