Slow loading and editing times for long sequences with Multicam clips

I'm having a really hard time loading and editing long sequences which contain Multicam clips, and I'm wondering if anyone in a similar situation found any solutions. Here's what I'm trying to do:

- I'm working on a project where we've done a couple of dozen interviews which are 2-7 hours long, each one with two camera angles. The interviews have been turned into Multicam clips. There's one Multicam clip per interview, which is 2-7 hours long.
- I've edited long assemblies for each chapter of the film, which include short clips from various different interviews.
- As soon as a sequences starts approaching 1 hour in length, it becomes very slow to open, slow to work with, and sometimes makes an entire Library unusable, usually if that Library has reached more than 1GB in size.
- I'm created Proxy of all the media, which seems to help make the editing smoother, but doesn't help with the freezing of the long sequences.
- I've done tests with most recent MacBook Pros (2015 and 2016) and 5K iMac, with similar results.
- There is an option I don't understand in the Preferences: make Optimized media for Multicam clips. Should I enable this even if I'm working in Proxy mode?

By 1GB Library, I assume you mean 1TB? My largest library is about 5TB and it works mostly OK, although having the content on a Thunderbolt SSD RAID helps.

The Preferences>Playback>"Create optimized media for multicam clips" simply creates optimized (not proxy) media after you create a MC clip. If you already have proxy media, I don't see the advantage of that, and it seems unlikely to solve your problem.

A 2-7 hour MC clip per interview is a lot of media. However this should work and FCPX should not become unstable or crash. Make sure you are on the latest version -- 10.3.2 which has some performance improvements for long timelines. Are you certain that all drive volumes have plenty of space and you aren't running out? That can destabilize FCPX or most other programs.

You may already know this but after creating proxy media you must switch the viewer to optimized or it won't be used. If there's any chance you didn't switch it to proxy, you won't see the performance benefits. You also must switch the viewer back to optimized/original before exporting, else it will export in proxy resolution.

I just tested a 2 hr 2-camera 4k H264 timeline on 10.3.2 and it is unusably slow without proxy. That is on a top-spec 2015 iMac 27 with all media on a 4 x 2TB Thunderbolt 2 RAID-0 array. Let me build the proxy files and I'll test it that way.

I do mean 1GB Library, although I'm keeping my Media and Cache in external folders, so that's just the project files adding up to 1GB. The media itself is more like 6TB including the Proxy media.

I've made sure to switch to Proxy View, so that's not the issue. Once the I get the timeline loaded and start playing back the content and making cuts, that seems to run okay, meaning there isn't a lag in playback, but getting the Project loaded into the Timeline seems to take forever or get stuck.

I've been able to work with longer sequences before which are 3 hours long, but that's just a single 2-camera Multicam clip strung out and chopped up. Once I start combining different Multicam clips together, that's when it seems the trouble starts.

Maybe because the Project is pulling from so many different hundreds of clips contained inside dozens of different Multicam clips, it's too much for it to handle?

OK I built proxy files for a 2 hr 14 min 4k H264 2-camera multicam and with those it is very fast and smooth. I made some edits and it stayed fast. Starting FCPX and loading the project takes 4 seconds.

Were your 2-7 hr multicam projects immediately slow upon loading them or did they gradually become slow as you edited them?

Re editing long assemblies for each chapter of the film, are these are rough assemblies to help you organize the material for use in a final timeline? If so the preferred method in FCPX is doing that organizational work in the Event Browser. You can easily keyword them "chapter 1", "chapter 2", etc. while also keywording subject names, locations, topics, etc. Obviously at some point you would transition to a timeline but in FCPX the goal is defer that transition to later in the workflow and spend the brainstorming and organizational phase in the Event Browser. Of course making multiple long assemblies should not cause FCPX to destabilize or crash.

Thanks joema. I can't remember whether the Multicam clips became slow to work with over time. Is there a reason that might happen? The issue just seems to be that the longer the sequence, the slower it becomes, until it reaches that 1 hour mark, and then becomes nearly impossible to work with.

The main difference between my situation and test you ran must be that you're working with one Multicam clip, even though it's laid out on a sequence that's twice as long as mine. I've got sequences that are pulling from maybe 10-15 different Multicam clips that were originally 2-7 hours and have now been chopped up. Could it be that FCPX is still having to reference the original Multicam clips every time it's loading a sequence, in which case it's actually loading something like 50 hours worth of media just to play back a 1 hour sequence?

I did notice something strange: when I started assembling the sequences, it would sometimes duplicate the Multicam clips in the clip browser, so that sometimes by the time I assembled this sequence, I'd have something like 20 different versions of the same Multicam clip in my clip browser. This seems to have happened when I had an assistant editor help pull from a copy of the Library on a different drive and then send me XMLs of his sequences.

One more thing to mention is that these interviews have been Logged with the Lumberyard app in order to attach the interview transcript to the metadata of the Multicam clip, in the "notes" column, so that we can find specific bites later. Could it be that all that additional metadata associated with the Multicam clips (sometimes thousands of words worth of transcript) is also bogging down the entire Library?

luis.dechtiar wrote: … Could it be that FCPX is still having to reference the original Multicam clips every time it's loading a sequence, in which case it's actually loading something like 50 hours worth of media just to play back a 1 hour sequence?…

Yes.
That's the way compounds/MCs are handled internally.

How else should an Angle Viewer or skimming work …

luis.dechtiar wrote: ...The issue just seems to be that the longer the sequence, the slower it becomes, until it reaches that 1 hour mark, and then becomes nearly impossible to work with....

What version of FCPX are you on? We know there were specific performance fixes for long timelines done in 10.3.2. If you are not on 10.3.2 we could be wasting time chasing a non-issue which has already been fixed.

Since 10.3.2 I've been having bug issues with Multicam clips. I've reported them to Apple. I know another editor who is having similar issues.

Now this is odd... I thought I was up to date with my version of FCPX since there are no updates available to download on the Updates section of the App Store. But when I checked my FCPX version it says I'm on 10.3.1. The page for Final Cut on the App Store says the latest version is 10.3.2, but I still can't download any updates. I'm all up to date with the version of the macOS, so that can't be the issue.

On a separate note, if the problem does turn out to be the slow loading of long sequences comprised of multiple long Multicam clips edited together, then is there any possible way to "flatten" or get rid of the Multicam and just end up with single individual clips strung out? Similar to how you can break apart compound clips with the shortcut Command+Shift+G? It's not ideal but I'm wondering if this would at least let us have workable sequences.

I'm also aware about the preference to organize content in the clip browser through Keywords, Favorites, etc, before laying things out on sequences, but there is a need in this case with my collaborators to string out long assemblies in order to watch back and cut the content down, so I am trying to find a way to keep working with what I have setup at this point.

luis.dechtiar wrote: ...when I checked my FCPX version it says I'm on 10.3.1. The page for Final Cut on the App Store says the latest version is 10.3.2, but I still can't download any updates....if the problem does turn out to be the slow loading of long sequences comprised of multiple long Multicam clips edited together, then is there any possible way to "flatten" or get rid of the Multicam and just end up with single individual clips strung out?

Since you are not on 10.3.2 and there are known performance fixes for your approximate situation, I would strongly recommend prioritizing getting that upgraded. As always, with any upgrade there are no guarantees, and there is risk of adverse behavior but you are already having a major problem. If you save the library file and current FCPX file package, it is easy to roll back to a prior version.