Add Audio to Video, Free & Private

How this audio adder works

Adding audio means laying a sound file over a video, either in place of the existing sound or mixed with it. You choose a video and an audio file, set the volumes, and drag the audio clip to decide where it starts. VimCut then writes a new MP4 that contains your video and the added sound.

The video stream is copied without re-encoding, so the picture keeps its original quality, and the audio is encoded to AAC. The result always runs as long as the video: audio that is shorter is padded with silence, and audio that is longer is cut at the end. The work runs on WebAssembly (ffmpeg.wasm) in your browser, so your files stay on your device. If your audio should start later, drag it to the right to delay its start in the video, or drag it to the left to skip its beginning. Two volume controls set the added sound and the original sound.

Formats and related tools

The audio file can be MP3, WAV, M4A, AAC or OGG. Press play to hear the result before you run it. If the video has no sound track of its own, the new audio is laid over silence. To clear the original sound first, use Mute Video. To get sound out of a video instead, use Extract Audio.