CoreVideo + Rosetta still clamps at 60Hz (since macOS 12)

Question

Created Sep ’25

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We set the CVDisplayLink on macOS to 0 or 120, and get the following. This then clamps maximum refresh to 60Hz on the 120Hz ProMotion display on a MBP M2 Max laptop. How is this not fixed in 4 macOS releases?

CoreVideo: currentVBLDelta returned 200000 for display 1 -- ignoring unreasonable value

CoreVideo: [0x7fe2fb816020] Bad CurrentVBLDelta for display 1 is zero. defaulting to 60Hz.

Answered by DTS Engineer in 858598022

Hello,

Much of CVDisplayLink is deprecated and as mentioned (thanks @galad87) Rosetta is "... available for the next two major macOS releases – through macOS 27".

The original intent of Rosetta was: "Rosetta is meant to ease the transition to Apple silicon, giving you time to create a universal binary for your app. It is not a substitute for creating a native version of your app."

All that said, time is of the essence to move on from CVDisplayLink (AVFoundation being the most straightforward alternative to CoreVideo). Likewise, dependencies on Rosetta need to be addressed within the documented timeframe.

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Answer 1

galad87 OP

Sep ’25

There will be no Rosetta for normal apps in the next major release, so I guess it will be technically fixed then 🤷‍♂️

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Answer 2

DTS Engineer OP

Apple

Sep ’25

Recommended

Hello,

Much of CVDisplayLink is deprecated and as mentioned (thanks @galad87) Rosetta is "... available for the next two major macOS releases – through macOS 27".

The original intent of Rosetta was: "Rosetta is meant to ease the transition to Apple silicon, giving you time to create a universal binary for your app. It is not a substitute for creating a native version of your app."

All that said, time is of the essence to move on from CVDisplayLink (AVFoundation being the most straightforward alternative to CoreVideo). Likewise, dependencies on Rosetta need to be addressed within the documented timeframe.

0

Answer 3

AlecazamTGC OP

1d

CVDisplayLink, which is already part of CoreVideo, is used by every macOS app. CADisplayLink is iOS. CAMetalDisplayLink is the compositor for Metal apps to avoid needing MTKView, but has a high iOS/macOS requirement. So I would assume CVDisplayLink isn't going away anytime soon unless Apple plans to break every app out there.

0 is a valid setting for the fps, and doesn't mean Apple computes 1/0 and gets some randomly large integer number, and then clamp the 120Hz display to 60Hz. 0 is meant to indicate "run at highest framerate of the monitor".

This only happens for apps compiled for x64 and run under Rosetta, and not if recompiled for arm64. macOS x64 runs the x64 app at 120Hz too. This has to also clamp any games using GPTK too.

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