Media nodes represent entries in the filesystems of media sources. Applications can obtain, from mm-player, the list of media nodes found in a certain path on a media source and then select a particular media node to browse more specific paths or to define tracksessions.
Each media node may correspond to an audio, video, or photo file or a folder. The file type is stored in the media node object, which also stores the media node ID and name (to distinguish it from other media nodes), information on the media source that stores the media node, and the number of children. For folders, when this last field is greater than 0, this means they contain other media nodes, which could be subfolders or media files. Applications must check each folder's number of children and retrieve the media nodes in any subfolders to explore content at all directory levels.
Clients must pass in a media node ID to mm-player when browsing a media source's contents, retrieving media metadata, and creating tracksessions (i.e., track sequences). To start browsing the contents of a new media source whose directory structure is unknown, clients must specify the root directory (/) as the media node ID.