loopsplugin allows you to define and play custom range length of video or audio duration in a loop.
By clicking on the custom loop button in the control bar you can assign looping section start and end. You can adjust both positions anytime by dragging loop markers. The third click cancels the looping section.
Code snippet
<script src="/path/to/videojs/video.min.js"></script><script src="/path/to/videojs/nuevo.min.js"></script><script src="/path/to/videojs/plugins/nuevo.loops.js"></script>
<script>const player = videojs("my_player", {license: "key"});player.nuevo(); player.loops();</script>