Change M4A audio to OPUS for any player or device, with the bitrate, sample rate and channels you choose. Free, with no upload.
Drop audio or video files here
or paste them, or click to choose — several files at once
Choose filesMP3, WAV, FLAC, OGG, M4A, AAC, OPUS, AIFF, WMA, APE, AMR, MP4 and more · up to 300 MB per file
The converter (about 30 MB) is downloaded once on first use and then cached. Your files never leave your device.
Drop M4A files onto the converter, paste them, or click to choose. You can add many at once.
OPUS is already selected. If you like, adjust the quality, sample rate or channels before or after adding files.
Each file is converted in your browser in seconds. Save them one by one, or all at once as a ZIP.
MPEG-4 Audio
Apple's everyday music format
M4A is an MPEG-4 audio file, usually containing AAC. It is the standard format of Apple Music, iTunes and the iPhone Voice Memos app.
Opus Interactive Audio Codec
The most efficient modern codec
Opus is an open, royalty-free codec designed for the internet. It powers WhatsApp voice messages, Discord, video calls in the browser and YouTube streaming.
Audio is converted by ffmpeg running inside your browser. Your files never reach a server.
Queue up to 50 files and download them one by one or together as a ZIP.
Set the bitrate, bit depth, sample rate and channels — or simply keep the sensible defaults.
Add your M4A files to the converter above. OPUS is already selected as the output, so conversion starts right away. When a file is ready, click Download, or use Download all to get a ZIP.
Both formats are lossy, so re-encoding adds a little loss. Choose a bitrate equal to or higher than the original (for example 192–256 kbps) and the difference will be inaudible.
Opus shines at low bitrates: 64 kbps is plenty for speech and 96–128 kbps sounds transparent for almost all music. It always works at 48 kHz internally.
No. The M4A to OPUS conversion runs entirely in your browser using ffmpeg compiled to WebAssembly. Your files are never sent to a server, so even private recordings stay on your device.
Yes. Add up to 50 files; they are converted one after another, and you can download each OPUS file separately or all of them together as a ZIP archive.