New MERIT Version for MPEG-2 Encoded Files

摘要

The MPEG Encoded Retrieval and Indexation Toolkit (MERIT) performs video segmentation of MPEG files in the compressed domain, using an algorithm based on macroblock type statistics. It was written in C by V. Kobla in 1995 for his doctoral work at the University of Maryland. Kobla's code dealt with MPEG-1 files only. In this report, we update MERIT to analyze MPEG-2 files as well. We modify the file parsing process to account for the MPEG-2 specifications. We account for the new motion compensation modes introduced by MPEG-2 specifications. We account for the new motion compensation modes introduced by MPEG-2 in preliminary computations, generating data structures that allow the original MERIT segmentation algorithm to work properly. A series of tests confirmed the validity of our solutions. The new version 4.0 of MERIT is a superset of MERIT 3.3, insofar as it gives the same results for MPEG-1 files, and is able to analyze MPEG-2 files using almost all the available options. Further improvements could be made to address key-frame storage and higher chrominance formats.