How to record HD on Nikon d3100?

I have a nikon d3100 I film HD and when i watch them on the computer its on HD too I use ASV to edit the videos and when I upload them to youtube the quality says 480p it doesn't give me the HD choise. How can i change that?

Make sure you set the asv output to 1080 p

What the first guy said

First I guess you need to know that the Nikon D3100 shoots video, NOT film.

Second the D3100 will shoot both Full HD and HD video, 1920 x 1080 (24 fps), 1280 x 720 (30, 25, 24 fps).In addition I will also shoot the old VGA mode, 640 x 424 (24 fps)

No matter what resolution you shoot your video, Youtube has its own rules when it comes up uploading video files. Check with them before you blame your camera