Video and compression basics
On this page, we will look at “video compression format”, but why is “compression” necessary in the first place?
And although it is called “video compression”, several questions arise about “what does compression mean?”
In this way, I would like to take a look at the important points to understand “video compression”.
What is compression in the first place?
First, let’s look at “compression”.
When you think of “data compression”, you may think of it as “reducing the amount of data”, but in reality there is “lossless compression” and “lossy compression”.
Lossless compression reduces the amount of data while retaining the amount of information in the data.
As it is called “reversible”, it is a method that can be reverted to “before compression”. In other words, lossless compression is a method that enables complete restoration of compressed data.
Lossy compression, on the other hand, compresses data and cannot be fully restored to its pre-compressed state.
In other words, the method that can be restored before compression is “lossless compression” and the method that cannot be restored before compression is “lossy compression”.
In this way, compressed data is classified into lossless compression and lossy compression according to “whether the data can be restored before compression.”
And most video data compression methods fall under this “lossy compression”.
Why do you need “compression”?
This is because “video data” is “a continuous image data set”.
Video is “continuous still image”
The animation looks like a flip book, with several images stacked on top of each other, but the “video” is similar to this and expresses the “change” by stacking the images.
In this way, a video is made up of a series of still images.
Even if there is only one image, a certain amount of data is required, but imagine if there are multiple images … You also need to operate all the time and keep storing data as a “surveillance camera”.
If you handle it “as is” without compressing it, the amount of data will be enormous.
