Digital Video and HDTV Algorithms and Interfaces

long time I had a chat with Drake and Dan about where the hell gamma 2.2 from? Base on Dan said from the book "Digital Video and HDTV Algorithms and Interfaces by Charles Poynton", gamma 2.2 that invert human eye's gamma 0.4545 happen in video it's a coincidence, really? for me it's really hard to believed.

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