AU file (AU) stores data in the AU format. AMR file (AMR) stores data in the AMR format. This conversion changes the file's encoding, compression method, and supported feature set. Metadata such as creation date and embedded colour profiles is preserved where the target format supports it. The result is a standard AMR file readable by any compatible application. 1converter handles AU-to-AMR conversion server-side: files are uploaded over HTTPS, processed on isolated cloud infrastructure, and the converted output is available for download for 24 hours before automatic deletion. No account is required for standard conversions.