Hello @mfuszner
the file transfer feature has internal limits to avoid congestion, especially with many clients. It currently sends chunks of 256 KB every 25 ms, i.e. about 10 MB/s. Can you confirm similar transfer rates? We might add configuration options to configure the chunk size and send interval in the future. If this is urgent to you we can prioritize the development on a commercial base - contact support@veyon.io to discuss further details.
The demo mode uses unicast in order to work across subnets. It's therefore not suitable for video playback.