HDMI v2.1 Specifications including HDMI v2.1a, HDMI v2.0 HDMI v1.4 and older

The HDMI v2.1 Ultra High Speed specification is backwards compatible with earlier versions in addition to higher video resolution and refresh rates, including 8K@60Hz and 4K@120Hz, it also brings support for Dynamic HDR, Game Mode variable refresh rate (VRR), eARC support for advanced audio formats and a 48G cable that will provide 48Gbps of bandwidth which is a key for 8K HDR support.

The full list of resolutions and refresh rates start with 4K at 50/60Hz and 100/120Hz and climbs all the way up to 10K resolution at both 50/60Hz and 100/120Hz.

The big surprise is the new Game Mode VRR, which is similar with AMD FreeSync and Nvidia G-Sync, and meant to provide stutter-, tearing- and lag-free gaming, on both consoles and the PC.

Another big novelty is the all new 48G cable, which will provide enough bandwidth for higher resolutions with HDR. The old cables will be compatible with some of the new features, but for 8K/10K with HDR, you will need the new HDMI v2.1 cable especially on longer lengths cables.

HDMI^® HDMI 2.1a Specification

HDMI^® Specification HDMI 2.1a is the most recent update of the HDMI^® specification and supports a range of higher video resolutions and refresh rates including 8K60 and 4K120, and resolutions up to 10K. Dynamic HDR formats are also supported, and bandwidth capability is increased up to 48Gbps.

Supporting the 48Gbps bandwidth is the new Ultra High Speed HDMI Cable. The cable ensures ultra high-bandwidth dependent features are delivered including uncompressed 8K video with HDR. It features exceptionally low EMI (electro-magnetic interference) which reduces interference with nearby wireless devices. The cable is backwards compatible and can be used with the existing installed base of HDMI devices.

HDMI v2.1a Features

• Higher video resolutions support a range of high resolutions and faster refresh rates including 8K60Hz and 4K120Hz for immersive viewing and smooth fast-action detail. Resolutions up to 10K are also supported for commercial AV, and industrial and specialty usages.
• Dynamic HDR support ensures every moment of a video is displayed at its ideal values for depth, detail, brightness, contrast and wider color gamuts—on a scene-by-scene or even a frame-by-frame basis.
• Source-Based Tone Mapping (SBTM) is a new HDR feature that allows a portion of the HDR mapping to be performed by the Source device instead of the Display device. SBTM is especially useful in cases where HDR and SDR video or graphics are combined together into a single picture, such as picture-in-picture or a program guide with an integrated video window. SBTM also enables PCs and gaming devices to automatically produce an optimized HDR signal in order to maximize the utilization of the display’s HDR capabilities without manual user configuration of the Source device.
• The Ultra High Speed HDMI Cable supports the 48G bandwidth for uncompressed HDMI 2.1a feature support. The cable also features very low EMI emission and is backwards compatible with earlier versions of the HDMI Specification and can be used with existing HDMI devices.
• eARC simplifies connectivity, provides greater ease of use, and supports the most advanced audio formats and highest audio quality. It ensures full compatibility between audio devices and upcoming HDMI 2.1a products.
• Enhanced gaming features ensure an added level of smooth and seamless motion and transitions for gaming, movies and video.
  • Variable Refresh Rate (VRR) reduces or eliminates lag, stutter and frame tearing for more fluid and better detailed gameplay.
  • Auto Low Latency Mode (ALLM) allows the ideal latency setting to automatically be set allowing for smooth, lag-free and uninterrupted viewing and interactivity.
  • Quick Frame Transport (QFT) reduces latency for smoother no-lag gaming, and real-time interactive virtual reality.
• Quick Media Switching (QMS) for movies and video eliminates the delay that often occurs when a device changes from one HDMI frame rate to another.
• HDMI Cable Power enables active HDMI Cables to be powered directly from the HDMI Connector, without attaching a separate power cable. This makes attaching and using active HDMI Cables as easy as using passive, wired HDMI Cables.

HDMI v2.0 Features

HDMI 2.0, which is backwards compatible with earlier versions of the HDMI specifications, significantly increases bandwidth up to 18Gbps and adds key enhancements to support continuing market requirements for enhancing the consumer video and audio experience. New functionality includes:

• 4K@50/60,      (2160p), which is 4 times the clarity of 1080p/60 video resolution
• Up to      32 audio channels for a multi-dimensional immersive audio experience
• Up to      1536kHz audio sample frequency for the highest audio fidelity
• Simultaneous      delivery of dual video streams to multiple users on the same screen
• Simultaneous      delivery of multi-stream audio to multiple users (up to 4)
• Support      for the wide angle theatrical 21:9 video aspect ratio
• Dynamic      synchronization of video and audio streams
• CEC      extensions provides expanded command and control of consumer electronics      devices through a single control point

