Add Audio to Video

Replace or mix a soundtrack into an H.264 video and export an MP4 in your browser. Free to use with no generation credits.

Results

Editing monitor showing three colored tracks

Example

Your exported MP4 will appear here.

See examples

Replace the soundtrack or keep the original sound

Upload an H.264 MP4 or MOV up to two minutes and an audio file. Keep each file at or below 48 MB. Select Replace to swap the existing track or Mix to blend both tracks, then export an MP4.

When this helps

To add music under dialogue, choose Mix. For silent product footage or a clean replacement recording, use Replace.

Examples

Tripod camera pointed at a seated presenter — Keep the original dialogue audible when you add music to an interview.

Example

Mix a short music bed into interview footage to keep the original dialogue underneath. Select Replace for footage that should only play the new track.

Choose Mix or Replace for the soundtrack
Mode	Use when	Output to check
Mix	The original dialogue or ambience should remain audible	Listen for music masking speech or a jump in level.
Replace	The new track should be the entire soundtrack	Check that the new track starts in sync and covers the ending you need.

How to use it

Upload the video and a separate audio file.
Choose Mix or Replace and start the export.
Play the beginning and end of the downloaded MP4 to check timing and balance.

Settings & limits

Video: H.264 MP4 or MOV, up to 2 min
File size: Up to 48 MB per file
Export: MP4 in your browser, 0 credits

Questions about Add Audio to Video

Which source video format works?

Use H.264 MP4 or MOV, up to two minutes. Each input file can be at most 48 MB.

Will this tool send my source files to a provider?

The mix and export take place in your browser. Stay on the page until the export completes.

Does the MP4 export use credits?

The browser export costs zero credits. Generating the soundtrack with another tool has its own quote.

When should I choose Mix over Replace?

Choose Mix when dialogue or ambient sound should remain audible under the new track. Choose Replace when you only need the new soundtrack. Listen near the first spoken line and the ending to check balance and timing.