DisplayPort General FAQs

DisplayPort 1.3 Standard FAQs

DisplayPort Alt Mode for USB Type-C Standard FAQs

Display Stream Compression (DSC) FAQs

DisplayPort General FAQs

Q: Who owns and develops DisplayPort Standards?

A: DisplayPort is a video interface standard administered by VESA, the Video Electronics Standards Association. DisplayPort is the new generation AV interface developed by the GPU/display industry segment and it continues to gain market momentum. DisplayPort enables high display performance, robustness, and versatility, highest degree of system integration, and greater interoperability among various device types.

Q. What is the current version of the DisplayPort Standard?

A. DisplayPort 1.3 was published in September, 2014 and defines the new normative requirement and informative guideline for component and system design.  Most DisplayPort products currently available in the market today (as of January 2015) were built to the previous version, DisplayPort v1.2a. Testing that is performed for DisplayPort device certification is also still based on the DisplayPort v1.2a Standard (devices must be certified to use the DisplayPort logo). Products built to DisplayPort 1.3, as well as compliance testing based on DisplayPort 1.3, should become available within 2015.

For more information on DisplayPort 1.3, see DisplayPort 1.3 Standard FAQs

Q. Which types of products include DisplayPort?

A. DisplayPort was originally developed as the next generation personal computer display interface and is now available on a wide range of tablets, notebooks, and desktop computers as well as monitors. It is now also becoming available on digital televisions, including some 4K TVs, as a display input.

Q. What are the user benefits of DisplayPort?

A. DisplayPort provides several direct and indirect benefits to the user. Direct benefits include higher performance capability, the availability of display adapters for legacy display types, and the ability to connect multiple displays to a single video output. Indirect benefits include smaller system form factor and lower system cost, because DisplayPort enables higher system integration, requires less RF shielding, and is royalty free. DisplayPort also uses a small connector, or can be combined with other interfaces onto a single common connector. As the only AV interface with link training, a more robust and stable link is established.

Q. How is DisplayPort different from HDMI? Aren’t they very similar?

A. DisplayPort and HDMI are very different technically, and each began with a different product focus. For over ten years, HDMI has been the de-facto connection for home entertainment systems and is used widely on HDTVs as an AV interface. Some PCs and monitors include HDMI to enable connectivity with HDTVs and other consumer electronics gear. DisplayPort, a newer standard originally developed to support the higher performance requirements of personal computers, is based on updated signal and protocol technology similar to that already used in today’s computer systems, enabling an increase in performance and integration. Because DisplayPort uses common signaling technology in use for data communications and a packetized data structure, through a common connector, it can be combined with standards such as USB and Thunderbolt. With link training/link quality monitoring as in data communications, DisplayPort provides a more robust and stable AV link.

Q. How can I use my existing display or digital TV set with a new computer that has a DisplayPort output?

A. DisplayPort has the unique ability to support external display adapters. The DisplayPort Source device (such as a notebook computer) provides power at the DisplayPort plug to power such an adapter, and it detects the type of adapter connected, as well as the type of monitor. Inexpensive DisplayPort adapters are readily available for VGA, DVI, and HDMI displays. Adapters for HDMI 2.0 will become available in the near future.

Q. Does DisplayPort also support audio?

A. Yes, DisplayPort supports multi-channel audio and many advanced audio features. DisplayPort to HDMI adapters also include the ability to support HDMI audio.

Q. Can DisplayPort support 3D Stereo?

A. Yes, DisplayPort includes protocol support for transmitting left and right eye display data. DisplayPort 1.3 enables the support of 4K Stereo at 120Hz frame rate with full 24 bit 4:4:4 color.

Q. Does DisplayPort include content protection capability?

A. Just like DVI and HDMI, DisplayPort supports HDCP content protection. DisplayPort 1.3 supports the latest HDCP 2.2 content protection that is required for the latest premium AV contents.

