Convert Opus to AAC on Mac.

Local file processing, by renaming the file in Finder. No converter window and no upload queue.

Finder rename

report.opusreport.aac

How the rename works

  1. 1

    Start with report.opus

    Put the Opus file in a folder RenameTo watches, such as Desktop or Downloads.

  2. 2

    Rename it to report.aac

    In Finder, change .opus to .aac, then press Return. The rename is the command.

  3. 3

    Find the AAC beside it

    RenameTo produces the requested output and keeps a restorable backup of the original.

What happens under the hood

RenameTo reads the Opus with the appropriate local macOS media or document framework, then writes a new AAC beside it. The file itself is not sent to a conversion server.

About the formats

Opus is a modern codec tuned for efficient speech and audio. AAC is raw AAC audio.

Questions, answered

Does my file get uploaded anywhere?

No. File processing happens on your Mac. RenameTo does use the network for license validation, trial activation, and update checks, but your source files are not part of those requests.

What happens to the original Opus file?

RenameTo keeps a backup before processing. Undo restores the original alongside a format-changing output and does not delete that output. If the original name is already occupied, the restored copy gets “(restored)” in its name.

Can I convert a whole folder?

Yes. Rename multiple selected files in Finder and RenameTo queues each supported conversion, with a separate result and backup for every file.

Can I run the same conversion from a script?

Yes. The CLI command is: renameto aac *.opus

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