EDID — Extended Display ID Data
Definition
EDID (Extended Display Identification Data) is a data structure defined by VESA in which a display describes its capabilities to the source: supported resolutions and refresh rates, colour formats and, through the CTA-861 extension used by HDMI, audio formats and HDR support. The base block has 128 bytes in the E-EDID standard (version 1.4), followed by optional 128-byte extension blocks, and the source reads it over the DDC channel when the link is connected. Extenders, splitters and matrices often present their own EDID, or merge the EDIDs of several displays. When the EDID seen by the source does not match the display, the source outputs a format the display cannot show, or falls back to a low resolution.
In the field
A source that outputs the wrong resolution behind an extender or a matrix is usually reading an EDID other than the display's own. The common fix is to load a fixed EDID into the extender, the matrix or an EDID emulator, so that the source always sees the intended format.
Related lessons
Sources
- VESA, E-EDID Standard Release A2 (EDID 1.4) : bloc de base de 128 octets, blocs d'extension, lecture par DDC · glenwing.github.io
- Extron, Understanding EDID : extension CEA-861 (audio, formats HDMI, HDR), gestion de l'EDID dans les extendeurs et matrices · extron.com
- Wikipédia, Extended Display Identification Data : versions, extension CTA-861 (pointeur secondaire) · en.wikipedia.org