There is disclosed a multimedia processing method comprising: converting multimedia items into versions of multiple compression levels for storage within a media catalog; and estimating the likelihood of a user consuming each multimedia item based on a consumption history of items within said media catalog and said user; computing the multimedia items to be downloaded and a per-item compression level in dependence on resource constraints at a client device of said user and said estimated consumption likelihoods; downloading a compressed version of the multimedia items; and storing a record of consumed downloaded items.