EDID Extensions assigned by VESA

• Timing Extension (00)
• Additional Timing Data Block (CTA EDID Timing Extension) (02)
• Video Timing Block Extension (VTB-EXT) (10)
• EDID 2.0 Extension (20)
• Display Information Extension (DI-EXT) (40)
• Localized String Extension (LS-EXT) (50)
• Microdisplay Interface Extension (MI-EXT) (60)
• Display ID Extension (70)
• Display Transfer Characteristics Data Block (DTCDB) (A7, AF, BF)
• Block Map (F0)
• Display Device Data Block (DDDB) (FF): contains information such as subpixel layout^[6]
• Extension defined by monitor manufacturer (FF): According to LS-EXT, actual contents varies from manufacturer. However, the value is later used by DDDB.

Structure, version 1.4

Detailed Timing Descriptor

When used for another descriptor, the pixel clock and some other bytes are set to 0:

Monitor Descriptors

Currently defined descriptor types are:

• FF: Monitor serial number (ASCII text)
• FE: Unspecified text (ASCII text)
• FD: Monitor range limits. 6- or 13-byte (with additional timing) binary descriptor.
• FC: Monitor name (ASCII text), for example "PHL 223V5".
• FB: Additional white point data. 2× 5-byte descriptors, padded with 0A 20 20.
• FA: Additional standard timing identifiers. 6× 2-byte descriptors, padded with 0A.
• F9: Display Color Management (DCM).
• F8: CVT 3-Byte Timing Codes.
• F7: Additional standard timing 3.
• 10: Dummy identifier.
• 00–0F: Manufacturer reserved descriptors.

Display Range Limits

Additional white point descriptor

Color management data descriptor

CVT 3-byte timing codes descriptor

${\displaystyle {\mathsf {Vertical\ lines}}=({\mathsf {Addressable\ lines\ per\ field}}+1)*2}$
${\displaystyle {\mathsf {Horizontal\ pixels}}=\lfloor {\mathsf {Vertical\ lines}}*{\mathsf {Aspect\ ratio}}/8\rfloor *8}$

Additional standard timings

CTA-861 Standard

The ANSI/CTA-861 industry standard, which according to CTA is now their "Most Popular Standard",^[10] has since been updated several times, most notably with the 861-B revision (published in May 2002, which added version 3 of the extension, adding Short Video Descriptors and advanced audio capability/configuration information), 861-D (published in July 2006 and containing updates to the audio segments), 861-E in March 2008,^[11] 861-F, which was published on June 4, 2013,^[12] 861-H in December 2020,^[13] and, most recently, 861-I, which was published in February 2023.^[14] Coinciding with the publication of CEA-861-F in 2013, Brian Markwalter, senior vice president, research and standards, stated: "The new edition includes a number of noteworthy enhancements, including support for several new Ultra HD and widescreen video formats and additional colorimetry schemes.”^[15]

Version CTA-861-G,^[16] originally published in November 2016, was made available for free in November 2017, along with updated versions -E and -F, after some necessary changes due to a trademark complaint. All CTA standards are free to everyone since May 2018.^[17][18]

The most recent version is CTA-861-I,^[19] published in February 2023, available for free after registration. It combines the previous version, CTA-861-H,^[20] from January 2021 with an amendment, CTA-861.6,^[21] published in February 2022 and includes a new formula to calculate Video Timing Formats, OVT.^[22] Other changes include a new annex to elaborate on the audio speaker room configuration system that was introduced with the 861.2 amendment, and some general clarifications and formatting cleanup.

CTA Extension Block

Version 1 of the extension block (as defined in CEA−861) allowed the specification of video timings only through the use of 18-byte Detailed Timing Descriptors (DTD) (as detailed in EDID 1.3 data format above). DTD timings are listed in order of preference in the CEA EDID Timing Extension.

Version 2 (as defined in 861-A) added the capability to designate a number of DTDs as "native" (i.e., matching the resolution of the display) and also included some "basic discovery" functionality for whether the display device contains support for "basic audio", YC_BC_R pixel formats, and underscan.

Version 3 (from the 861-B spec onward) allows two different ways to specify digital video timing formats: As in Version 1 & 2 by the use of 18-byte DTDs, or by the use of the Short Video Descriptor (SVD) (see below). HDMI 1.0–1.3c uses this^[which?] version.

