such as the FIFA World Cup, Olympics, Super Bowl, MLB Playoffs, and NBA Playoffs. A 2019 Sports Video Group survey revealed that 213 out of 257 HD mobile production trucks were using some form of EVS replay gear. Evertz Microsystems' DreamCatcher replay system is also widely used by college and pro sports clubs including teams in the NBA, MLB and NHL. Variant Systems Group's Envivo Replay, is also used by college and pro sports clubs including University Of Oregon, Western Michigan University, and the NBA Portland Trail Blazers. Use by officials Some sports organizations allow referees or other officials to consult replay footage before making or revising a decision about an unclear or dubious play. This is variously called video assisted referee (VAR), video referee, video umpire, instant replay official, television match official, third umpire or challenge. Other organizations allow video evidence only after the end of the contest, for example to penalize a player for misconduct not noticed by the officials during play. The role of the video referee differs varies; often they can only be called upon to adjudicate on specific events. When instant replay does not provide conclusive proof, rules may say whether the original call stands, or whether a specific call must be done (most usually no score). Leagues using instant replay in official decision making include the National Hockey League, National Football League, Canadian Football League, National Basketball Association, and Major League Baseball. It is used international in field hockey and rugby union as well. Since 2017, some association football competitions have employed the use of a "Video Assistant Referee" (aka "VAR"). Due to the cost of television cameras and other equipment needed for a video referee to function, most sports only employ them at a professional or top-class level. Baseball In Major League Baseball, instant replay has been introduced to address "boundary calls", which include questions on whether or not a hit should be considered a home run (HR). Among reviewable plays are: Fair Ball-HR; Foul Ball, Ball Clearing Wall-HR; Ball Staying in Play-Live Ball; Ball Leaving Field of Play-HR; and, Ball or Player interfered with by spectators (called Spectator Interference). The latest MLB collective bargaining agreement, expands instant replay to include: Fair Ball; Foul Ball along foul lines, or Ball Caught for Out; Ball Trapped Against Ground or Wall; as well as expanding Interference calls to all walls regardless of whether it is