Q. What are some of the unique capabilities in DisplayPort?

A. Because of its high data rate, DisplayPort 1.2a systems today can support 4K displays at 60Hz refresh and full 30-bit 4:4:4 color (non-chroma subsampled).  DisplayPort 1.3 systems will support 5K displays (5120 x 2880) at 60Hz refresh, and for 4K displays will enable deeper color and higher refresh rates. When enabled with DisplayPort’s Multi-Stream feature, several monitors can be connected to a single output on a video source device (such as a laptop or computer), using a daisy-chain or hub configuration.

Q. How does VESA assure interoperability among DisplayPort enabled systems?

A. VESA manages the DisplayPort Compliance program which is designed to assure interoperability between various systems. To bear the DisplayPort Logo, a system must pass compliance testing and the system OEM needs to be a VESA member, which assures they are aware of the latest DisplayPort related specifications and updates.

Q. How has the adoption of Thunderbolt affected DisplayPort?

A. Thunderbolt takes advantage of DisplayPort technology, and Thunderbolt Hosts (such as notebooks and personal computers) are backward-compatible with DisplayPort cables and DisplayPort monitors. This means you can plug a DisplayPort monitor into a Thunderbolt computer output, using a standard DisplayPort cable. The adoption of DisplayPort technology by Thunderbolt has helped to accelerate the adoption of DisplayPort in high-end computing and video post-production.

DisplayPort 1.3 FAQs

Q: Does the release of DisplayPort 1.3 mean that DisplayPort 1.2 products are obsolete?

A: Not at all. VESA develops and publishes standards like DisplayPort prior to their actual deployment in the field. DisplayPort 1.2a represents the latest interconnect technology now available to consumers from manufacturers. The new DisplayPort capabilities included in DisplayPort 1.3 have begun the cycle of hardware development that will result in such technology becoming available to consumers in a range of products over the next few years. And like other new versions of DisplayPort, DisplayPort 1.3 is backward compatible with earlier DisplayPort standards.

Q: What is the data transfer bandwidth of DisplayPort 1.3?

A: By providing the option to support a new higher data transfer rate known as HBR3 (High Bit Rate 3), which provides a link rate of 8.1 Gbps per lane, DisplayPort 1.3 offers a 50% increase in total link rate to 32.4 Gbps when using all 4 lanes in the DisplayPort cable. Allowing for data coding overhead, this provides a total data transport capacity of 25.92 Gbps or 3240Mbytes/sec.

Q: Will DisplayPort 1.3 enable further performance enhancements to 4K UHD displays?

A: Yes, when including the new HBR3 link rate option, DisplayPort 1.3 will enable a 4K UHD display to operate at a 120Hz refresh rate using 24-bit pixels, or a 96Hz refresh rate using 30-bit pixels.

Q: Will DisplayPort 1.3 enable support beyond 4K resolution?

A: Yes, as DisplayPort 1.3 with HBR3 becomes available for production, we should see computers and displays that support 5K x 3K using a single cable.

Q: Will DisplayPort 1.3 support 8K displays?

A: Yes, by using the new HBR3 link rate, DisplayPort 1.3 will support 8K displays with a 60Hz refresh rate at 24-bit-pixel visual quality, however, until DSC is enabled, the 4:2:0 chroma sub-sampled pixel encoding format must be used. 4:2:0 is normally acceptable for the playback of pre-recorded content, such as movies, which uses 4:2:0 pixel format for compression, but is less desirable for rendered graphics from computer or other graphics generating video sources.  In the future, DisplayPort will support DSC which will provide a better alternative for 8K display support. See Display Stream Compression (DSC) FAQs for more information.

Q: When will I be able to buy products that use DisplayPort 1.3?

A: Products that support new DisplayPort features defined in DisplayPort 1.3 should become available in 2015. Early implementations could very likely use DisplayPort Alt Mode over USB Type-C – See DisplayPort Alt Mode for USB Type-C FAQs for more information.

Q: How will I know if my device supports new DisplayPort 1.3 features?

A: Vendor packaging and on-line information should indicate the DisplayPort features supported for each product.

Q: Will DisplayPort Alt Mode on the Type-C connector support DisplayPort 1.3?

A: Yes. All of the features associated with DisplayPort 1.3 will be available for the DisplayPort Alt Mode.

