We shouldn't judge what's going on here as we have no idea what happened earlier on. But given that they've just came out of a junction and kept left to make the U-turn, perhaps they might have cut off the motorcyclist.
However, no one should resort to violence regardless of how persistent the provocation was, or how easily one's provoked.
And from what we can see from the video, the motorcyclist is clearly acting aggressively, and then going outright bananas later.
We hope the driver brought forth the video recording to the nearest police station after this video ends.
Our advice to both parties?
To the motorcyclist: Don't be stupid.
To the driver: Get a higher resolution recorder.