Multimedia Metadata Processing: A Format Independent Approach

In multimedia applications, XML is being increasingly used to represent metadata; examples are MPEG-7 multimedia description schemes and MPEG-21 usage environment descriptions. 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. However, using binary encoded XML should not introduce interoperability issues with existing applications, nor add additional complexity to new applications. In this paper we investigate a solution for this issue by handling the binary encoded XML data by the XML parser. As such, applications do not need to be aware of the type of encoding of the XML data. In this paper, we introduce such an XML parser and evaluate its usability in different scenarios. We measure the memory requirements and compare the processing speed of parsing binary encoded XML to plain text XML.