Chrono Cross Video Format Notes
Little exploration has been done as yet, but the format is similar to the Playstation-standard STR format. http://www.romhacking.net/docs/455/ purports to document the format in its section 3.4, but it may be incorrect—however, it is likely that the format is again similar to those used in the PSX Final Fantasy games. If the Modern!Schala end-credits sequence is in fact different from the other movies, it's likely due to it including sampled, rather than sequenced, audio (it's unlikely that they could have gotten such clear vocals from a sequenced track).
Video files start with a magic byte sequence of 60 01 00 00 00 00 02 00 01 00 (CD 1) or 60 01 00 01 00 00 02 00 01 00 (CD 2).
There is a tool called ExtractVid in the old Terminus toolset which may give a clearer indication of what's going on, but no one appears to have bothered to dissect it yet and see how it works. Also, a non-Cross-specific program called PSXTulz may be able to play back the video.