Is it possible to edit a photo or a video caption and description after it was uploaded to facebook using the GraphAPI?
what I mean is can you upload the video using your own application and some time afterwards the application updates the caption?
Yes, using the Graph API, just HTTP POST to the {photoId} with the updated parameters in the form post. Play with that functionality here: http://developers.facebook.com/tools/explorer?method=GET&path=me