@nonoise
There are fundamental differences between digital video and digital audio.
Digital video is always lossy because compression is used to make the bit rate manageable. 4K Blu-ray uses less aggressive compression than streaming, but there is still compression. The Motion Picture Expert Group has combined a range of lossy compression techniques which are realised as mpeg formats in various versions.
If no video compression were used, the bit rates are fairly easy to calculate. Take the bits for one video frame and multiply by the frame rate of your choice. The bits for one video frame are the bits per pixel times the number of horizontal pixels times the number of vertical pixels. At 24 bits per pixel and 4K resolution we need about 24 * 2,000 * 2,000 bits, or about 100-million bits per frame. With a 60-Hz refresh rate, that's about 6-trillion bits per second. Fortunately, there's not much change between most frames and the following one, and one compression technique is to just send the changes, with an occasional complete refresh.
Our eyes are much more forgiving than our ears.
Audio can be losslessly encoded at bit rates which are achievable with today's technology. However, while lossless encoding and decoding can always recover the original digital sequence if all the packets are delivered and error corrected, it does not stop packets getting lost or corrupted when streaming.
