The latest version of Handbrake no longer supports avi files as output.
You would have to get an earlier version of the program.
What exactly do you mean by “video ts” file lisataruschio58? Do you have a folder named Video_TS? If so, that is a dvd-video folder that contains .vob, .ifo and .bup files.
Dvd-video can be converted to .avi files with AutoGK, or AviDemux among many other programs.