Can added audio make the video longer?

No. Playback is limited to the original video duration, and any added track extending beyond that endpoint is truncated.

How do Replace and Mix differ?

Replace outputs only the added track. Mix combines it with the source soundtrack using separate volume values.

Which part repeats when Loop is enabled?

Only the trimmed interval between the audio handles repeats from its insertion point until the video ends.

Does trimming change the original audio file?

No. The handles define the segment used in preview and export; the uploaded audio remains untouched.

Back to Video Tools

Add Audio to Video

Position and trim a separate soundtrack, then replace the video's audio or mix both tracks with independent volume controls.

Add a video

Add or mix a separate audio track with one video.

Choose video

MP4, MOV, WebM, MKV or AVI · or drag and drop

Your files are processed locally and are never uploaded.

How to use Add Audio to Video

1
Choose a video, then add one MP3, M4A, WAV, OGG, Opus, FLAC or WebM audio file.
2
Drag the Audio block to set its insertion point and use the two handles to trim the source track non-destructively.
3
Choose Replace or Mix, set new-track and original-track volume where available, and enable Loop when the selected segment is short.
4
Preview synchronization, click Add Audio to Video and download the resulting MP4.

Frequently asked questions

About Add Audio to Video

Add Audio to Video aligns two independent media sources on one compact timeline. The block controls when the soundtrack begins, while its handles select the exact portion used without modifying the audio file itself.

Replace mode creates a new soundtrack; Mix mode balances the new and existing tracks. A chosen segment may play once or loop, but output length always follows the video. Compatible video can remain stream-copied during local audio processing.