Final Cut Pro project re-renders after reopening

I'm the one who wrote that description, and it is *not* isolated to background rendering. In that description, I specifically stated that the user's problems were not related to background rendering but were a broader, multi-faceted issue with FCP render cache management.

The same is likely true with your case. You definitely notice the problem if background rendering is enabled, because the lack of cache durability after re-launching FCP causes background rendering to resume. But the underlying problem is that there are various cases where the render cache is invalidated, and re-rendering (either manual or background) is required if you want a fully rendered timeline.

The issue is especially noticeable when using certain compute-bound temporal effects, such as Neat Video, but it is not limited to those. I think there are some FCP built-in effects that also cause some versions of this, but I don't remember the specifics.

This is not unique to FCP. Resolve also does this in some cases.

Your question about "project re-renders after reopening" is perfectly logical. Similar cache behaviors exist from (say) switching between proxy and original media.

There are separate render caches for proxy and original media, and if both are fully rendered, just switching between them should not cause parts of the cache to become invalid (IOW render dots should not appear). Yet it sometimes does.

There is nothing wrong with submitting a request to "Provide Final Cut Pro Feedback" on this topic, in fact I encourage this. You can get to that by using the menu Final Cut Pro > Provide Final Cut Pro Feedback...

Apple has said they read each one of these. Your particular request is a good use of the feedback tool, because it is self-contained, this issue is widely known, and IMO does not require an extensive replication scenario.

There are seemingly several separate manifestations of this, but you need not list all of those. Just list what you have observed and state the negative impact it has on your work.

Some examples of apparent anomalies in the FCP render cache system I have observed myself:

• Relaunching FCP can invalidate parts of the render cache
• Switching between proxy and original media mode can invalidate parts of the cache
• Certain third-party utilities, such as Neat Video, may appear fully cached, but the render cache is not used during export.
• Some built-in titles exhibit different caching behavior between the first render and subsequent renders. E.g., if Basic Titles are rendered to cache and FCP is relaunched, the timeline range will appear uncached (render dots appear). But if you then re-render that to cache and re-launch FCP a 2nd time, the render cacher persists. That is illogical.

From an FCP developer standpoint, they can argue that these nuances are not documented, are subject to change without notice between versions, hence are not viable candidates for a bug or improvement request.

However there is an opposing view (which I hold) that these are clearly illogical and indicate a loss of efficiency that negatively impacts editors. It is not necessary that every FCP behavior be documented before engineering takes corrective action. E.g, if Magnetic Mask exhibits exponential performance degradation on longer clips, improving that is a valid request. Just because the FCP manual doesn't make any promises about Magnetic Mask behavior doesn't mean an enhancement request that clearly shows a problem is invalid. It is appropriate. The case with FCP render cache durability is similar.

So I encourage you to give feedback on this using the "Provide Final Cut Pro Feedback" form.

Is background rendering turned off?

Hi(bonjour),

This is a known problem:

Render every time again and again. - Apple Community

Michel

What effects are you applying that require rendering? Built-in or 3rd party?

The render/don't render decision that FCP makes is complex and depends on many factors. @joema had a good write up here recently. I'll see if I can find it. Perhaps if he sees this thread he can chime in.

My gawd, the site's search capabilities are terrible and seem even worse than the last time I used it. It took quite a bit of time hunting for something that I knew existed and who wrote it. Can't imagine searching for something in general. Here's where @joema talks about the render cache. Render every time again and again. - Apple Community

CafeSaxophone wrote:

Sorry I am struggling with this forum as posts are not showing up in order.

To change the sort order to the standard oldest-first/Newest-at-the-end, choose Oldest in the "Sort by" popup on the top right of the first reply. Annoying this isn't the default.