Video Stutter when ‘displays have separate spaces’

[Star72]

Just picked up a MacBookPro 16” M1 Max 32gb 1TB. Have it connected to a 5k Lg + Apple Thunderbolt Display 27” (Apple thunderbolt adapter) + 27” iMac in target display mode via an HDMI to DisplayPort adapter.

All displays work fine however video playback (QuickTime or VLC - playing h.264) stutters every 10 seconds for a fraction of a second. Some investigation traced this to my use of the setting in Mission Control - ‘Displays have their own spaces’. If I have this de-selected any video I play stutters - even a single 1080p video on one screen. If I leave it selected every video plays flawlessly - even 4 x 4K videos one on each screen.

Strangely only QuickTime and VLC do this - IINA works fine with smooth playback regardless of the ’displays have their own spaces’ setting.

I have also recreated this across 3 full installs of Monterey 12.4.

Has anyone else experienced similar or have any ideas what could be causing this?

 

[chabig]

I think you probably nailed it. When ‘Displays have their own spaces’ is deselected, the computer is probably managing more pixels because each space contains two screenfuls of bits. Letting each display have its own space reduces the number of pixels in each space.

 

[Star72]

Just to close this out, I visited the Apple store, surprisingly the laptop passed their diagnostics tests for graphics but once attached to two Studio Displays the stuttering video was so bad on the laptop itself it barely played at all. Its now in the process of being swapped out for a new one which is great news.

 

[Star72]

Just to close this out, I visited the Apple store, surprisingly the laptop passed their diagnostics tests for graphics but once attached to two Studio Displays the stuttering video was so bad on the laptop itself it barely played at all. Its now in the process of being swapped out for a new one which is great news.

Replacement MacBook Pro M1 max now received and the issue remains, connect 2 5k external displays and deselect ‘displays have their own spaces’ - multiple simultaneous video playback in QuickTime stutters. Bug report filed with Apple.

Workaround for now is to utilise Iina - although that comes with some color management trade-offs.

 

[Pressure]

I can confirm this behaviour with my M1 Max Mac Studio.

The monitor I use requires two DP connections for each half of the screen (each side being 3840x4320 pixels) and when I have deselected "Displays have separate Spaces" videos will start to stutter when using the full width (3840 pixels) the moment it no longer is the "front facing" / active application (be it through Safari, Chrome, Brave, VLC or Apple TV+ applications) and I use the other part of the screen. If I make the application smaller than the full width it will play smoothly most of the time.

I couldn't figure out why until I just tested this by selecting "Displays have separate Spaces".

This could be a power saving feature bug which messes with playback of media.

We should definitely report this behaviour with the Feedback Assistant.

 

[Star72]

Thanks for confirming it’s not an isolated issue Pressure! As the issue is also in the Ventura Beta I have lodged a report with Feedback Assistant, hopefully it gets picked up and looked at.

 

[simacc]

I have this exact issue too. I'm only seeing it in Safari (Youtube) and Photos app videos.

All other browsers are fine (Chrome, Vivaldi), and VLC...

Just found this thread now. Had started a thread here: https://forums.macrumors.com/thread...ideos-2x-displays-studio-and-a-2k-32.2361747/

 

[Pressure]

This appears to be fixed in the newest beta of Ventura (at least with the Dell UP3218K). No dropped frames now with "Displays have separate Spaces" unchecked.

 

[Boomhowler]

I can confirm this behaviour with my M1 Max Mac Studio.

The monitor I use requires two DP connections for each half of the screen (each side being 3840x4320 pixels) and when I have deselected "Displays have separate Spaces" videos will start to stutter when using the full width (3840 pixels) the moment it no longer is the "front facing" / active application (be it through Safari, Chrome, Brave, VLC or Apple TV+ applications) and I use the other part of the screen. If I make the application smaller than the full width it will play smoothly most of the time.

I couldn't figure out why until I just tested this by selecting "Displays have separate Spaces".

