Abstract: A system for sharing playlists and playlist essence with different users. A user desiring to share his or her playlist generates the playlist and a playlist characterization. The playlist characterization is based on acoustic analysis data of one or more songs in the playlist. The playlist and playlist characterization is then transmitted to another end user device. The end user device receiving the shared playlist searches the user's music collection for the songs in the playlist. If a gap is detected in the playlist because the receiving user does not own a particular song, the receiving end user devices automatically selects another song that is owned by the user to fill-in the gap. The song is selected based on the playlist characterization with the aim of preserving the essence of the shared playlist.

Abstract: Table of contents (TOC) information contained in an audio CD is used to generate a TOC print which may be used for identifying the CD. The TOC print is generated based on the lengths of the tracks contained in the CD. A track vector is generated based on each track length and a matrix is created using the generated track vectors. A singular value decomposition (SVD) computation is performed on the matrix for decomposing the matrix into a set of linearly independent basis vectors. One or more of the basis vectors are selected and set as the TOC print for the CD. Once the TOC print has been generated, the TOC print may be compared against the TOC prints of known CDs in a central database to retrieve from the database metadata information stored in association with the known CDs.