Replace audio in video: add new sound to a video
Put a new soundtrack on any video, keeping the picture exactly as it is.
10M+ files processed since 2021
More options
Free for the first hour, 10 times a day. No sign-up.
Hear the difference
Play Original, then New sound.
Made with Replace audio in video
How to add audio to a video
- 1
Add the video, then the new sound.
- 2
Keep the video first, and shift the sound if it needs it.
- 3
Download the video with its new sound.
Replace, or mix in
Audo's Replace audio in video tool takes a video (MP4, MOV, MKV, WebM, AVI) and a new sound, either an audio file (WAV, MP3, M4A, AAC, FLAC, OGG, Opus, WebM, AIFF) or another video, each up to 10 GB without an account, free for the first hour of each video, 10 times a day, with no sign-up. It merges the audio and video into one file: the new sound replaces the old one whole, and the picture is copied untouched.
Use it for a voiceover recorded after filming, narration in another language, a cleaned-up copy of the original sound, or music for a clip with nothing worth hearing. The new sound keeps its own volume, turned down slightly only if it would clip. If it needs to start later or earlier, Offset under More options shifts it, such as 0.5 or −0.5 seconds.
Music under people talking is mixing, not replacing: set the music under the voices in Mix audio, which lowers it while anyone speaks, then bring the mix back here. The page takes files, not links, so for a video already on YouTube, download your own copy from YouTube Studio first.
Questions
How do I add audio to a video?
Add the video at the top of this page, then the new sound, and download the video with its new sound. The new sound takes the place of the old one completely.
Is there a free way to add audio to a video?
Yes. Swapping a video's sound on Audo is free for the first hour of each video, 10 times a day, with no sign-up. Longer videos cost $0.01 a minute ($0.60 an hour) with no subscription: see pricing.
Can I keep the voices and add music under them?
Not on this page, which swaps the whole sound. Take the sound out with Extract audio from video, layer it with the music in Mix audio, then put the mix back on here.
Can I add sound to a video that has none?
Yes. A silent video works the same way, and the new sound becomes its only sound.
How do I add audio to a video on iPhone?
Open this page in your iPhone's browser, add the video and the sound, then download the new video. Android works the same way. Files up to 10 GB work, and up to 10 hours when signed in.
What if the new sound is shorter or longer?
The video keeps its length. Sound that runs past the end is cut off, and if the sound ends first, the rest of the video plays silent.
Does the picture change?
No. It's copied frame for frame, so it loses nothing. You get the same kind of file back: an MP4 stays an MP4, and a MOV a MOV.
Can ChatGPT add music to a video?
Yes, with Audo added to it. Attach the video and the music, then ask ChatGPT to put the music under the voices, and it mixes them with Audo and hands back the video with its new sound. Claude works the same way. Add Audo to your assistant once, and it's there in every chat.
More tools
- Audio enhancerMake any recording sound studio‑quality.
- Remove noiseClears the background, keeps your voice.
- Remove echoMake voices sound close.
- Vocal removerSeparate vocals, music, and stems.
- Stem splitterSplit vocals, drums, and bass.
- Karaoke makerRemove vocals, keep the music.
- Change pitchMove the key up or down.
- Change speedSpeed up or slow down audio.
- Key and BPMFind a song's key and tempo.
- Transcribe audioSpeech to text, who said what.
For AI assistants and developers
Ask ChatGPT, Claude, or a coding agent to do this for you, or call it from your own code. When an agent's free result is cut short, it gives you a link to finish the whole file, no sign-up.
Show the free API call
curl -F video=@talk.mp4 -F audio=@talk-clean.wav https://audo.ai/api/try/swap-audio -D response.headers -o response.body