Instant replay is the replaying of video footage of an event or incident very soon after it has occurred. In television broadcasting of sports events, instant replay is often used during live broadcast, to show a passage of play which was important or remarkable, or which was unclear on first sight. Replays are typically shown during a break or lull in the action; in modern telecasts, it will be the next break, though older systems were sometimes less "instant". The replay may be in slow motion, or from multiple camera angles. More advanced technology has allowed for more complex replays, such as freeze frame, frame-by-frame review, and overlaying of virtual graphics. Sports commentators analyze the replay footage when it is being played, rather than describing the concurrent live action.

Some sports organisations allow officials to consult replay footage before making or revising a decision about an unclear or dubious play. This is variously called video referee, video umpire, instant replay official, television match official or third umpire. Other associations 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.

History

The first instant replay came in a 1950s episode of Hockey Night in Canada (HNIC) broadcast by the Canadian Broadcasting Corporation (CBC). George Retzlaff, director in Toronto, used a "hot processor" to develop kinescope footage of an ice hockey goal for replay within 30 seconds. Retzlaff had no approval for his experiment. MacLaren, HNIC's advertising agency, was annoyed it could not publicize the technique, and the Montreal studio did not have the technology to replicate it; so CBC prevented Retzlaff reusing it.

In American football broadcasting, a prototype videotape replay machine was trialled by CBS on 7 December 1963, for the Army–Navy Game. After technical hitches, the only replay broadcast was Rollie Stichweh's winning touchdown. It was replayed at the original speed, with commentator Lindsey Nelson advising viewers "Ladies and gentlemen, Army did not score again!"

Slow motion replay was initiated a few years later by ABC. Replay from analog disk storage was trialled by CBS in 1965, and commercialized in 1967 by the Ampex HS-100, which had a 30-second capacity and freeze frame capability.

Use by officials

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. The role of the video referee differs varies, often they can only be called upon to adjudicate on specific events. 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.

Gridiron football

American football

Canadian football

Basketball

In NBA basketball, the officials must watch an instant replay of a buzzer beater to determine if the shot was released before time expired. Since 2002, the NBA also has mandated installation of light strips on both the backboard and the scorer's table that illuminate when time expires, in order to assist with any potential review.

Instant Replay came to the NBA in 2002-2003 season. In Game 4 of the 2002 Western Conference Finals end of the 2nd quater, Lakers Reserve Power Forward Samaki Walker threw up a half court heave that went in. Replays show that Walker shot was late. The clock at 0.0 seconds in Walkers hand and the red flashing behind the backboard. The Start of Instant Replay was instituted after this game. Costing the Kings the Game which losing by 1 (Robert Horry game winning shot game. Beginning with the 2007-08 season, replay also can be used in determining players being ejected from contests involving brawls or flagrant fouls. In the 2008-09 season, replay may also be used to correctly determine whether a scored field goal is worth two or three points. It may also be used to determine the correct amount of free throws awarded for a missed field goal. It may also be used in cases where the game clock malfunctions and play continues to decide how much time to take off the clock

In college basketball, the same procedure may also be used to determine if a shot was released before time expired in either half or an overtime period. In addition, NCAA rules allow the officials to use instant replay to determine if a field goal is worth two or three points, who is to take a free throw, whether a fight occurred and who participated in a fight. The officials may also check if the shot was made before the expiration of the shot clock, but only when such a situation occurs at the end of a half or an overtime period. Such rules have also required the NCAA to write new rules stating that, when looking at instant replay video, the zeros on the clock, not the horn or red light, now determine the end of the game.

In Italy, host broadcaster Sky agreed with LEGA A for the adoption of instant replay for special tournaments and playoff games, and in 2005, for the entire season. Instant replay would be used automatically on situations similar to the NCAA, but coaches may, like the NFL, have one coach's challenge to challenge a two or three point shot, officials may determine who last touched the ball in an out-of-bounds situation, or back-court violations.