This could be a power saving feature bug which messes with playback of media.

We should definitely report this behaviour with the Feedback Assistant.

wait, the Dell 8k display works fine with MacOS M1 max/ultra?

 

[Pressure]

wait, the Dell 8k display works fine with MacOS M1 max/ultra?

Fine might be overstating it. It will occasionally detect both sides of the display correctly for glorious 4K HiDPI 😅

It will appear as two 3840x4320 monitors if doing some fiddling and adding that resolution with either SwitchResX or by other means.

You can see the issue in this video:

If you reconnect the display enough times it will show up correct though ... but it's honestly a ****** situation. I already had the Dell UP3218K when I bought the Mac Studio, so I am not going to downgrade to a lesser monitor.

 

[Don MacDonald]

Checking in as I am having this issue as well (16” M1 MBP with Studio Display). Turning on Displays Have Separate Spaces does resolve it, although I would prefer not to use spaces like this, oh well...hoping there is a fix. Although I suspect it may be a memory issue as suggested above. That said, I’ve noticed the behavior not just on QT, but on YouTube and AppleTV as well (although it is intermittent...sometimes the video works just fine!)

 

[Tagbert]

Replacement MacBook Pro M1 max now received and the issue remains, connect 2 5k external displays and deselect ‘displays have their own spaces’ - multiple simultaneous video playback in QuickTime stutters. Bug report filed with Apple.

Workaround for now is to utilise Iina - although that comes with some color management trade-offs.

I’m curious, what is the benefit from displays having their own spaces?

 

[galad]

Are you running the latest version of macOS 13? I remember reading that it had been fixed recently.

 

[terhorstj]

Mac mini with M2 Pro and 2x27" 4K displays. Disabling "displays have separate spaces" causes bad video stutter in Chrome, Arc, Firefox, but NOT Safari. If you disable hardware acceleration in Chrome settings the problem goes away - however this means that all graphics are being rendered by the CPU which uses higher loads. I also get UI lag in a few random apps like Photos and SublimeText. I have found however that all of this stutter/lag only occurs when the windows are placed along the "inside" edges of the screens. This is such a bizarre set of conditions. I think Apple has some serious bugs with the M chip GPU.

 

[terhorstj]

I’m curious, what is the benefit from displays having their own spaces?

I absolutely hate the behavior of macOS with the "screens have separate spaces" options turned on - I have been turning off this feature ever since it was introduced in (I think) Mavericks. With the option turned on, apps always open in the active screen, rather than the last screen they were placed on; the dock hops from one screen to the other if you place your mouse at the bottom of the screen; menu bar is duplicated on both screens which happens to drive me crazy. I'm sure there are more.

 

[Don MacDonald]

Good catch on the UI stutter in Photos...I don’t know what you mean by “inside edges of the screens” though. I find that Photos will do a stutter or lag when opening a photo that hasn’t been opened recently (so it’s opening from the cloud perhaps). I don’t mean that it’s initially blurred (which is expected behavior), I mean the zoom animation will stutter and there will be a visible screen refresh. Although it seems once I have been playing around in Photos a while, this behavior stops.

I absolutely hate the behavior of macOS with the "screens have separate spaces" options turned on

Totally agree on this. I’m debating whether to just endure the video stutter from time to time; whether the “Displays have separate spaces” behavior is worse than the video stutter is now an open question.

 

[terhorstj]

.I don’t know what you mean by “inside edges of the screens” though.

I mean the right edge of the left screen and the left edge of the right screen.

There's a discussion board here with a bunch of people trying to sort out the issue. They all seem to think it's a bug in the software, but it really does appear to be a graphics or OS thing. https://youtrack.jetbrains.com/issue/JBR-4983/MacOS-Ventura-External-monitor-lagging

 

[5580463]

is anyone on the Sonoma beta that can see if the problem persists?

edit: problem still present in dev beta 5