M1 Mac BRAW playback glitching at 60fps - normal?

I've been experimenting with some BMPCC 4K footage on an M1 Mac mini, and while I'm generally happy with performance, I do notice some stuttering playing with 60fps BRAW @8:1 compression.

I initially though I had a timeline conformance issue using HFR with 23.976 / 60 (rather than 24/60 or 23.976/59.94), so did some tests with a 60fps project. Playback in the camera seems to be fine, but has a few "stutters" in Resolve. Curiously, the playback fps counter shows 60 and remains green when this happens, although it does often have a brief "hicough" right at the beginning of playback where I see the frame rate drop to 57 - 58 for an instant.

I also wondered whether optical image stabilisation in my lens my be interfering (I did a panning test on a tripod of some passing cars), but I can see the same effect, even when handheld and doing a fast pan.

Have I just reached the limit of the M1 Mac? CPU and GPU usage seem to be moderate so it's a bit surprising.

I'm using a 1080p timeline, and also experimented with optimized media (ProRes 422 HQ) and proxies (ProRes Proxy). The proxy is better, but still not perfectly smooth.

I also copied the clip from the external Samsung T7 I use for editing (connected via a TB3 dock which improves speeds) to the internal SSD. Again this was a bit better, but it was disappointing that an external SSD that should read at least 750MB/s has troubles playing back a BRAW 8:1 clip that is reported to have a bit-rate of 774Mb/s - note the difference between mega-bytes and bits. The SSD should have (in theory) plenty of bandwidth to play back the stream.

The M1 only has the free version of Resolve, but I have the Studio edition on a MacBook Pro 16 (8-core with AMD 5500M GPU) and a Windows Xeon E5-1650 workstation with a GTX1060 GPU). Both of these also show some issues with playback.

I should stress that these does not impact the ability to edit the footage. It's just very minor timing glitches that results in less than buttery-smooth playback.

I'm actually curious whether it's nothing to do with the computers, and some other issue. If proxies, optimised media and fast SSDs don't completely resolve the issue, perhaps something else is going on?

Any suggestions? Thanks!

Yes, Resolve sucks at vsync-ing its UI. It can't playback anything smooth when playback FPS equals screen panel refresh rate.

In that regard Resolve still lives in the 90s. Many threads about it. No fix whatsoever for years.

I suppose it's left broken to sell Decklink cards.

Yes, Resolve sucks at vsync-ing its UI. It can't playback anything smooth when playback FPS equals screen panel refresh rate.

In that regard Resolve still lives in the 90s. Many threads about it. No fix whatsoever for years.

I suppose it's left broken to sell Decklink cards.

That's a very interesting answer, and one that I hadn't even considered! I'll check if I can change the frequency of my monitor to see if it makes a difference.

It's not a huge deal for me because I will probably only shoot at 60fps to get slow-motion on a 24 or 25fps timeline, and even if I were to use 60fps playback, it's still useable...

Thank you for the feedback.

Just posting some further information on this based on @peterjackson's suggestion for the cause of glitchy 60fps playback in Resolve:

viewtopic.php?f=21&t=105097

viewtopic.php?f=21&t=86042

viewtopic.php?f=21&t=86623


I'll do some more tests recording in ProRes 422 & H.264 (on a GH5) and importing these into FCPX to confirm whether I have any hardware playback issues with 60fps UHD footage, but I expect it will be fine.

Another thing to try is to change the panel frequency on my MBP16 to see if that resolves the issue (which is an accidental pun!).

Try setting your timeline frame rate to match your footage frame rate. Mismatched rates incur extra processing, which can even cause discontinuities in playback when footage/timeline is 23.976/24, let alone 60/x.

And the current M1 lineup isn’t really going to be great at pushing Resolve to the limit, so 60p is probably a little dicey anyway.

ProRes should run the same in Resolve as it does in FCPX. In terms of playback performance, prores LT and proxy are both very speedy, then there’s a big jump to 422, HQ, and above. I wouldn’t recommend coloring either, though. I normally edit LT or Proxy and color the camera originals.

The free version of Resolve throttles GPU usage in some situations (and I don’t think the exact situations are clearly documented anywhere). Moving licenses from one computer to another is as simple as deactivating it on one and activating it on the other. Deactivation is under the “help” menu.

Sent from my iPad using Tapatalk

Try setting your timeline frame rate to match your footage frame rate. Mismatched rates incur extra processing, which can even cause discontinuities in playback when footage/timeline is 23.976/24, let alone 60/x.

And the current M1 lineup isn’t really going to be great at pushing Resolve to the limit, so 60p is probably a little dicey anyway.

ProRes should run the same in Resolve as it does in FCPX. In terms of playback performance, prores LT and proxy are both very speedy, then there’s a big jump to 422, HQ, and above. I wouldn’t recommend coloring either, though. I normally edit LT or Proxy and color the camera originals.

The free version of Resolve throttles GPU usage in some situations (and I don’t think the exact situations are clearly documented anywhere). Moving licenses from one computer to another is as simple as deactivating it on one and activating it on the other. Deactivation is under the “help” menu.

Sent from my iPad using Tapatalk

I initially thought that I had a discrepancy between timeline and footage frame rates, but no. The issue does not appear to be related to the encoding of the clip, because even ProRes Proxy and optimised media show the same issue.

As someone suggested, running the clip in the Color page doesn't show the problem - it plays back smoothly - so the issue is with playback in the Cut and Edit pages. The threads I posted above discuss this is more detail.

It's a bug, but not a serious one for my usage. I will rarely use 60fps on a 60fps timeline, and even if I did, playback is good enough for editing.

The M1 Mac seems to be quite capable of playing back 4K 60fps BRAW or ProRes 422 HQ, (at least with a basic LUT applied) which is nice to know. No doubt it will struggle with more complex edits, but it's quite good for the price.

As someone suggested, running the clip in the Color page doesn't show the problem

ive found this be the case with every tab between the color page, edit, cut, fusion. they all operate like completely different programs in some regards. im really falling into a love/hate relationship with this. good luck