Files: - "collection.xml": checking the video id based on the Trec video file name. - "xxx.mp7.xml" : Mpeg-7 output, where "xxx" is the video id instead of the video file name. A few small points that are related to the Mpeg-7 output: - Shots are contiguous, there is no gap or overlap in between each shot. - The media time format is based on the Gregorian day time (ISO 8601) norm. Fractions are defined by counting pre-sepcified fractions of a second. In our case, the frame rate is 29.97. One fraction of a second is thus specified as "PT1001N30000F". - Trec video id has the format of "XXX" and shot id "shotXXX_YYY". The "XXX" is the sequence number of video onto which the video file name is mapped, this is based on the "collection.xml" file. The "YYY" is the sequence number of the shot. Information about the segmentation: The segmentation was performed using the system used by CLIPS-IMAG for the TREC 2001 SBD task (variant "CLIPS-1"). More information about this system ca be found from the CLIPS-IMAG TREC 2001 paper: From the TREC 2001 SBD evaluation, it appeared that this system was quite good for cuts but not so (in the average) for gradual transitions. Also, it is a highly recall oriented system (which means significant over-segmentation). More precisely, the figures were : cuts gradual all Insertion rate: 10.5% 56.6% 26.6% Deletion rate: 1.2% 29.3% 11.0% Since the TREC 2002 data is older, we expect that there will be less special effects and that the gradual transitions will be a bit more accurately extracted (the CLIPS system actually detects only dissolves in the gradual transtion category). From the 295 files, the system detected 20868 cuts and 14231 dissolves which indicate a ratio comparable to the one of the TREC 2001 SBD collection. The CLIPS system used the MPEG-2 decoder from the MPEG Software Simulation Group (http://www.mpeg.org/MPEG/MSSG/#source). The frame numbering and therefore the shot bound timings are defined according to the output of this decoder. Both frame numbering and shot bound timing can vary slightly (a few frames) if one uses another decoder. The information about transition type (CUT vs. GRADUAL) and duration (for GRADUAL ones) are not available from the reference segmentation since only contiguous shots are described. When gradual (dissolve) transitions were found, the middle of the extracted transition was chosen as the shot transition, leaving half of the transition duration at the beginning of the next shot and at the end of the previous one. Georges Quénot. Email: Georges.Quenot@imag.fr CLIPS-IMAG, 385, rue de la Bibliothèque, B.P. 53, 38041 Grenoble Cedex 9