Netflix enhances FPS signal conversion to reduce juddery motion

Mike Wheatley

Netflix is looking to solve the ongoing problem of juddery motion that results from watching content with a frame rate that doesn’t match the refresh rate of the TV it’s being displayed on.


Judder is what happens when content is not replayed smoothly by the TV. The cause of this issue is that most content on Netflix comes with a frame rate of 23.97 frames per second, which for our purposes we’ll just round up to 24fps. But most TVs, especially in the U.K. feature a refresh rate of 50Hz or higher, which means that 24fps signal has to be converted to 50fps before it can displayed on the TV.

The issue is that 50 doesn’t divide into 24 quite so nicely, and although 24 frames can be duplicated in order to create 48fps, there are two extra frames left over that must be added somewhere to match the TVs’ 50Hz refresh rate. These two additional frames are what causes judder, or the lack of smoothness in the content being replayed.

The industry has attempted to solve judder with innovations such as “frame rate matching”, which works fairly well but is only available on more modern TVs. Also, it’s often forced to show a very brief blank screen as the frame rate is switched between content. So it’s not a perfect solution, by any means. Quick Media Switching has since been introduced to eliminate this blank screen, but it is currently limited to just a few modern devices, such as the Apple TV 4K and LG’s new C3 and G3 OLED televisions. Worse, the early reception of QMS has not been great, with the general consensus being that it leaves a lot to be desired.

So given the limited applicability of these solutions, Netflix has struck out on its own with a solution it rather clunkily named “Frame Rate Conversion within Netflix Application”.

We won’t bore you with the technical details, which can be found on the Netflix Tech Blog for those who are interested. Essentially, it involves processing the content conversion in three-second chunks, as opposed to one-second chunks, making it possible to spread out those two extra frames more evenly. As such, while it doesn’t completely eliminate judder, it does make it much less noticeable, Netflix promised.


The best thing about Netflix’s solution is that it’s all done inside the Netflix app itself, so it doesn’t matter what TV is being used. It will work on older TVs without the latest HDMI 2.1 features, but that TV must come with the most up to date version of the Netflix application. Unfortunately, that will mean quite a few TVs will still be left out, as many TV manufacturers tend to bypass older models when it comes to app updates.

Even so, Netflix says quite a few TV devices stand to benefit from this update, which is being rolled out now. With any luck, users will notice that content is now being replayed much more smoothly than before.