Evaluation of models for parsing binary encoded XML-based metadata

In multimedia applications, XML is being increasingly used to represent metadata. As with the media data, the size of, or the overhead induced by, the XML metadata is important, particularly when used on constrained mobile devices. Therefore, compression (binary encoding) of the XML data becomes relevant to reduce this overhead. Within the MPEG-7 standardization effort, a binary format for metadata (BiM) was developed, providing good compression efficiency and facilitating random access into, and manipulation of, the binary encoded bit stream. In order to support processing of metadata streams in the binary domain and making this task for client applications as simple as possible, we are developing a universal parser for handling both plain text and binary encoded XML-based metadata. The parser exposes a single interface making it transparent for the application whether a plain text or a binary XML document is being processed. As part of this effort, this paper provides a detailed study of five existing XML parser models and evaluates their applicability to serve as a model for parsing binary XML data.