Opus to M4A Converter
Convert Opus to M4A free — no upload, no signup
To convert Opus to M4A, drop your Opus audio files into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. Make Opus recordings play on iPhones and Macs.
Drop audio files here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
Advanced
How to convert Opus to M4A
Add your Opus files
Drag and drop Opus files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Pick a bitrate
192 kbps suits music and 128 kbps or less suits speech. Sample rate and mono/stereo are under Advanced.
Convert and download
Click Convert, then download each M4A file or all of them as one ZIP.
Why convert Opus to M4A?
Apple's Music and Voice Memos apps handle M4A, not Opus.
What happens when you convert Opus to M4A?
Fylo re-encodes to AAC in M4A at 160 kbps.
How does Fylo convert Opus to M4A?
Fylo decodes the Opus audio in the Opus with ffmpeg compiled to WebAssembly and encodes it with FFmpeg's AAC encoder at 160 kbps inside an MPEG-4 (M4A) container. Both formats are lossy, so each conversion discards a little detail — start from the highest-bitrate Opus you have. A 3-minute song is ≈ 2.9 MB at 128 kbps as Opus and ≈ 3.6 MB at 160 kbps as M4A. The original sample rate and channel layout are kept unless you change them under Advanced.
What's the difference between Opus and M4A?
Opus is an open, royalty-free codec standardised by the IETF as RFC 6716 in 2012. It blends speech technology from Skype's SILK with music coding from Xiph's CELT, so it handles both voice and music well. Files are usually stored in the Ogg container with the .opus extension.
M4A is an MPEG-4 container that holds only audio — usually AAC, or Apple Lossless (ALAC). Apple popularised the extension with the iTunes Store in 2003; iPhone Voice Memos and many podcasts also use it. Audiobooks often use the related .m4b extension.
Learn more: Opus format guide · M4A format guide
| Property | Opus | M4A |
|---|---|---|
| Compression | Lossy | Lossy (AAC) or lossless (ALAC) |
| Typical bitrate | 24–160 kbps | 128–256 kbps |
| 3-minute song | ≈ 2.9 MB at 128 kbps | ≈ 3.6 MB at 160 kbps |
| Tags and cover art | Yes (Vorbis comments) | Yes (full, with cover art) |
| Compatibility | Browsers, Android, WhatsApp, Discord; partial on Apple | Apple devices, Android, Windows 10+, browsers |
| Best for | Voice notes, podcasts, streaming at low bitrates | iTunes/Apple Music libraries, voice memos, audiobooks |
| Introduced | 2012 | 2003 |
Frequently asked questions
Will it play in Apple Music?
Yes.
Is it good for voice notes?
Yes, use 96–128 kbps to keep files small.
Is my Opus file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your Opus file is read directly from your device and never sent anywhere.
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