In this scenario, do you have priority over the rail vehicle?

In the video you are driving on a roundabout marked with signs C-12 and A-7, with tram tracks running through its centre; in front of you there is sign A-21 "tram", and a tram is approaching from the left. You do not have right of way over it. The answer is: no.

The Road Traffic Act states that the rules of right of way at a junction do not apply to a rail vehicle, which has right of way over other vehicles regardless of the direction it is coming from; this rule also applies where traffic directions cross outside a junction. Sign A-7 together with C-12 requires only those entering the roundabout to give way - a tram is also subject to it when it enters. Here, however, the tram is already on the roundabout: it is running on the tracks across the central island and leaving the roundabout, crossing the roadway at the place that sign A-21 "tram" warns about. At such a place the tram, as a rail vehicle, has right of way regardless of the direction it is coming from; when driving across tram tracks, the Act requires you - as before a level crossing - to make sure before driving onto the tracks that no rail vehicle is approaching, so you stop before the tracks if a tram is approaching.

Legal basis: Art. 25 para. 2 and 3 and Art. 28 para. 1 and 6 of the Road Traffic Act (Prawo o ruchu drogowym); § 10 para. 3 and § 36 para. 2 of the Regulation on road signs and signals