Caution: Unexplained Timeline Slowdowns in Final Cut Pro

Tangier Clarke brought this issue to my attention.

If you have a complex Apple Final Cut Pro timeline, especially if it was imported using XML, it may slow almost to unresponsiveness.

Tangier used XML and SendToX from Intelligent Assistance to transfer a Premiere Pro project into Final Cut Pro. SendToX adds red to-do markers to items to draw your attention to what has changed or been substituted on the FCP timeline.

Once that XML file was imported, Final Cut performance drastically slowed down. Tangier detailed the issues this way:

Here’s the thread on that explains this in more detail.

Link: Too Many To-Do Markers Cause Timeline Slowdowns

Tangier also emphasized:

“Gregory Clarke at Intelligent Assistance is always helpful to me and very responsive; so much so that he’s updated apps after I’ve discovered an issue or requested a feature that would significantly help the FCP community.

Although SendToX is incredibly thorough in bringing as much information over as it can and translating one NLE’s timeline for another, I hope people don’t read this and think SendToX is the problem. Its results can give FCP a lot to chew on, but from user Joema’s findings, those results shouldn’t impede FCPs heralded responsiveness. There’s something else going on still to be discovered. Joema is reporting all of this to Apple.”

I contacted Greg Clarke, at Intelligent Assistance, about this. He, too, thinks this is more than a marker problem. He wrote:

I have some insight into markers I’ll share with you, but I don’t think it explains this situation.

In the XML file, markers on a clip in a timeline always represent the total markers on the clip even if they are not visible. For example, if you have a clip in the browser that you’ve added 10 markers to, then you edit parts of that clip into the timeline as 10 separate “subclips”, then the XML will show that each subclip has 10 markers for a total of 100. I think it does this because if you changed the in/out points to lengthen the clip then the “hidden” markers will appear.

With SendToX, though, the to-do markers are added only on the clip in the timeline, but of course there can be many of these depending on the original sequence. I wonder if this applies only to to-do markers or if the other marker types are affected?


Adding a few dozen To-Do markers to any Final Cut project won’t cause any problems. However, if you regularly import transcripts into FCP, or use XML to transfer projects, take the time to read this thread, especially if your system seems to be slower than usual.

We don’t yet have a solution, but we do have a better understanding of the problem. I’ve also sent a note to Intelligent Assistance to see if we can learn more.

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