Crowd-test planner

A dependency-light Python script (standard library only) that plans and screens a crowdsourced subjective video quality test. From your clip count, ratings-per-session, target valid panel (default 35 = the ITU-T P.910 10/2023 uncontrolled floor), and expected reject rate it computes: (1) how many workers to recruit so >=35 survive screening, recruit = valid / (1 - reject_rate); (2) the gold and trapping budget at ~1 of each per 10 real trials, per the open P.808 / P.910 implementations; (3) a ro