DaVinci major timeline issue - please help!

I’m on the latest version of DaVinci Resolve (Studio 18 version 18.0.1 Build 3) running on a high end iMac with OS Monterey.

I have never had this issue before, but it just started a couple of Resolve updates ago a few months back. Like I said, before it was perfect, but a recent update has messed something up for me and I can’t find a fix.

I’m editing 3840x2160 60fps .mov files that were shot on an iPhone X and an iPhone 12 using FilMic Pro in 4k, 60fps using the FilMic Quality setting (I was using Extreme, but thought this was the issue so went to lower bitrate FilMic Quality).

The issue is this. When I grab the playhead in the ‘Edit’ window to ‘scrub’ through the timeline it jitters all over the place, like it’s jumping between quarter and 1 second, which makes it hard for me to scrub and land on an exact frame. It always scrubbed super smooth, but now it jitters and I have to scrub really slow, no more than about twice speed, to edit, which is really slowing me down.

The codec I shoot on is the HLVEC thing in FilMic Pro, but, again, this was never a problem before, just a recent DaVinci Resolve update has changed something, a default setting perhaps, what I don’t know, but it was fine in Resolve for the past few years, now it is jittery when I scrub.

I’ve tried deleting the render cache and changing timeline proxy resolution to half, but none made any difference.

Anybody have any ideas, again, it was fine before so it’s not my computer or the footage or the codec I’m shooting on as it was always perfect for the past two years, just the past two months it changed with an update to Resolve.

One thing does fix it, and that’s if I right click on a clip and click the ‘Render cache colour output’ - where on my clip I get a red line that slowly turns to blue. Once it is blue I can scrub and it is smooth as silk. The only trouble with this is all the clips I edit are about 18 minutes long and about 10GB in size and I need to make cuts about every 5 to 10 seconds to chop out a few seconds and as soon as I make that cut the blue line goes back to red and I have to sit and wait an age for it to render out again. Given I make about 30 to 50 cuts that red to blue would add up to several hours so it is not an option.

Also, this is stuff I do on a regular basis so I don’t want to have to mess about creating proxies etc as the time it would take me for all these 18-minute 10GB clips before I could edit them would take longer than me just editing in real time without scrubbing. I’m trying to speed up my workflow, not slow it down.

Any ideas as to what I can do to not have this jitter thing going on in the timeline when I scrub. Again, it was fine until last or last but one update.

I’ve tried re-installing fresh download of Resolve, but that does not fix it either.

I’m desperate for help here to get this working as it did a few months back.

[Shrinivas Ramani]

Since we're not sure what the media resolution, format or codec is, it would be good to add that information, along with the iMac description - hardware description, OS version, peripherals to your post.

Please also check if generating proxies from Resolve (and setting playback to prefer proxies) helps. Unlike render cache, proxies don't need recalculating with edits or timeline changes.

I mentioned the format, codec and resolution, all above.

A "a high end iMac" is not a clear description. If it's not an M1, it may have difficulties decoding H.265.

A "a high end iMac" is not a clear description. If it's not an M1, it may have difficulties decoding H.265.

But like I said in my original post. It was perfect before. I bought he iMac brand new three years ago and I have never had a problem editing this footage, codec, frame rate before. I've edited hundreds of videos with this iMac with Resolve and this 4k footage. Again, I feel the need to 'repeat' the important fact that it was always a very smooth timeline before, it was just a couple of updates of Resolve back that screwed everything up.

But, for the record (again, it was always perfect so the iMac is not the issue here) the specs are: 27-inch 2017 iMac with 4.2 GHZ quad-core intel core i7 and 40gb memory and a Radeon Pro 580 8GB graphics card and a 1TB internal SSD hard drive. But, again, it was alway flawless before, same Mac, same video footage, just Resolve going through a few updates in recent months buggered things up.

I have exactly the same machine around here, working fine with DR 18.0.1.

So, maybe time for a fresh install, something may have got screwed up. Did you do a fresh install when going to Monterey? I always do that for a major OS version. Some people call me overcautious, but I never had a problem like yours.

