Over the past four years, Indiana University’s Media Digitization and Preservation Initiative has digitized more than 315,000 audio and video recordings. In the meantime, we’ve heard from many other folks who are planning digitization projects that predicting file size and recording length is difficult. Of course, every collection is different, and nobody else will have exactly the same mix of holdings as we do at IU. Still, the general statistics we’ve gathered from the 315,000+ items we’ve reformatted to date may help provide others with at least some rough guidance for project planning.
The winner in the duration contest for video formats is VHS with an average running time of just about 100 minutes. This is not a surprise given that VHS is a fully consumer format. Consumers place higher value on the length of time available for recording than other characteristics, and so the format was developed with an emphasis on maximizing this variable. That’s why the EP (extended play) version of the format—that triples the possible recording time while reducing quality—was introduced. Over 3,000 of our VHS tapes are EP. One practical implication of this fact is that we must acquire and integrate consumer-level playback machines into our digitization signal chain, since professional decks do not support EP.
Direct to MDPI Website