What is your operating system?
Win 10 Professional x64
What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
Shotcut-Version 20.11.28 x64
Can you repeat the problem? If so, what are the steps?
(Please be specific and use the names as seen in Shotcut, preferably English. Include a screenshot or screen recording if you can. Also, you can attach logs from either View > Application Log or right-click a job and choose View Log.)
Everytime when i use a negative audio offset (-350 ms in settings/audio) for my videos, the video output becomes laggy. Not only in preview, also in final video the picture is still stuttering. Looks like there are missing frames.
I export with 30 fps, final videos has exact 30 fps.
Settings > Synchronization has no affect on the export. That is strictly for preview in the app. However, it is not clear if you refer to Properties > Audio > Sync instead because you said “settings/audio” and there is no such thing exactly. It is unclear.
Most laggy problems can be attributed to filter or effect processing and their impact on real-time display depends on the number or complexity of the effects (filters) and the user’s computer.
To improve performance there are two features in Shotcut that do not seem to be active in your project:
Preview scaling and proxy function.
With this, the display in Shotcut should be more stable.
The problem of export is something else.
what features does the video source have?
