Why extract MP4 audio to WAV instead of MP3?

WAV is uncompressed, so it is the right choice when you intend to edit the audio. Editing a lossy MP3 and re-exporting stacks compression on compression, degrading quality. Working in WAV avoids that — you only compress once, at the very end, when you export your finished audio.

Does converting MP4 to WAV improve the audio quality?

No. The MP4's audio is compressed AAC, and decoding it to WAV gives you the exact same audio as uncompressed PCM. You will not recover detail lost in the original encoding, but you will have a lossless working file that does not degrade further as you edit.

Why is the WAV file so much bigger than the MP4?

WAV is uncompressed — roughly 10MB per minute for CD-quality stereo. A small MP4 can produce a large WAV because all the compression is removed. This is expected and is exactly what makes WAV good for editing.

Are my videos uploaded to a server?

No. FFmpeg.wasm runs entirely in your browser. The MP4 is processed on your device and is never uploaded, stored, or logged.

Can I import the WAV into Audacity or Premiere?

Yes. WAV is the most universally supported audio format. Audacity, Adobe Premiere Pro, DaVinci Resolve, Logic Pro, Reaper, and Pro Tools all import it directly without any plugins or conversions.

What sample rate and bit depth does the WAV use?

The WAV preserves the source audio's sample rate (commonly 44.1 kHz or 48 kHz) and is written as standard PCM. 48 kHz is typical for video, which is convenient since most video editors work at 48 kHz.

What is the maximum MP4 file size?

100MB per file. Because WAV output is large and uncompressed, long videos quickly exceed practical limits — for hour-long recordings, use desktop FFmpeg, which has no memory ceiling.

Can I do this on a phone?

Yes — open FileConvertir in Safari or Chrome on your phone, select the MP4, and extract the WAV. All processing happens on the device, though large WAV files are easier to handle on a computer.

MP4 to WAV Converter

Convert MP4 to WAV free online — no upload, no signup. Extract an uncompressed audio track for editing in Audacity, Premiere or any DAW. 100% private, browser-based.

FileConvertir — Free Online File Converter