Field sequential 3D was used on DVDs in the days before 3D Blu-rays. It takes the two fields of each frame (as in 30 frames per second = 60 fields per second), and uses one field for the left view, the other field for the right view, effectively offering a progressive stereoscopic image but with only half of the vertical resolution, so the player needs to interpolate the vertical lines to restore the full vertical resolution.

Most software players that understand 3D can handle the field-sequential DVD, while standard DVD players will just produce a fuzzy 2D image.

At any rate, you could use AviSynth to split the alternating fields into a left and a right video, then use my AviSynth 3D Toolbox to convert the result to whatever other 3D format Vegas can handle.

I was thinking that line alternate would be the same as field sequential. I'll have to check into avisynth.. I used to have a method in vt3 that would convert in real-time I'll have to see if I can locate it.

Red Prince > I don't think I noted any function in AviSynth 3D toolbox to handle field sequential 3d?? What would the commands be to convert to anaglyph?

After importing the 3D media, did you change the property of the media to "Line Alternate?" If you right-click on the media in the Project Media bin, select properties, then change the Stereoscopic3D property from "None" to "Line Alternate."

In addition to that, did you try swapping the Left and Right eye?