During the edit of a 60-second spot using RED footage I used QuickTime proxy files. Although this meant continuous rendering of transitions and effects it was painless. Eventually I needed to conform the proxies to their 1080/24p ProRes 422 counterparts. I didn't bother with Crimson because there were only about 20-30 cuts.

With speed changes and video effects reapplied I prepared for the final render. It wasn't long before Final Cut Pro generated this error message:

The effect 'Scrub' cannot be rendered in a sequence of this size with the current graphics card.

The Scrub filter had been successfully used throughout the entire edit: from proxy files to scrubbing the timeline in ProRes. I tested different video effects and received the same error message.

A forum post at CreativeCOW describes a similar problem. This was just one of many issues plauging my project so I took the easy way out by replacing the Scrub filter with one from Joe's Filters.

While I was writing this I found a solution at LAFCPUG. Modify the render depth from 10-bit to 8-bit in the sequence settings.

This solution is also referenced in an Apple Support document. Unfortunately it doesn't address why late-model Apple video cards generate the error. Lack of 10-bit color support or a bug?

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