In this situation, are you obliged to stop, even if this would mean rapid braking?

In the video you are approaching a junction with traffic lights and a pedestrian crossing, beyond which there is a roundabout; the traffic lights show green, and when you are just before the crossing, the amber light comes on. In this situation you are not required to stop if this would require rapid braking. The answer is: no.

The Regulation on road signs and signals states that the amber signal means that driving past the traffic lights is prohibited, unless at the moment it comes on the vehicle is so close to the traffic lights that it cannot be stopped before them without rapid braking; this signal also announces that the red light will come on in a moment. The Road Traffic Act prohibits braking in a way that creates danger - stopping suddenly just before the crossing creates a risk of being hit from behind. You complete your passage calmly; however, this does not give you the right to speed up on amber.

Legal basis: § 95 para. 1 point 2 of the Regulation on road signs and signals; Art. 19 para. 2 point 2 of the Road Traffic Act (Prawo o ruchu drogowym)