In this situation, are you obliged to stop your vehicle before the level crossing?

In the video you are approaching a level crossing with barriers in winter; the barriers are raised, the traffic lights are not showing a red signal, and there is no sign B-20 before the crossing. You do not have to stop the vehicle before the crossing. The answer is: no.

The Road Traffic Act requires a driver approaching a level crossing to exercise particular caution and, before driving onto the tracks, to make sure that no rail vehicle is approaching; it prohibits driving onto the crossing when the barriers are down or have started to come down, when a red signal is shown and when there is no space beyond the crossing to leave it. You must come to a complete stop only when sign B-20 "STOP" or a red signal requires it. Here the barriers are raised, the light is not on, and there is no STOP sign - so you cross without stopping, but slowly and after making sure that the tracks are clear in both directions. Stopping for no reason before an open crossing surprises the drivers behind you, and on a slippery surface it risks someone driving into you. On the tracks you do not change gear or stop; if there is a traffic jam beyond the crossing, you wait in front of the crossing.

Legal basis: Art. 28 para. 1 and para. 3 point 1-2 of the Road Traffic Act (Prawo o ruchu drogowym); § 21 para. 1 and 4 of the Regulation on road signs and signals