Exported video has lip-sync errors: how do you check frame rate and timebase?

Record real durations and sync positions before and after export

This applies to correct editor playback but misaligned exports or progressively drifting clips from different sources. Preserve sources and project settings and record rates and durations. One average frame rate does not describe every timestamp in variable-rate media. Audio codec delay and editing starts need separate inspection.

Inspect video timestamps, audio starts and speed changes

Inspect stream starts, timebases and durations with media tools and check whether video time was rewritten without corresponding audio changes. Distinguish duration-preserving conversion from playing frames at a different rate. If offset appears at one join, inspect that clip’s trim and timing rather than immediately stretching the whole soundtrack.

Preserve one timeline during frame-rate conversion

Normalize source starts on one timeline and intentionally choose duration-preserving frame conversion or speed changes with matching audio treatment. Export to a new file and preserve settings. Validate a short sample first; repeated fixed delays cannot track proportional drift. Repair source misalignment before exporting the entire set.

Check synchronization at the beginning, end and joins

Check clear speech near the beginning, middle and end and at every join, confirming matching mouth movements and complete endings. Review the actual final file in the target player. Success requires whole-timeline synchronization, not playability or a correct rate property. Equal reported durations can still conceal local mismatches.

This article processed no private video or measured a particular delay. Containers, encoders and players can handle starts differently and require destination testing. Video frame rate and audio sample rate are distinct. Irregular freezes or local speed changes usually cannot be repaired by one global offset.