Pull the soundtrack out of MP4 videos as uncompressed WAV for editing, transcription, sampling or archiving. Choose the bit depth, sample rate and channels, convert a whole batch at once, and keep every file on your own device.
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WAV format
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How to use the MP4 to WAV
Add your videos: drop MP4 files on the box or click Choose video files. Each file shows its audio codec, length and the expected WAV size.
Pick the WAV format: 16-bit for general use, 24-bit or 32-bit float for audio editing.
Choose sample rate and channels, or keep the originals. 16 kHz mono is ideal for speech recognition.
Press Convert to WAV and watch each file's progress.
Download the WAV files one by one or all together as a ZIP.
WAV file size per minute
WAV stores uncompressed PCM audio, so its size depends only on the format, not on the content: bytes = sample rate × channels × (bit depth ÷ 8) × seconds.
Format
Typical use
Per minute
Per hour
48 kHz · stereo · 16-bit
Video soundtracks
11.0 MB
659 MB
44.1 kHz · stereo · 16-bit
CD audio, music
10.1 MB
606 MB
48 kHz · stereo · 24-bit
Audio editing, film post-production
16.5 MB
989 MB
48 kHz · stereo · 32-bit float
DAW processing without clipping
22.0 MB
1.29 GB
16 kHz · mono · 16-bit
Speech recognition, transcription
1.8 MB
110 MB
8 kHz · mono · 16-bit
Telephone systems, IVR prompts
0.9 MB
55 MB
The audio inside an MP4 is usually AAC at 128 to 256 kbps (about 1 to 2 MB per minute), so expect the WAV to be 5 to 10 times larger than the soundtrack alone.
16-bit, 24-bit or 32-bit float?
16-bit PCM gives about 96 dB of dynamic range, more than any AAC soundtrack holds. It is the most compatible choice: every player, phone, editor and transcription service reads it.
24-bit PCM gives about 144 dB of range. It does not add detail to a lossy source, but it keeps rounding noise far below hearing when you apply gain, EQ or effects later.
32-bit float stores the decoder output exactly as calculated, including peaks above 0 dBFS that would clip in 16 or 24-bit. Use it when the WAV goes straight into a DAW such as Audacity, Reaper or Premiere.
How the extraction works
An MP4 file keeps an index (the moov box) that lists where every audio and video sample is stored. The tool reads that index, copies only the audio samples into a small in-memory M4A file and lets your browser's built-in decoder turn it into raw PCM. Resampling uses the browser's high-quality resampler, and channel mixing follows the ITU downmix for 5.1 sound (centre and surround channels at −3 dB). For formats without such an index, such as WebM and MKV, the whole file is decoded.
Frequently asked questions
How do I convert MP4 to WAV?
Add the MP4 file, choose the WAV format and press Convert to WAV. The tool reads the audio track of the video, decodes it with your browser's audio decoder and writes an uncompressed PCM WAV file you can download. The video picture is ignored.
Does converting MP4 to WAV improve the audio quality?
No. MP4 audio is usually AAC, a lossy format; WAV stores the decoded audio exactly, without further loss, but cannot restore detail AAC already removed. WAV is useful because editors, DAWs and transcription tools handle it easily and further editing adds no new compression loss.
Which sample rate and bit depth should I choose?
Keep the original sample rate, usually 48 kHz for video and 44.1 kHz for music. 16-bit is enough for listening and transcription; choose 24-bit or 32-bit float if you will process the audio further in an editor. For speech-to-text engines 16 kHz mono 16-bit is a common requirement.
How big will the WAV file be?
Size = sample rate × channels × bytes per sample × seconds. At 48 kHz stereo 16-bit that is 192,000 bytes per second, about 11 MB per minute, roughly 10 times larger than the AAC audio in the MP4.
Can it handle large video files?
Yes. For MP4 and MOV files the tool reads only the audio samples using the file's index, so a 4 GB video needs little more memory than its soundtrack. WAV files are limited to 4 GB by the format, about 6 hours at 48 kHz stereo 16-bit.
Why does my file fail to convert?
The browser must be able to decode the audio codec. AAC, MP3, Opus, FLAC and Vorbis work in all major browsers; AC-3, E-AC-3 and AMR only in some. Damaged files or videos without an audio track cannot be converted.
Are my videos uploaded?
No. Everything runs in your browser with the Web Audio API, so your files never leave your device.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.