Fix Audio Delay
If lips move before the words arrive, or after, shift the audio by a few hundred milliseconds until they line up. The video stream is not re-encoded.
- Nothing is uploaded
- Free, no sign-up, no watermark
- Works offline once loaded
Drop a video here
or choose a file, or paste
MP4, MOV, WEBM, MKV, AVI, M4V, 3GP, FLV, WMV and more
Processed on your device. Nothing is uploaded.
How to use Fix Audio Delay
- 1
Add the video
Drop the out-of-sync video on the drop zone.
- 2
Find the offset
Watch a moment where someone speaks or something makes a sharp sound, and judge whether the sound is early or late.
- 3
Shift the audio
Move the Shift audio slider. Positive values delay the sound; negative values bring it earlier. 100 to 300 ms is common.
- 4
Apply and check
Press Shift audio, play the result to confirm the sync, then Download. Repeat with a small change if needed.
Why use Aback Video for this
10 ms steps
Fine control for lip-sync, where differences of 40 ms are noticeable.
Earlier or later
Fix sound that arrives late as well as sound that runs ahead of the picture.
Picture untouched
Only the audio timing changes; the video stream is copied.
Local
Done on your device, with no upload.
Frequently asked questions
How do I know which way to shift?
If lips move before you hear the words, the sound is late: use a negative value. If you hear the words first, the sound is early: use a positive value.
My video drifts out of sync over time. Will this help?
A single shift fixes a constant offset. If the gap grows through the video, the recording has a frame rate problem; re-encode it with Change Frame Rate or Convert Video first.
Is the video re-encoded?
No. The picture is copied, and only the audio is re-timed, so quality is unchanged.
Is my video uploaded?
No. Everything happens in your browser.
Can I fix subtitles that are out of sync?
Use Subtitle Sync Fixer, which shifts or stretches SRT, VTT and ASS timing.
Does it work on my phone?
Yes, and it is fast since nothing is re-encoded.