Q: Will Thunderbolt, which uses DisplayPort for video, support DisplayPort 1.3?

A: We expect that other interconnect technologies that use DisplayPort as a video transport will adopt the DisplayPort 1.3 features.

Q: How many 4K displays could I expect to connect to my computer using a single DisplayPort 1.3 connection?

A: Assuming the DisplayPort Multi-Stream feature is enabled and the Source can support such monitor configuration, DisplayPort 1.3 with HBR3 can support two 4K UHD (3840 x 2160) displays at 60Hz refresh with and 24-bit pixels, using the VESA video timing that is used with DisplayPort connections. This will also require the appropriate Multi-Stream hub or at least one monitor with Multi-Stream daisy-chain capability.

Q: Does DisplayPort 1.3 enable support for the latest content protection?

A: Yes, DisplayPort 1.3 enables support for HDCP version 2.2. This requirement will apply to DisplayPort-to-HDMI 2.0 converters as well (including USB Type-C to HDMI 2.0 converters that utilize DisplayPort Alt Mode).

Q: Can I connect a DisplayPort 1.3 device to a new television that supports HDMI 2.0?

A: Existing DisplayPort source devices, such as PCs, already support HDMI televisions up to 1080p through the use of a DisplayPort to HDMI adapter. DisplayPort 1.3 defines new adapters that will enable DisplayPort source devices to support HDMI 2.0, enabling the support for 4K UHD with up to 60Hz refresh and up to full 24 bit color with the 4:4:4 pixel format. These adapters do not require the new HBR3 link rate, requiring only HBR2, but will depend on some of the protocols within the DisplayPort 1.3 Standard. Some DisplayPort 1.2a systems will most likely be upgradable through firmware to support this new feature. These new adapters will also be available in DisplayPort Alt Mode over the USB Type-C connector.

Q: Does DisplayPort 1.3 still support adapters to VGA, DVI and HDMI?

A: Yes.

Q: Does DisplayPort 1.3 enable support for camera RAW format data?

A: Yes, this is a new feature for DisplayPort 1.3.

Q: Is VESA’s new AdaptiveSync supported?

A: Yes. AdaptiveSync was first supported by DisplayPort 1.2a, and it is already supported in some available products. This is also branded as “Free-Sync” from AMD, which is based on VESA’s AdaptiveSync Standard.

Q: How does DisplayPort 1.3 impact the capabilities of Multi-Stream?

A: Using the DisplayPort Multi-Stream feature, combined with the new HBR3 link rate option, DisplayPort 1.3 can enable the following example display configurations, without the use of compression:

• Two 4K UHD (3840 x 2160) displays

• Up to Four 2560 x 1600 displays (see note 2 below)

• Up to Seven 1080p or 1920 x 1200 displays (see note 2 below)

• One 4K UHD display with up to Two 2560 x 1600 displays


(1) The examples above assume the following:

• HBR3 and Multi-Stream supported by both the video source and displays

• 60Hz refresh with 24 bit color, using the 4:4:4 pixel format and VESA monitor timing

(2) The number of connected displays might be limited by video source capability. Typical personal computers support a maximum of 3 to 6 displays.

DisplayPort Alt Mode for USB Type-C FAQs

Q: What is the DisplayPort™ Alternate Mode (or Alt Mode) for USB Type-C?

A: The DisplayPort Alt Mode enables the USB Type-C connector and cable to support the DisplayPort interface for audio/video (AV) transport capability.

Q: Is DisplayPort Alt Mode a VESA Standard?

A: Yes, DisplayPort Alt Mode was published by VESA, but the development of the DisplayPort Alt Mode for USB Type-C Standard was developed in collaboration with the USB 3.0 Promoters group. VESA continues to collaborate with USB for the refinement of the specification and for compliance test development.

Q: What type of products will use this standard?

A: Because the USB Type-C connector is designed to be the next generation USB interface, it will appear on Smart Phones, Tablets, PCs, Notebooks, Docking Stations, Displays, and Peripherals, replacing all existing USB ports. Many of these systems are expected to support DisplayPort Alt Mode as it concurrently supports USB 3.1 GEN2 BR and 4Kp60Hz display at 24 bits per pixel.

