Fission

Fission is Rogue Amoeba's compact Mac audio editor, designed for a specific job: cutting, joining, and splitting audio files without re-encoding the underlying audio. For podcasters that matters when you're working with already-compressed MP3 or AAC files and you want to trim a beginning, split an episode at chapter marks, or join segments without a generation loss from re-compression.

Standard DAWs re-render everything on export, so if you load an MP3 into Logic and bounce it out as an MP3 again, you've stacked two rounds of lossy compression and the listener can hear it. Fission keeps the original encoding intact and only re-encodes the small portion you actually edit, which preserves quality on the unchanged parts.

It's not a mixing tool, it's not a DAW, and it doesn't have effects beyond basic fades. What it is is a precision scalpel for finished files. Pair it with Audio Hijack for capture, or use it as the final step after a DAW workflow when you need to slice a longer file into chapters or segments for delivery.

The price is reasonable for a perpetual license, and Rogue Amoeba's track record on Mac audio software means updates keep arriving year after year. The app remains useful even alongside a full DAW workflow, as the final delivery step when you need to split chapters or trim heads and tails without re-encoding.