Will superMHL Replace HDMI?

Integrators prepare for superMHL cable with reversible 32-pin connectors capable of carrying 8K @120fps supporting HDR, advanced color, Dolby and DTS. Technology developed by Sony, Samsung and Toshiba.

C.H. Chee

Since the introduction of MHL in 2010, 900 million devices with MHL technology have been shipped worldwide. Now MHL is set to bring its unique, proven combination of video, audio, power and control to the home theater with superMHL.

superMHL is the first connectivity standard to deliver 8K resolution video at 120 frames per second (fps). Advanced color and High Dynamic Range (HDR) support ensures that the picture not only packs in more pixels, but that the colors are deeper and brighter, delivering a more true-to-life image. Audio also gets a boost from previous MHL generations, with immersive object audio technology from Dolby and DTS. The superMHL specification also introduces a new reversible connector and cable helping simplify those blind plug-ins behind your TV, and unlocks new ways of connecting and controlling your devices by integrating USB 2, more intelligent control channels, and up to 40 watts of power in either direction.

Why Home Theater?

The MHL Consortium started out to solve a specific problem: Output of pristine quality audio and video from mobile devices to larger displays. To accomplish this they had to overcome a number of technical challenges. How do you send multiple gigabytes of data over a single twisted pair of wires? How do you reuse the same cable to carry high definition video, audio, and data while powering the mobile device? How do you ensure that the TV’s remote can also control the video, regardless of who made the TV, remote, or mobile device? 

Solving these challenges for the mobile market involved developing and standardizing numerous new technologies. However as often happens, these solutions once standardized were found to also solve challenges in the home theater space. Recognizing this, the MHL Consortium founders, including technology veterans like Sony, Samsung, and Toshiba, developed superMHL to combine these technologies into a new multi-lane architecture that would provide the bandwidth to support not just the needs of today, but provide a platform that can grow to meet the needs of the home theater market in the future.

Do We Really Need Another Connector?

The superMHL connector responds to two trends in the market; the need for a future-proof connector that can handle the bandwidth needs of the nascent 8K market today, with room for bandwidth expansion in the future, and the recent trend towards reversible connectors. The new superMHL connector meets both of these needs with a single, 32-pin reversible connector that can support a staggering 108Gb per second bandwidth today, and a path to double that bandwidth in the future.

This bandwidth is required to support the push for increasing screen resolution, deeper colors, and higher refresh rate requirements, which has continued unabated. Demonstrations of 8K resolution screens are already making the rounds at technical conferences and trade shows. NHK, the Japanese public broadcaster, has conducted or announced test 8K broadcasts at major sports events, including the 2015 Wimbledon, 2016 Super Bowl, and 2016 Rio Olympic games, and is preparing for a full rollout in 2018.

The past few years have seen the rise in popularity of reversible connectors, solving one of those small annoyances that we always tolerated. With superMHL, this convenience comes to the home theater, in a future proof connector that will help make those ‘blind plug-ins’ a bit easier.

superMHL’s features can broadly be defined in two categories, quality and flexibility. Features like 8K, Advanced Color Space support, and object audio are designed to ensure that you always have the highest quality picture and sound your equipment can deliver, while features like the new reversible connector, and integrated power, data, and control are designed to make connecting and using superMHL simple and intuitive.

8K, Advanced Color Space Support

superMHL is the first connectivity standard to bring 8K 120fps resolution into the living room. Shown in the figure below, 8K UHD (7680 x 4320 pixels) resolutions have four times the pixels of 4K UHD and 32 times the pixel density of 1920x1080p HD resolution. superMHL devices can support 8K UHD resolution with refresh rates up to 120fps. A wide array of specification resolutions are supported by MHL, ensuring that all HDTVs and UHDTVs are able to work when connected to an MHL source without compatibility issues.

superMHL expands its maximum rendered color range from 35 percent to 80 percent by implementing BT.2020 support. This provides a stunning visual experience for consumers and it is expected to be widely adopted by DTVs, digital recording equipment, enhanced broadcasting, and next generation Blu-ray Disc players.

Supports HDR, Deep Color, Immersive Audio

superMHL is also the first video connectivity specification to support HDR. HDR is a unique way to render hyper realistic videos and images with lighting exposure levels that more closely mimic the dynamic range of the human eye. Viewers will be able to see the most brilliant whites and the darkest darks with extremely dazzling transitions in both 8K and 4K UHD resolutions. This allows a true-to-life rendition of video scenes with shadows, sunsets, low lights and panoramic scenes. superMHL supports HDR using static metadata as per the SMPTE 2084 and is also geared to support HDR with dynamic metadata once it’s specified by organizations like SMPTE.

