Contents
Why use this free toolHow to add audio to a video in 3 stepsAdd any kind of audioUse the add audio tool on any deviceSafe, private and freeThis tool vs other ways to add soundPopular usesHow adding audio worksAdd audio tool features at a glanceFor developers: the ffmpeg commandFrequently asked questionsA silent screen recording needs narration. A clip with bad sound needs a clean voice-over. A video needs a sound effect or an audio track recorded separately.
Rekreate's free tool adds any audio file to a video. Replace the original sound completely, or mix the new audio with it at the volume you choose. The finished video is always exactly as long as the original.
Why use this free tool
Replace audio in a video
Swap the original sound for a new track.
Mix new audio with the original
Keep the original sound and add a second track under it.
Add a voice-over to a video
Narration for a tutorial, a demo or a silent clip.
Set the volume
Add the new track at 100%, 50% or 25%.
Loop short audio
Repeat a short sound to fill the whole video.
No watermark, no sign-up
Free and clean.
How to add audio to a video in 3 steps
Upload the video and the audio
Drop the video in the first box and the audio file in the second.
Choose replace or mix
Set the volume of the added track, and whether it should loop.
Download
Press Start and save the MP4.
Add any kind of audio
Voice-overs
Narration recorded separately, as MP3, WAV or M4A.
Sound effects
Add a whoosh, a click or ambience under the video.
Separately recorded sound
Put audio from an external microphone on the camera video.
Audio from another video
Upload a video as the audio source and its sound is used.
Music
For a music bed that ducks under speech, use add music to video.
Any audio format
MP3, WAV, M4A, AAC, FLAC and OGG.
Use the add audio tool on any device
On Windows PC and Mac
Add audio to videos in any browser on Windows or Mac.
On iPhone and Android
On iPhone or Android, pick the video and a voice memo or audio file and save the result.
In any modern browser
Chrome, Safari, Edge and Firefox all work. There is no app, plugin or extension to install — the processing happens on our servers, so an old laptop is as fast as a new one.
Safe, private and free
No account, no sign-up
Open the page and use it. There is nothing to register and no email address to hand over.
Files deleted automatically
Your upload is deleted the moment processing finishes, and the result 60 minutes later. Files are not shared, published or used for anything else.
Encrypted in transit
Uploads and downloads go over HTTPS, the same encryption your bank uses in the browser.
No watermark, ever
The file you download is clean. No logo in the corner, no intro card, no "made with" frame at the end.
This tool vs other ways to add sound
vs. video editors
An editor gives a timeline, but for putting one track on a video it is a lot of steps.
vs. apps with watermarks
Many mobile apps add a logo to the result. This does not.
vs. add music
This tool adds audio at a fixed level. Add music lowers the music automatically when someone speaks.
Popular uses
Narrate a screen recording
Record the voice-over separately, then add it.
Replace bad camera audio
Use the clean sound from a separate microphone.
Dub a video
Replace the voice with a translated voice-over.
Add ambience to a silent clip
Rain, city or nature sounds.
Put a voice note on a video
Combine a WhatsApp voice note with a clip.
How adding audio works
Your video and audio are uploaded over HTTPS and processed on Rekreate's servers with FFmpeg. In replace mode, the new audio is set to your volume and becomes the only sound track; in mix mode, it is blended with the original sound. The result is cut to exactly the length of the video, and short audio is repeated if you chose loop.
When possible the picture is copied without re-encoding, so it keeps its original quality. Uploads are deleted after processing, results after 60 minutes.
Add audio tool features at a glance
| Modes | Replace the sound, or mix with the original |
|---|---|
| Added track volume | 100%, 50% or 25% |
| Audio formats | MP3, WAV, M4A, AAC, FLAC, OGG, or a video with sound |
| Output | MP4, same length as the video |
| Price | Free |
| Sign-up | Not needed |
| Watermark | None |
| File size | Up to 95 MB per file |
| Video length | Up to 10 minutes |
| Files kept | Upload deleted after processing, result after 60 minutes |
For developers: the ffmpeg command
Replace a video's sound on your own machine.
ffmpeg -i video.mp4 -i audio.mp3 -map 0:v:0 -map 1:a:0 -c:v copy -c:a aac -b:a 192k -shortest output.mp4-map- Take the picture from the first file and the sound from the second.
Frequently asked questions
How do I add audio to a video for free?
Upload the video and the audio file above, choose replace or mix, and press Start.
How do I replace the audio in a video?
Choose "Replace the sound". The original sound is removed and the new audio is used.
Can I keep the original sound and add more?
Yes, choose "Mix with the original" and set the volume of the added track.
What if the audio is shorter than the video?
The rest is silent, unless you turn on loop.
What if the audio is longer than the video?
It is cut at the end of the video.
Can I add a voice-over recorded on my phone?
Yes, voice memos in M4A or MP3 work.
Can I add music that gets quieter when people talk?
Yes, use add music to video.
Can I use this on my phone?
Yes, on iPhone and Android.
Is there a watermark?
No.
What is the maximum size?
Up to 95 MB per file and 10 minutes.
Does the video lose quality?
No, the picture is copied without re-encoding when possible.
Can I use a video as the audio source?
Yes, upload a video in the audio box and its sound is used.
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