Version 3 also defines a format for a collection of data blocks, which in turn can contain a number of individual descriptors. This Data Block Collection (DBC) initially had four types of Data Blocks (DBs): Video Data Blocks containing the aforementioned Short Video Descriptor (SVD), Audio Data Blocks containing Short Audio Descriptors (SAD), Speaker Allocation Data Blocks containing information about the speaker configuration of the display device, and Vendor Specific Data Blocks which can contain information specific to a given vendor's use. Subsequent versions of CTA-861 defined additional data blocks.

CTA Extension data format

The Data Block Collection contains one or more data blocks detailing video, audio, and speaker placement information about the display. The blocks can be placed in any order, and the initial byte of each block defines both its type and its length:

If the Tag code is 7, an Extended Tag Code is present in the first payload byte of the data block, and the second payload byte represents the first payload byte of the extended data block.

Once one data block has ended, the next byte is assumed to be the beginning of the next data block. This is the case until the byte (designated in byte 2, above) where the DTDs are known to begin.

CTA Data Blocks

Audio Data Blocks contain one or more 3-byte Short Audio Descriptors (SADs). Each SAD details audio format, channel number, and bitrate/resolution capabilities of the display as follows:

Video Data Blocks will contain one or more 1-byte Short Video Descriptors (SVDs).

Notes: Parentheses indicate instances where pixels are repeated to meet the minimum speed requirements of the interface. For example, in the 720x240p case, the pixels on each line are double-clocked. In the (2880)x480i case, the number of pixels on each line, and thus the number of times that they are repeated, is variable, and is sent to the DTV monitor by the source device.

Increased Hactive expressions include “2x” and “4x” indicate two and four times the reference resolution, respectively.

Video modes with vertical refresh frequency being a multiple of 6 Hz (i.e. 24, 30, 60, 120, and 240 Hz) are considered to be the same timing as equivalent NTSC modes where vertical refresh is adjusted by a factor of 1000/1001. As VESA DMT specifies 0.5% pixel clock tolerance, which 5 times more than the required change, pixel clocks can be adjusted to maintain NTSC compatibility; typically, 240p, 480p, and 480i modes are adjusted, while 576p, 576i and HDTV formats are not.

• The EIA/CEA-861 and 861-A standards included only numbers 1–7 and numbers 17–22 (only in -A) above (but not as short video descriptors which were introduced in EIA/CEA-861-B) and are considered primary video format timings.
• The EIA/CEA-861-B standard has the first 34 short video descriptors above. It is used by HDMI 1.0–1.2a.
• The EIA/CEA-861-C and -D standards have the first 59 short video descriptors above. EIA/CEA-861-D is used by HDMI 1.3–1.3c.
• The EIA/CEA-861-E standard has the first 64 short video descriptors above. It is used by HDMI 1.4–1.4b.
• The CTA-861-F standard has the first 107 short video descriptors above. It is used by HDMI 2.0–2.0b.
• The CTA-861-G standard has the full list of 154 (1–127, 193–219) short video descriptors above. It is used by HDMI 2.1.

A Vendor Specific Data Block (if any) contains as its first three bytes the vendor's IEEE 24-bit registration number,^[23] least significant byte first. The remainder of the Vendor Specific Data Block is the "data payload", which can be anything the vendor considers worthy of inclusion in this EDID extension block. For example, IEEE registration number 00 0C 03 means this is a "HDMI Licensing, LLC" specific data block (contains HDMI 1.4 info), C4-5D-D8 means this is a "HDMI Forum" specific data block (contains HDMI 2.0 info), 00 D0 46 means this is "DOLBY LABORATORIES, INC." (contains Dolby Vision info) and 90 84 8b is "HDR10+ Technologies, LLC" (contains HDR10+ info as part of HDMI 2.1 Amendment A1 standard^[24]). It starts with a two byte source physical address, least significant byte first. The source physical address provides the CEC physical address for upstream CEC devices. HDMI 1.3a specifies some requirements for the data payload.

If a Speaker Allocation Data Block is present, it will consist of three bytes. The first and second bytes contain information about which speakers (or speaker pairs) are present in the display device:

The Room Configuration Data Block and Speaker Location Data Blocks describe the speaker setup using room coordinates. If sources can decode these blocks, they should ignore data in the Speaker Allocation Data block above.