system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How we have hundreds of HD channels on cable, but streaming HD on Internet seems to require more bandwidth?
gpt
Cable TV works much like a radio station: Your cable receiver tune into a certain frequency to find a channel and shows the video stream of that channel. It does not matter if just you or any number of people watch that channel, they all get the same content at the same time.

Internet streaming works differently. Your computer )or whatever device you use for watching) talks to a server and requests a video stream. That server then sends that stream to your computer alone. It does not matter if your neighbour is watching the same video or something completely different, he will need his own stream from some server.

Now, let's say that the cable in your neighbourhood has the bandwidth to transfer 100 streams side by side, at any time. For cable TV, that means there could be 100 diffferent channels that everyone can tune into. For internet streaming, that means that just 100 people can each watch a stream.