Video to audio — extract the soundtrack from MP4, MOV or WebM

How to use video to audio

1. Drop a video onto the box or click to choose one (MP4, MOV, M4V, WebM or MKV; older formats need the ffmpeg option).
2. Pick an Audio format: Original stream (lossless, fastest), M4A (AAC), WebM (Opus), OGG (Opus), WAV (uncompressed) or MP3 (via ffmpeg fallback).
3. For compressed formats, choose a Bitrate: 64 or 96 kbps for speech, 128 kbps or more for music.
4. Tick Mono to halve the size of spoken audio.
5. Press Extract audio and download the file. The result shows the audio size next to the original video size.

What it does and when to use it

Sometimes you only need the sound. A recorded lecture or meeting is easier to replay as audio on a walk. A talk you filmed on your phone can become a podcast episode. A music rehearsal video can be turned into a track to practise with. Editors also extract a soundtrack to clean it up separately.

Audio is much smaller than video, so this is also a way to keep a long recording without filling your storage. A video of a talk can be hundreds of megabytes, while its speech at 64 kbps mono takes under 30 MB per hour (64,000 bits × 3,600 seconds ÷ 8 = 28.8 MB).

To keep only part of the recording, trim the audio afterwards with the audio trimmer, or trim the video first with the video trimmer. To change the audio format later, use the audio converter.

How it works

The tool opens the video with Mediabunny (about 0.7 MB, loaded the first time) in a Web Worker and ignores the picture.

• Original stream copies the compressed audio packets into a new container. Nothing is decoded, so it works quickly even on long files.
• M4A, WebM, OGG and WAV decode the audio with WebCodecs and encode it again at your chosen bitrate (WAV is written as 16-bit PCM).
• MP3, and videos in formats such as AVI, WMV or FLV, go through ffmpeg.wasm if you allow the fallback.

Examples

Keep the original quality. For an MP4 phone video, Original stream copies the AAC soundtrack out as an M4A file without re-encoding. The result says the stream was copied and no quality was lost.

A compact lecture. For a two-hour lecture, M4A at 64 kbps with Mono ticked gives an audio file of roughly 58 MB (28.8 MB per hour), small enough to keep on a phone.

Limits and tips

• Videos without sound have nothing to extract; the tool reports “This file has no audio track.”
• Several audio tracks (for example two languages): the main track is extracted.
• Re-encoding needs WebCodecs audio support. If your browser lacks it, choose Original stream, which copies the audio without decoding it.
• Respect copyright. Extracting audio does not change who owns it.