OPUS to M4A Converter

How to Convert OPUS to M4A Online

1. Upload Your OPUS File: Drag and drop or click "Add Files" to select .opus audio. WhatsApp voice notes, Telegram voice messages, Discord recordings, web call exports, and any Opus-in-Ogg audio all work. Batch is supported — drop in a whole folder of voice notes.
2. Pick AAC Bitrate (M4A's codec): Default is constant bitrate at 128 kbps AAC. Pick a quality preset (Lowest through Highest) for one-click selection, target a percentage of the source size or an exact file size, or set a custom CBR/VBR rate (24, 48, 64, 96, 128, 192, 256, 320 kbps). Opus voice notes are typically recorded around 24 kbps mono — there's no benefit to picking 320 kbps. 64-96 kbps mono AAC is the sweet spot for voice; 128-192 kbps stereo is the right call for music.
3. Set Sample Rate, Channels, and Trim (Optional): Match the source rate (Opus runs at 8/12/16/24/48 kHz internally; the file says 48 kHz) or downsample to 16/22.05 kHz for voice. Pick mono or stereo — mono cuts file size roughly in half and is correct for WhatsApp / Telegram voice notes. Optionally trim with start time and duration in seconds or HH:MM:SS.sss.
4. Convert and Download: Click Convert. Files process on our servers and download individually or as a ZIP — no sign-up, no watermark, no 1 GB cap.

Why Convert OPUS to M4A?

OPUS is a modern, royalty-free audio codec developed by Xiph.Org and standardized by the IETF in 2012. It's the format WhatsApp, Telegram, Discord, Microsoft Teams, Zoom, and WebRTC-based browser calls record into because it sounds excellent at very low bitrates (a 24 kbps Opus voice note is clearly intelligible). M4A is Apple's preferred audio container — an MPEG-4 wrapper around AAC (Advanced Audio Coding) introduced with iTunes in 2001. The reason to convert OPUS → M4A is almost always Apple compatibility, since iOS, iTunes, and Apple Music refuse to play .opus files natively:

• iPhone, iPad, and Apple Watch playback — iOS has no built-in Opus support. Voice Memos, Apple Music, the Files app, and CarPlay all expect M4A/AAC. Converting once means the file opens with a tap on every Apple device including over CarPlay.
• Forwarding WhatsApp / Telegram voice notes outside the app — Both apps record voice messages as Opus. Save-to-disk and AirDrop/email a .opus file to an iPhone user and it won't play. M4A plays everywhere on iOS without a third-party app.
• iTunes / Apple Music library import — iTunes refuses to import .opus files (the import dialog silently skips them). M4A imports cleanly with metadata, and the file appears in your library, in playlists, and across devices via iCloud Music Library.
• iMovie, GarageBand, Final Cut, Logic Pro — Apple's creative apps accept M4A/AAC natively but reject Opus on import. Converting once unlocks the entire Apple media-creation workflow for podcast clips, voiceovers, and game audio.
• Discord recording and voice channel exports — Craig and other Discord recording bots export per-user tracks as Opus. Re-encoding to M4A makes those tracks editable in Logic Pro / GarageBand and importable to podcast hosting platforms like Apple Podcasts Connect.
• Bluetooth headphones and car stereos — Many newer Bluetooth headphones and head units decode AAC natively over Bluetooth (better sound than the SBC fallback). Apple's AirPods specifically prefer AAC, so an M4A streams at full quality where an Opus file would have to be transcoded by the phone first.

If you want a more universal target instead of Apple-specific, see OPUS to MP3; for the more general Ogg audio extension see OGA to M4A.

OPUS vs M4A — Format Comparison

Source Bitrate Quick Guide (What's Inside Your OPUS)

If you don't know what's inside, 128 kbps stereo AAC is a safe universal default and yields files about 20% smaller than 128 kbps MP3 at the same perceived quality.

AAC Bitrate Choice (Inside the M4A)

Frequently Asked Questions

Will my WhatsApp voice notes (.opus) convert correctly to M4A?

