Extract audio from a video

What it's for

Handy to save the music or voice from a video, get a podcast or a track from a clip, or keep just the audio of a lecture or interview. The extraction happens without re-encoding the video: it takes only the audio stream and converts it to the format you choose.

MP3 or M4A?

MP3 is the most compatible format, recognized by any device and player. M4A (AAC) gives slightly better quality at the same size and is ideal for the Apple ecosystem. When in doubt, pick MP3.

Extracting is not converting

Inside a video file the audio is already a separate track, compressed in its own format, usually AAC. Extracting it as M4A means copying those bytes as they are, without touching them: the result is identical to the original, and the job takes seconds even on a long file.

Asking for MP3, instead, forces a recompression: the audio is decoded and compressed again into a different format, with a small extra loss. It is hardly ever audible, but it is the reason why, if the file is only for you and your device opens it, M4A is the cleaner choice.

Does the video already have the right audio?

Two things are worth checking first. The first is how many audio tracks the file contains: dubbed films and professional recordings often have more than one, and the extracted track may not be the one you expect. The second is the volume, because the audio of a video mixed for a screen is nearly always lower than that of a music track, and heard alone it sounds underpowered.

If the video comes from a phone, there is a third thing: many recordings are mono even when the file declares two channels, because there was only one microphone. Converting them to stereo adds nothing, and keeping them mono halves the size.

What it is for, and where the limit is

There are three real uses: keeping the spoken track of a lecture or an interview to listen again in the car, getting the audio of a podcast recorded on video, and removing the video from a recording that had nothing visual in it, saving a great deal of space.

The limit is copyright: extracting the audio from a video you have no rights to, in order to reuse or publish it, does not become lawful because it is technically easy. A copy for strictly personal use is another matter, but it does not cover publishing or sharing.

Why it is better done here than on any random site

Almost every online converter asks you to upload the file to a server. A video may contain a work meeting, a medical appointment, your children, the inside of your home: exactly the content it is unwise to hand to a service you do not know, and which often states it will delete it «within a few hours».

Here the file stays in the browser and no network request goes out during the extraction. In exchange, the work is done by your own computer: on a very long video it takes a few minutes, and that is the price of sending nothing to anyone.

Nearby tools

To work on the extracted audio there are Audio trimmer, Merge audio and Audio converter. On the video side there are Video trimmer, What video is it really and Video loudness.