Hi. Here is a video I shot with my
P4 (sorry, didn't have my Mavic yet as it was not available for sale). However, the camera on the
P4 is very similar to the Mavic so this should give an idea of what the Mavic can do at night. What I did was shoot first in Auto to get a baseline on the settings. Then I switched to Manual (I am a photographer so I am well versed in how to use the aperture, ISO, shutter speed, etc...) and play with the settings until I see what I like. The key being to know that the sensor in the Mavic and
P4 are not optimized for night shooting. In fact they are terrible, however it is what it is and you have to make the best of what you are working with. In the video post processing make sure you move your contrast a bit to the right to try and hide digital as much as possible. Try not to over saturate but boost enough color so that your fireworks "pop". Hope this helps... Here is the video:
p.s. I am not a videographer so your mileage may vary.