Browser Source audio control causes excessive WindowServer CPU usage on Intel macOS Tahoe

Operating System Info

macOS 26

Other OS

No response

OBS Studio Version

32.2.1

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/rUnt628GBmlbGq83

OBS Studio Crash Log URL

No response

Expected Behavior

Expected Behavior

Enabling OBS audio control for a Browser Source should not significantly increase WindowServer CPU usage while OBS is idle.

Current Behavior

Summary

Enabling "Control audio via OBS" for a Browser Source causes WindowServer CPU usage to increase dramatically on macOS.

The issue occurs before streaming or recording starts, suggesting it is unrelated to the video encoder.

Actual Behavior

• With Browser Source audio control disabled:

  • WindowServer remains around 20–40% CPU.

• Immediately after enabling "Control audio via OBS":

  • WindowServer jumps to approximately 90–100% CPU.

• Disabling audio control again (without restarting OBS):

  • WindowServer immediately returns to approximately 20–40% CPU.

The behavior is reproducible.

Steps to Reproduce

1. Create a new Scene Collection.
2. Create a new Scene.
3. Add one or more Browser Sources (tested with https://ccfolia.com pages).
4. Confirm that "Control audio via OBS" is disabled.
5. Observe WindowServer CPU usage in Activity Monitor.
6. Enable "Control audio via OBS" for a Browser Source.
7. Observe WindowServer CPU usage again.
8. Disable "Control audio via OBS" again.

Anything else we should know?

Environment

• macOS: Tahoe 26.5.2
• Hardware: Intel Mac (Intel GPU)
• Output encoder: Apple VT H.264 (Hardware)
• Audio encoder: CoreAudio AAC

Additional Investigation

I performed several isolation tests:

• Streaming not started → issue still occurs.
• Recording not started → issue still occurs.
• Hardware encoder settings do not affect reproduction.
• Browser Sources alone do not cause high CPU usage.
• The trigger is specifically enabling "Control audio via OBS".
• Disconnecting the external display does not change the behavior.
• OBS itself does not consume unusual CPU; the increased usage is almost entirely in WindowServer.

I also noticed that macOS Tahoe appears to have increased WindowServer CPU usage in Photoshop after updating the OS, so this may involve an interaction between OBS Browser Source audio handling, Chromium/CEF, and macOS Tahoe's rendering or media pipeline.

If additional logs or testing are needed, I'd be happy to provide them.

Start by reproducing the issue with a Browser Source and the “Control audio via OBS” option, then inspect the provided OBS log at https://obsproject.com/logs/rUnt628GBmlbGq83 and the Browser Source audio-control path. The work is done when enabling the option no longer causes the reported WindowServer CPU increase on Intel macOS Tahoe, while Browser Source audio control still functions.