How do I repair a corrupt .mov file?

Hello. I've recently recorded a movie using my Nikon of a storm that just passed through. During the storm, I stopped recording the video, changed SD cards, and began recording again, as the card was nearly filled up. I'm not sure exactly what happened, but I guess in the heat of the moment, I may have ejected the SD card before the camera officially stopped recording. When I popped the SD card in my computer, the video wouldn't play, not in Quicktime or VLC. The computer does however show an accurate file size, 4gb. (20 minutes long in 1080p). I am no photographer, and I've never encountered this problem before. Does anyone know what I should do? I opened the file in a hex editor and there's a lot of data, and I'm no expert, but I guess that means there's something there. Are there any programs you could suggest to repair the video?. Any advice or suggestions are appreciated. Thank you very much.