Mobile High-Definition Link

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Mobile High-Definition Link
Headquarters Sunnyvale, California, United States
Key people Rob Tobias
(President)
Products Adapters, automotive accessories, AV receivers, Blu-ray players, cables, DTVs, media sticks, monitors, projectors, smartphones, tablets, TV accessories

Mobile High-Definition Link (MHL) is an industry standard for a mobile audio/video interface that allows consumers to connect mobile phones, tablets, and other portable consumer electronics (CE) devices to high-definition televisions (HDTVs) and audio receivers. The MHL 3.0 standard supports up to 4K (Ultra HD) high-definition (HD) video and 7.1 surround-sound audio, including TrueHD and DTS-HD, while simultaneously charging the connected device. MHL-enabled products include adapters, automotive accessories, AV receivers, Blu-ray Disc players, cables, DTVs, media sticks, monitors, projectors, smartphones, tablets, TV accessories, and more.

MHL was developed by the MHL Consortium, a consortium made up of leading companies in the mobile and CE space that includes Nokia, Samsung, Silicon Image, Sony, and Toshiba.

History[edit]

Silicon Image originally demonstrated a mobile interconnect, based on its transition-minimized differential signaling (TMDS) technology, at the January 2008 Consumer Electronics Show (CES).[1] This interface was termed "Mobile High Definition Link" at the time of the demonstration, and is a direct precursor of the implementation announced by the MHL Consortium. The company is quoted as saying it did not ship that original technology in any volume, but used it as a way to get the working group started.[2]

MHL, LLC is the agent for overseeing the licensing and promotion of the MHL specification. A Working Group was announced in September 2009,[3] the MHL Consortium was founded in April 2010 by Nokia, Samsung, Silicon Image, Sony and Toshiba, the MHL specification version 1.0 was released in June 2010 and May 2011 marked the first retail availability of MHL-enabled products.

An abridged version of the specification was made available for download on April 14, 2010.[4] MHL specification version 1.0 was released in June 2010.[5] The Compliance Test Specification (CTS) was announced on December 21, 2010.[6]

There are now more than 400 million MHL products developed by the growing base of more than 200 global adopters (licensees).[when?] One area that is beginning to embrace the technology is the automotive sector, with manufacturers such as Hyundai, JVC-Kenwood and Pioneer viewing MHL as a compelling solution to integrate the phone into the car infotainment experience.

Overview[edit]

MHL is an adaptation of HDMI intended for mobile devices such as smartphones and tablets. While not compatible with HDMI in the way DVI is, MHL has several aspects in common with HDMI.

To better accommodate the needs of mobile devices, MHL differs from HDMI as follows.

  • Five wires in place of HDMI's nineteen, namely ground, power, control, and a differential pair for data. This permits a much lighter cable and a much smaller connector on the mobile device.
  • Whereas HDMI uses the power line to provide 5 volts from the source at 50 mA (0.25 W) for the purpose of awakening a sleeping sink, MHL uses it to provide that voltage from the sink at 900 mA (4.5 W) to maintain the state of charge of the source. This allows a mobile device with only one port for both charging and MHL to operate indefinitely without exhausting the battery provided 4.5 W is sufficient. Devices needing more power from the port used for MHL may not be suitable candidates for MHL 2.0; MHL 3.0 raises the power requirement to 2 A (10 W).
  • Although MHL ports can be dedicated to MHL alone, the standard is designed to permit port sharing with the most commonly used ports.
  • A typical MHL source will be shared with USB 2.0 on a standard 5-pin micro-usb receptacle, which switches from USB to MHL when it recognizes an MHL-qualified sink detected on the control wire.
  • A typical MHL sink will be shared with HDMI on a standard 19-pin HDMI receptacle. The standard uses the same pins for power (pin 18) and ground (pins 5, 11, and 17), HDMI's Hot Plug detect (pin 19) for MHL control, and HDMI's Data0 channel (pins 7 and 9) for MHL's data.
  • Whereas HDMI transmits the three bytes of a pixel in parallel over three physically separate differential pairs along with a fourth pair for a clock, with a separate ground for each pair (pins 1-12), MHL transmits them sequentially over the one pair (7 and 9).
  • Whereas HDMI uses five wires to cater for HDMI-CEC (13), DDC (15 and 16), and HEC (14 and 19), MHL controls these functions with a single wire.

