Yes — drop a folder of MP3 files in and we process them in parallel. Pro has more parallel workers and no per-file size cap, so a 500-file batch finishes in minutes rather than tens of minutes.
Same-codec re-mux: 10-30 seconds. Re-encode to a different codec: typically 10-20% of source duration, so a 1-hour MP3 -> M4R finishes in 6-12 minutes on the standard pipeline.
Why is the M4R file louder / quieter than the MP3 source?