This extension is almost exactly what I’ve been looking for — it’s a great concept and very close to being perfect for dancers or anyone who wants to repeat specific parts of a video.

Here’s what would make it truly useful for that purpose:

Shortcut for “Apply” or “Play From Start Time”
Add an extra shortcut option to instantly play from the most recently set start time, without needing to specify an end time. Too often I just want to mark a single point and quickly replay from there — not necessarily define a full interval.

Enable shortcuts in Fullscreen mode
Currently, the keyboard shortcuts don’t work while the video is in fullscreen. Having them work there would make practice sessions much smoother.

Fix UI overlap with “Enhancer for YouTube™”
The interface elements overlap when both extensions are active. Since “Enhancer” is widely used, it would be great if this could be made compatible.

Add “Options” to the add-on list drop-down menu (gear icon)
It’d be convenient to access preferences directly from the extension menu.

As a side note, I realize that what I’m suggesting might simplify or even bypass some of the extension’s advanced multi-interval features. Maybe a add-on checkbox option like a “Quick Replay Mode” could help — a lightweight setting focused purely on fast marking and replaying from a single timestamp, while keeping the full functionality available for regular use.

In short, I’m looking for a way to quickly set a start time and replay from it — all via keyboard shortcuts, ideally without leaving fullscreen. Thanks for the fantastic work so far and for considering these improvements!

Excellent, plain looper.

I've been waiting years for a video bookmarks extension for FF, and this is exactly what I've been looking for, with one exception - I'm looking for one that works on any HTML5 video, not just YouTube. I don't suppose that it could be modified to support HTML5 video across the board, could it? IDK what all it would entail, but I ask because the Chrome extension that first introduced me to the video bookmarking concept (Video Bookmarks Controller) and ultimately leading to my complete dependence on it 😂 isn't available for FF. It was also created specifically with YouTube in mind and to this day still has a few extra features/perks exclusive to YT, but at some point the developer added support for any video site using HTML5. Your extension and it are very similar. In fact, without having used yours extensively yet, the only pronounced difference I spot is that you utilize local device storage while it uses a dedicated site/server that also allows for managing the saved bookmarks hosted there. Anyway, obviously you should do what you wish, but I'd be beyond appreciative if you did something similar with this add-on, i.e., chose to add support for any HTML5 video.

Edit - I've discovered that it's possible in some cases to convert a Chrome extension to FF add-on, so I'm going to try that but sadly the simpler automated process via add-on appear to be broken so I'll need to do it manually

This is incredibly useful for learning guitar and better than the chrome equivalent. Thank you!

Plain & Simple - Works like a charm. Great for musical instruments tutorials, to do complex parts over-and-over again. Thxs!!!

Thank you

The Addon doesnt really work for me, there is no buttons for looping for me. Edit: Nevermind im just dumb. I forgot too reload the webpage

This is perfect! Now I can include those 8-hour videos in my playlists, without listening to all 8 hours... Usually I only want to hear 15 - 30 minutes of the video. Thank you so much!

works, but it would improve the functionality a lot if i could select the times to loop from the current time on the video. i don't know. i've been trying for the last hour to stitch together a replacement for mirrortube on chrome and though i guess i've done it, it just doesn't function nearly as smoothly.
edit: by smoothly i just meant like. going through the motions of use, if that makes sense. it isn't a problem with the extension. have a nice day!

I often listen to songs on YouTube on repeat for hours (apparently this is an ADHD trait) but some videos have intros/outros you want to cut off. This can do it via a simple interface. Looper For YouTube on Chrome has a slider which would be nice to add but I am just fine with typing in the timestamps, not a biggie.