Because film framerates and screen refresh rates do not match, ‘judder’ often occurs; Netflix says it has the solution.
When you watch a ‘real’ film on your home screen, often a portable screen like a tablet or smartphone, via platforms like Netflix, you regularly notice that fast movements don’t flow smoothly and buttery. This is because the film’s refresh rate and your screen’s refresh rate are not properly synchronized. Traditionally, films are (still) shot at 23.97 (almost 24) frames per second, a remnant from the time when physical film reels were used. The problem is that a refresh rate of approximately 24 Hz cannot be evenly divided into 50 or 60 frames per second. Therefore, a certain number of frames are interpolated, resulting in the ‘messiness’ of smooth motion. There’s a nice English term for this: judder.
Every three seconds
Netflix has announced that they have come up with an in-app solution called ‘Frame Rate Conversion within Netflix Application,’ leaving nothing to the imagination. Essentially, the trick works by looking at frames per three seconds instead of frames per second. This yields mathematically smoother values for interpolating frames and syncing them. It’s still not one hundred percent perfect, but it’s a lot better than it used to be. According to Netflix, with the new technique, you will hardly notice any judder. What’s interesting is that it is handled within the app and compatible with any screen used. In principle, the trick is immediately available, but as far as is known at the time of writing, it has not yet been rolled out to the Netflix apps. It will probably happen soon though!
It’d be nice if DVD players and TV’s could do this. I’ve yet to see a TV where, for example, one can see where a tennis ball lands relative to the line(s).