The adoption of instant replay would be crucial in the 2005 LEGA A championship between Armani Jeans Milano and Climamio Bologna. Bologna led the best-of-five series, 2-1, with Game 4 in Milan, and the home team leading 65-64, as Climamio's Ruben Douglas connected on a three-point basket at the end of the game to apparently win the LEGA A championship.

Officials, knowing the 12,000 fans on both sides would learn the fate of the series on their call, watched replays of the shot before determining it was valid.

The ULEB will adopt instant replay for the 2006 Euroleague Final Four and made a rule change determining the lights on the backboard, not the horn, will end a period, thus assisting with instant replay.

On April 6, 2006, FIBA announced instant replay for last-second shots would be legal for their competitions.

"The referee may use technical equipment to determine on a last shot made at the end of each period or extra period, whether the ball has or has not left the player's hand(s) within the playing time."

Ice hockey

In the National Hockey League, goals may only be reviewed in the following situations:

• puck crossing the goal line completely
• puck in the net prior to end of period
• puck in the net prior to goal frame being dislodged
• puck being directed into the net by hand or foot
• puck in the net after deflecting directly off an official
• puck deflected into the goal by the high stick by an attacking player

The review may only be initiated by the on-ice referees or by the video replay judge; neither team can initiate a review. Such a review must take place immediately (if play is stopped) or at the next stoppage in play (if play continues). In the Winter Olympics ice hockey tournament, all goals scored are automatically reviewed to ensure they were legitimate. The NHL also reviews all goals. In addition to goals scored, many plays in the NHL are monitored in "the war room" at the NHL league office in Toronto by head replay official (and former Winnipeg Jet) Kris King and his assistants, who can contact replay judges at games (usually high-level local referees) and ask them to review the plays, or to mete out punishments to players for illegal on-ice actions that were not noticed by the on-ice officials.

Field hockey

In field hockey, the International Hockey Federation allows the match umpire to request the opinion of a video umpire as to whether or not a goal has been validly scored, and whether there was a violation in the build-up to a goal. The video umpire can advise on whether the ball crossed the line there was a violation. Ordinarily, teams are not allowed to make such a request or to press the match umpire to do so. On a trial basis, the 2009 Men’s Champions Trophy allows for "team referral" by each team captain, to query a goal, penalty stroke, or penalty corner decision. The team retains the right to a referral if its previous referrals were upheld..

Baseball

Tennis

In tennis, systems such as Hawk-Eye and MacCAM calculate the trajectory of the ball by processing the input of several video cameras. They can play a computer rendering of the path and determine whether the ball landed in or out. Players can appeal to have the system's calculation used to override a disputed call by the umpire. In March 2008, the International Tennis Federation, Association of Tennis Professionals, Women's Tennis Association and Grand Slam Committee agreed unified challenge rules: a player can make up to three unsuccessful challenges per set, and a fourth in a tie-break. Television broadcasts may use the footage to replay points even when not challenged by a player.

Rugby league

Video referees are used in rugby league in the National Rugby League (Australia/New Zealand) and Super League (Europe), as well as in international matches. In rugby league the video referee can be called upon by the match official to determine the outcome of a possible try. The "video ref" can make judgements on knock-on, offside, obstructions, hold-ups and whether or not a player has gone dead, but cannot rule on a forward pass. If a forward pass has gone un-noticed by the on-field officials it must be disregarded by the video ref, as such judgements cannot reliably be made due to camera angle effects.

Rugby union

The laws of rugby union allow for "an official who uses technological devices" to be consulted by the referee in decisions relating to scoring a try or a kick at goal. The decision to call on the video referee (now called "Television Match Official (TMO)" is made by the referee, then the call is made by the replay referee, who takes his place in the stand of the host team. He either tells the pitch referee by radio link-up or by the use of a big screen during televised matches. Unlike in the NFL, a coach cannot challenge a call made by the pitch referee.

Cricket

Cricket also uses an instant replay. It is used in the areas of run outs, stumpings, doubtful catches and whether the ball has crossed the boundary for a six or short of a four.

