Camera Preview Shows Cinematic-Like Delay After ~2 Hours of Streaming

[noho501]

Hi,

I encountered an issue with the camera preview when using HaishinKit 2.1.0. After streaming for about 2 hours, the preview in PiPHKView starts to show a cinematic-like delay/lag. It looks similar to when preferredVideoStabilizationMode = .cinematic, but in my case it is explicitly set to .off. Re-setting this property does not resolve the problem.

• The stream output to viewers remains fine — the issue only affects the local preview.
• No relevant logs appear (even with LBLogger.level = .trace).
• Resetting with attachVideo(nil) and removeOutput fixes the issue temporarily.

Environment:

• Streaming to Twitch 1080p60fps
• Using VideoEffect (adding image overlay)
• Device: iPhone 13 Pro Max
• iOS: 18.5

I would like to know if there’s a recommended way to keep the preview smooth without this delay. Any guidance would be greatly appreciated.

Thank you!

[shogo4405]

I don’t have that kind of experience, so I’m not sure.
Would it be the same with MTHKView as well?

[noho501]

I tested with MTHKView for more than 3 hours, and it worked fine without any delay. Could the issue be related to AVSampleBufferDisplayLayer in PiPHKView? I also tried using self.cameraScreenPreview.layer.flushAndRemoveImage(), but the problem still persists when using PiPHKView. Do you have any idea what might be causing this?

[shogo4405]

It seems that the host clock held by AVCaptureSession differs from the host clock of AVSampleBufferDisplayLayer, causing the display to drift during long streams.
Fixing this will require some changes on the HaishinKit side.

[shogo4405]

Since testing takes time, I was only able to run it about twice, but I believe this improves the issue.
#1796

[noho501]

Thank you so much. I’ll run a test and share the results with you.

[noho501]

Thank you very much. I tested it for 6 hours and everything worked fine.