M4A is a audio format: it stores AAC-encoded audio in an MPEG-4 container, the standard audio format produced by iTunes and Apple devices. WMV is a video format that stores video encoded with the proprietary VC-1 or WMV codec in a Microsoft ASF container, primarily a Windows ecosystem 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 WMV natively or when the target platform only accepts WMV. 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.