It's easy to test before you go through that hassle: find a storage device you can erase, put a fresh Monterey on it, boot from there and add DR. Does it work?

I’m editing 3840x2160 60fps .mov files that were shot on an iPhone X and an iPhone 12 using FilMic Pro in 4k, 60fps using the FilMic Quality setting (I was using Extreme, but thought this was the issue so went to lower bitrate FilMic Quality).

H.264/H.264 has been a bad choice for post for years. Many years. If you can transcode the files to something with less overhead like ProRes 422HQ, I bet it'll do fine.

But in reality, 60fps on an 5-year-old iMac with an 8GB GPU will be a challenge. If it were a very recent (full-tilt) iMac Pro... maybe. The Mac Studios are good, the Mac Pros even better. The MacBook Pro M1 Maxes can work to a point. If you shot at 30fps, you might have a better chance of success.

How does the system rate when using Blackmagic Disk Speed Test?

If those files are H.265 (which is probably the case), transcode. Only Apple silicon has a decoder for that.

Uli Plank, thanks for that. So you have the same machine and no problem, which renders the following few posts pointless as you’ve just proved it is not the machine and I I said, and repeated, it was always fine before on this machine, it’s since DR updated a few months ago that I started having issues so it is a Resolve update thing that caused it. Definitely not my iMac as it was perfect before. Not sure how many times I have to try and drum this fact home - sorry to have a tad of attitude now, but I can’t stress this enough, yet folk keep coming back saying my Mac is too slow, which is it not, again, it was fine with Resolve before, same 4, video, same codec etc etc, then DaVinci put out an update and I do said update and it falls to crap since then.

Marc, yes, H.264 etc is a bad choice, but, again, I never had an issue with it in Resolve on my Mac before, it’s the update that killed it.

I need 60fps as this is what the person shoots in as I have to slow a lot of footage down to half speed, 30fps, and I need the smoothness of that for slow motion. Again, it was always shot at 60fps in 4k and, I repeat, I never had a problem until Blackmagic updated Resolve a few months back.

System rates as follows with Blackmagic Disc Speed Test is 2072.6 MB/s for Write and 2579.3 MB/s for Read so blistering there.

Marc, it’s pointless me transcoding files to ProRes. I’ve tried and converting an 18-minute clip takes about 15 minutes which means it takes even longer than it would for me to just scrub very slowly with the original clip so that will add time to my workflow. Remember, I’m doing loads of these videos every day and getting into transcoding would take too long so that option is definitely out.

I’ll cut/paste something from my original post:

“One thing does fix it, and that’s if I right click on a clip and click the ‘Render cache colour output’ - where on my clip I get a red line that slowly turns to blue. Once it is blue I can scrub and it is smooth as silk. The only trouble with this is all the clips I edit are about 18 minutes long and about 10GB in size and I need to make cuts about every 5 to 10 seconds to chop out a few seconds and as soon as I make that cut the blue line goes back to red and I have to sit and wait an age for it to render out again. Given I make about 30 to 50 cuts that red to blue would add up to several hours so it is not an option.”

Any thoughts on the the latter as to what the issue could be?

I have no problem using Resolve with it and H.264.
H.265 from a current iPhone does not work!

Check what you got there with MediaInfo (second tab).
To drive your point home, do a clean install of the system and DR 17 and tell us if it does what you expect.

I have no problem using Resolve with it and H.264.
H.265 from a current iPhone does not work!

Check what you got there with MediaInfo (second tab).
To drive your point home, do a clean install of the system and DR 17 and tell us if it does what you expect.

MediaInfo (second tab)?

When you say do a clean install of system, you mean Mac OS? I can't do that, I'll lose everything.

Do you actually read the posts?
"It's easy to test before you go through that hassle: find a storage device you can erase, put a fresh Monterey on it, boot from there and add DR. Does it work?"

And, yes, MediaInfo (free).

For whatever it might be worth:
Along with many other suggestions here have you also set your timeline to a lower resolution for editing which can then be put back for delivery?

