Yes — drop a folder of MP4 files in and we extract audio in parallel. Premium users get more parallel workers and no per-file size cap; on a 50-file batch this is the difference between 90 seconds and 8 minutes.
Audio extraction is much faster than video re-encoding — typically 5-15% of source duration. A 1-hour MP4 → AC3 finishes in 3-9 minutes on the standard pipeline; a 5-minute video finishes in under a minute.