EDID is like a business card that includes a serial of information. It describes the specification of a display device, such as manufacturer, product ID, serial No., production date, monitor size, supported resolutions, and frame rate...etc.
There are so many display manufacturers in the A/V market and each has different specifications. Without EDID, video sources can hardly communicate with display devices, thus causing resolution unmatched between video sources and displays. The most common issues are black screen, image distortion, flickers...etc.
How Does EDID Work?
Create Common Ground for Sources and Displays
EDID allows video sources and display devices to communicate in the same "language". Given that, a monitor can tell a video source what resolution it can support and the video source can properly provide the corresponding signal. This communication process is initiated as soon as the monitor and video source are connected via a cable and powered on. However, EDID can be much more complicated when you have multiple video sources and monitors. We will cover more details for you at the end of the article.
Most Common EDID Issues
We have been in the industry for more than 20 years and handle a variety of EDID issues for customers around the globe. In the following, we're going to share the most common issues and their solutions for you.
Issue: No Video Shown
Possible Cause: EDID is broken or incorrect
The EDID is broken or incorrect so that your A/V source is unable to recognize the EDID information of your screen.
Apply an EDID emulator for your monitor to properly send EDID to your video source.
Issue: No Video Shown after Switching to a New Source
Possible Cause: HPD signal Miscommunication
This often happens in A/V integrations, because HPD (Hot Plug Detect) signal fail to communicate between HDMI devices.
Use an HDMI repeater or distributor to separate HPD signal, allowing the video output and inputcommunicate with HPD respectively.
Issue: Resolution Mismatch between a Source and a Display
Possible Cause: Unrecognizable EDID
When your PC is unable to recognize EDID, it will automatically switch to a default resolution. At the moment, If you manually switch to a resolution of your display to match that of your video source, some graphics card drivers will enforce to a lower resolution. This inconsistency will thus cause resolution mismatch.
Try to manually switch to a mutual resolution that both devices can support. If EDID of your display is broken, you can use an EDID emulator for your monitor to allow the video source to read EDID.
Possible Cause: Graphic Card limitation
Even though your A/V source is able to read the EDID of your display, the communication process can still go wrong. Some graphic card drivers limit the output resolution at 1024 x 768, a resolution most display devices can support. However, If the native resolution of your display does not match 1024 x 768, the font size might appear with errors.
Manually switch to 1024 x 768 for your monitor or use an EDID emulator for your display to set up a common resolution supported by your source.
Possible Cause: Difference between Displays
EDID can also go wrong when your video source is connected to multiple displays with different native resolutions. Since one video source can only read EDID from one display at a time, the resolution mismatch will happen in the displays with unread EDIDs.
Switch to a resolution supported by all monitors. You can also use an HDMI distributor that has EDID management to set up resolutions for each output.
Although we do not produce EDID emulators, your can still solve EDID issues with our products that have built-in EDID emulators, such as HDMI distributors, switchers, and matrix switchers...etc. For the next chapter, we're going to explain the technique of how EDID is processed for multiple monitors and sources.
How to Handle EDID with Multiple Monitors and Sources?
EDID in Distributed A/V Systems
A professional A/V system usually includes more than one A/V source and one monitor, and it's very likely using HDMI distributors, switchers, and matrix switchers for A/V setups. That also means EDID communication will become more complicated. As a professional A/V manufacturer, we're going through how EDID is handled in distributed systems.
Managed EDID without Scaler
Manufacturer like SC&T has HDMI distributors, switchers, and matrices that support EDID management. They default 1080p EDID information in the input ports and the sources can detect the EDID and send back the 1080p signal to your HDMI monitor. If 1080p resolution is not satisfying, you can manually switch to a higher resolution for each monitor via the EDID function of the products.
Managed EDID with Scaler
Moreover, we provide devices with advanced features which support not only EDID management but also a video scaling function. The scaler allows video sources to send the highest resolutions that each of your monitors can support.
We have worked with companies around the world for more than 20 years. From experience, we use an efficient method to analyze your situation and provide immediate help.
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