ST. PETERSBURG, Russia (AP) Not perfect, but good enough to avoid game-changing referee mistakes at the World Cup.
Football's governing body set out its aims for an experimental video review system ahead of live trials at the Confederations Cup starting on Saturday.
''To eliminate a clear scandal in football, the mistake that after many years you still remember,'' FIFA's head of refereeing Massimo Busacca said Thursday of technology designed to help referees avoid and correct errors within seconds.
FIFA wants video review approved next year before the World Cup to help decide key incidents: goals scored, penalty awards, red cards and cases of mistaken identity.
Still, video-assisted decisions this month at the Under-20 World Cup in South Korea and international friendly matches have been widely debated.
''I think the quality of the decisions are very high, never perfect,'' FIFA technical director Marco van Basten said at a briefing in the St. Petersburg stadium that will host the Confederations Cup's opening game and final.
FIFA will also use the eight-nation World Cup rehearsal tournament to stress themes it wants to be more widely accepted in one year's time, including more actual playing time.
Referees must add more stoppage time for excessive goal celebrations and time-wasting by goalkeepers, because ''the audience wants to see action,'' Van Basten said.
Video review, however, is likely to define refereeing success at a World Cup that kicks off just 18 months after the 2016 Club World Cup was the first FIFA tournament to have live trials.
At the Under-20 World Cup, one decision causing confusion after advice from referee assistants watching replays was a red card for an Italy defender in a quarterfinals win over Zambia.
The referee awarded a penalty for an apparent foul by the goalkeeper, then was told to award a free kick and send off the defender for a challenge seconds earlier. Replays provoked doubt if the Zambia forward was fouled at all.
''We still have to improve of course,'' said Busacca. ''We are not afraid. We don't have many hours to instruct but the top referees are really learning very fast.''
The nine referees on FIFA duty in Russia includes Damir Skomina, the Slovenian who handled the Champions League final, and Mark Geiger of the United States, who worked at the 2014 World Cup. FIFA appointed 25 refereeing teams to the last World Cup.
A lesson from South Korea - where 12 decisions were made on review in a 52-game tournament - is the need for faster judgments.
''In some situations we are taking too long, we know,'' acknowledged Busacca, who has previously set a target of six seconds.
Busacca said FIFA also wants video review to be ''an incredible tool of prevention'' and singled out a red card at the Under-20 World Cup for an Argentina forward for striking an opponent with an elbow.
''Be careful, a camera is following you,'' Busacca said FIFA is telling players in Russia. ''We are talking with teams -don't do it.''
Teams have also been warned that FIFA wants referees to be strict with players crowding around them to influence decision, and goalkeepers who hold the ball for more than six seconds.
''We have asked referees to remind goalkeepers that this rule still exists,'' said Van Basten, who showed footage of Italy's goalkeeper taking 21 seconds to release the ball against Zambia.
Van Basten said he believes ''no one will complain'' when referees add on longer periods of stoppage time, especially in the second half.
While FIFA has learned from other sports which adopted video review much earlier, it is not ready to follow the NFL or rugby in having referees announce their decisions or be wired for sound to broadcast how they reach a decision.
''We don't have to explain immediately why we make a decision,'' Van Basten said. ''It is important to show it on the screens and let the people know what is the reason. That is enough.''