Q: When will I be able to buy these products?

A: Products should be available in 2015.

Q: What user benefits are derived from DisplayPort Alt Mode on USB Type-C?

A: When using the DisplayPort Alternate Mode, the USB Type-C connector becomes the single system connection point for data, full performance AV interface, and power, with such features combined or supported individually. DisplayPort Alt Mode will enable the USB Type-C connector to support full DisplayPort capability including video resolutions of 5K and beyond. The USB Type-C connector is also reversible, which further simplifies the consumer experience.

Q: Does this mean that with the addition DisplayPort Alt Mode, I can still expect the same USB data and USB Power Delivery capabilities across USB Type-C connector?

A: Yes. DisplayPort, USB data, and USB Power Delivery can all be carried simultaneously through the same USB Type-C connector and cable. This is supported by a standard full-featured USB Type-C cable.

Q: Can DisplayPort Alt Mode provide the same level of performance and features as the standard DisplayPort connection?

A: Yes. Just like in standard DisplayPort connectors and cables, DisplayPort Alt Mode can take advantage of the four high-speed data lanes in the USB Type-C connector and cable to provide 4K display resolutions and beyond.

Q: How will I know if the Type-C connector on my device supports DisplayPort?

A: USB Type-C connectors that support the DisplayPort Alt Mode will include the DisplayPort (DP) logo near the connector. This is described in the new USB-IF Trademark License Agreement and Usage Guidelines document published by the USB IF and available here:  http://www.usb.org/developers

Q: Can I connect an existing monitor to a new computer, tablet or phone that uses the USB Type-C connector with DisplayPort Alt Mode?

A: Yes. Adapter cables, as defined in the DP Alt Mode Standard will be available to connect a USB Type-C output with DP Alt Mode to DisplayPort, HDMI, DVI, and VGA monitor inputs.

Q: Can I connect my HDTV to a device that uses USB Type-C connector with DisplayPort Alt Mode for video output?

A:  Yes. Adapter cables will also be used to connect a USB Type-C output with DP Alt Mode to an HDMI input on the HDTV.  HDMI 2.0 will also be supported to enable 4K resolution. If the HDTV has a DisplayPort input, then another type of adapter cable can be used to provide DisplayPort display capability.

Q: Can we expect to see displays using the USB Type-C connector with DisplayPort Alt Mode for video input?

A:  Yes. Displays will also take advantage of the USB Type-C connector to enable the use of the reversible connector as well as carry USB data and power over the same cable. This can allow the inclusion of a USB hub in the monitor, for example, and allow the monitor to provide power to the computer – thereby enabling a single cable for desktop use of a portable system. A standard, full-featured USB Type-C cable would be used in such configuration.

Q: Will hub devices that use the USB Type-C connector support DisplayPort Alt Mode?

A:  USB Type-C with DisplayPort Alt Mode will allow the use of a single cable to power the system (notebook, tablet or phone), transport USB data, and transport AV data using DisplayPort. The hub can also include one or more DisplayPort outputs for connection to external monitors, using USB Type-C and/or native DisplayPort connectors. The hub can also include DisplayPort protocol conversion to support HDMI, DVI, and VGA outputs. DisplayPort’s Multi-Stream capability would be utilized within the hub for multiple monitor support.

Q: Can a user connect a DockPort™ hub to a video source device that uses the new Type-C connector?

A: Yes. An adapter should be available to connect a DockPort capable source device that uses a USB Type-C connector to a DockPort Hub, which uses a tethered cable with a mini DisplayPort connector.

Q: How does the USB Type-C Standard share its interface with DisplayPort?

A: The USB Type-C Standard includes provision for Alternate Modes, which involves repurposing of the connector pins and cable wires for other interface types. Discovery of Alternate Mode support and enablement is performed through leveraging the use of the USB Power Delivery protocol.

Q: What happens if I plug my display into a Type-C port that does not support the DisplayPort Alt Mode?

