AudioRoo

AudioRoo is a native macOS audio converter. Files or entire folders are dropped into a queue, which shows the channels, sample rate, and estimated output size for each item before anything runs. Batches detect the machine's performance cores and assign an FFmpeg instance to each, so large libraries convert in parallel rather than one file at a time.

Folder structures are handled directly: a collection can be flattened into a single destination, or converted files can be written into an existing library tree. Settings have a simple mode for basic options, with an advanced mode exposing CBR and per-format options such as FLAC lossless level or WAV bit depths. A built-in command monitor displays the exact FFmpeg command for whatever settings are selected, so the same conversion can be run from Terminal instead.

Everything runs locally with no upload step and no account. MP3 conversion is free, including batch and advanced settings, as is the command monitor. Other formats are free for 15 conversions, after which a one-time purchase unlocks them. There is no subscription.