> if I understand correctly once the EC2 instance transcodes the video it gets sent to the OCA that stores it and provides the chunk of video as fast as possible?

correct. But the video goes live only after many OCA gets a copy.

> do you know how these videos are transferred to the OCA and if there is a lot more process and optimization that goes into it?

I don't know the exact details. But I'd assume that they replicate transcoded file to S3 in different locations. And the OCA downloads it from the nearby S3.

Hope that helps, thanks for asking.