Yes — i-codec ifunyenwe kwi-stream, ngoko uluhlu olunophawu olungalunganga aluyi kususa umsebenzi. It is worth knowing before you overwrite an original you might need again.
No. Cima Audio is free without an account, and nothing is added to the audio. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.