Just trying Premiere out on my first project since jumping ship from FCP. All great thus far, but I'm having an issue with some ProRes assets which have an alpha channel. They're some animated titles which were made in AE, which are supposed to sit on top of the live action footage. The live action footage is P2 (DVCPro HD), and so are the sequence settings. On playback the ProRes titles composite fine over the P2 footage, but when I hit stop, the alpha areas in the titles show black instead of showing the underlying image. On export to H264 too, the clips do not composite together correctly; the titles have black under them instead of the underlying P2 footage.
Anyone shed any light on why it would work fine on preview playback but fail when the playhead is stopped and, more importantly, on export?
Instead of the Prores export, have you tried bringing in the AE comps using Dynamic Link?
Thanks for your reply. I guess I could do, but it's not really addressing the actual issue. There may be other instances in the future where we might want to use assets with an alpha channel where dynamic link would not be possible. It would be good to know how this can be addressed, or if there is some inherant problem with Premiere's compositing system.
I believe the issue is actually with the QuickTime container. That's why I suggested a method which doesn't use that. Another method is to use a PC and create lossless AVI files. Lagarith is a free lossless codec that can create RGB32 files (with alpha) that work fine in Premiere Pro.