What is the Input Lag?
The input lag of a television is the time from a picture is generated by the source to the picture appearing on the screen. An input lag of more than 50ms starts to be noticeable by competitive gamers, > 75ms by good gamers of fast games and > 100ms by the majority of people. Anything more than 125ms is not playable for a fast game.
Input lag of 2014 TVs
The following table lists all input lags that we measured for 2014 TVs.
Input lag of 2013 TVs
The following table lists all input lags that we measured for 2013 TVs.
How do I fix the input lag problem of my television?
Don't worry, most televisions can be adjusted to not have a high input lag. Try the following (which is how we setup the TVs in our tests):
- Set the TV into the Game Mode or PC Mode
- Disable all the settings of the television
Additionally, you can try a lot of combinations of settings/mode/inputs.
Why is the input lag important?
The input lag is only important if you are playing video games. Movies or televisions shows are not affected because there is no interaction with the signal that you can do. If your television has a high input lag, you will see all your movements and interactions delayed on the screen. This is even more important in timing critical games like FPS or rhythms based (like Guitar Hero). When watching a movie however, even if the video is delayed by 1 minute, you will not see a difference unless the sound is not also delayed.
Why does the television take time to display a picture?
There are 3 main parts that delays the television: acquiring the source image, processing the image and displaying it.
Acquisition of the image
The source signal does not always come in a native format for the television. A digital television will have to convert the analog RGB component signal to digital. This conversion takes time. If you are seeing a lot of lag from an analog signal, try using a digital signal instead because the television will need to do fewer operations to transform it. The closer you are to the television native format, the less input lag you will have.
Once the image is in a format understandable by the video processor, it can change it. This includes:
- Adding overlays (like menus)
- Adjusting the colors and brightness
- Interpolating the picture to match the television refresh rate
- Scaling it (720p -> 1080p)
The time of this step is affected by the speed of the video processor and the amount of processing needed. Even if you cannot control the speed of the processor, you can control which operations it needs to do with the settings of the television. The more settings you enable, the more work the processor needs to achieve.
Some televisions have a dual core processor in them. This can help reducing the input lag if a lot of processing options are turned on.
Displaying the image
Once the television has processed the image, it is ready to be displayed on the screen. This is the step where the video processor sends the image to the screen. However, the screen cannot change its state instantly, the time will depend on the technology and components of the television. A plasma screen can change its picture faster than an LCD screen. You cannot control the time of that phase, it is fixed per television.
How is it measured?
The input lag is not in an official television specification because it depends on two varying factors: the type of source and the settings of the television. The easiest way you can measure it is by connecting a computer to the TV and displaying on both the same timer. You can find such timer here. Then, if you take a picture of both screens, the difference of times will be your input lag. This is however an approximation because your computer does not necessary output both signals at the same time. For example, the setup to the right indicates an input lag of 40ms (1:06:260 – 1:06:220).
Televisions makers knows that adding a lot of video processing increase the input lag which is why they usually have a gaming mode setting. The gaming mode will disable some of the most time consuming processing of the television. However, the gaming mode is not necessary the setting that guarantees the lowest input lag of the television; you will sometime need to play with the other settings to get an optimal input lag time.
Have a question?
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