Suppose we have a digital video with 720x1080 frame size at 30 fps frame rate which plays for 20 minutes. Assume each pixel is encoded on 8 bits. We need to store it on maximum 2 GBytes storage. The frames are organized into groups (GOPs) of 45 frames each. Each GOP is headed by an I frame and followed by P and B frames. There are at most four B frames between P and I frames.

a)   How the GOP stream would look like?

b)   How many GOP in 20 min would the camera record? And how many I, P and B frames?

c) What is the compression ratio?

d)   What would be the size of the video if I, B and P frames are compressed to 50% of its original size?

e)   Assuming I frames compress to 10% of its original size and P frames to 1%, compute the minimal B frame compression ratio needed?