MHL announced its 3.0 specification to address the latest consumer requirements for connecting a mobile device to displays, marking major advancements in the areas of audio and video transmission over an MHL link. Features of the MHL 3.0 specification include:·

• 4K (Ultra HD): Support of 4K formats up to 3840 × 2160 at 30 Hz.
• Simultaneous high-speed data channel
• Improved Remote Control Protocol (RCP) with new commands
• HID support for peripherals such as a touch screen, keyboard and mouse
• Higher power charging up to 10 W
• Backward compatible with MHL 1 and MHL 2
• Latest HDCP 2.2 content protection
• Enhanced 7.1 surround sound with Dolby TrueHD and DTS-HD
• Connector agnostic – uses as few as five pins
• Support for simultaneous multiple displays

HDMI 2.0 does not define new cables or new connectors. Current High Speed cables (Category 2 cables) are capable of carrying the increased bandwidth.

HDMI v1.4 Features

HDMI Licensing, LLC has announced new features that will be included in HDMI v1.4, some of which directly relate to Blu-ray playback. One of the biggest additions is an Ethernet channel that will allow two-way Ethernet communication at speeds up to 100Mb/s over an HDMI connection.

As more and more home theater devices require Ethernet connections, the necessity to run CAT-5 Ethernet cable in addition to the already existing audio and video cables has increased. Now, consumers will be able to run one CAT-5 cable to their controlling devices (such as a HDMI v1.4 compatible AV Receiver), and then a single HDMI cable to their numerous HDMI v1.4 compatible components – such as a BD-Live Blu-ray player, DVR, or HDTV.

Another additional feature is support for two simultaneous 1080p streams for use in displaying 3D images. While no 3D Blu-ray spec has been approved at this time, the resulting spec will likely include the necessity for two 1080p video streams, and HDMI v1.4 will support it.

Some other new features include:

• Audio Return Channel
• 4K x 2K Resolution Support
• Expanded Support For Color Spaces
• Micro HDMI Connector
• Automotive Connection System

All HDMI Category 1 Cables are certified up to 720p/1080i (Normal HDMI cables – Can support up to 1080p depending on source signal strength) and Category 2 Cables (High Speed HDMI Cables) are all 340Mhz tested, >1080p resolutions (Exceeds current 1080p – 1920 x 1080 HD specifications). All Cables are manufactured using the highest quality cables rated from 24 – 30 AWG (American Wire Gauge Rated) depending on bandwidth and length, Triple Shielded for electromagnetic interference and gold plated connectors for best possible signal transfers.

Graphics layout of display resolutions. Category 1 Cables support up to HD 1080p and Category 2 Cables support up to WQXGA (2560×1600) or 4k UltraHD Resolutions. HDMI v1.4 and above cables support up to 3840×2160 24Hz/25Hz/30Hz, 4096×2160 24Hz. DSTV / Multichoice currently broadcast their HD Channel on HD 720 (1280 x 720) – 720p.

Blu-ray Disc, introduced in 2006, offers new high-fidelity audio features that require HDMI for best results. Dolby Digital Plus (DD+), Dolby TrueHD, and DTS-HD Master Audio use bitrates exceeding TOSLINK capacity. HDMI 1.3 can transport DD+, TrueHD, and DTS-HD bitstreams in compressed form. This capability allows a preprocessor or audio/video receiver with the necessary decoder to decode the data itself but has limited usefulness for Blu-ray.

Blu-ray permits interactive audio whereby the disc content tells the player to mix multiple audio sources together before final output. Most players will consequently handle audio-decoding internally and simply output LPCM audio all the time. Multichannel LPCM can be transported over an HDMI 1.1 (or higher) connection. As long as the audio/video receiver (or preprocessor) supports multi-channel LPCM audio over HDMI, and supports HDCP, the audio reproduction is equal in resolution to HDMI 1.3. Many of the cheapest AV receivers, however, do not support audio over HDMI and are often labeled as HDMI pass through devices and only passes HDMI video/audio to the next device in the HDMI stream e.g display device or HDMI Distribution device.

Note that not all of the features of an HDMI version may be implemented in products adhering to that version since certain features of HDMI, such as Deep Color and xvYCC support, are optional.

* = 36-bit support is mandatory for Deep Color compatible CE devices with 48-bit support being optional.
** = CEC has been in the HDMI specification since version 1.0 but has only begun to be used in CE products with HDMI version 1.3.
*** = Large number of additions and clarifications for CEC commands. One addition is CEC command allowing for volume control of an AV receiver.
**** = Playback of SACD may be possible for older revisions if the signal source (such as the Oppo 970) converts to LPCM. For those receivers that have only PCM DAC converters and not DSD this means that no additional resolution loss occurs.
***** = Even for audio bitstream formats that a given HDMI revision cannot transport it may still be possible to decode the bitstream in the player and transmit the audio as LPCM.