VideoDelete
VideoDelete[video,t] deletes the first t seconds of video.
VideoDelete[video,-t] deletes the last t seconds of video.
VideoDelete[video,{t1,t2}] deletes from time t1 to time t2, returning the remaining video as a single Video object.
VideoDelete[video,{{t11,t12},…}] deletes multiple time intervals.
Please visit the official Wolfram Language Reference for more details and examples on core symbols.