Patent ID: 7680827

Claim:
In a system including a main unit including a first memory storing a plurality of multimedia files and a first digital signal processor for digitally processing the multimedia files, a portable unit including a second memory storing a plurality of multimedia files, the second memory having a storage capacity smaller than storage capacity of the first memory and storing fewer multimedia files than the first memory, and a second digital processor for digitally processing the multimedia files, and an interface connecting the first and second memories to each other for selectively transferring multimedia files stored in the first memory to the second memory, a method for selecting a subset of the multimedia files stored in the first memory for transfer to the second memory and transferring the multimedia files selected to the second memory, the method comprising: determining a weighting for each multimedia file, the weighting being based upon (i) popularity information, P(i), given by P ⁡ ( i ) = ∑ { j ❘ j ∈ S ⁡ ( i ) } ⁢ [ duration ⁢ ⁢ of ⁢ ⁢ access ⁢ ⁢ of ⁢ ⁢ file ⁡ ( j ) duration / length ⁢ ⁢ of ⁢ ⁢ file ⁡ ( j ) ] ⁢ , where i is multimedia file name, multimedia file artist, multimedia file album, multimedia file genre, and publication year of the multimedia file, and S(i) is a set comprising all multimedia files, and (ii) last-play duration weight, T(i), given by T ⁡ ( i ) = ∑ j = 1 5 ⁢ ⁢ l j × t , where l is a coefficient for the j th access of the multimedia file such that l j >l j+1 and t ⁢ ⁢ is ⁢ [ duration ⁢ ⁢ of ⁢ ⁢ the ⁢ ⁢ j th ⁢ ⁢ access ⁢ ⁢ of ⁢ ⁢ ⁢ the ⁢ ⁢ multimedia ⁢ ⁢ ⁢ file ⁢ ⁢ ( i ) duration ⁢ ⁢ of ⁢ ⁢ the ⁢ ⁢ multimedia ⁢ ⁢ file ⁢ ⁢ ( i ) ] or 1 if the multimedia file has not been accessed previously, and the weighting, W(i), is given by W ⁡ ( i ) = [ ∑ { P ⁡ ( i ) ❘ P ⁡ ( i ) ∈ I } ⁢ ⁢ K ⁡ ( i ) × P ⁡ ( i ) ] × T ⁡ ( i ) , wherein I is a set comprising at least one of the multimedia file name, the multimedia file artist, the multimedia file album, the multimedia file genre, and the publication year of the multimedia file, and K is a weighting constant; and transferring to the second memory from the first memory the multimedia files with the highest weighting until the second memory is completely filled with multimedia files.