When I use an HDMI cable to link to a display screen or data projector when showing a Quicktime movie or a PowerPoint slide show the sound and video get more and more out of sync. I am using a MacBook Air M1 running Sequoia 15.5. It happens if the HDMI cable is 4k or not. I do NOT want to have to restart my laptop every time I go to use an external display using and HDMI cable.
MacBook Air 13″, macOS 15.5
Go to System Settings > Sound, select HDMI as the output device, and change its output format to 2-channel, 24-bit, 48.0 kHz. This resolves the vast majority of audio-video synchronization issues caused by audio processing delays.
Go to System Settings > Sound, select HDMI as the output device, and change its output format to 2-channel, 24-bit, 48.0 kHz. This resolves the vast majority of audio-video synchronization issues caused by audio processing delays.
Is the audio being output through the "display screen" or "data projector" ... or are you sending the audio out via the headphone port on your MBAir?
Drifting audio sync usually means that the sample rates do not match across the source media, the video output and/or the receiving unit (display, projector, etc.) Check the audio sample rate settings in your Mac, your display or projector and the QT movie(s) you are using.
Does this happen on ALL QT movies or PPT shows, or just certain ones?
That is the setting I am using. It means the audio and video get increasingly out of synch. Fun for my classes but no fun for the teacher.
Fix Sound and video not synched using HDMI cables with QuickTime and PowerPoint