Deep Color helps to eliminate color banding and ensure smooth tonal transitions between colors. superMHL sources and sinks support up to 48-bits of color per pixel at different color depths to ensure that consumers are able to see the most accurate color representations their devices can deliver.

In addition to supporting existing Blu-ray audio formats and legacy-based uncompressed PCM formats, superMHL technology supports leading-edge 3D, object audio, 1-bit audio formats, and an exclusive audio-only mode. This offers consumers an advanced listening experience not only with existing audio formats, but also next-generation immersive audio.

Object audio is the next innovation in creating an immersive sound space. Traditional channel-based audio only works in predefined, fixed locations and uses a specific number of speakers to optimize the audio experience. With object audio, the sound is mapped to individual objects instead of fixed position speakers. Object based audio can adapt to the content of the movie and ensures the best audio experience regardless of the number of speakers and their placement. Both Dolby and DTS object audio protocols and metadata can be carried by superMHL.

Content Protection

You may not think that content protection is important to ensuring quality, but in fact it’s critical. Whatever its challenges, content protection is what gives the entertainment industry confidence to release the highest quality movies into the market quickly. The superMHL specification supports HDCP 2.2 content encryption in all operating MHL A/V link data streams without latency even at the maximum resolution of 8K UHD 120fps. Also, superMHL ensures that devices are able to operate with HDCP 1.4 encryption when linked with MHL 1 and 2 capable products.

superMHL doesn’t just deliver the best possible video and audio, but by combining enhanced control, USB data, and integrated higher charging power on a single cable opens up new use cases in the home theater. With superMHL, a single connection between a DTV and a set top box could power the device, control it, and allow for file transfers with no additional cables. This holds the promise to significantly simplify home theater systems, reducing or even eliminating the cable clutter behind our home theaters.


superMHL Connector: One of the highlights of the superMHL specification is the introduction of the 32-pin, reversible superMHL connector. In addition to the practical convenience of a reversible connector, the new superMHL connector can carry up to six audio/video lanes and provides ample room for future bandwidth growth. The superMHL connector also delivers 40W of power.

HDMI Type A Connectors: superMHL can also be supported over the popular HDMI Type A connector giving manufacturers the flexibility to create DTVs and monitors with a dual-purpose HDMI/superMHL input. In this legacy mode, maximum video quality is limited to 4K 60fps and other advanced superMHL features (including USB data transfer) are also disabled.

USB Type-C Connector: superMHL can also be supported over the new USB Type-C connector. Using superMHL over a Type-C connector allows video resolutions of up to 8K 60fps with simultaneous USB 2.0. Concurrent USB 3.1 with up to 4K 120fps is also supported.

Enhanced Control, Data & Charging

superMHL continues to improve the control of your devices with the latest enhancements to RCP. Enhanced RCP, available on supported superMHL systems gives you more control over your devices. The new Stream Control Protocol (SCP) allows you use one remote to control multiple superMHL products in the same SCP network. SCP can be used for simple tasks such as turning on and off devices, or more complex commands such as routing which screen video content from a DVR should play on.

superMHL also integrates High Speed USB 2, a key feature in today’s data driven home theaters. With superMHL the same cable that is being used to deliver audio and video can also be used to send images, web pages, or other data.

Using appropriate cables, the power across the cable can be up to 40 watts of power in either direction. This gives you super-fast charging of battery powered devices and maximum flexibility when setting up your home theater network. For example, not only can consumer electronics devices such as streaming media sticks, set top boxes, and Blu-ray Disc players get operating power from the display itself, but a Blu-Ray Disc player or AVR could power a TV directly over the same cable that is providing the video.

To support all of these features, solutions have been quickly released by market leaders within the video space. Lattice recently released a family of products to support the new superMHL standard – the SiI9779, SiI9630 and SiI9398 – to enable consumers to connect superMHL source devices to TVs and monitors using the user friendly, reversible superMHL connector. The superMHL link also enables MHL mobile devices to deliver resolutions of 4K 60fps and beyond through existing and new connectors such as the USB Type-C with MHL Alt Mode. 

Since 2010, 900 million MHL devices have shipped and counting. With its powerful combination of features designed to provide the best quality and flexibility along with a continued commitment to backward compatibility with previous MHL 1, 2 and 3 specifications, the MHL Consortium has positioned superMHL as a strong entrant into the home theater space. Manufacturers and original device manufacturers (ODMs) will be able to take advantage of many of the innovative features in superMHL to create devices that are not just delivering the best quality audio and video, but that connect, communicate and are controlled in new ways.  One connection: Infinite possibilities.

C.H. Chee is Senior Director of CE Product Marketing for Lattice Semiconductor.