What is wrong with my 1999 audi a4 quattro here is a video of the car?

You're gonna need to get the codes pulled and cleared for your car before anything can really be done. The car wanting to shut off after reving is probably due to a sticking throttle plate. You can remove the intake pipe to the throttle body and check to see if there is crud blocking the plate from opening and closing. Just use a rag and some rubbing alcohol to remove this stuff and the car should be running a little better. It would be best if you can remove the throttle body and give it a really good cleaning on the front and back of the plate all around the rim where the plate makes contact with the side of the housing. The engine seems to have plenty of power from your video, reving high enough but you didn't drive it so its not a very good indicator of how the car is actually running. You may want to get it checked out by a reputable mechanic, preferably someone with Audi or VW experience.