HDMI 1.4
Direct Answer
HDMI 1.4, released in 2009, added the HDMI Ethernet Channel, Audio Return Channel (ARC), and stereoscopic 3D video support, plus a 4K mode -- but capped at 24-30Hz, since bandwidth stayed at 10.2 Gbps. The even smaller Type D Micro connector was also introduced.
Source: HDMI 1.4 Specification
Specs
| Release Date | 2009 |
| Max Bandwidth | 10.2 (unchanged from 1.3) Gbps |
| Max 4K Resolution | 3840x2160 @ 24, 25, or 30Hz only |
| HDMI Ethernet Channel | 100 Mbps |
4K Arrives, But Not at 60Hz
HDMI 1.4 was the first version to support 4K resolution (3840x2160), but only at 24, 25, or 30Hz -- since total bandwidth stayed at 1.3's 10.2 Gbps, there wasn't enough headroom for smooth 60Hz motion at that pixel count. Full 4K60 wouldn't arrive until HDMI 2.0 raised bandwidth to 18 Gbps four years later.
What 1.4 did add was a new HDMI Ethernet Channel (HEC), letting connected devices share a 100 Mbps network connection over the same cable, and Audio Return Channel (ARC), which lets a TV send audio back upstream to a soundbar or receiver over the same cable normally used to send audio and video to the display -- eliminating the separate optical cable that setup previously needed. ARC supports stereo and compressed surround formats like Dolby Digital and DTS up to 5.1 channels, but not uncompressed or lossless formats; that capability came later with HDMI 2.1's enhanced ARC (eARC).
3D and the Micro Connector
HDMI 1.4 also added stereoscopic 3D video support across multiple formats (frame packing, top-and-bottom, side-by-side), aligned with the wave of 3D TVs and Blu-ray players released around 2010-2012, and introduced the Type D "Micro" connector -- smaller than 1.3's Mini connector -- for phones, tablets, and other compact devices.