Help on DE2_TV demo code

Hi, I am new to this field. I feel confused about this code. The code is attached .This demo code is used for initialize the Audio and Video configuration.

My question is when will be the parameter "mSetup_ST" changed from 0 to 1 ( or 2 )??

After reset , the mSetup_ST and LUT_INDEX were set to 0 , then go to code in line 88

if(LUT_INDEX<SET_VIDEO) ,

The parameter "SET_VIDEO" <=51, but the LUT_INDEX increases only when mSetup_ST changed to 2. The LUT_INDEX remained at 0 , the code will not go to line 91 to set mSetup_ST <=1 ??

Please help to advise where did I go wrong !! Very much thanks for your help !!