In normal mode MHL supplies the same 24 bit color signal as HDMI, at a pixel clock rate of up to 75 MHz for MHL 2.0, sufficient for 1080i and 720p. Each of the three bytes is in a 10-bit frame whence at 75 MHz the data channel operates at 2.25 Gbit/s.

MHL 2.0 caters for 1080p with a PackedPixel mode utilizing only the first two of HDMI's three channels. This shrinks each pixel to 16 bits carried in two 10-bit frames. The pixel clock is doubled to 150 MHz and the data channel then operates at 3 Gbit/s.

MHL's serial signaling makes it incompatible with the three-channel parallel signaling of HDMI and DVI. Hence both ends of an MHL channel must implement the standard in full. In particular an MHL source cannot drive an ordinary HDMI or DVI display, though this limitation is easily overcome with an MHL dongle converting MHL to HDMI. An MHL source must be realized in hardware as the typical 5-pin USB 2.0 port on mobile devices is much too slow at 480 Mbit/s for a software-only implementation.

MHL 3.0 features[edit]

On August 20, 2013, 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. The first devices to include the specification are the Sony Xperia Tablet Z2 and the Sony Xperia Z2. At Mobile World Congress 2014 Silicon Image demoed MHL 3.0 powered by its SiI8620 transmitter chip. 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

MHL 1 and MHL 2[edit]

  • The TV provides power to the connected device (5 V DC/500 mA with MHL 1.0, 5 V DC/900 mA with MHL 2.0)
  • Uses a single, thin cable to connect the mobile device to the TV.
  • The TV remote will control the connected device with guaranteed mixed manufacturer interoperability (CEC).[7] (Also see Silicon Image's press release about MHL on December 14, 2010). Note: The built-in Remote Control Protocol (RCP) function allows you to use the remote control of the TV to operate the MHL mobile device through TV’s Consumer Electronics Control (CEC) function.
  • 1080p uncompressed HD video.
  • 8 channel uncompressed audio (e.g., 7.1 surround sound).
  • Supports High-bandwidth Digital Content Protection (HDCP).
  • MHL is connection agnostic (i.e., not tied to a specific type of hardware connector). The first implementations used the 5-pin MHL-USB connector described below. Other proprietary and custom connections are also allowed.

By transporting the digital content in digital form, the full impact of the picture (whether still images or video) can be seen on TVs.[8]

Comparison with SlimPort / Mobility DisplayPort (MyDP)[edit]

SlimPort is a proprietary alternative to MHL, based on the DisplayPort standard integrated into common microUSB ports. SlimPort is offered both license and royalty free, and supports up to 1080p60 or 1080p30 with 3D content over HDMI 1.4 (up to 5.4 Gbit/s of bandwidth), in addition to support for DVI, VGA (up to 1366×768 and 720p at 60 Hz), and DisplayPort.

Like MHL, SlimPort does not require external power or extra cables and draws no power from the source to operate.

Connectors[edit]

Not all micro USB 2.0 ports are identical. Compare connectors for original Galaxy Note with the Note II

Standard Micro-USB-to-HDMI adapter (five-pin)[edit]

The first implementations use the most popular mobile connection (micro USB) and the most popular TV connection (HDMI). Other than the physical connectors, USB and HDMI technology are not being used. It is exclusively MHL signaling through the connectors and over the cable.

Samsung Micro-USB-to-HDMI adapter and tip (eleven-pin)[edit]

The Samsung Galaxy S III, and later Galaxy Note II and Galaxy S4, use an 11-pin connector and the six additional connector pins in order to achieve functional improvements over the 5-pin design[which?]. However, if consumers have a standard MHL-to-HDMI adapter all they need to purchase is a tip. With the launch of the Samsung Galaxy S4, Samsung also released a Samsung 2.0 smart adapter with a built-in 11-pin connector. Samsung 2.0 smart adapter does require external power and is able to work with HDMI TVs.[9]

MHL Passive cable[edit]

Passive cables allow consumers to connect an MHL-enabled device directly to an MHL TV and does not require external power. And above all, the passive cable simultaneously charges your cell phone battery while mirroring. Unlike older MHL Adapter and Older MHL Cables, the Battery of your cell phone is charged up instead of being drained out, while screen mirroring via a MHL Passive cable with a MHL-Enabled HDTV.