A: No video data will be received by the display, so there will be no image on the screen. Doing this will not harm your device. A warning message will also be displayed on the screen of a USB product.

Q: How do I know which end of the cable to plug into my device?

A: The USB Type-C to Type-C cable is reversible, and so is the USB Type-C to DisplayPort adapter cable. These can be plugged in either direction. The USB Type-C to HDMI, DVI, VGA, and DockPort converters need to be plugged into a video source device that has the USB Type-C connector.

Q: I have a Mac with Thunderbolt that uses DisplayPort for video. Will there be a Thunderbolt to USB Type-C adapter to connect a DisplayPort monitor that uses a Type-C connector?

A: A Thunderbolt connector on a Mac or PC uses the standard mini DP connector and supports DisplayPort as well as Thunderbolt. So for the Thunderbolt connector, you can use the standard mini DP to USB Type-C adapter cable to connect to the monitor.

Q: Will products using the DisplayPort Alternate Mode be certified?

A: Yes. VESA and the USB-IF are working on a comprehensive certification program.

Q: Other Display Interface Alt Modes, such as MHL Alt Mode, are being introduced for the USB Type-C connector.  Will the end user see any particular benefit for the DisplayPort Alt Mode?

A: The DisplayPort Alt Mode is natively supported by a standard “full feature” USB Type-C cable. As video Source devices, display devices, and docking stations begin supporting DisplayPort Alt Mode, this most common USB Type-C cable type will seamlessly transport both USB and DisplayPort data. In comparison, the MHL Alt Mode, for example, will likely require a special cable to carry Display or Display + data content. DisplayPort Alt Mode will also offer higher performance.

Q: How does the DisplayPort Alt Mode performance compare with MHL Alt Mode?

A: While MHL supports 4K displays, its performance is reportedly limited to 30 frames per second. It can be assumed this is because MHL was originally developed for the earlier 5 pin USB connectors (4 signal pins), and backward compatibility with existing MHL Sink devices will be maintained. The DisplayPort Alt Mode was developed to take full advantage of the USB Type-C connector that has 24 pins (14 signal pins), allowing it to support 4K and 5K displays at 60 frames per second. Even higher performance displays will be enabled by DisplayPort Alt Mode in the future. Using the DisplayPort Multi-Stream feature, DisplayPort Alt Mode can also support multiple high resolutions displays.

Q: Will the same cables be used for MHL Alt Mode and DisplayPort Alt Mode?

A: No. To support the MHL Alt Mode, a USB Type-C to MHL adapter cable will be used, which will have an HDMI plug at the display or “sink” end. For DisplayPort Alt Mode, assuming the video source and sink use the USB Type-C connector, a standard, full-feature USB Type-C cable can be used. If the Source or Sink uses a standard or mini DisplayPort connector and the other end uses USB Type-C (and supports DisplayPort Alt Mode), then a USB Type-C to DisplayPort adapter cable can be used.

Q: Will the MHL Alt Mode and DisplayPort Alt Mode use the same adapters to support HDMI, DVI and VGA?

A: No. MHL Alt Mode protocol adopters will not work on systems that only support DisplayPort Alt Mode, and visa-versa. Such adapters should include labeling to identify MHL Alt Mode or DP Alt Mode support to avoid consumer confusion. Both MHL Alt Mode and DisplayPort Alt Mode will support the use of protocol adapters to support HDMI, DVI, and VGA displays.

Q: What products are expected to support MHL Alt Mode vs. DisplayPort Alt Mode?

A. MHL is available today from certain smart phone manufactures, and MHL Alt Mode will allow the introduction of USB Type-C into these product lines to maintain interoperability with the existing ecosystem. DisplayPort Alt Mode is expected to accelerate the adoption of DisplayPort in personal computer systems, notebooks, and tablets as well as smart phones.

Q: What might influence a product manufacturer to implement DisplayPort Alt Mode vs. MHL Alt mode?

A: DisplayPort Alt Mode provides increased capability and performance. And unlike MHL, DisplayPort uses electrical signaling that is similar to SuperSpeed USB, which is easier to integrate into today’s submicron chips, including the SoC’s used in phones and other portable devices. And unlike MHL, DisplayPort Alt Mode is an open, royalty-free standard, and participation in the definition and development of the standard and ecosystem is open to any VESA member.

