I needed a solution for online presentation of a ppt that contained embedded jing created videos (mp4format). I compared the sources I usually use and found out this:
Scribd Video - I don't see anything to indicate it is possible. This is still my favorite option for uploading a plain ppt and having it come out looking great.
SlideRocket Video - has support for some video formats. I recorded my videos in Jing and they are mp4 - but I looked into Jing and found out that I could have chosen to video in swf from the beginning! I can now either re-video in SWF or convert with a free download a have mp4 to swf. Then upload to RocketSlide. Quality will be interesting - I'll report back.
SlideShare- has no video/audio support within a ppt unless you upload the ppt and then do a slidecast(audio podcast)and upload that with the ppt.
Flowgram - would offer same type of presentation as SlideShare. You can import your slides and then voice voice - either live or with an audio
upload you've done elsewhere.
Sharing this because I thought it might be helpful. Not guaranteeing this to be the finite resource on the subject!