Ask HN: Are there any good media management systems available?

I have been tasked with finding or creating a media management database to store and serve audio, video, and images ala a Flickr/YouTube like site. On one side, we have staff members who are trusted to add content that will be featured and all. On the other, we want individual users to upload content to share and comment on and such.

This isn't a project to take over the world or anything like that - we won't be competing with YouTube, Flickr, et. al. It doesn't need to scale to high concurrency and so a nice Rails application that allowed users to upload media and transcoded it, administrators to sort through it, comments to be applied to the media, etc. would be ideal.*

If you were going to be hosting some social video, audio, and images, what software would you use?

*That's not any judgement on whether Rails can scale: more a judgement that we don't need things like sharding or some fancy storage interface or some transcoding process that will handle large volumes of video.