the video cataloger 110 registration processes are invoked for the four primary extensibility aspects of the video cataloger metadata track registration 476 feature extractor registration 472 output filter registration 478 and event registration 472 a set of output filters 484 are installed during system start up these registration processes as well as user input and output functions 550 554 are further described in conjunction with fig1 below fig9 depicts the main architectural elements of the extensible video engine 440 incoming media is processed by the media capture services 430 consisting of timecode capture 502 video capture 504 audio capture 506 and text capture 508 digital media 509 is then made available to the feature extractor framework 510 for processing metadata from the feature extractors 512 514 516 518 520 522 is then committed to the metadata track index manager 530 in a time based track representation as shown in fig6 and 7 during metadata capture the user may mark video clips and annotate them this input 552 is captured by the gui input capture element 550 event monitoring 540 and dispatch 544 also occurs during capture driven by an event dictionary 542 finally when capture is complete the metadata may be output in a variety of formats such.