Mike Curtis at HD for Indies has been soliciting feedback on how long it takes iMovie HD or Final Cut Express HD to render HDV video back to the Sony HDR-FX1 HD camera. Unlike standard-def DV, it's not a real-time process; the Mac has to encode its AIC (Apple Intermediate Codec) footage, which is what the apps use for editing, to MPEG-2 (HDV).
A quick poll of readers got this back:
Mac: dual 2.0 GHz G5
encoding time ratio: 6:1 (it takes 6 minutes to encode to HDV MPEG-2)
Mac: dual 1.25 GHz G4
encoding time ratio: 10:1 (10 minutes to encode one minute of AIC to HDV MPEG-2)
Mac: Mini 1.42 GHz
encoding time ratio: 15:1 (15 minutes to encode one minute of HD resolution AIC back to MPEG-2 for HDV layback)
A dual 2.5 GHz G5 might nudge that a little closer to 5:1, but it's clear that 1080i60 HDV footage takes a long time to cook. Important to remember when you're on deadline.