I think your best bet may be Visual Understanding Environment (VUE). I can't say for sure if it will store or play videos but they make a big deal about "digital media" on their website.
There is always the option of simply including the path to a video on the note for a node in the map.
I like Visual Understanding Environment (VUE), free from Tufts Univeristy. It’s kind of a mind mapping program, but I find it less limiting than most I’ve tried. I’ve used it for plotting out D&D campaigns.
VUE- Visual Understanding Environment
Open Source mind mapping software from Tufts University.
Here's an example of something I did when we were solving the Cards Against Humanity Puzzle Hunt in 2015:
http://robotguy.net/EightSensibleGifts/EightSensibleGifts.html
When I was running a mystery game, I used this program, Visual Understanding Environment. Helped me organize plot threads, connections, NPCs, organizations, places, clues, etc. Simple, easy to use GUI.
I came close to grabbing that 50% bargain but waited too long.
You might also explore Tuft University's free VUE concept map tool which is similar to a mind map. A concept map lets you see that the relationships are between nodes. A mind map only tells me that things are related. XMind can draw relationship lines, but it's not a concept mapping tool like VUE which has specialized features for creating those types of maps quickly.
VUE also supports multiple tabs (similar to XMind sheets) as well as overlay layers. You can also drag nodes inside nodes. Sometimes that's useful. Penn State University shows an example of how a Concept Map's edges (connecting lines) can be helpful.
I don't use VUE for learning purposes but a Google search shows how educational institutions recommend Concept Maps for learning purposes.
VUE can't replace XMind. I use different programs depending on the need at the time. This morning was a toss-up between VUE and XMind.
It's called Visual Understanding Environment (https://vue.tufts.edu/).
There are a lot of programs like this though, google charts (or whatever it's called...) I see used more normally, but I like the simplicity of this one.
It's not quite the same... but I'm asking myself that kind of question for the analysis of qualitative data in the social sciences. Example: keep extracts from interviews or articles that I code with "tags". I discovered an Orgqda tool to do this... and then export to.csv
This allows the csv file to be imported into VUE for a "graph-like database" visualization. It can be improved but it's interesting.
Edge List creation (where the script creates a CSV file that can be imported into other network graphing software) is one of the main features, alongside generation of "quick-view" graphs like the one at the bottom of the post. Since the quick-view graphs aren't as colorful as maps created in VUE, I figured I'd lead with the latter : )