Audio from video · Windows 10 and 11
Convert MP4 to WAV
Pull the sound out of your MP4s as WAV files, the uncompressed audio that every editor, sampler and transcription tool opens without fuss. Octoolo keeps each video's sample rate and channels unless you change them, and it never sends your files anywhere.
How to convert MP4 to WAV
- 1
Find the tool
Open Converters from Octoolo's home screen and pick Extract audio. On its first run Octoolo sets up FFmpeg, a single 77 MB download.
- 2
Load the MP4s
Drop in your videos or the folder they live in. Add more brings in others later, and Clear empties the list.
- 3
Pick WAV, then the details
Click WAV. There is no quality to choose, since WAV keeps every bit it is given. More settings holds Bit depth, Sample rate and Channels for when you need something other than the video's own.
- 4
Convert
Start it, and each WAV appears beside its video with the same name. Open plays one in your usual player, and the folder icon opens File Explorer at it.
MP4 and WAV compared
| Detail | MP4 | WAV |
|---|---|---|
| Full name | MPEG-4 Part 14 | Waveform Audio File Format |
| Holds | Video, sound and subtitles | Sound only |
| Plays in | Nearly everything: Windows, Mac, iPhone, Android, TVs, browsers, editors and websites | Every audio editor and music app, Windows and Mac |
| Best for | Sharing, uploading and playing anywhere | Editing, mixing, samples, sound effects and burning CDs |
| Since | 2003, MPEG (based on Apple's QuickTime) | 1991, Microsoft and IBM |
What a video's sound is needed as WAV for
WAV is the plain, uncompressed form of sound. Programs that cut, mix and analyze audio like it because there is nothing to decode. Typical reasons to pull it out of an MP4:
- Editing the sound on its own in a program such as Audacity, Reaper or a full studio app, then laying it back under the picture.
- Sampling a sound from your own footage for a song or a game.
- Transcription and speech software that asks for WAV, often at 16 kHz mono.
- Cleaning up a recording with hum or uneven levels. Octoolo's Audio Editor can reduce background noise and even out loudness.
- Audio CDs, which need 44.1 kHz, 16-bit stereo.
Several videos from one shoot can go through together, so a whole day's interviews come out as WAVs in one batch, each named after its clip.
Settings for each job
| The WAV is for | Sample rate | Bit depth | Channels |
|---|---|---|---|
| Going back under the video | As it is | 16-bit or 24-bit | As it is |
| Mixing with other tracks | As it is | 24-bit or 32-bit float | Stereo |
| Burning an audio CD | 44.1 kHz | 16-bit | Stereo |
| Speech recognition | 16 kHz | 16-bit | Mono |
As it is keeps the video's own sample rate, which for video sound is very often 48 kHz. Changing it to 44.1 kHz is only worth doing for a CD or a program that insists on it. The bit depth starts at 16-bit for compressed sound such as the AAC in most MP4s, because that holds everything it plays; choose 24-bit or 32-bit float when you plan heavy processing and want room for it. If a video has 5.1 sound, the WAV keeps all six channels unless you pick Stereo or Mono.
How big the WAV files get
Uncompressed sound takes room. At 48 kHz, 16-bit stereo, a WAV fills about 11.5 MB a minute, or nearly 700 MB an hour. The same minute at 24-bit is about 17 MB, and six channels of surround sound triple the stereo figure. The MP4 the sound came from was probably much smaller, because its sound was compressed.
Speech can be much lighter. Choosing Mono for a single voice halves the file, and 16 kHz takes a third of the room 48 kHz does, which is fine for transcription though not for music.
Plain WAV files stop at 4 GB, a little over six hours of 48 kHz, 16-bit stereo. Octoolo switches longer files to RF64, the extended form of WAV, on its own, so nothing gets cut off. Most current audio editors open RF64; if an older program refuses one, FLAC is lossless too and takes about half the space.
Uncompressed does not mean better
The sound inside an MP4 was compressed when the video was made, usually as AAC. A WAV writes out exactly what that sound plays, sample for sample, but the detail the compression dropped is gone for good. So the WAV sounds the same as the video, not better, at around ten times the size of its sound track.
That is also why Octoolo shows no quality choice for WAV, only the words “Lossless. WAV keeps every bit of the sound it is given.” There is nothing to trade away.
It is still the right file for work. Editors open it without decoding and cut it to the sample, and saving it again after an edit loses nothing, where each new save as MP3 or AAC would compress it once more. If you only want to listen, MP4 to MP3 or MP4 to M4A make far smaller files.
Octoolo or an online converter?
| Detail | Octoolo | A typical online tool |
|---|---|---|
| Your files | Stay on your computer | Usually uploaded to the site's server |
| Without internet | Works | Does not work |
| File size | No limit | Often capped on free use |
| Many files | Whole folders at once | Often a few at a time |
| Watermarks and ads | None | Common on free plans |
| Cost | $4.99 a month, all 17 apps | Free with limits, or a plan per site |
Questions, answered
Why is my WAV bigger than the whole video?
The video's picture and sound are both compressed, and the WAV's sound is not. A long talk filmed at a modest quality can easily make a WAV larger than the MP4 it came from.
Which bit depth should I pick?
16-bit holds everything the sound of an MP4 contains, and it is what most programs expect. Pick 24-bit or 32-bit float only for heavy editing, where the extra room guards against rounding and clipping as you process.
Can I take WAV sound out of MOV, MKV or WebM videos too?
Yes. The tool reads any video FFmpeg can, so the steps are the same for MOV, MKV and WebM files: just choose WAV.
Can it handle a three-hour recording?
Yes. There is no length limit, and past 4 GB Octoolo writes RF64 so the file is complete.
Can I get the WAV at 44.1 kHz for a CD?
Yes. Open More settings and pick 44.1 kHz as the sample rate and 16-bit as the depth, which is the CD standard. Stereo, if the video has more channels, completes it.
Do my recordings leave the computer?
No. The conversion is done by FFmpeg on your own PC, so recordings of meetings, patients or clients stay where they are.
MP4 to WAV, and 16 more apps.
Download for Windows7 days free, then from $3.99 a month for all 17 apps. Windows 10 and 11.