Update device EDID
Extended display identification data (EDID) is data provided by a video display device (usually a monitor) to describe its capabilities to a video source (usually a graphics or video output card in a PC or another device). The video source uses the EDID to determine the capabilities of the monitor to determine the resolution, color depth and other settings that the monitor can support.
In the case of your DVI2USB 3.0, it's acting as the monitor for your video source. Epiphan factory-loads your video grabber with a comprehensive EDID that describes all the video modes it can support. When you connect a video source (such as a laptop or video camera), this source interprets your DVI2USB 3.0 as a monitor and uses its EDID to negotiate which video signal to send.
EDID is crucial for DVI sources but mostly ignored by VGA sources.
Generally, the factory loaded EDID correctly emulates a monitor that supports your video source. However sometimes, particularly if your source uses a custom set of display properties, you need to help the video grabber by uploading a custom EDID to force the capture card to report that it emulates a resolution, color depth, etc needed by your laptop, camera or other video source.
For example, you can upload a custom EDID file to your DVI2USB 3.0 that reports that it only operates at 1040x768. When the video source reads the EDID from the video grabber, the video source will reset to operate at 1024x768 as set in the EDID.
In addition to needing to load a specific EDID, you may from time to time, want to upgrade your capture device with the latest factory EDID from Epiphan.
Upload a new EDID
In most circumstances the factory installed default EDID, is sufficient. However, there may be some cases where a video source uses resolutions that you do not want to use. In that case you can choose an EDID that forces the video grabber to use a specific set of attributes.
EDID changes are permanent until you replace them with another EDID.
- First, download a new EDID file, by going to the Epiphan support web page.
- Select the support page for DVI2USB 3.0.
- Scroll to the EDID section.
- Click an EDID from the list; the file is saved to your downloads folder on your hard drive.
To return to the factory default EDID, select the "default configuration" EDID from the download list.
- Connect your video grabber to the capture computer.
- Disconnect your video source from the video grabber.
- Launch the Epiphan Capture Tool.
- Select the Tools » Upload EDID to device... menu option; a file selection dialog opens.
- From the Open dialog, find the downloaded EDID file and select it.
- A warning dialog reminds you to disconnect your source. Make sure no source is connected to the video grabber and click OK.
- In a few short moments, the EDID upload is complete.
Practical EDID example
Here's an example of how a custom EDID can resolve a capture issue.
Let's say you have a flat panel monitor connected as your video output device that has a fixed screen resolution of 640×480. Then you replace that flat panel monitor with a DVI2USB 3.0 and the source system changes its video output resolution to 720×400.
Why did the resolution of the system change? That's because the video source prefers 720×400. Originally, the video source. was forced to operate at 640×480 because the flat panel monitor didn't support 720×400. But since the DVI2USB 3.0 supports 720×400, the system automatically changed to its preferred resolution.
But what if you want a screen resolution of 640×480 and you can't force the video source to operate at that resolution?,A custom EDID is what you need. Epiphan creates custom EDIDs for the DVI2USB 3.0. For example, a custom EDID that excludes support for 720×400 would resolve this situation. Now when you upload the custom EDID to the video grabber, the video source no longer finds support for 720×400 and it returns to operating at 640×480.