To differentiate a bit in the image, you have to work with what the eye can see. You keep that and throw away what the eye can't see. The same technique applies to audio coding. In audio coding, you keep what you can hear and throw away the rest. Today's digital wireless communications services rely on compression technologies.
Regular television is analog.
To describe each picture element takes 24 bits. In uncompressed form, this amounts to a bit rate of roughly 250 million bits per second. Satellite and digital cable are using between two and three million bits per second. These compression numbers now need to be achieved in transmitting video to computers for video to the desktop to be a viable option, Cox says. As we evolve toward streaming video to a computer, we need to balance the video bit rate and the communication bandwidth.