M4A vs WAV
| Property | M4A | WAV |
|---|---|---|
| Full name | MPEG-4 Audio | Waveform Audio File Format |
| File extensions | .m4a | .wav, .wave |
| Created by | MPEG container, popularised by Apple (iTunes) | Microsoft and IBM |
| Introduced | 2003 | 1991 |
| Compression | Lossy AAC (or lossless ALAC) | Usually none: uncompressed PCM |
| Codecs inside | AAC, usually 128–256 kbps; sometimes ALAC | PCM, typically 16-bit at 44.1 or 48 kHz |
| Typical size | About 1 MB per minute at 128 kbps | About 10 MB per minute at CD quality |
| Opens on | iPhone, Mac, Android and Windows 10+; some car stereos, older players and upload forms want MP3 | Every computer, phone and audio editor |
| Best for | Voice memos, iTunes purchases and good sound at small sizes | Recording, editing and archiving master audio |
Why convert M4A to WAV?
Voice memos, interviews recorded on a phone and lectures captured with an iPhone are usually M4A. When you move them into an editing or analysis workflow, WAV is often what the next tool expects: older versions of Audacity without the FFmpeg add-on, many speech-to-text engines, forensic and research tools, hardware samplers and phone-system prompts.
The WAV contains the decoded AAC audio exactly, with nothing more lost from here on. It will be much larger: a 64 kbps mono voice memo grows roughly ten to twenty times as uncompressed 44.1 kHz audio. Choosing 22.05 kHz and Mono keeps it manageable and is still more than speech-recognition systems use (most resample to 16 kHz themselves).
To share a memo rather than edit it, M4A to MP3 keeps the file small. To cut out the part you need first, use the Audio Trimmer.