in a system comprising media files resident on various devices , devices equipped with media servers can deliver files to devices with media clients for purposes of playback and / or storage . some media servers may be capable of delivering files in various formats and may offer clients delivery format options . media clients are aware of preferential list of formats that can be supported on a device and can choose from delivery options provided by media servers . media files are introduced on the devices either via means external to this system or by leveraging system &# 39 ; s media servers and media clients to transfer content between devices . when media files are introduced on the devices by means external to this system , media scanners detect such media files and make it available to media servers and thus to the rest of the system .