Add Audio to Video
Upload Video
Click or drag & drop a video file
Upload Audio
Click or drag & drop an audio file
Audio Track
Audio Added Successfully!
Merge Info
Audio Mode
Audio Volume
Output
How to Use
Upload Files
Upload a video file and an audio file side by side.
Choose Mode
Replace the original audio entirely or mix in the new audio.
Adjust Settings
Set audio volume, output format, and duration handling.
Merge & Download
Click "Merge" and download the combined video.
Use Cases
Add royalty-free music or a custom soundtrack to your video content.
Record narration separately and merge it with your video footage.
Add intro music, background tracks, or commentary to YouTube content.
Add trending audio or sound effects to videos for TikTok, Reels, or Shorts.
Add explanatory audio to screen recordings or slideshow videos.
Combine a static image or animation video with podcast audio for video platforms.
Replace noisy, low-quality, or unwanted audio with a clean recording.
Replace the original language audio with a dubbed voiceover in another language.
Frequently Asked Questions
What file formats are supported?
For video: MP4 (H.264), WebM (VP8/VP9), MOV, AVI, OGG and more. For audio: MP3, WAV, AAC, OGG, FLAC, M4A. MP4 + MP3 is the most universally compatible combination.
Is my data uploaded to a server?
No. All processing happens 100% in your browser using FFmpeg WebAssembly (ffmpeg.wasm). Your files never leave your device. No data is sent to any server.
What happens if the audio is longer than the video?
By default, the audio is trimmed to match the video duration. You can also choose "Shortest" to end the output when either the video or audio finishes.
What happens if the audio is shorter than the video?
In "Match video duration" mode, the remaining portion of the video will be silent after the audio ends. In "Shortest" mode, the output will be cut to the audio length.
What is the difference between Replace and Mix mode?
Replace removes the original audio entirely and uses only the new audio file. Mix keeps both the original audio and the new audio, blending them together. Use Mix to add background music while keeping the original dialog.
Can I adjust the audio volume?
Yes! Use the volume slider to set the new audio volume from 0% to 200%. This is especially useful in Mix mode to balance the new audio against the original track.
Will this reduce video quality?
In Replace mode, the video stream is copied without re-encoding (zero quality loss). In Mix mode, the audio streams need to be decoded and mixed, but the video stream is still copied as-is.