[Edit: Removed redundant commentary about headline.]
In: Mathematics
There’s a lot of different ways video can be compressed. The simplest is by “grouping” pixels of similar colors. If I’ve got a red barn made up of 1,000 individual pixels, I can probably shrink the filesize by grouping 5 pixels into a single piece of data. This has some loss of quality, but if the grouping is only done in large sections of the same color it wouldn’t be super noticeable. This is largely what JPEG files do to pictures.
One could also decrease the frame rate. This is done by removing frames from a video; while this loses quality, if the video isn’t particularly fast it shouldn’t be particularly noticeable.
More modern algorithms can use predictive algorithms. If I take a picture of your face frowning and a picture of your face smiling, a decent algorithm could probably predict how you got there. This is done by the use of “motion vectors.” When you’re changing faces, a lot of your body doesn’t move very much. If I record *only the changes in the frame,* I can encode a lot less data because your body isn’t moving. This means that each frame after the first one contains a lot less information, because not the entire image changes.
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