Also, as to your system, how full are your disks?... and for some disks, how fragmented? I mention this as to your statement that things worked in the past but differ now. One thing that has likely changed is more stored data on your drives.

I shoot at 6K 60fps and 120fps a lot and even with what I keep I got a lot stored. I've got 8 M.2 drives on my system some SSD and a bunch of spinners (as well as a bunch of drives on a second system for backup.) The M.2 drives I use for working footage (5 of them), I do not delete from them unless I then reformat and copy from backup fresh. I have found that not doing so could slow things a bit.

My guess would be that your system is a bit weak for 4K 60fps, but since it has worked in the past then perhaps borderline. With my system I run my 6K, 8K or 12K 60fps footage at 1080p for editing when I have noticed a jittery jog on the timeline it has been either something that has messed up GPU (overload or something... don't know but restarting program fixes), some heavy color grading (selectively disable those nodes) or a full or stressed drive that the footage is on (put footage on fresh, fast drive.)

@Jeffrey
He posted data throughput values, which look fine.

@Nigel
A five years old iMac can have collected a lot of dust and might be throttling due to thermal issues. Get TGPro, which will work for a few days without payment and check temperatures.

Uli, I don’t have any spare drives and don’t want to spend £500 on a decent SSD external just on the hope that it fixes things, which I’m not sure it will.

Ok, MediaInfo, I had to google it, I thought you were talking about the second tab along called ‘Media Info’ in DaVinci Resolve, and I could not find such tab so, yes, I do read, but it was not clear.

Anyway, if I download MediaInfo, why? Again, please be clear about what I’m to do with that, apart from check what codec it is, frame rate, bit rate etc, all of which I know via Apple’s Quicktime and ‘display video monitor details’ tab.

Jeffrey, yes, my discs are only 20 percent used, mostly empty. In the past I’ve edited directly off SD (fast ones) cards in the card reader, but I can’t do that anymore, though I’ve tried with brand new cards. Just everything that was smooth is now a jitter fest.

Uli, with TGPro, should I only run this when the fans are spinning like mad, usually after 2 minutes of timeline scrubbing, or can I check temps etc anytime, like a few seconds after turning Mac on in morning?

I've just installed TG Pro and the menu bar says 55 degrees C and 1194 for RPM, not doing anything at the moment though, no editing, just have Safari browser open, Mail, Messages and the TG Pro software in 'trail' mode as I have not bought it. How does this temperature seem? Not sure what they should run at?

Hi Nigel. I feel your pain.

Everyone: what I hear from Nigel is that he's got the same footage that Resolve has been happy playing on this very computer. But now it's not. He's asking why.

So telling him to change his workflow isn't helpful.

Nigel: can you verify with more precision that it's a change in Resolve that's the issue here?
To do that I'm wondering if you'd install an earlier version of Resolve that DOES work with your footage.
Once you've found such a version I'd suggest screen capturing or videoing it working with that version. Probably also make a logfile dump from Help/Create Diagnostics Log on Desktop.

Do the same with 18.0.1 and then put all that and a project with enough media to exhibit the problem up on a cloud service and post a link here or PM BMD with it.

Once people here can see this actually happening and be able to reproduce it they'll be much more likely to investigate rather than telling you to change what you're doing.

Makes sense, Joe. Where can I find old versions to download?

Also, regarding temperature question above, I've just edited and rendered out a video in Resolve, fans lightly spinning away while doing the scrubbing and rendering and the temp to up as high as 88 during scrubbing and to 94 during the rendering out. The RPM got up to 2706 during the render out.

You can find lots of back releases on the BMD support page if you first click on the Resolve and Fusion icon.
Here's a direct link:

https://www.blackmagicdesign.com/suppor ... and-fusion

The first scrolling list has the releases.

Those older versions might be the first thing to try.

But if it doesn't help, get any cheap HDD, they should be under 50 bucks these days. They are OK to throw a boot system at them and see if anything is screwed up. It just means slower booting. Keep your video clips for testing on a SSD, though.