Movie window turns black when moved to an external display

[PierreFunck]

Hello, I just installed DP 10.11 on a brand new iMac Pro (macOS 10.15.2), and the movie window turns black as soon as I move it to an external display (HDMI via a HDMI-to-USB-C adapter). Can anyone reproduce this behaviour? Is there a workaround?

Thanks for your help!
Pierre Funck

[PierreFunck]

There is a simple workaround: resizing the movie window brings back the video display. So it's not a serious bug...

[mikehalloran]

I also have an iMac Pro but mine is running Mojave. My monitors are hooked up via USB-C to DisplayPort cables. Moving the Movie window to either of my external monitors works great.

I had heard of issues with the adapters so I went for cables instead. In addition, DisplayPort supported features that HDMI did not (some Apple firmware updates addressed this). I have no idea if any of this is an issue.

I won't get to it today but I can check my MBP running Catalina. It has Thunderbolt 2, not TB3 and I don't know if I have the right adapters to hook it up to my LG 4K monitors but I will check. If there's a MiniDP to HDMI cable around here somewhere, I'm in business (MiniDP plugs into TB 1/2 ports on an older Mac).

[mikehalloran]

There is a simple workaround: resizing the movie window brings back the video display. So it's not a serious bug...

Maybe but some display issues are not bugs. Here are a couple of suggestions—if they don't work, click on the default to undo any changes. Try a different profile under

System Profiles/Displays/Display Scaled
Not all scale profiles work for everything — this goes back to the earliest external monitors.

or

System Profiles/Displays/Color Color Profile
There's an issue with 10 bit color that can affect performance of some apps. Selecting any other profile other than Default can sometimes make a difference.

[PierreFunck]

There is a simple workaround: resizing the movie window brings back the video display. So it's not a serious bug...

Maybe but some display issues are not bugs. Here are a couple of suggestions—if they don't work, click on the default to undo any changes. Try a different profile under

System Profiles/Displays/Display Scaled
Not all scale profiles work for everything — this goes back to the earliest external monitors.

or

System Profiles/Displays/Color Color Profile
There's an issue with 10 bit color that can affect performance of some apps. Selecting any other profile other than Default can sometimes make a difference.

Thanks for your reply! The display is not scaled, and I tried changing the profile – doesn't help. So it's definitely a bug (can't tell whether in Catalina or in DP). The external display works perfectly for all other applications and types of window, it's only the DP movie window that has problems.

[mikehalloran]

Thanks for your reply! The display is not scaled, and I tried changing the profile – doesn't help. So it's definitely a bug (can't tell whether in Catalina or in DP). The external display works perfectly for all other applications and types of window, it's only the DP movie window that has problems.

Technically, there's no such thing as a DP movie window. The window is QuickTime. It syncs with DP so, if the audio wasn't behaving, I could see a DP issue but it's the video that doesn't appear on your external monitor till re-sized. If you have access to telephone support like we do in the States, I would try to get Apple to look at this — especially since it may relate to Catalina.

[PierreFunck]

Technically, there's no such thing as a DP movie window. The window is QuickTime. It syncs with DP so, if the audio wasn't behaving, I could see a DP issue but it's the video that doesn't appear on your external monitor till re-sized. If you have access to telephone support like we do in the States, I would try to get Apple to look at this — especially since it may relate to Catalina.

It's not as simple as that... Windows in the QuickTime Player app can be viewed on the external monitor without problems, so it's about the way how DP interacts with QuickTime.

Meanwhile I got a response from MOTU tech support: they are aware of the issue (be it in DP or in Catalina or both) and working on a fix.