Seriously mate, you undertook a left signalling car and squeezed up between it and the bus, in the car's blind spot. You should have dropped behind the car and took primary position in the 2nd lane to overtake the bus. I know you may feel that everyone is jumping down your throat right now, but you need to look at this video again and realise what you did wrong. Please do not mistake this for riding assertively; taking primary position behind the car as you overtake the bus would have been riding assertively. You may have also put yourself in the blind spot of the bus driver. Quite frankly, you're lucky you got away with that. but we all make mistakes, there is not one person on here that hasn't at some time. Watch the video again, learn from it, take a deep breath (phew!) and move on.
the bottom line is, whether he was indicating or not, you undertook him and squeezed between him and the bus. it was a risky move and you almost didn't make it. if he had hit you, and killed you, i doubt the police would prosecute him if they saw that video. you're only supposed to filter when it's safe to do so.