Convert OPUS to M4A
Turn an Opus voice note from WhatsApp or Discord into M4A, the AAC format the Apple ecosystem is built around. Everything runs locally in your browser, so the recording is never sent anywhere.
Why convert OPUS to M4A?
M4A is what Apple devices speak natively: iPhone voice memos are M4A files themselves, and the Music app, GarageBand, and iMovie all take the format without complaint. If you want a WhatsApp voice note to sit in your Music library or drop into an iOS editing app, M4A is the natural target. AAC is also more efficient than MP3 at the same bitrate, so you get slightly smaller files at comparable quality. People land on this conversion when saving voice messages from relatives, moving Discord recordings onto an iPad, or keeping an audio collection inside Apple software.
Quality and file size
Going from Opus to AAC is a transcode between two lossy codecs, so expect a small generation loss rather than a perfect copy. Both codecs are efficient, which keeps the damage minor, but pick a generous bitrate (256 kbps AAC is a sensible choice) so the second compression pass has room to work. Avoid chaining conversions: Opus to M4A once is fine, but bouncing a file through several formats degrades it a little more each time. Keep the original .opus file as your master.
OPUS to M4A: common questions
Is M4A better than MP3 for this?
For Apple devices, yes. AAC is more efficient than MP3 at the same bitrate and it is the default across iPhone, iPad, and Mac, so M4A files behave like first-class citizens there.
Will I lose quality converting Opus to M4A?
A little, since both formats are lossy and the audio gets re-encoded. At 256 kbps the difference is very unlikely to be audible in a voice note. Just avoid re-converting the result again later.
Does my voice message get uploaded to a server?
No. The whole conversion runs in your browser through FFmpeg in WebAssembly. We never see the file, store it, or train on it.
Can I add the converted file to Apple Music or Voice Memos?
The Music app on Mac accepts M4A imports directly, as does iTunes on Windows. Voice Memos does not import files, but the M4A will open in the Files app and most iOS audio players.
Who makes this?
We're the small team behind Xport Studio, a private, fully offline app for AI vocals, stems, and mastering. These free tools are side experiments we wanted to share. No upsell, but if you're curious about the bigger thing, take a look.