DisplayPort is a digital display interface developed by the Video Electronics Standards Association (VESA). The interface is primarily used to connect a video source to a display device such as a computer monitor, though it can also be used to carry audio, USB, and other forms of data.
VESA designed it to replace VGA, DVI, and FPD-Link. DisplayPort is backwards compatible with VGA, DVI and HDMI through the use of passive and active adapters.
DisplayPort is the first display interface to rely on packetized data transmission, a form of digital communication found in technologies including Ethernet, USB, and PCI Express. It allows both internal and external display connections and, unlike legacy standards where differential pairs are fixed to transmitting a clock signal with each output, the DisplayPort protocol is based on small data packets known as micro packets, which can embed the clock signal within the data stream, allowing higher resolutions with fewer pins. The use of data packets also allows DisplayPort to be extensible, meaning additional features can be added over time without significant changes to the physical interface itself.
DisplayPort can be used to transmit audio and video simultaneously, but each one is optional and can be transmitted without the other. The video signal path can have six to sixteen bits per color channel, and the audio path can have up to eight channels of 24-bit 192 kHz uncompressed PCM audio or can encapsulate compressed audio formats in the audio stream. A bi-directional, half-duplex auxiliary channel carries device management and device control data for the Main Link, such as VESA EDID, MCCS, and DPMS standards. In addition, the interface is capable of carrying bi-directional USB signals.
The DisplayPort LVDS signal protocol is not compatible with DVI or HDMI. However, Dual-mode DisplayPorts are designed to transmit a single-link DVI or HDMI 1.2/1.4 TMDS protocol across the interface through the use of an external passive adapter that selects the desired signal and converts it from 3.3 volts to 5 volts. Analog VGA and dual-link DVI require powered active adapters to convert the protocol and signal levels and do not rely on Dual-Mode. VGA adapters are powered by the DisplayPort connector, while dual-link DVI adapters may rely on an external power source (see Dual-mode).
The DisplayPort connector can have one, two, or four differential data pairs (lanes) in a Main Link, each with a raw bit rate of 1.62, 2.7, 5.4, or 8.1 Gbit/s per lane with self-clock running at 162, 270, 540, or 810 MHz. The effective data rates after decoding are 1.296, 2.16, 4.32, or 6.48 Gbit/s per lane (or 80% of the total), since data is 8b/10b encoded so each eight bits of information are encoded with a ten-bit symbol.
1.0 to 1.1
The first version, 1.0, was approved by VESA on 3 May 2006. Version 1.1a was ratified on 2 April 2007.
DisplayPort 1.0 allows a maximum of 8.64 Gbit/s data rate over a 2-meter cable. DisplayPort 1.1 also allows devices to implement alternative link layers such as fiber optic, allowing a much longer reach between source and display without signal degradation, although alternative implementations are not standardized. It also includes HDCP in addition to DisplayPort Content Protection (DPCP). The DisplayPort 1.1a specification can be downloaded for free from the VESA website.
1.2
DisplayPort version 1.2 was approved on 22 December 2009. The most significant improvement of the new version is the doubling of the effective bandwidth to 17.28 Gbit/s in High Bit Rate 2 (HBR2) mode, which allows increased resolutions, higher refresh rates, and greater color depth. Other improvements include multiple independent video streams (daisy-chain connection with multiple monitors) called Multi-Stream Transport, facilities for stereoscopic 3D, increased AUX channel bandwidth (from 1 Mbit/s to 720 Mbit/s), more color spaces including xvYCC, scRGB and Adobe RGB 1998, and Global Time Code (GTC) for sub 1 µs audio/video synchronisation. Also Apple Inc.'s Mini DisplayPort connector, which is much smaller and designed for laptop computers and other small devices, is compatible with the new standard.=
DisplayPort version 1.2a may optionally include VESA's Adaptive Sync. AMD's FreeSync utilizes the DisplayPort Adaptive-Sync feature for operation. FreeSync was first demonstrated at CES 2014 on a Toshiba Satellite laptop by making use of the Panel-Self-Refresh (PSR) feature from the Embedded DisplayPort standard, and after a proposal from AMD, VESA later adapted the Panel-Self-Refresh feature for use in standalone displays and added it as an optional feature of the main DisplayPort standard under the name "Adaptive-Sync" in version 1.2a. As it is an optional feature, support for Adaptive-Sync is not required for a display to be DisplayPort 1.2a-compliant.
1.3
DisplayPort version 1.3 was approved on 15 September 2014. This standard increases overall transmission bandwidth to 32.4 Gbit/s with the new HBR3 mode featuring 8.1 Gbit/s per lane (up from 5.4 Gbit/s with HBR2 in version 1.2), for a total data throughput of 25.92 Gbit/s after factoring in 8b/10b encoding overhead. This bandwidth is enough for a 4K UHD display (3840×2160) at 120 Hz, a 5K display (5120×2880) at 60 Hz, or an 8K UHD display (7680×4320) at 30 Hz, with 24-bit RGB color. Using Multi-Stream Transport (MST), it can support two 4K UHD (3840×2160) displays at 60 Hz, or up to four WQXGA (2560×1600) displays at 60 Hz in 24-bit RGB mode. The new standard includes mandatory Dual-mode support for DVI and HDMI adapters, with support for the HDMI 2.0 standard and HDCP 2.2 content protection.The Thunderbolt 3 connection standard was originally to include support for DisplayPort 1.3, but the final release ended up only including support for version 1.2.