Products announcements[edit]

  • MHL announced on August 20, 2013 the MHL 3.0 specification with major advancements for mobile and CE connectivity
  • MHL announced on August 26, 2013 its MHL Experience Program with SEGA, PowerA, Nyko, MobiSystems, Green Throttle and FilmOn.TV
  • MHL announced on May 28, 2013 that it had reached 200 adopter milestone
  • Samsung March 14, 2013, Samsung release Galaxy S4 with MHL 2.0
  • HTC February 19, 2013, HTC release the New HTC One with MHL
  • MHL announced on January 7, 2013 that there was an installed base of more than 220 million products and greater than 200 products in the marketplace.
  • Hyundai announced on January 4, 2013 that it would be showing working versions of future vehicle infotainment systems, including MHL technology.
  • Silicon Image expanded its MHL product line with four new products that included the latest MHL 2.0 features on September 25, 2012.[10]
  • Roku unveiled the 'Roku Streaming Stick' on January 4, 2012 in an official blog post entitled 'There’s a Better Way to Build a Smart TV'. The Streaming Stick is said to include everything comprised in a Roku player—built-in WiFi, processor, memory and software—and will deliver all the channels found on the Roku platform today.[11]
  • LG Electronics available on December 4, 2011 AT&T Wireless and LG Electronics Nitro HD (AT&T) / Optimus LTE (LTE carriers), a True HD AH-IPS panel display on the device with MHL output abilities for any TV equipped with HDMI input.[12][13][14]
  • HTC announced at the 2011 CTIA that their 'EVO 3D' mobile device supports MHL output and in addition that the HTC 'Sensation' will also have this capability, as well as its successor, the 'Sensation XE'. The HTC Rezound, which is a sister device to the Sensation XE also has the MHL port.
  • Samsung announced at the 2011 Mobile World Congress that their Galaxy S II mobile devices feature MHL connections.[7][15]
  • Onkyo and Silicon Image announced the world's first A/V receivers featuring InstaPrevue and MHL technologies.[16]

See also[edit]

References[edit]

  1. ^ "HDMI plugs into cameras, cellphones". EE Times. January 8, 2008. Retrieved 2010-04-14. 
  2. ^ "Consortium backs mobile interface for high def video". EE Times. April 14, 2010. Retrieved 2010-04-14. 
  3. ^ "Leading Companies Form Mobile High-Definition Interface Working Group to Drive Industry Standard for Mobile Wired Connectivity". Silicon Image. September 28, 2009. Retrieved 2009-09-30. 
  4. ^ "Adopter Information". MHL, LLC. June 30, 2010. Retrieved 2010-06-30. 
  5. ^ "MHL 1.0 SPECIFICATION AND ADOPTER AGREEMENT NOW AVAILABLE". MHL, LLC. June 30, 2010. Retrieved 2010-06-30. 
  6. ^ "MHL CONSORTIUM RELEASES COMPLIANCE TEST SPECIFICATION TO GROWING ADOPTER BASE". MHL, LLC. December 21, 2010. Retrieved 2010-12-22. 
  7. ^ a b "MHL High-definition Link". YouTube. February 15, 2011. Retrieved 2011-02-15. 
  8. ^ "Play Mobile Games on Your Television with MHL". FlashMush Reviews. 23 October 2012. 
  9. ^ "MHL 2.0 HDTV Smart Adapter". 
  10. ^ "Silicon Image Unveils First MHL Products". Silicon Image. October 4, 2010. Retrieved 2011-02-15. 
  11. ^ "There’s a Better Way to Build a Smart TV". Roku Official Blog. January 4, 2012. Retrieved 2012-01-04. 
  12. ^ "LG Nitro HD Delivers First True High-Definition Experience for AT&T Customers" (Press release). AT&T Wireless. November 28, 2011. Retrieved 2011-11-28. 
  13. ^ "WORLD’S FIRST HD LTE SMARTPHONE ANNOUNCED IN CANADA" (Press release). LG Electronics. November 8, 2011. Retrieved 2011-11-08. 
  14. ^ "LG LAUNCHES OPTIMUS LTE, FIRST 4G HD SMARTPHONE IN KOREAN MARKET" (Press release). LG Electronics. October 4, 2011. Retrieved 2011-10-04. 
  15. ^ "The Samsung Galaxy S2 is Announced". MobileReview. February 15, 2011. Retrieved 2011-02-15. 
  16. ^ "Onkyo and Silicon Image Announce the World’s First A/V Receivers Featuring InstaPrevue and MHL Technologies." (Press release). Onkyo US. December 21, 2011. Retrieved 2012-06-06. 

External links[edit]