mobile high-definition link (video) (MHL)
Mobile High-Definition Link (MHL) is an interface concept specified by the MHL Consortium, an industry consortium consisting of well-known manufacturing companies, which is used in smartphones, tablets and other mobile devices. With this concept, streaming video downloaded from the Internet can be shown as HD video with audio on displays or projected with projectors via the micro- USB interface of mobile devices.
The MHL (Mobile High-Definition Link) concept developed by Nokia, Samsung, Silicon Image, Sony and Toshiba is an alternative to the HDMI interface. MHL requires that the mobile device and the display device are MHL-compatible and equipped with appropriate MHL converters: An MHL transceiver chip on the transmitter side, and an MHL receiver on the receiver side. If the MHL transceiver detects the MHL receiver, it automatically switches to MHL mode and sends the audiovisual data via the TMDS protocol. The MHL control signals for detecting the MHL reception signals and for encoding the AV signals are transmitted via an MHL Control Bus.
Depending on the MHL version, the data transmission is encrypted with High-Bandwidth Digital Content Protection( HDCP) in versions 1.4 and 2.2. In theMHL 3.0 version, data rates of up to 6 Gbit/s are achieved. With these data rates, MHL 3.0 supports the 4K standard and can transmit Ultra-HD( UHD) with a data rate of 30 Hz. Ultra-HD is not yet a resolution used in mobile devices, but MHL 3.0 can display videos in the 4K standard. In addition, the trend is moving toward high-resolution tablets with a resolution of over 3 million pixels. External devices can be supplied with power via MHL 3.0. The transmittable electrical power is 10 W, with 7.5 W specified for MHL 2.0 and 2.5 W for MHL 1.0.
Specifically for smartphones, the MHL consortium has specified another high-resolution video standard: SuperMHL, which also supports the 8K standard for ultra HDTV. MHL follows a similar concept as Mobility DisplayPort( MyDP) with which it competes.