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Extract Audio from Video

Pull the audio track out of an MP4, WebM or MOV video and save it as lossless WAV (16 or 24-bit) or as compact Opus where supported. Optional mono mixdown. Decoded locally, never uploaded.

Overview

Extracts the audio track from a video file and saves it as WAV or, where the browser can record it, as compact Opus audio. Drop an MP4, WebM or MOV, see its duration, sample rate and channel count, optionally mix down to mono, and download. The file is decoded on your device and never uploaded. There is no MP3 output, and the tool explains why.

How It Works

Drop a video, or an audio file you want in another format. The audio track is decoded and the panel shows duration, sample rate, channels and the size the WAV will be. Choose WAV 16-bit PCM, which plays everywhere, WAV 24-bit PCM, or Opus at 128 kbps in a WebM or Ogg file if your browser can record it. Tick Mix down to mono to halve the size of stereo audio. Click Extract audio, listen in the player and download a file named after your video.

Step-by-Step Usage Guide

  1. Drop the video file whose audio you want.
  2. Check the duration, sample rate and channels that were detected.
  3. Choose WAV 16-bit, WAV 24-bit or Opus, and mono if you want it.
  4. Click Extract audio, preview the result and download it.

Technical Specifications & Standards

The file is read into memory and passed to the Web Audio API's decodeAudioData, which demuxes the container and decodes the audio with the browser's codecs, giving uncompressed 32-bit float samples per channel. WAV output is written by this tool: a RIFF header, a fmt chunk with the channel count, sample rate and bit depth, and a data chunk of interleaved little-endian samples, clipped rather than wrapped if a value goes beyond full scale. Opus output instead plays the decoded audio silently into a MediaStream and records it with MediaRecorder, which takes as long as the audio itself. MP3 is not offered because browsers include no MP3 encoder, and shipping one would mean bundling a large library. WAV is lossless, so you can convert it to MP3 later without extra loss beyond that one encode. Browsers may resample to the device rate when decoding, so the reported sample rate can be 48,000 Hz even if the video stored 44,100 Hz. Files over 1 GB are refused, as they do not fit in browser memory.

Targeted Use Cases

  • Saving the soundtrack of a recorded lecture or talk to listen to offline.
  • Pulling music or dialogue out of a clip to edit in an audio editor.
  • Getting a WAV file of an interview to send to a transcription service.
  • Making a voice memo from a phone video to share without the picture.

Notes & Gotchas

  • Choose WAV 16-bit for editing or transcription, since every app reads it.
  • Use Opus for speech you want to share, as it is about a tenth the size of WAV.
  • Mix to mono for spoken word to halve the file size with no audible change.
  • Trim or fade the result in the Audio Trimmer and Converter if needed.

Frequently Asked Questions

Why can I not save as MP3?

Browsers can decode MP3 but contain no MP3 encoder, and this site does not upload files to a server to encode them. Save as WAV, which is lossless, and convert it to MP3 in any audio app if you need that format.

It says there is no decodable audio track. Why?

The video may have no audio, or its audio uses a codec the browser lacks, such as AC-3 or E-AC-3 in some MKV and MOV files. Chrome, Edge and Firefox decode AAC, MP3, Opus and Vorbis.

Why is the WAV file so large?

WAV stores uncompressed samples: CD-quality stereo uses about 10 MB per minute. Choose mono to halve that, or Opus for a compressed file roughly a tenth the size.

Is the audio quality reduced?

WAV output keeps the decoded samples exactly, so there is no further loss beyond the compression already in the video. Opus is lossy but at 128 kbps is very hard to tell from the source.

Related tools

  • Audio Trimmer & Converter - Cut audio on a waveform, add fade in and fade out, normalise the peak, change speed or mix to mono, then export WAV (16, 24 or 32-bit float) or Opus. Preview the result before saving.
  • Video Compressor & Converter - Re-encode a video to WebM (VP9 or VP8) or MP4 where your browser can record it. Pick resolution, frame rate and bitrate, trim, and compare sizes. Shows which formats this browser supports.
  • Voice Recorder - Record audio from your microphone with a live timer, preview playback, and download - recordings never leave your browser.
  • Video to GIF Converter - Turn a clip of an MP4, WebM or MOV video into an animated GIF. Trim start and end against a preview, choose frame rate, width, speed and colours, then download. Nothing is uploaded.
  • Multitrack Audio Editor & Recorder - Record from your mic, import MP3, WAV, OGG or FLAC, and edit on multiple tracks with clip fades, crossfades, EQ, compressor, reverb, delay and gate. Mix down to WAV or Opus. Runs locally in your browser.
  • Online Video Editor (Timeline, Trim, Text & Music) - Edit video in your browser on a multi-track timeline: trim, split, speed, fades, filters, transitions, titles, logos and music, then export WebM or a WAV mix. Files never leave your device.