Instructions:

1. Turn off 3DS
2. take out SD card
3. put SD card in computer
4. put videos in SD card under: SD(E:)DCIM 100NIN03
5. safely eject SD card when transfer is complete
6. put SD card back in 3DS
7. turn on 3DS
8. go to "Nintendo 3DS camera" ....
9. View Photo/videos (Bottom left) ...
10. Watch The Avengers in 3D on your 3DS

Works on Both 3DS's