Display Stream Compression (DSC) FAQs

Q: What is the VESA Display Stream Compression (DSC) Standard?

A: VESA, the Video Electronics Standards Association, has published a new Standard in 2014 that uses visually lossless image compression to increase the amount of data carried by a display interface data rate, saving power.

Q: What is meant by visually lossless?

A: By being visually lossless, a typical observer of a display, under typical viewing conditions, would in most cases not notice any difference or degradation of images or video after compression, when compared with the uncompressed image or video.

Q: Is DSC designed to be used with DisplayPort or other display interface standards?

A: DSC is an open standard that was developed in liaison with the MIPI Alliance for general purpose display interface compression. It is currently included for optional use in VESA’s Embedded DisplayPort (eDP) Standard v1.4, and MIPI’s DSI Specification v1.2, and is open for use in other display interface standards as well. VESA anticipates on-going liaison activity other parties interested in the DSC Standard as upcoming improvements or revisions arise.

Q: What are the main applications for the DSC Standard?

A: The initial application for DSC is portable, battery powered systems with an embedded display. DSC is used in the internal embedded display interface to both save system power, which extends battery life, and reduce the system form factor’s weight, and cost by decreasing the number of interconnect wires. It also decreases the display’s frame buffer size which further decreases cost. In the future, DSC will be used to further increase display resolution for external displays. For example, DisplayPort 1.3 will be able to support 8K video at 60Hz and 24-bit color using a low 2:1 compression ratio or 30-bit color using a low 2.5:1 compression ratio, which will provide visually lossless image quality (indistinguishable from the original image), unlike the use of chroma subsampling.

Q: How does VESA’s DSC Standard compare to other image compression standards?

A: Compared to other image compression standards such as JPEG or AVC, etc., DSC achieves visually lossless compression quality at a low compression ratio by using a much simpler codec (coder/decoder) circuit. The typical compression ratio of DSC range from 1:1 to about 3:1 which offers significant benefit in interface data rate reduction. DSC is designed specifically to compress any content type at low compression with excellent results. The simple decoder (typically less than 100k gates) takes very little chip area, which minimizes implementation cost and device power use, and adds no more than one raster scan line (less than 8 usec in a 4K @ 60Hz system) to the display’s throughput latency, an unnoticeable delay for interactive applications.

Q: What testing did VESA perform to determine that DSC is visually lossless?

A: During the development of DSC, the contributing VESA member companies performed ongoing visual tests to uncover visual compression artifacts using different image types and image motion. This testing was used to fine tune the DSC codec (coding / decoding algorithm). For the final DSC codec, the visual performance of DSC was evaluated through clinical testing by VESA in collaboration with member companies. The evaluation included a statistically significant number of observers who viewed many images over four image categories including artificial engineered images, text and graphics, such as street maps or different examples of printed material, people, landscape, animals and stills. Overall, observers completed nearly 250,000 subjective image comparisons. VESA members also concluded subjective testing as a far more robust method to verify visually lossless quality rather than using objective metrics, such as, PSNR which typically designates one value for an image. The results of this testing indicated that DSC met the visually lossless criteria set by VESA. The details of testing methodology and results will be published by VESA in early 2015.

Q: Does the implementation of the VESA DSC Standard require royalty payment?

A: The VESA DSC Standard is open and royalty free.

Q: Is there a VESA membership requirement to implement the DSC Standard?

A: The VESA DSC Standard was designed to be an open standard available for use by other video interface standards. The VESA DSC Standard, including the codec C source code files, is available from VESA for a nominal fee, and is available to VESA members for free.

Q: Does VESA plan to update the DSC Standard or publish other compression standards?

A: The current VESA DSC Standard is version 1.1, and it is likely that the VESA contributing members will make future optimizations and publish future updated versions that will be backward-compatible with version 1.1. VESA is also starting work on another display compression standard that will provide higher compression with the tradeoff of higher codec complexity. This should be announced in early 2015.