The first of the four blocks is intended to describe the display's preferred video timing. These resolutions must adhere to standard VESA defined timings.ĭetailed Timing Descriptions – The next 72 bytes are organized into four 18-byte blocks that describe additional video resolutions in detail, so that custom video timings/resolutions can be supported. Standard Timing Identification – The next 16 bytes define eight additional video resolutions supported by the display. The last of the three bytes defines the manufacturer's reserved timing, if any. Each bit represents an established timing such as 640x480/60.
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Vendor/Product Identification Block – The first 18 bytes identify the display manufacturer and product, including serial number and date of manufacture.ĮDID Structure Version & Revision – The next two bytes identify the version and revision of the EDID data within the structure.īasic Display Parameters/Features – The next five bytes define characteristics such as whether the display accepts analog or digital inputs, sync types, maximum horizontal and vertical size of the display, gamma transfer characteristics, power management capabilities, color space, and default video timing.Ĭolor Characteristics – The next 10 bytes define the RGB color space conversion technique to be used by the display.Įstablished Timings – The next three bytes define the VESA-established video resolutions/timings that are supported by the display. DisplayID is not directly backward compatible with previous EDID/E-EDID versions, but is not yet widely incorporated in AV products.
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It is meant to encompass PC display devices, consumer televisions, and embedded displays such as LCD screens within laptops, without the need for multiple extension blocks. DisplayID is a variable length data structure, of up to 256 bytes, that conveys display-related information to attached source devices. It is intended to replace all previous versions. In December 2007, VESA released DisplayID, a second generation of EDID. In fact, the CEA - Consumer Electronics Association has defined its own EDID extensions to cover additional video formats and to support advanced multi-channel audio capabilities. This is known as E-EDID and has been implemented in many consumer devices. The original DDC protocol defined 128 bytes to be sent from the display to the video source, with data formatting defined by the EDID specification.Īs display types and capabilities increased, 128 bytes became insufficient, and both EDID and DDC were extended so that multiple 128-byte data blocks could be exchanged. This allowed for much more information to be exchanged, so that EDID and other forms of communication were possible between the source and the display. VESA extended this scheme by redefining VGA connector pins 9, 12, and 15 as a serial bus in the form of the DDC - Display Data Channel. These ID bit pins carried either high or low values to define different screen resolutions. Prior to the development of EDID, pins 4, 11, 12, and 15 on the VGA connector were sometimes used to define monitor capabilities. HistoryĮDID was developed by VESA - the Video Electronics Standards Association, with version 1.0 introduced in 1994 within version 1.0 of the DDC standard. Originally developed for use between analog computer-video devices with VGA ports, EDID is also now implemented for DVI, HDMI, and DisplayPort. Generally, the source device will be a computer graphics card on a desktop or laptop PC, but provisions are in place for many other devices, including HDTV receivers and DVRs, DVD and Blu-ray Disc players, and even gaming consoles, to read EDID and output video accordingly.
This maximizes the functional compatibility between devices without requiring a user to configure them manually, thus reducing the potential for incorrect settings and adjustments that could compromise the quality of the displayed images and overall reliability of the system. The premise of this communications is for the display to relay its operational characteristics, such as its native resolution, to the attached source, and then allow the source to generate the necessary video characteristics to match the needs of the display. EDID data exchange is a standardized means for a display to communicate its capabilities to a source device.