Item-generation: Sample indices of mono items
For all mono input items, there should be sample indices, i.e.
m1_s1 .. m1_s12
f1_s1 .. f1_s12
...
f3_s1 .. f3_s12For all mono input items, there should be sample indices, i.e.
m1_s1 .. m1_s12
f1_s1 .. f1_s12
...
f3_s1 .. f3_s12