Add Audio To Video

What Add Audio To Video does

Add Audio To Video replaces a clip soundtrack or mixes new audio with the original. Preview plays both in the browser without encoding.

Export keeps the picture as a stream copy and encodes AAC audio with optional fades, volume, and trim or loop to the video length.

How to use it

1. Choose a video and an audio file.
2. Play the preview. Video controls drive the synced audio element.
3. Pick Replace or Mix, Trim or Loop, volumes, and fade times.
4. Select Apply audio, wait for progress, then Download.

Formats and limits

• Video: common formats the picker allows. Audio: MP3, WAV, M4A, AAC, OGG, FLAC, and other types FFmpeg can decode.
• Output is an MP4 with copied video and AAC audio.

Settings explained

Mode

Replace drops the original soundtrack. Mix blends both (the video must already have audio).

Audio length

Trim cuts the audio to the video duration. Loop repeats short audio until the video ends.

Volumes and fades

Video volume applies in Mix mode. Audio volume and fade in/out apply to the added track.

Privacy

Processing stays in this tab. Nothing is uploaded.

FAQ

Mix failed on my file.

Mix needs an audio stream on the video. Use Replace, or mute the video first and then add audio.

Related tools

• Mute Video - drop the original soundtrack first.
• Extract Audio From Video - pull a soundtrack out of another clip.
• Audio Cutter - trim the music to length first.
• Volume Changer and Normalizer - set the music level before mixing.
• Voice Recorder - record a voice-over to add.