L'explication d'ESPN HD par exemple (bon elle date de 2003) :
Why Did ESPN Choose 720p versus 1080i?
ESPN chose 720p because of the "p," which stands for progressive scan technology. Progressive scan technology paints the picture on your television screen from top to bottom on a line-by-line basis&.as in lines 1,2,3,4,5,6,7, etc. Interlace technology, the "i" in 1080i, paints the picture on an every-other-line basis, first painting lines 1,3,5,7,9 and then a split second later painting lines 2,4,6,8 and 10. Your eyes then assemble the painting into one image.
Progressive scan technology produces better images for the fast moving orientation of sports television. Simply put, with 104 mph fastballs in baseball and 120 mph shots on goal in hockey, the line-by-line basis of progressive scan technology better captures the inherent fast action of sports. For ESPN, progressive scan technology makes perfect sense.