The International Cricket Council decided to trial a referral system during the Indian tour of Sri Lanka through late July and August 2008. This new referral system allows players to seek reviews, by the third umpire, of decisions by the on-field umpires on whether or not a batsman has been dismissed. Each team can make three unsuccessful requests per innings, which must be made within a few seconds of the ball becoming dead; once made, the requests cannot be withdrawn. Only the batsman involved in a dismissal can ask for a review of an "out" decision; in a "not out", only the captain or acting captain of the fielding team. In both cases players can consult on-field teammates but signals from off the field are not permitted.

A review request can be made by the player with a 'T' sign; the umpire will consult the TV umpire, who will review TV coverage of the incident before relaying back fact-based information. The field umpire can then either reverse his decision or stand by it; he indicates "out" with a raised finger and "not out" by crossing his hands in a horizontal position side to side in front and above his waist three times.

The TV umpire can use slow-motion, ultra-motion and super-slow replays, the mat, sound from the stump mics and approved ball tracking technology, which refers to Hawk-Eye technology that would only show the TV umpire where the ball pitched and where it hit the batsman's leg and it is not to be used for predicting the height or the direction of the ball. Snicko and Hot Spot can also be used.

Rodeo

The Professional Bull Riders organisation, beginning with the 2006-07 season, has instituted an instant replay system in cooperation with the Versus network.

A bull rider, a fellow competitor, or a judge may request a replay review by filing a protest to the replay official within 30 seconds of any decision.

Any competitor (it does not have to be the rider who is riding the bull in question, as fellow riders can observe the action and spot fouls by bull or rider) may file the complaint to the replay official by sounding a signal at the arena and pay a fee of $500 to PBR before explaining to the replay official why he is filing the request.

The replay official (usually a former bull rider) may request different angles and/or slow motion, as well as freeze particular frames. The replay judge will use all available technology to assess the call in question and supply his ruling. This includes using his own hand-held stopwatch to time bull rides, as the official eight-second clock used in PBR competition starts when the bull usually exits the bucking chute.

The replay will be used to evaluate timing issues, fouls against the rider for touching the bull or ground with his free hand or using the fence to stay on the bull, or fouls by the bull, such as dragging the rider across the fence.

If an appeal is successful, the $500 is returned to the competitor filing the request. If the appeal is unsuccessful, the $500 is forfeited and sent to PBR charities such as the Resistol Relief Fund to assist injured bull riders.

Motor sports

NASCAR utilizes instant replay to supplement their electronic scoring system. Video replays are used to review rules infractions and scoring disputes.

• Video replay is used to determine if a car has cross the pit entrance before the pit was closed for a yellow flag.
• Video is used to supplement electronic scoring to determine the positions in which cars exit the pits (during cautions).
• Video is used to supplement electronic scoring to determine the final race positions (particularly the race winner) when a race ends with a caution flag on the final lap or under a green-white-checker finish.

Association football

In association football, FIFA does not permit video evidence during matches, although it is permitted for subsequent disciplinary sanctions. The 1970 meeting of the International Football Association Board "agreed to request the television authorities to refrain from any slow-motion play-back which reflected, or might reflect, adversely on any decision of the referee". In 2005, Urs Linsi, general secretary of FIFA, said:

Players, coaches and referees all make mistakes. It's part of the game. It's what I would call the "first match". What you see after the fact on video simply doesn't come into it; that's the "second match", if you like. Video evidence is useful for disciplinary sanctions, but that's all. As we've always emphasised at FIFA, football's human element must be retained. It mirrors life itself and we have to protect it.

There have been allegations that referees had made or changed decisions on the advice of a fourth official who had seen the in-stadium replay of an incident. This was denied by FIFA in relation to the Zidane headbutt of Materazzi in the 2006 World Cup final, and in relation to the 2009 Confederations Cup match between Brazil and Egypt, in which Howard Webb signalled initially for a corner kick but then a penalty kick.

See also

• Photo finish

Notes

1. League officials work with Sky TV for technical progress
2. FIBA accepts video proof for last second shots
3. FIH Tournament Regulations, p.30: Appendix 6, §2.2
4. Trial Playing Condition - Review of Umpiring Decisions