What value of dapt:onScreen should be used for non-video content? #305
Description
There's nothing requiring that DAPT represents media that has a video image - it can equally well be used with audio only content. However the daptm:onScreen property appears to assume that there is a "screen" and imposes this assumption by having a default value of "ON", which is meaningless, though arguably harmless, for non-video content.
Should we have a different default value, or allow for an empty value where it isn't relevant?