AMR is a audio format: it stores data in the AMR format. F4V is a video format that 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. Converting between these two formats is common when the source application does not support F4V natively or when the target platform only accepts F4V. 1converter processes this conversion server-side using open-source tools. Files are transferred over HTTPS, converted on secure cloud servers, and automatically deleted after 24 hours.