DisplayPort
DisplayPort (DP) is a proprietary[a] digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device such as a computer monitor. It can also carry audio, USB, and other forms of data.[1]
Type
Digital audio/video connector
May 2006
Various
2008–present
DVI, VGA, SCART, RGB Component
None
Various
Yes
Yes
Optional; 1–8 channels, 16 or 24-bit linear PCM; 32–192 kHz sampling rate; maximum bitrate 36,864 kbit/s (4,608 kB/s)
Optional, maximum resolution limited by available bandwidth
20 pins for external connectors on desktops, notebooks, graphics cards, monitors, etc. and 30/20 pins for internal connections between graphics engines and built-in flat panels.
Yes
1.62, 2.7, 5.4, 8.1, or 20 Gbit/s data rate per lane; 1, 2, or 4 lanes; (effective total 5.184, 8.64, 17.28, 25.92, or 77.37 Gbit/s for 4-lane link); 2 or 720 Mbit/s (effectively 1 or 576 Mbit/s) for the auxiliary channel.
Micro-packet
ML_Lane 0 (p)[a]
GND
ML_Lane 0 (n)[a]
ML_Lane 1 (p)[a]
GND
ML_Lane 1 (n)[a]
ML_Lane 2 (p)[a]
GND
ML_Lane 2 (n)[a]
ML_Lane 3 (p)[a]
GND
ML_Lane 3 (n)[a]
CONFIG1
CONFIG2
AUX CH (p)
GND
AUX CH (n)
Hot plug
Return
DP_PWR
DisplayPort was designed to replace VGA, FPD-Link, and Digital Visual Interface (DVI). It is backward compatible with other interfaces, such as DVI and High-Definition Multimedia Interface (HDMI), through the use of either active or passive adapters.[2]
It is the first display interface to rely on packetized data transmission, a form of digital communication found in technologies such as Ethernet, USB, and PCI Express. It permits the use of internal and external display connections. Unlike legacy standards that transmit a clock signal with each output, its protocol is based on small data packets known as micro packets, which can embed the clock signal in the data stream, allowing higher resolution using fewer pins.[3] The use of data packets also makes it extensible, meaning more features can be added over time without significant changes to the physical interface.[4]
DisplayPort is able to transmit audio and video simultaneously, although each can be transmitted without the other. The video signal path can range from 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.[1] A bidirectional, half-duplex auxiliary channel carries device management and device control data for the Main Link, such as VESA EDID, MCCS, and DPMS standards. The interface is also capable of carrying bidirectional USB signals.[5]
The interface uses a differential signal that is not compatible with DVI or HDMI. However, dual-mode DisplayPort ports are designed to transmit a single-link DVI or HDMI protocol (TMDS) across the interface through the use of an external passive adapter, enabling compatibility mode and converting the signal from 3.3 to 5 volts. For analog VGA/YPbPr and dual-link DVI, a powered active adapter is required for compatibility and does not rely on dual mode. Active VGA adapters are powered directly by the DisplayPort connector, while active dual-link DVI adapters typically rely on an external power source such as USB.
Versions[edit]
1.0 to 1.1[edit]
The first version, 1.0, was approved by VESA on 3 May 2006.[6] Version 1.1 was ratified on 2 April 2007,[7] and version 1.1a on 11 January 2008.[8]
DisplayPort 1.0–1.1a allow a maximum bandwidth of 10.8 Gbit/s (8.64 Gbit/s data rate) over a standard 4-lane main link. DisplayPort cables up to 2 meters in length are required to support the full 10.8 Gbit/s bandwidth.[8] DisplayPort 1.1 allows devices to implement alternative link layers such as fiber optic, allowing a much longer reach between source and display without signal degradation,[9] although alternative implementations are not standardized. It also includes HDCP in addition to DisplayPort Content Protection (DPCP). The DisplayPort 1.1a standard can be downloaded for free from the VESA website.[10]
1.2[edit]
DisplayPort version 1.2 was introduced on 7 January 2010.[11] The most significant improvement of this version is the doubling of the data rate to 17.28 Gbit/s in High Bit Rate 2 (HBR2) mode, which allows increased resolutions, higher refresh rates, and greater color depth, such as 3840 × 2160 at 60 Hz 10 bpc RGB. Other improvements include multiple independent video streams (daisy-chain connection with multiple monitors) called Multi-Stream Transport (MST), 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.[1][12][13][14]
1.2a[edit]
DisplayPort version 1.2a was released in January 2013[15] and may optionally include VESA's Adaptive Sync.[16] AMD's FreeSync uses 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,[17] 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.[18] As it is an optional feature, support for Adaptive-Sync is not required for a display to be DisplayPort 1.2a-compliant.
1.3[edit]
DisplayPort version 1.3 was approved on 15 September 2014.[19] 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 with 24 bit/px RGB color, a 5K display (5120 × 2880) at 60 Hz with 30 bit/px RGB color, or an 8K UHD display (7680 × 4320) at 30 Hz with 24 bit/px RGB color. Using Multi-Stream Transport (MST), a DisplayPort port can drive two 4K UHD (3840 × 2160) displays at 60 Hz, or up to four WQXGA (2560 × 1600) displays at 60 Hz with 24 bit/px RGB color. The new standard includes mandatory Dual-mode for DVI and HDMI adapters, implementing the HDMI 2.0 standard and HDCP 2.2 content protection.[20] The Thunderbolt 3 connection standard was originally to include DisplayPort 1.3 capability, but the final release ended up with only version 1.2. The VESA's Adaptive Sync feature in DisplayPort version 1.3 remains an optional part of the specification.[21]
1.4[edit]
DisplayPort version 1.4 was published 1 March 2016.[22] 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, HDR10 metadata defined in CTA-861.3, including static and dynamic metadata and the Rec. 2020 color space, for HDMI interoperability,[23] and extends the maximum number of inline audio channels to 32.[24]
1.4a[edit]
DisplayPort version 1.4a was published in April 2018.[25] VESA made no official press release for this version. It updated DisplayPort's Display Stream Compression implementation from DSC 1.2 to 1.2a.[26]
2.0[edit]
On 26 June 2019, VESA formally released the DisplayPort 2.0 standard. VESA stated that version 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.
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 23% increase.[27][28] 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."[29] 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.[30]
In December 2010, several computer vendors and display makers including Intel, AMD, Dell, Lenovo, Samsung and LG announced they would begin phasing out FPD-Link, VGA, and DVI-I over the next few years, replacing them with DisplayPort and HDMI.[64][65][66]
DisplayPort has several advantages over VGA, DVI, and FPD-Link.[67]
Although DisplayPort has much of the same functionality as HDMI, it is a complementary connection used in different scenarios.[71][72] A dual-mode DisplayPort port can emit an HDMI signal via a passive adapter.
[edit]
Figures from IDC show that 5.1% of commercial desktops and 2.1% of commercial notebooks released in 2009 featured DisplayPort.[64] The main factor behind this was the phase-out of VGA, and that both Intel and AMD planned to stop building products with FPD-Link by 2013. Nearly 70% of LCD monitors sold in August 2014 in the US, UK, Germany, Japan, and China were equipped with HDMI/DisplayPort technology, up 7.5% on the year, according to Digitimes Research.[81] IHS Markit, an analytics firm, forecast that DisplayPort would surpass HDMI in 2019.[82]
– the official site operated by VESA