1.4
DisplayPort version 1.4 was published March 1, 2016. No new transmission modes are defined, so HBR3 (32.4 Gbit/s) as introduced in version 1.3 still remains as the highest available mode. DisplayPort 1.4 adds support for Display Stream Compression 1.2 (DSC), Forward Error Correction, high dynamic range (HDR) extension defined in CTA-861.3, the Rec. 2020 color space, and extends the maximum number of inline audio channels to 32.
DSC is a "visually lossless" encoding technique with up to 3:1 compression ratio. Using DSC with HBR3 transmission rates, DisplayPort 1.4 can support 8K UHD (7680×4320) at 60 Hz with 10-bit color and HDR, or 4K UHD (3840×2160) at 120 Hz with 10-bit color and HDR. 4K at 60 Hz with 10-bit color and HDR can be achieved without the need for DSC. On displays which do not support DSC, the maximum limits are unchanged from DisplayPort 1.3 (4K 120 Hz, 5K 60 Hz, 8K 30 Hz)
1.4a
DisplayPort version 1.4a was published in April 2018. VESA made no official press release for this version. It updated DisplayPort's DSC implementation from DSC 1.2 to 1.2a.
2.0
According to a roadmap published by VESA in September 2016, a new version of DisplayPort was intended to be launched in "early 2017". It would have improved the link rate from 8.1 to 10.0 Gbit/s, a 24% increase. This would have increased the total bandwidth from 32.4 Gbit/s to 40.0 Gbit/s.
However, no new version was released in 2017, likely delayed to make further improvements after the HDMI Forum announced in January 2017 that their next standard (HDMI 2.1) would offer up to 48 Gbit/s of bandwidth. According to a press release on 3 January 2018, "VESA is also currently engaged with its members in the development of the next DisplayPort standard generation, with plans to increase the data rate enabled by DisplayPort by two-fold and beyond. VESA plans to publish this update within the next 18 months."
At CES 2019, VESA announced that the new version would support 8K @ 60 Hz without compression and was expected to be released in the first half of 2019.
On June 26, 2019, VESA formally released the DisplayPort 2.0 standard. VESA stated that DP 2.0 is the first major update to the DisplayPort standard since March 2016, and provides up to a ≈3× improvement in data rate (from 25.92 to 77.37 Gbit/s) compared to the previous version of DisplayPort (1.4a), as well as new capabilities to address the future performance requirements of traditional displays. These include beyond 8K resolutions, higher refresh rates and high dynamic range (HDR) support at higher resolutions, improved support for multiple display configurations, as well as improved user experience with augmented/virtual reality (AR/VR) displays, including support for 4K-and-beyond VR resolutions.
Products incorporating DP 2.0 are not projected by VESA to appear on the market until late 2020.
DP 2.0 configuration examples
With the increased bandwidth enabled by DP 2.0, VESA offers a high degree of versatility and configurations for higher display resolutions and refresh rates. In addition to the above-mentioned 8K resolution at 60 Hz with HDR support, DP 2.0 across the native DP connector or through USB-C as DisplayPort Alt Mode enables a variety of high-performance configurations:
- Single display resolutions
- One 16K (15360 × 8640) display @ 60 Hz with 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (with DSC)
- One 10K (10240 × 4320) display @ 60 Hz and 8 bpc (24 bit/px, SDR) RGB/Y′CBCR 4:4:4 color (uncompressed)
- Dual display resolutions
- Two 8K (7680 × 4320) displays @ 120 Hz and 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (with DSC)
- Two 4K (3840 × 2160) displays @ 144 Hz and 8 bpc (24 bit/px, SDR) RGB/Y′CBCR 4:4:4 color (uncompressed)
- Triple display resolutions
- Three 10K (10240 × 4320) displays @ 60 Hz and 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (with DSC)
- Three 4K (3840 × 2160) displays @ 90 Hz and 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (uncompressed)
When using only two lanes on the USB-C connector via DP Alt Mode to allow for simultaneous SuperSpeed USB data and video, DP 2.0 can enable such configurations as:
- Three 4K (3840 × 2160) displays @ 144 Hz and 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (with DSC)
- Two 4K × 4K (4096 × 4096) displays (for AR/VR headsets) @ 120 Hz and 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (with DSC)
- Three QHD (2560 × 1440) @ 120 Hz and 8 bpc (24 bit/px, SDR) RGB/Y′CBCR 4:4:4 color (uncompressed)
- One 8K (7680 × 4320) display @ 30 Hz and 10 bpc (30 bit/px, HDR) RGB/Y′CBCR 4:4:4 color (uncompressed)
