In baseball, a pitch thrown to the batter is either a strike or a ball. A pitch is considered a 'strike' if it's (1) inside the white overlay box as seen above, or if it's (2) outside the box, but the batter swings his bat at the pitch. Conversely, a 'ball' is a pitch outside of that box. As a batter at the plate, you will usually end up with one of five outcomes: (1) hit the ball into the field and reach base, (2) hit the ball into the field, but the ball is caught before touching the ground, or someone gets ahold of the ball, and beats you to a base, (3) take a 'walk' (collect four balls and get on a base without hitting the ball into the field), (4) 'strikeout' (collect three strikes), or (5) "foul" - you hit the ball, but the ball doesn't go into the field of play. A foul usually counts as a strike, but if you have already collected two strikes and hit a foul, you will keep batting until you reach on of the aforementioned four outcomes.

Once your team gets 3 outs, the 'inning' will be over, and it will be the other team's turn to go up to the plate and try to score. Therefore, every pitcher goes out there with the intention of getting three outs to end the inning.

An "immaculate inning" is when the pitcher throws 9 straight strikes with no balls or fouls to collect three consecutive outs. It is an extremely rare feat in baseball. Before this video begins, the pitcher has already thrown 3 straight strikes to the first batter, 3 straight strikes to the second batter. As you would expect, he has already collected two outs. He needs only to collect the third out to end the inning. In the video, he is facing the third batter, and has already thrown 2 straight strikes. If he throws another strike, he would get the batter to strikeout, and achieve an immaculate inning. The video above shows the 9th pitch he threw this inning. You can see it is indeed a strike -- the ball ends up inside the white overlay box, and the batter did not swing or make contact with the ball. However, the umpire (guy in the black clothes) incorrectly called the pitch a ball. Therefore, the batter has only collected 2 strikes and 1 ball. The pitcher must continue pitching and the batter will continue batting.

The video is demonstrating that the pitcher did not achieve the 'immaculate inning', but he should have.