Pulling the Audio Track Out of a Video File
What this tool does
A video file is really two streams wrapped in one container: the moving picture and a separate audio track. This tool ignores the picture entirely and lifts out just the sound, handing it back as a standalone MP3 or WAV. It opens the container — MP4, WebM, MOV, AVI, MKV, or OGG — decodes the embedded audio with the audio decoder built into your browser, then writes it either as an MP3 with an encoder that runs inside the page, or as an uncompressed 16-bit WAV.
Source files up to 500MB are accepted, and you decide the output shape with the format, bitrate, and channel controls before extraction begins. The extracted audio comes out at 44.1 kHz.
When to reach for it
The classic case is turning an MP4 lecture, interview, or music video into an MP3 you can drop onto a phone, a podcast feed, or a playlist. It is equally useful for salvaging the audio from a screen recording, pulling a backing track out of a WebM clip, or preparing a clean audio file to send off for transcription.
Because only the audio matters here, you skip video editors entirely — there is no timeline to scrub and no need to render a whole movie just to keep its soundtrack.
A concrete example
Suppose you have a 90-second MP4 talk. Load it, choose MP3 at 192 kbps in stereo, and press Extract Audio; the track is decoded and encoded, returning a file of roughly 2MB. An MP3's size depends only on its bitrate and length, so mono would not change that — dropping to 128 kbps would, to about 1.4MB, which is plenty for spoken word. Pick WAV instead and you get an uncompressed 16-bit file of about 16MB for stereo, or half that for mono. It is larger, but it keeps the decoded sound as it is; it cannot bring back detail the video's own audio had already lost.
Notes and edge cases
Decoding relies on the codecs your browser already understands, so an unusual codec inside an AVI or MKV may refuse to decode even though the container is on the supported list — re-wrapping the file as MP4 first almost always clears it up. A video that has no audio track at all has nothing to extract, and the tool reports that its audio couldn't be decoded. MP3 bitrates run from 128 to 320 kbps, where a higher number preserves more detail at the cost of size.
One thing to keep in mind: the entire audio track is decoded into memory before encoding, so a long or high-resolution source is memory-heavy and can run slowly, or run out of memory, on devices with little RAM. Trimming to a shorter clip is the simplest workaround.