Final Cut Pro/Youtube sync problems

[Badagri]

I'm having major issues with uploads that the video becomes out of sync with the sound with mobile devices. Clips play fine on Windows and OS X but as soon as I upload to Youtube to view on mobile devices, the video drifts out of sync (slows down) with the sound going on. But everything stays in sync on two computers with VLC, QuickTime and via the browser.

I've checked many articles and Youtube videos on exporting for Youtube yet none of them solve the issues. As I'm now really stumped on what is wrong.

Gameplay videos were recorded 60fps, mp4, H264. Exported mp4 and H264.

Even checked to compare setting for Youtube. https://support.google.com/youtube/answer/1722171?hl=en-GB

Totally at a loss what would be wrong. Restarted the iPad and iPhone both iOS 11.2.6, reinstalled Youtube apps. Tried many settings in Final Cut Pro and nothing solves it.

Surely if the video was out of sync it would be on all devices, right?

 

[casperes1996]

Is it out of sync on all devices on YouTube, or is that only mobile? Do you use the export option for YouTube or manual YouTube export?

How severe is the sync issue? Could it be an internet issue? Does it occur on all quality settings on YT?

 

[Badagri]

Only mobile devices such as pads and phones but fine on laptops and computers. I used a customised Master default setting for more control then tried compressor so I can manually upload the file.

The video starts drifting about 10 minutes and gradually gets worse out of sync where it can build up to 10 seconds out of sync the longer it keeps playing. Yet I'm not suffering it with other videos on Youtube with iPad's and iPhones. Only my own once uploaded. It does happen with all quality settings on my file on Youtube.

The video seems to run faster while the audio remains perfect.

 

[casperes1996]

Only mobile devices such as pads and phones but fine on laptops and computers. I used a customised Master default setting for more control then tried compressor so I can manually upload the file.

The video starts drifting about 10 minutes and gradually gets worse out of sync where it can build up to 10 seconds out of sync the longer it keeps playing. Yet I'm not suffering it with other videos on Youtube with iPad's and iPhones. Only my own once uploaded. It does happen with all quality settings on my file on Youtube.

The video seems to run faster while the audio remains perfect.

I would contact YouTube's support team if I were you. Sounds incredibly strange