violent banging noise from the engine?

It sounds like you have a rod bearing that has spun, but if you upload a short video of the engine running, I can tell for sure what's going on. These guides may help as well:

https://www.2carpros.com/articles/understanding-and-repairing-engine-knocking-noise-an-in-depth-guide

and

https://www.2carpros.com/articles/engine-noises

Please upload videos in your response of any problems so we can see what to help you with. Please check the engine oil level/condition as well.

The oil is good.About 50% life left. Level is good as well.

That does not sound good. can I ask you to confirm the engine size? Also, please remove the serpentine belt and start the engine to see if the noise goes away, this will confirm the engine is having an issue internally. Do not drive the car with the belt off or let the engine run for more than 1 minute. Thanks for the video, it helps.