AV Media Descriptors
The discrete physical items – whether discs, rolls of tape or film, cassettes and so on – are generically referred to as carriers. The particular type of material used – vinyl pressing, photographic film, videotape etc – is the medium. The typical collection contains a variety of media in various sizes, shapes, configurations – or formats.
Groups of related, technically identical carriers forming a cohesive whole – such as several reels of film comprising the complete picture negative of a feature film – are sometimes referred to as elements or components.