AIFC to OPUS Converter

Convert AIFC to Opus Online

AIFC (Apple's AIFF-C container, introduced July 1991) holds Mac-side audio that is usually uncompressed PCM but can also be a legacy Mac codec — and either way the files are big and awkward to share. This converter re-encodes them to Opus, the modern royalty-free codec the web, messaging apps, and streaming services rely on, turning a bulky old .aifc into a tiny file that sounds the same to most ears. When the source is uncompressed PCM, this is a clean first-generation encode: a lossless master into one of the best lossy codecs available.

How to Convert AIFC to Opus

1. Upload Your AIFC File: Drag and drop your .aifc file onto the page or click "+ Add Files." Queue several at once and they all run with the same settings.
2. Set the Bitrate: Open Advanced Options and leave it on the recommended Quality Preset, or switch to Custom Bitrate / Constant Bitrate / Variable Bitrate to dial in an exact rate. Opus is efficient, so a smaller number goes further than it would for MP3 — see the table below.
3. Adjust Audio Channel or Sample Rate (Optional): Leave both on Original to copy the source, or downmix to mono and lower the sample rate for an even smaller file. Use Trim to keep only part of the clip.
4. Convert and Download: Click Convert and save your .opus file individually or as a ZIP. No sign-up, no watermark.

Choosing an Opus Bitrate for Your AIFC Source

Opus scales from 6 kbps up to 510 kbps and is unusually good at holding quality, so you can usually match a PCM source with a smaller bitrate than MP3 would need. The table below is a starting point — push higher only if you hear a difference.

Frequently Asked Questions

Will I lose quality converting AIFC to Opus?

It depends on what's inside the AIFC. If the source is uncompressed PCM — what most modern Mac apps write, including CD imports and "AIFF" exports from GarageBand and Logic — then Opus is a clean first-generation lossy encode, and blind listening tests rank Opus ahead of MP3 and AAC at matched bitrates up to transparency, so 96-128 kbps sounds the same to most people. If the AIFC was already compressed with a legacy Mac codec (such as µ-law or IMA ADPCM, common in older files), Opus preserves that audio but can't restore detail the earlier compression already discarded. Either way, pick a bitrate at or near the source quality to avoid stacking new artifacts on old ones. In our testing, a 3-minute uncompressed stereo AIFC (about 31 MB of PCM) encoded to 112 kbps Opus produced a file of roughly 2.5 MB that was hard to tell from the source in normal listening.

Is Opus a good format for archiving my old Mac audio?

For day-to-day listening, web use, and streaming, yes — Opus gives you the smallest files at a given quality. For a true archive, no: Opus is lossy, so it permanently drops data even on a perfect encode. If these recordings are masters you want to keep at full fidelity, hold onto the original PCM .aifc, or convert to a lossless format with AIFC to FLAC instead. A good workflow is to keep one lossless copy for safekeeping and make Opus files for everyday use.

Will the .opus file play on my phone, browser, and other devices?

On modern hardware, almost always; on a long tail of old devices, not reliably. Every current browser (Chrome, Firefox, Edge, Safari) plays Opus, Android has recognized the bare .opus extension since Android 10, and modern iPhones play it through Safari and the system audio stack. The gaps are older devices — some pre-2018 smart TVs, certain legacy car stereos, and a few basic media players never added Opus. If you need guaranteed playback on old hardware, convert to AIFC to MP3 instead, which plays virtually everywhere, or to AIFC to AAC for better efficiency that Apple devices handle natively.

What makes Opus a better target than MP3 for this conversion?

Opus is an open, royalty-free codec standardized by the IETF as RFC 6716 in September 2012. It combines the SILK speech engine with the CELT music engine, scales from 6 kbps to 510 kbps, and beats MP3 and AAC at matched bitrates until transparency. That efficiency is why WhatsApp, Discord, YouTube, and WebRTC all use it — and why it is a sensible target for shrinking bulky old Mac audio. The one trade-off is reach: MP3 plays on more legacy hardware, so choose MP3 when broad compatibility matters more than file size. Need to go the other way? See Opus to AIFC.

How are my files handled, and how long are they kept?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public. On a big batch the practical limit is upload time, not a per-file size cap.