What are Jews and why does television have this problem?

Close-up of a hand holding a remote control in front of a TV screen
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Have you noticed that movement is not always smooth on your TV when watching movies? This phenomenon is known as Judder, and it occurs when the frame rate of the content you see is not evenly distributed in the refresh rate of your television.

What are Jews and why does it happen?

Jews are due to inconsistencies during the time a frame appears on the screen. This is often displayed when 24p movie content is displayed on a panel using a 60 Hz refresh rate, which means that the screen is refreshed 60 times every second.

Since 24p content is not evenly distributed in 60, the TV must perform what is called a 3: 2 drop-down list. This is where every other frame appears a little longer than the one that came before it. So, for example, frame 1 is displayed for two updates (every 1/60 second), while frame 2 is displayed for 3 updates (also 1/60 second each).

This pattern is repeated, causing the movement on the screen to have uneven pacing, causing jews. This is the main reason for this phenomenon, as the vast majority of televisions still use 60 Hz panels. Newer 120 Hz panels can eliminate this problem by performing a 5: 5 tap-down that involves adjusting the refresh rate to better fit the content.

There are other reasons for judder, including the fact that the cinematic 24p frame rate is not suitable for fast-moving objects on the screen. This is often visible in fast-paced panoramic images and is as much a problem on a projector in a theater as on the latest televisions.

Finally, frame drops can also introduce judder, and these are often caused by hardware limitations, e.g. A frame rate drop in a game or playback of a high bit rate video on an older device that simply cannot keep up, causing some images to be ignored. This introduces inconsistencies in frame time that cause Jews.

RELATED: How do frame rates affect the gaming experience?

Some televisions can remove Jews

It is not uncommon for television to remove the type of judder associated with 24p content on a 60 Hz display. Many will do this automatically for all sources by reducing the frame rate to 48 Hz or increasing it to 72 Hz. Panels updated at 120Hz simply display each image five times (5: 5 drop-down menu), since 5 x 24 = 120 .

This includes movies you watch using internal apps, signals sent from DVD or Blu-Ray players, or set-top boxes like Apple TV and Google Chromecast. You need to research to find out which models remove judder from 24p content before buying your TV.

Do not confuse Jews with tribes

Jews and tribes are similar in that they affect how motion is displayed on your screen, but the two questions have different characteristics. Although Jews are a result of inconsistent picture times, tribes are usually due to low picture speeds.

Although the video on the screen is not completely smooth if the time between frames (and the number of times a particular frame is displayed) remains constant, this qualifies as tribes rather than Jews.

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