Sorry I thought I was clear.
FCP5 won’t play back “Blackmagic 10-bit (10V)” with RT EFFECTS. i.e. any colour correction or disolves need rendering to play back. This is a limitation of the Blackmagic codec in FCP5. (It’s advantage is that it correctly takes advantage of 16-bit AE comps. The Apple uncompressed codec doesn’t)
The solution for the record: It turns out After Effects re-names the standard apple “Uncompressed 10bit 4:2:2” codec “Blackmagic 10bit” in its list of codecs, and the black magic one “Blackmagic 10-bit (10V)”. Go figure.
Nils
Sydney, Australia