Import custom field.. possible?

Here is the deal.. I have a blog which I want to update to a new theme. It is currently running 3.4.1. Here is the scary part, the blog has 582 video posts and quite a bit of traffic. The theme I am using now has a custom field where I put the video embed code. The new theme uses video url instead of embed code. I installed wamp and strted working on a local installation to get everything working before I switch to the new theme. However, the problem is everything is importing fine except for that custom field. Other than copy and pasting 582 urls by hand, is there a better way for me to do this?

Here are the two different themes’ post fields:
https://imageshack.com/f/pduSE5Zop
https://imageshack.com/f/eyLvoNHip

Thanks