The HDMI 1.4 standard is a more advanced form of HDMI cable that combines a variety of small upgrades to support new features and functionality. The physical difference between HDMI 1.4 or 1.4a and earlier standards aren't particularly important, but the various features that are enabled by the more sophisticated solution are extremely noteworthy.
We've already talked about HDMI functions like Ethernet Channel and Audio Return Channel. The HDMI 1.4 solution features both of these capabilities built into a single cable. 2
HDMI cables are capable of supporting high-definition resolutions in general, but HDMI 1.4 technology allows for enough data to move through the cable to enable 3D content viewing and to support 4K resolutions.
HDMI 1.4 also supports a variety of intelligent picture management features. These include the ability to automatically adjust display settings based on the content type being delivered (game, movie, etc.) and being able to support additional color spaces for deeper, richer hues.
The HDMI 1.4 architecture can be used to support both micro-HDMI connectors and the connector systems used in automotive solutions. HDMI 1.4 and 1.4a may not revolutionize the electrical architecture of the media cabling solution, but the standard does deliver considerable functionality upgrades over earlier models.