WMA is a audio format: it encodes audio with Microsoft's proprietary WMA codec, primarily found in files created by Windows Media Player. MKV is a video format that stores video, audio, subtitles, and chapters in an open-standard container that supports virtually every codec. 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 MKV natively or when the target platform only accepts MKV. 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.