OPUS file (OPUS) stores data in the OPUS format. F4V file (F4V) stores data in the F4V format. This wraps the audio track in a video container, which some platforms require for upload. Metadata such as creation date and embedded colour profiles is preserved where the target format supports it. The result is a standard F4V file readable by any compatible application. 1converter handles OPUS-to-F4V 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.