Sports Video Analysis or “Tagging” is a way of marking events in a videoed sports activity. Examples of events might be line-outs, scrums, goals, fouls, red or yellow cards, tennis serves, volleys, in fact any event in any sport.
Events are recorded in a timeline showing the exact points in the match video the events happened, the timeline also shows how long each event lasted.
An example of this might be volleys that happen in a tennis match. The analyst would be able to see how long the volleys lasted and generate reports as to which player won most of the volleys. This information could be used to ascertain the strength or weakness of each player’s volley skills, and over time map improvements due to training etc.
Events are tagged using a code window. When an event happens in a match the analyst clicks a button in the code window that represents the event. If a “home line-out” happens in a rugby match the analyst would click a “home line-out” button in the code window.
The code window event button may have other buttons associated to it that describe the event in more detail, in rugby this might be “home line-out -> Catch & drive” or “home line-out -> Off top”. In some software used to analyse matches the “Home line-out” would be an “Action” and the associated “Catch & drive” or “Off top” would be “Tags”. This terminology varies but the idea is the same. This prevents mistakes being made like “Red card -> Catch & drive” – in rugby this doesn’t make sense.
Code windows are usually created by the analysts tagging a match; some code windows are very basic and others can be incredibly detailed. There isn’t a set code window that analysts use for any given sport although some software used to analyse or tag matches do provide default code windows to get you started.
Once an analyst has tagged all the events in a match the data can be used to generate reports similar to the tennis report previously mentioned. Reports might contain home possession and away possession percentages, home score and away score, home penalties and away penalties etc. The reports would be relevant to the sport being analysed and they can be as detailed as the analyst wants them to be.
So why tag matches? Sports video analysis provides measurable performance gains as well as easy to understand visual feedback for coaches, players and athletes. Analysis is a very effective way of pointing out praise worthy moments as well as possible team weakness and areas that may need improving. It helps to assess game plans, sometimes of both competing teams to gain the competitive edge.
Sports Video Analysis is now seen as a crucial part of coaching and training in a wide range of sports including football, rugby, hockey, cricket, baseball, soccer etc, not only for elite athlete’s and teams but also for universities, colleges, private school and grass roots sports clubs.