The opening ceremony of the 2016 Rio Olympic Games was successfully held on the evening of August 5, local time (the morning of August 6, Beijing time). The previous poor preparations caused the host Brazil to be criticized, and was jokingly called "the poorest Olympics in history" by netizens.
But this opening ceremony seems to have turned around the Rio Olympics. The Internet has been praised for "exceeding expectations", and some mainstream media have even commented that it is "beautiful"! Some netizens commented that Rio gave people all over the world a light projection show.
Basic science on light projection shows
According to media reports, the cost of the opening ceremony of the Rio Olympics is only 1/10 of that of the London Olympics. It can be said that "the budget is not enough, so lighting is provided." While you are shocked by the light projections at the opening ceremony of the Rio Olympics, how much do you know about light shows? How does the projection show present the images we want through audio and video?
According to Panasonic officials, the Rio Olympics opening ceremony used 110 20,000 lumens high-brightness and high-quality projectors, using a distributed management system. A simple understanding of the distributed management system is that each projector corresponds to a set of playback units, and 110 projections correspond to 110 sets of playback units. The advantage is that it can expand an infinite projection area without losing video quality.
So, how do these 110 sets of playback units achieve the overall picture display?
First, the video needs to be divided into 110 parts and stored on the computer corresponding to the management projector, that is, the media player. A projector is equipped with a computer to store the corresponding 1/110 video content. Each unit has an address code.
Then, the timeline of video playback is synchronized through the network server, which is the media management center in the system.
Picture caption: The picture above shows the back of the Expo Axis Sky Curtain Projection taken by a drone. We can clearly see that this is a complete picture composed of 50 frames. (The bright bar is the overlapping part of the two pictures)
Picture caption: The picture above shows the actual viewing surface.
The difficulty lies in the management platform (or synchronized playback).
We learned earlier that a projector is connected to a computer to form a unit. The video content is divided and stored in the corresponding unit. The network server broadcasts the synchronization signal. The unit receives the corresponding synchronization signal and plays the video content of this timeline.
When we want to simultaneously manage the video signals of 110 projectors, the accuracy requirements are very high, because even one delay will affect the entire picture effect. Therefore, this is also a key factor in testing the projection show technology.
Picture caption: On this picture, we can see the ip address in the unit. (Pictures not from the projection show of this Olympic Games)
The Rio Olympics was held at the Maracanã Stadium (the largest professional football stadium in Brazil). This is also a typical example of spending a small amount of money to do big things. Its actual projection area is about 6,000 square meters, which is equivalent to the Shanghai World Expo cyclorama projection area.
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