Why extract MP4 audio to WAV rather than MP3?
If you just want to listen, MP3 is smaller. But if the audio is going into another tool, WAV is the better choice. It is uncompressed, every editor reads it identically, and it does not add a second lossy encode on top of the one already in the video.
- Cleaning up dialogue in Audacity, Adobe Audition, iZotope RX or Reaper.
- Syncing phone or camera audio with a separate recording in a DAW.
- Sampling a sound from your own footage for a beat or track.
- Feeding an interview into transcription software that asks for WAV.
- Separating vocals or stems from a performance video with a tool such as a stem splitter.
MP4 and WAV compared
MP4 is the MPEG-4 Part 14 container used by phones, cameras and screen recorders. Its audio is typically AAC at 128 to 256 kbps, sampled at 44.1 or 48 kHz. WAV is Microsoft and IBM's audio-only format holding raw PCM samples.
| MP4 audio track | WAV | |
|---|---|---|
| Codec | Usually AAC, lossy | PCM, uncompressed |
| Typical sample rate | 48 kHz on phones and cameras, 44.1 kHz on some exports | Matches the source |
| Size per minute (audio only) | about 1 to 2 MB | 10.1 MB at 16-bit / 44.1 kHz, about 11 MB at 16-bit / 48 kHz |
| Editing behaviour | Needs decoding, can vary between tools | Sample-accurate in every editor |
| Best for | Delivering finished video | Audio editing and post-production |
What happens to quality
Converting MP4 to WAV cannot make the audio better than the video's own track. If the MP4 holds AAC, that compression has already happened, and the WAV is a faithful uncompressed copy of the decoded sound. It will match the original exactly, just in a format that is easier to edit.
The big benefit is that you stop losing quality from here on. Edit, process and export as often as you like from the WAV, then encode to your final format once at the end.
A few professional cameras record PCM audio at 24-bit inside MOV or MP4. AudioDrop writes 16-bit WAV, so that extra depth is reduced to CD-quality 16-bit.
Sample rate and sync
The WAV keeps the MP4's sample rate. Most phone and camera video uses 48 kHz, the standard for film and TV, so the WAV will be 48 kHz too. Keeping the rate avoids resampling and keeps the audio length in step with the video, which makes re-syncing in an editor simple.
If your project runs at 44.1 kHz, let your DAW convert on import.
Because the video is discarded, the WAV has no timecode or picture. To line it back up, place it at the start of the clip in your editor, or use your editor's auto-sync by waveform feature, which works well with an uncompressed file.
An MP4 to WAV converter that keeps your footage private
Everything runs locally. The browser opens the MP4, AudioDrop reads its primary audio track with WebCodecs, and the WAV is written in memory before you save it. The video frames are never decoded, and nothing is sent to a server.
- Free, no account, no watermark.
- Works offline once loaded.
- Batch mode extracts audio from several videos in parallel, each WAV downloading individually.
- No fixed file size cap. Long, large videos are limited by your device's memory.
On Mac, Windows, iPhone or Android
On a computer, drop the MP4 into this page in Chrome, Edge, Safari or Firefox. On iPhone, save the video from Photos to Files, then choose it in Safari. On Android, pick it from your storage in Chrome. An hour of 48 kHz stereo WAV is roughly 660 MB, so check you have space before converting long recordings on a phone.