I think it's a new live DVD, chris, but no-one seems sure!

Here's what the good folk at Pitchfork have to say:

On their website, Icelandic dream-rock kings Sigur Rós have posed a new teaser video for something called Inni. The clip consists mostly of grainy black-and-white shots of the band onstage, soundtracked by on ominous, building ambient drone that suddenly turns into the sort of gorgeously still music that the band remains known for. So: New album? Live album? Live DVD?

Apparently its a film (& sadly not the reunion album)

http://blogs.indiewire.com/theplaylist/archives/2011/08/12/mysterious_ne...

It may be their attempt at Heima Part 2? As the first Heima also featured new music and alternate versions, this may prove to be the same, although Kjartan Sveinsson has had some of his classical works and soundtracks played live recently, so it may be music from that tour mixed in with the Sigur Ros tour for the last album.

The online translator gave me the words "away / inside / locked up" when I put Inni into it. You've got to love the complexity of the Icelandic language. I hope they put out special editions of whatever it is. The one's for Heima and Hlemmur were fantastically beautiful works of art.