I’ve spent a little while playing with my new Elgato Turbo H.264 hardware video encoder. There’s good news and bad news, so far.
The good news is that it does, in fact, add a profile to iMovie, so you can export/encode video directly from there without an intermediate step of exporting in raw DV format to then encode in the little Turbo H.264 app. That’s nice, and I was worried it would be a problem. I presume this is also the case with Final Cut Express and Pro, which are mentioned in the same light as iMovie in the documentation.
More good news: the encoding is fast. Noticeably faster than just using the CPUs in my 2.33GHz Core 2 Duo Mac Book Pro. 4x faster, like they claim? Unknown, but it feels possible. I’ll try to get some benchmarks and some numbers soon, to quantify this.
The bad news: the video file encoded with the Turbo H.264 is very slightly larger (filesize), and very slightly lower quality visually (seems jaggy/aliased - a problem with interlacing?) compared to the one I exported manually using similar settings in iMovie (Quicktime, H.264, same res, etc.). 
That’s not to say at all that the quality is bad - it’s not. It’s really quite good, and the differences are only noticeable upon close side-by-side inspection. The source footage I tested on was shot in HDV 60i (60 frames per second, interlaced). I’ll try some progressive footage, and see if that makes a difference. I’m not targeting anything higher than 30fps anyway, so it’s not a big deal to switch to 30p from 60i on my camera.
More to come as it’s available…
TinyScreenfuls Feed (this blog)
Very cool. I remember ADS had a USB h264 encoder as well. It’s good to hear these things actually work.