At the broadcast center, the high-tech electronic stream of video travels via an MPEG encoder, which converts the programming to mpeg4 video of the suitable dimensions and format to the satellite receiver into your home.
Encoding works along with compression to analyze each video frame and then eliminate redundant or immaterial data and data data from other frames. This process lowers the overall size of the file. Each frame may be encoded in one of three ways:
As an intraframe, which includes the complete graphic data for that frame. This method provides the least compression.
As a forecasted frame, which comprises only enough info to tell the satellite receiver how to show the frame in line with the most recently displayed intraframe or predicted frame. A predicted framework comprises only data that explains the way a picture has changed from the prior frame.
As a bi directional frame, which displays information out of the nearby intraframe or called frames. Using data from the closest surrounding frames, then the recipient interpolates the color and position of each pixel.
This process sometimes generates artifacts — glitches in the video image. One artifact is macro-blocking, where the fluid picture dissolves in to cubes. Macro-blocking is frequently wrongly referred to as pixilating, a technically incorrect term which has been accepted as slang with this annoying artifact. Graphic artists and video editors use “pixilating” more accurately to make reference to this distortion of a graphic. There really are pixels onto your own TV screen, but they’re too small for your human eye to comprehend them — they are tiny squares of video data that make up the image you see. (For more information about perception and pixels, observe how TV Works.)
The pace of compression depends on the type of the programming. When the encoder is converting a newscast, it may work with far more predicted frames because a lot of the scene stays the same in 1 frame to another location. In more fast-paced programming, things change quickly from one frame to another location, so the encoder must create more intraframes. Because of this, a newscast generally compresses to a smaller size than something such as a car race.
Encryption and Transmission
After the video is compressed, the provider encrypts it to help keep people from getting it for free. Encryption scrambles the electronic data in such ways it could only be decrypted (converted back to usable data) when the receiver has got the correct decryption algorithm along with security keys.
When the signal is compressed and encrypted, the broadcast center beams it directly to at least one of its tanks. The satellite accumulates the signal by having an onboard dish, then amplifies the signal and uses another dish to beam the signal back to Earth, where audiences may pick it up.