That's strange, it's hard to think of a good reason for that.

I see you have Blocksite. Did you try this pattern:

http://*.vine.co

Edit: You might also need:

https://*.vine.co

When Firefox crashes, it usually records information about what was happening at that moment. You can submit that data to Mozilla and share it with forum volunteers to see whether it points to the solution. Please check the support article "Firefox Crashes" (especially the last section) for steps to get those crash IDs, and then post some of the recent ones here.

If you don't get the Mozilla Crash Reporter and instead get a Windows dialog, perhaps the videos are somehow triggering an incompatibility with your graphics card driver. As a workaround, you could try disabling Firefox's use of hardware acceleration for graphics.

orange Firefox button (or Tools menu) > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

That takes effect after you exit and restart Firefox.

adding vine to blocksite seems to have solved my problem

I'll have to look at vines with my android phone

If you later want to troubleshoot the desktop version of Firefox, go ahead and dig up those crash report IDs.