I tried this solution in order to embed my S3 video to my site, but (1) my management console isn’t giving me a video/mp4 option in the drop-down menu and (2) I wonder if I still have the protections that the Javascript EZS3 player gave me before I moved to Sensei? I liked that my video would only play on my URL, and I don’t know how to do that here. Of course, the biggest concern, like OP, is that I’m getting the application/octet error message but can’t follow through on your solution to fix it (but did find your suggestion VERY helpful, as I wasn’t able to get video to play at all until I combined your advice with someone else’s to install Flowplayer).