Yes. WhatsApp records voice messages as Opus audio inside an Ogg container with the .opus extension (sometimes .oga after export from older WhatsApp builds). The converter re-encodes to AAC inside an M4A wrapper. Since voice notes are mono and recorded around 24 kbps, 64-96 kbps mono AAC is the right target — picking 320 kbps just makes the file larger without adding any quality back. The resulting M4A plays natively in iPhone Voice Memos, the Apple Music app, iMessage, and CarPlay.

Will I lose quality converting OPUS to M4A?

Some loss occurs because both Opus and AAC are lossy codecs — you're transcoding lossy → lossy. At 192-256 kbps AAC the loss is inaudible to almost everyone, even on good headphones. For voice notes (where the Opus source is already 24-32 kbps), there's no audible difference between 64 kbps AAC mono and 256 kbps — the source quality caps what's recoverable. Match or modestly exceed the source bitrate; don't try to "upgrade" by picking a much higher rate.

Why can't iPhones play OPUS files natively?

Apple has never shipped Opus support in iOS or macOS Music/Voice Memos/Files, partly historical (Apple committed to AAC starting in 2001) and partly licensing/API surface area. Safari 17 (iOS 17, macOS Sonoma) finally added Opus playback inside the browser, but the rest of the system still refuses .opus files. Third-party apps like VLC for iOS will play them, but Apple Music, Voice Memos, the Files app preview, iMessage, and CarPlay all reject the format. Converting to M4A is the only way to get one-tap playback across the Apple stack.

Is OPUS better quality than M4A (AAC)?

At very low bitrates (below 64 kbps), Opus is widely considered the best-sounding codec available — it was specifically designed for voice and low-bitrate streaming and outperforms AAC in that range. From 96 kbps and up, the two are very close, with AAC pulling slightly ahead for stereo music in some listening tests. Above 128 kbps, both sound essentially transparent on most material. So you're not "downgrading" by going to AAC at typical music bitrates — you're just trading codec efficiency for Apple compatibility.

Should I pick AAC or ALAC inside the M4A?

AAC (Advanced Audio Coding) is lossy and produces typical music-sized files (3-6 MB for a 3-minute track). It's what you want for everyday listening, podcasts, and Apple Music compatibility. ALAC (Apple Lossless) is mathematically lossless. Since your Opus source is already lossy, ALAC just preserves the lossy artifacts in a much larger file — there's no archival benefit. For any Opus source, AAC is the right answer; pick the bitrate based on whether the source is voice or music.

Should I pick CBR or VBR for AAC?

VBR (variable bitrate) spends more bits during complex passages and fewer during silence — better quality-per-byte at the same average rate, ideal for music. CBR (constant bitrate) has predictable file size and is required by some podcast hosts (Apple Podcasts accepts both, but a few legacy aggregators still want CBR). For WhatsApp/Telegram voice notes or audiobooks, CBR mono at 64-96 kbps is the cleanest default. For music going into your iTunes library, VBR at the equivalent of ~190 kbps matches Apple's iTunes Plus standard.

Can I trim a long OPUS recording before converting?

Yes. Use the trim section to enter a start time and a duration. Both fields accept seconds (12.5) or HH:MM:SS.sss format (00:01:30.500). Useful for pulling a single sentence from a long WhatsApp voice note before forwarding to a non-WhatsApp user, isolating one speaker's segment from a Discord/Craig recording, or extracting a quote from a Zoom call export. Trim runs before AAC encoding so you don't pay the encoding cost on parts you discard.

Will track titles and tags transfer from OPUS to M4A?

Yes — Vorbis comments (the metadata format inside Ogg/Opus files) map cleanly to MPEG-4 atoms used by M4A. Title, artist, album, year, track number, and genre carry across to iTunes/Apple Music. Embedded album art transfers when present. WhatsApp, Telegram, and Discord voice notes don't have meaningful metadata, so the resulting M4A won't either, which is normal and expected.

Are there file size or batch count limits?

No. Unlike CloudConvert and FreeConvert (which cap free uploads around 1 GB and limit batch counts), XConvert processes files entirely on our servers — there's no sign-up, no count cap, and no per-file size limit beyond upload size and connection speed. Drop in a folder of every WhatsApp voice note you've ever exported and they all convert in parallel.