VideoReplace
VideoReplace[video,{t1,t2}->new] replaces the video between t1 and t2 with the new video new.
VideoReplace[video,{{t11,t12},…}->new] replaces multiple intervals with the same video new.
VideoReplace[video,{{t11,t12}->new1,…}] replaces multiple intervals.
VideoReplace[video,…,durfitting] uses the specified durfitting method to replace an interval of a different duration.
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