AudiowaveAudioWave

Upload a video file and an audio file to replace the video's original audio track with your own. Adjust the new audio volume before processing.

Video File

Click or drag video (MP4, MOV, MKV, WebM, AVI, FLV, 3GP, MPEG, WMV, OGV, and more)

Audio File

Click or drag audio file

Audio Replacer – Replace Audio Track in Video Online

Replace the audio track in any video file online for free. Upload your video (MP4, MOV, MKV, WebM, AVI, FLV, 3GP, MPEG, WMV, OGV, and many more) and a new audio file to change the soundtrack, add a voiceover, or swap the original audio. Adjust the new audio volume before processing. Private, no signup, all in your browser.

What Is an Audio Replacer?

An audio replacer is a tool that swaps the original audio track in a video file with a new one. Unlike remuxing or re-encoding the entire video, audio replacement preserves the original video quality by keeping the video stream untouched while replacing only the audio stream. This makes it ideal for changing video soundtracks, adding professional voiceovers, fixing audio issues, or creating content with custom audio — all without quality loss to the video portion.

How to Replace Audio in Video — Step by Step

  1. Upload your video file by clicking the video upload area or dragging and dropping. Supports MP4, MOV, MKV, WebM, AVI, FLV, 3GP, MPEG, WMV, OGV, and many more formats.
  2. Upload the new audio file you want to use as the replacement track. Supports MP3, AAC, WAV, FLAC, OGG, M4A, OPUS, AIFF, AC3, and AU.
  3. Optionally adjust the new audio volume using the slider — increase or decrease it from 0% to 200% to achieve the perfect mix.
  4. Click 'Replace Audio' to start the process. The tool keeps the original video quality by copying the video stream without re-encoding.
  5. Preview the result video with the new audio, then download it to your device with one click.

Who Needs an Audio Replacer?

  • Video Editors & Content Creators — Replace original camera audio with high-quality recorded voiceovers or professional soundtracks.
  • YouTubers & Streamers — Swap game audio with custom music, add commentary tracks, or fix audio sync issues without re-encoding the whole video.
  • Filmmakers & Producers — Replace on-set audio with studio-recorded dialogue or ADR, preserving the original video quality.
  • Educators & Trainers — Replace lecture video audio with translated narrations, corrected explanations, or multi-language versions.
  • Social Media Managers — Quickly swap audio in marketing videos to adapt content for different platforms, audiences, or campaigns.

Frequently Asked Questions About Audio Replacement

1. What video formats can I use with this audio replacer?
The audio replacer supports most common video formats: MP4 (H.264/H.265), MOV (QuickTime), MKV (Matroska), WebM, AVI, FLV, F4V, 3GP, MPEG, MPG, TS, MTS, M2TS, VOB, WMV, ASF, OGV, DIVX, DV, RMVB, MXF, and more. The output video will be in the same format as your input. For audio input, we support all major formats including MP3, AAC, WAV, FLAC, OGG, M4A, OPUS, AIFF, AC3, and AU.
2. Will the video quality be reduced when I replace the audio?
No. Our audio replacer copies the video stream without re-encoding it, which means the video quality remains exactly the same as the original. The original video frames are preserved bit-for-bit. Only the audio stream is replaced and re-encoded to AAC at 192 kbps for optimal compatibility. This is significantly faster and higher quality than re-encoding the entire video.
3. Is my video file uploaded to a server during audio replacement?
No. Everything runs entirely in your browser using FFmpeg.wasm (FFmpeg compiled to WebAssembly). Both your video and audio files never leave your device. This makes the audio replacer 100% private and secure — perfect for sensitive, confidential, or copyrighted content. No signup required, no server uploads.
4. Can I adjust the volume of the new audio track?
Yes. You can adjust the volume of the new audio track from 0% (silent) to 200% (double volume) using the volume slider. This is useful when the new audio is quieter or louder than the original, or when you want to create specific audio effects. At 100%, the new audio plays at its original volume.
5. What happens if the new audio is longer or shorter than the video?
The tool automatically matches the duration of the new audio to the video length using the '-shortest' flag. If the audio is longer than the video, the video will end at its original duration with the audio cut to match. If the audio is shorter, it will loop or end when the video ends. For best results, use an audio file with a duration close to your video length.
6. Does the audio replacement work on mobile devices?
Yes, the audio replacer works on any device with a modern browser, including smartphones and tablets (iOS Safari, Chrome for Android). All processing happens in your browser via WebAssembly, so no app installation is needed. The interface is fully responsive and optimized for touch input on mobile screens.

Replace Audio in Video – Free, Private, and High Quality

The Audio Replacer is a fast, private, and easy-to-use online tool that lets you swap the audio track in any video file. With support for 5 video input formats and 10 audio input formats, adjustable volume mixing, lossless video quality preservation, instant preview, and one-click download — all processed locally in your browser with zero server uploads — it's the perfect solution for video editors, content creators, educators, and anyone who needs to change a video's soundtrack. No signup, no watermarks, no limits.