Merge Video and Audio Online for Free
Merge video and audio directly in your browser with a fast, private, and watermark-free tool. Add background music, replace the original sound, or combine a voiceover with your footage in just a few clicks.
Online Video and Audio Merger
This online video merger runs fully on your device using FFmpeg.wasm. Your video and audio files are never uploaded to our servers, making it a secure choice for personal, client, or business content.
- Merge video and audio: Combine any supported video file with an MP3 or other audio track.
- Replace original audio: Remove the existing sound and add new background music or narration.
- Keep video quality: The video stream is copied without re-encoding, so quality stays the same.
- No watermark or signup: Export clean videos without watermarks, accounts, or subscriptions.
- Works in your browser: Use it on Chrome, Firefox, Safari, Edge and more.
Supported Video and Audio Formats
The tool supports many common formats used for social media, presentations, and professional projects.
- Video formats: MP4, MOV, AVI and other popular containers.
- Audio formats: MP3, WAV, AAC and more.
As long as your file plays in a modern browser, it will usually work with this video and audio combiner.
How to Merge Audio with Video Online
- Select your video: Click the video box and choose the file you want to edit.
- Add your audio: Click the audio box to select an MP3 or other audio file you want to add.
- Adjust options (if available): Choose whether to keep or replace the original sound.
- Merge and export: Press the merge button and wait for processing to finish, then download your new video.
If your audio track is longer than the video, it is automatically trimmed to match the video duration so they stay in sync.
Privacy, Speed and Quality
- Local processing only: All merging happens on your device. We do not store, see, or upload your media.
- Fast performance: The tool uses your own hardware, so you avoid server queues and long upload times.
- High-quality output: The video stream is not re-encoded, helping preserve original resolution and bitrate.
Use Cases for the Video Merger
- Social media videos: Add royalty-free music to clips for TikTok, Instagram, YouTube Shorts and more.
- Presentations and tutorials: Combine screen recordings with voiceovers.
- Marketing content: Replace noisy on-site audio with clean background tracks.
- Personal projects: Attach music to travel, event, or family videos.
This free online video and audio merger is designed for quick edits while keeping your files private and secure.
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Frequently Asked Questions
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Yes. The merge video and audio tool is completely free to use with no hidden fees, watermarks, or usage limits.
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No. All processing happens locally in your browser using FFmpeg.wasm. Your video and audio files are not uploaded or stored on our servers.
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In most cases, no. The tool uses stream copying for the video track, which preserves the original video quality without re-encoding.
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Common video formats like MP4, MOV and AVI are supported, as well as audio formats such as MP3, WAV and AAC.
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Yes. You can mute or replace the existing audio track and add new background music or a recorded voiceover to your video.
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It works in most modern browsers, including Chrome, Firefox, Safari, and Edge on desktop and many mobile devices, as long as they support WebAssembly.
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If the audio track is longer, it is automatically trimmed to match the video length so that the final merged file stays synchronized.