In this situation, are you obliged to yield the right of way to the vehicle approaching from the right?

In the video, you enter a roundabout - before the entry there were signs A-7 "give way" and C-12 "circular traffic" - and you are already driving round the roundabout towards the exit; a car is waiting at the entry on the right. You do not have to give way to the vehicle approaching from the right. The answer is: no.

The Regulation on road signs and signals states that sign C-12 means that at the junction traffic moves around an island in the direction shown on the sign, and sign C-12 together with sign A-7 means that a driver already within the junction has right of way over a driver entering the junction. Since you are already on the roundabout, you have right of way, and the driver waiting at the entry on the right waits until you pass - the right-hand rule from the Road Traffic Act does not apply here, because right of way is set by the signs. This does not release you from caution: the driver at the entry may misjudge your speed or not notice the sign, and the principle of limited trust tells you to allow for their mistake. You drive smoothly, watch the car at the entry and switch on your right indicator before leaving the roundabout.

Legal basis: § 36 para. 1 and 2 of the Regulation on road signs and signals; Art. 4 and Art. 22 para. 5 of the Road Traffic Act (Prawo o ruchu drogowym)