Extract Audio from Video

Which sample rate you get

The browser's audio decoder always delivers samples at the rate of its own audio system, which follows the sound output of your device, usually 44.1 or 48 kHz. A video whose soundtrack was recorded at 48 kHz, as most camera and phone footage is, is therefore resampled to 44.1 kHz on a device that runs at 44.1, and the other way round. The result panel shows the rate that was written.

For listening, transcription, or editing, the difference is inaudible. It matters when the WAV has to line up sample for sample with other audio from the same shoot, or when a delivery spec asks for a fixed rate: check the reported rate, and switch the device's output to the rate you need before extracting if it does not match.

Size and long recordings

WAV stores every sample as two bytes per channel, so the size is simple arithmetic: 48 kHz stereo is about 11.5 MB per minute, 44.1 kHz stereo about 10.6 MB, and a mono track half that. A 5.1 soundtrack keeps all six channels and is three times the stereo size.

The whole track is decoded into memory before the file is written, and decoded audio takes twice the space of the finished WAV. An hour of stereo sound needs around 2 GB in total, which can exhaust a phone or a busy tab. For long recordings, trim the video into parts and extract each one; to keep only a passage from a WAV that did extract, cut it with the audio trimmer.

How to use it

1. Choose a video file.
2. Extract the audio track.
3. Download the WAV.

Privacy & limitations

The video is read straight from your device and never uploaded. Everything — decoding, resizing, and encoding — happens in this browser tab, so large files are limited by your own memory rather than an upload queue. Output is uncompressed WAV, which is lossless but considerably larger than the source — roughly 10 MB per minute of stereo.