module_need(vlc_object_t *obj, const char *cap, const char *name,

bool strict)

->vlc_module_load(obj, cap, name, strict, generic_start, obj);

->ssize_t total = module_list_cap (&mods, capability);

example:     core scale: looking for video filter2 module matching "any": 36 candidates

cap=video filter2,name=any,total=36

module_list_cap:bank.c

The list is sorted from the highest module score to the lowest.

->module_load 

set_capability 设置score