Which menu template are you selecting and is it for DVD or HD?
If you are burning a standard DVD are you viewing it on a HD TV - if so what type of player are you using - DVD or BD?
Playing DVD on a HD TV requires the image to be upscaled and, depending on the player, this may be reasonably good or result in a soft/pixellated image.
Also, if you have a DVD menu (SD) that contains video thumbmails (chapter markers or P in P's) from you original HD footage you may experience aliasing (shimmering) on the thumbnails.
Check the image quality you create the movie probably less than 9 push to 15. Check also the bitrate is too low less quality use the default or higher. More data means more quality. Check also the menu quality is designed for SD or HD.