somehow this sounds more like a medial-overwhaul ;=)
can't this be done by a blog?
Why do you want PP to do it, do you want to mix these videos with your photos?
as PP always demands a graphic file which will be embedded by the "<img..-tag", will you replace that by the video? Then you will need a moderated form to add this
if you want to do it additional, you can always include a small 1px-image and add the embedding-code to the text. but by that you won't get a thumbnail,
so you see you will need a replacement for the normal image-upload-dialogue, because you will need the embedded video + the thumbnail for the video...