showing customfield data below oembed video

i am trying to show 2 customfields (vhost and vcreatorsite) directly below any video that’s autoembedded by wordpress using oembed. i tried entering code into the class_oembed.php file but that’s not working somehow.

So i’m wondering where the basic customfield call should go in my wordpress installation to show the customfield data (if present) everytime a video is embedded by oembed.

Thanks in advance!

Matt