Convert M4A to OPUS
Take an M4A from Voice Memos or iTunes and get a lean .opus file out the other side. Your recording stays on your device the whole time.
Why convert M4A to OPUS?
Every voice memo recorded on an iPhone is an M4A file, and so are most downloads from the Apple world. People convert them to Opus when the destination lives outside that ecosystem: a Discord bot that expects Opus input, a web app that plays audio in the browser, or a self-hosted archive where storage efficiency matters. If you are a journalist or student sitting on hundreds of iPhone interview and lecture recordings, converting the pile to Opus shrinks it without losing intelligibility. Opus is simply the better fit once audio leaves Apple hardware and heads for modern cross-platform software.
Quality and file size
AAC and Opus are both lossy, so this is a transcode and each generation shaves off a little quality. For voice memos the loss is very hard to hear, and it stays subtle on music if you pick a healthy bitrate: 256 kbps gives plenty of headroom. What you should avoid is bouncing the same audio back and forth between lossy formats, since the artifacts stack. Expect the Opus file to match or undercut the M4A's size at comparable quality, because Opus is the more efficient codec of the two.
M4A to OPUS: common questions
Can I convert iPhone voice memos with this?
Yes. Voice Memos saves recordings as M4A, and this tool turns them into compact .opus files. AirDrop the memo to your computer first, or open this page on the phone itself.
Will my voice memos stay private?
Completely. The conversion happens locally in your browser, so your recordings are never uploaded. We never see them, store them, or train on them, which matters when the audio is personal.
Does M4A to Opus reduce quality?
A little, because both formats are lossy and re-encoding always costs something. For speech the effect is negligible, and at 256 kbps it is hard to detect on music. Avoid converting the same file multiple times.
Why choose Opus over keeping M4A?
M4A is fine inside the Apple world, but Opus is smaller at equal quality and is the native format of Discord voice, WhatsApp voice notes, and WebRTC. If your audio is heading into modern cross-platform software, Opus travels better.
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.