The standard for HD television in the US, ATSC A/53, provides for: "The maximum bitrate of the MPEG-2 video stream is exactly 19.4 Mbit/s for broadcast televis

The standard for HD television in the US, ATSC A/53, provides for: "The maximum bitrate of the MPEG-2 video stream is exactly 19.4 Mbit/s for broadcast television, and exactly 38.8 Mbit/s for the "high-data-rate" mode (e.g., cable television). (The practical limit is somewhat lower, since the MPEG-2 video stream must fit inside a transport stream, with overhead, sent out at 19.3927... Mbit/s for broadcast.)" 38.8 megabits per second is 291 megabytes per minute, or 17.5 gigabytes per hour. You're more likely to be watching something that's compressed an order of magnitude more, because businesses think they can cheap out on it without consequences. Here's Youtube's bitrates: http://www.sciencemedianetwork.org/Blog/20130624_YouTube_bitrates http://www.sciencemedianetwork.org/Blog/20130624_YouTube_bit... . Transferring analog content lossfully at similar resolution is another issue - if the VHS tape has about 240p equivalent resolution, and you transfer it with perfect fidelity to an uncompressed 240p digital stream, you're losing a lot of information, because those dots don't line up perfectly with those pixels, instead smearing out over multiple pixels. Instead of thinking 'equivalent resolution', think Nyquist frequency.