As a practical matter, you do not revalue an asset

As a practical matter, you do not revalue an asset such as the film library on a quarterly basis, unless there is an extreme change downward. First, this would become prohibitally expense; and Second it would normally not change that much in a three month period.

Be very aware that the valuation of a film library that is not for sale is more of an art than a science. I have discussed the concept of valuation with my daughter (who is a very senior executisve in one of the major studios) and she tells me that while they always forecast what a movie will do, they are often significantly over or under projection. And they use some wierd analyitics in their projections. I can only imagine the problems you might have when dealing with films in the second, third or fourth tier.