How to extract audio from a video (MP4, MOV, WebM to MP3 or WAV)

Sometimes the only part of a video you need is the sound: a recorded lecture you want to listen to on a walk, an interview you need to transcribe, a voice memo you filmed on your phone, or the audio track of your own clip that you want to edit separately. Extracting that audio is quick, and you do not need to install editing software to do it.

This guide explains what actually happens when you pull audio out of a video, which output format to pick, how to choose a bitrate, and what to keep in mind about rights.

What happens when you extract audio

A video file such as MP4, MOV or WebM is a container. Inside it there is usually one video stream and one or more audio streams, each compressed with its own codec. MP4 and MOV files commonly carry AAC audio, while WebM files typically use Opus or Vorbis.

Extracting audio means reading that audio stream, decoding it and writing it out as a standalone audio file. If you choose MP3, the sound is re-encoded with an MP3 encoder. If you choose WAV, it is written as uncompressed PCM audio, which any audio editor can open directly.

MP3 or WAV: which one do you need?

• MP3 is the right choice for listening. It is small, plays on practically every phone, car stereo, laptop and media player, and is easy to share or upload to a podcast host.
• WAV is the right choice for editing. Because it is uncompressed, it does not add another round of lossy compression when you cut, mix, normalise or process the audio in an editor such as Audacity or a DAW. When you are done editing, you can export the final result to MP3.

A useful rule: if the audio is the finished product, go MP3. If the audio is raw material for further work, go WAV.

Keep in mind that WAV files are large. At CD quality (44.1 kHz, 16 bit, stereo) WAV takes about 10 MB per minute, so an hour of audio is roughly 600 MB.

Choosing an MP3 bitrate: 128, 192 or 320 kbps

Bitrate determines how much data is used per second of audio, and so both file size and quality. Azpy lets you pick one of three values:

• 128 kbps (about 1 MB per minute). Good for speech: lectures, interviews, meetings and voice notes. Voices remain perfectly clear and the files stay compact.
• 192 kbps (about 1.4 MB per minute). The default, and a sensible middle ground for mixed content and most music. For everyday listening, most people will not hear a difference from higher settings.
• 320 kbps (about 2.4 MB per minute). The highest MP3 bitrate. Choose it for music you care about, or when you want to keep as much detail as MP3 allows.

One thing to know: the audio inside a video is almost always already compressed. Encoding it at a high bitrate preserves what is there as faithfully as possible, but it cannot restore detail that the original compression removed. If the source is a phone recording of a talk, 320 kbps will not make it sound better than 128 kbps; it will just make the file bigger.

How to do it in your browser

1. Open the converter that matches your file: MP4, MOV or WebM to MP3, or MP4 to WAV.
2. Drop your video onto the page or choose it from your device.
3. For MP3, pick the bitrate (128, 192 or 320 kbps; 192 is preselected).
4. Start the conversion and download the audio file.

These conversions run entirely in your browser. The video is decoded on your own device and the MP3 is produced by the LAME encoder compiled for the web, so your file is never uploaded to a server. That also means there is no upload wait, which matters with video files, since they tend to be large.

The free limit for browser-based tools is 25 MB per file. For long recordings, it helps to export a shorter or lower-resolution version from your camera app or editor first, since the video resolution does not affect the audio you get out.

Tips for a better result

• Trim first if you can. If you only need a two-minute segment of a long video, cutting it beforehand gives you a smaller file and less to scroll through later.
• Match the bitrate to the content. Speech at 128 kbps, general use at 192 kbps, music worth keeping at 320 kbps.
• Edit in WAV, publish in MP3. Converting back and forth between lossy formats degrades quality a little each time; working in WAV avoids that until the final export.
• Check the result. Play the first seconds and a part in the middle to make sure the audio track is the one you expected, especially with files that contain more than one language track.

Respect copyright

Being able to extract audio does not mean you are allowed to. Only convert content you have the rights to use: videos you recorded yourself, material you have permission to use, content under a licence that allows it, or files where the law in your country clearly permits it. Ripping the soundtrack of a film, a music video or someone else's content and redistributing it can infringe copyright, even if you do not charge for it. When in doubt, ask the rights holder.

In short

Pick MP3 when you want to listen or share, WAV when you want to edit. Use 128 kbps for speech, 192 kbps as the all-round default and 320 kbps for music. Browse all the converters at /en/tools, and your video stays on your device the whole time.