Advanced knowledge of EDID

Today's monitors support higher and higher video performance, earlier it was 2K monitors with 144 Hz and high refresh rates for gaming, but also high-resolution monitors supporting 4K and even 8K, such as e.g. B. SAMSUNG's Neo Qled series TVs.
So if we are using a monitor, how do we get the best performance from the input sources like laptops, consoles, DVDs, PS, Xbox series game consoles on the monitor? For example, if the monitor supports displaying up to 4K 60Hz, connected to a PC host, how do the two devices communicate with each other? The answer is related to the EDID that we're introducing today.
EDID stands for Enhanced Display Identification Data, and by definition EDID is a piece of data containing information about the screen. For example, in the case of the SAMSUNG Neo Qled TV, the manufacturer of the TV is recorded as "SAMSUNG" in the EDID. This is a three-letter reference to the full name "SAM", the monitor's brand name, the monitor's unique serial number, and so on .
For video, the most important recorded parameters are: the monitor supported resolution, refresh rate, color format, monitor supported aspect ratio, monitor size, gamma value, supported audio format, etc. Based on this information, the monitor uses when connecting the input source to the video port of the monitor - the common video ports are HDMI, DP, USB-C, DVI, VGA, etc. - the data of the video port to display the video data. The monitor transmits the EDID to the input source over the video connector data channel. The input source reads and analyzes this data and then transmits an appropriate screen to the monitor based on the content of the EDID, which is the same as when the input source is connected directly to the monitor.
How is the relationship between the input source monitor and an intermediate device, e.g. a KVM switch, how is the EDID transmitted and how can the monitor display an appropriate and accurate image of the input source even when using an intermediate device?
Before we do that, let's consider the example of a direct connection between an input source and a monitor, where the input source produces an image and the monitor displays the image of the input source, so the definition of the two is clear: the input source is that Device that creates the audio and video image, the monitor is the device that displays the image and does not have the ability to create the image itself.
Common sources of input in working life are computer consoles, laptops, DVDs, game consoles (PS series, Xbox series), streaming video boxes, set-top boxes, etc., and monitors are televisions, projectors, displays, etc
When connecting input sources, intermediate devices and monitors, two transmission paths are formed: "input source - intermediate device" and "intermediate device - monitor". For "Input Source - Intermediate Device", the Intermediate Device corresponds to the "Monitor" side; for "intermediate device - monitor", the intermediate device corresponds to the For "input source", the intermediate device corresponds to the "input source" side, so the full transmission direction for EDID is: "display --> intermediate device --> input source".
The first is not to process the EDID of the received monitor, but to transmit it directly to the input source, which reads and analyzes the EDID data, and then transmits the screen to the monitor through the intermediate device, taking into account whether the maximum resolution supported by the input source, the monitor and the intermediate device are compatible with each other. For example, if the input source, monitor, and intermediate device all support 4K 60Hz, there is no resistance in the transmission for the monitor to properly display a 4K 60Hz screen. However, if both the input source and the monitor support 4K 60Hz and the intermediate device supports 4K 30Hz, when the input source learns that the monitor's EDID can display 4K 60Hz, it will transmit 4K 60Hz video data to the intermediate device. However, since the intermediate device only supports 4K 30Hz video sources, it cannot transmit the video to the monitor. When you transfer the video to the monitor, the monitor shows a black screen with no video output.
It can also lead to a new concept: Intelligent EDID.
Some of our products (e.g. the Matrix) have an intelligent EDID management that allows the output with the smallest All screens are resolved and all screens display normally without worrying about black screens.

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