With USB Type-C slowly but surely gaining momentum, yet another outfit has decided to support this particular USB specification. That outfit is HDMI Licensing, and it is introducing HDMI Alternative Mode for USB Type-C devices.
The introduction of HDMI Alt Mode is a big one as the new specification will allow HDMI video signals to pass along a USB Type-C cable without any external hardware necessary. This means that dongles or docks that are meant to convert the DisplayPort signals will not longer be required. Furthermore, HDMI Alt Mode could also mean that lesser used HDMI connectors such as HDMI Type C (Mini HDMI) and HDMI Type D (Micro HDMI) can be phased out in favour of USB Type-C.
HDMI Alt Mode may seem like a brilliant idea, but there will be some drawbacks as well. The first problem that HDMI Alt Mode has is that it would not be backwards compatible with existing devices or upgradeable via software. This means that devices that require the use of dongles to work will still have to rely on said dongles. The other problem with HDMI Alt Mode is that it can only support the HDMI 1.4b standard, and not HDMI 2.0b. This means that while HDMI Alt Mode can support 4K playback, those playbacks will be limited to only 30FPS. High Dynamic Range (HDR) content will also not be supported on HDMI Alt Mode.
Source: HDMI Licensing, Ars Technica
