Final Cut Export takes ages when magnetic mask is already calculated!

Question

Final Cut Export takes ages when magnetic mask is already calculated!

I have a really weird issue in Final Cut Pro 11. I calculated the magnetic mask and it took some decent time (but reasonable because it's a computational heavy) now when I export the clip (no matter I select same as source or h264 etc. it takes even longer to export than to calculate the magnetic mask in the first place. Is this some kind of bug where the magnetic mask gets recalculated on export again? This is insane the work should be already done. Just to be sure I exported without magnetic mask applied and once with and the time difference on export is like 50-100x longer! how is this possible?

Mac mini, macOS 14.7

Posted on Nov 21, 2024 4:13 AM

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Answer 1

joema

Level 2

381 points

Nov 21, 2024 6:59 AM in response to jan_the_maker

I am investigating some performance issues in this general area. What other effects are on the clip? Are you also using a shape mask? Specifically, are you using FCP built-in video noise reduction or third-party Neat Video noise reduction? Are there other clips above it? Is it a simple clip or a compound or multicam clip? Is it retimed or is it running at 1x speed?

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Answer 2

Nov 21, 2024 10:21 PM in response to joema

no additional effects, just a standard clip. length is around 15min so it can be expected to take some time for the mask. but the export takes super long. if I deactivate the mask and run the export again it runs ok. which tells me that somehow magnetic mask gets calculated again during export or even worse ...

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Answer 3

joema

Level 2

381 points

Nov 22, 2024 6:43 AM in response to jan_the_maker

Jan, I tried many different tests using FCP 11.0 Magnetic Mask on MacOS Sequoia 15.1.1, and I cannot reproduce what you describe. I tried a ProRes 422 clip with ProRes 422 output, with H.264 output, an H.264 clip with H.264 output. I tried single-pass H.264 and multi-pass H.264. They all exported at the expected quick speed, not taking the extra time required for recalculating the mask.

I tried applying the Magnetic Mask as a stand-alone effect and as part of the Color Wheels effect. After the mask analysis ran, I tried exporting that without rendering the timeline to cache and after rendering it to cache (CMD+A, CTRL+R). Neither made any difference. They all exported at the expected speed, which was pretty fast.

I also tried two layers, applying the Magnetic Mask on the top layer so the bottom layer showed through the non-masked area. That also made no difference.

I think we need some more details about what year and model of Mac you have and what version of MacOS you are running. We also need the exact procedure when you apply the Magnetic Mask. IOW is it just the mask by itself and no masked effect? Is it applied as part of some effect such as Color Wheels? Are you retiming the clip to run at a different speed? Does the frame rate of the clip match the frame rate of the project?

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