I definitely suggest that you keep a backup somewhere centrally. So option 1 is out.
If you want to use SVN, it will depend. The reason why people generally don't like to store binary files in SVN is that binary deltas are usually useless. According to this stackoverflow question SVN also isn't good at storing very large files.
However, if you only have a few video files, that fall within the limits that SVN can handle. And if they aren't going to change too much, I would go ahead and put them in SVN. This will be the easiest solution with the least hassle.
Otherwise, I would look into a solution that doesn't require too many build steps. I'd suggest to point your links to the videos directly to S3 and not have an intermediary step of pulling the videos into your application and then deploying to a sever.