HDMI 2.1 Spec Released

The HDMI Forum used CES 2017 to announce the upcoming release of Version 2.1, which will offer support for higher data rates, dynamic metadata and improved audio signaling.

In terms of bandwidth, the data rate will rise from 18 Gbps obtained using 3 lanes running at 6 Gbps and 10/12 bit encoding to 48 Gbps using 4 lanes running at 12 Gbps using 16/18 bit encoding. That’s a huge increase and is enough to support uncompressed 8K 4:2:0 at 60 Hz or 4K, 4:4:4 at 120 Hz video streams. There is also support for DSC, a light compression scheme (typically 3:1) used in DisplayPort. This should allow 8K 4:4:4 at 60Hz or 4:2:0 at 120 Hz.

The connector will remain the same for backward compatibility, but the silicon for the receivers and transmitters will clearly need to be upgraded. HDMI Forum said they have set the specification and it is up to silicon providers to spin up the silicon, but they would not comment on when chip sets might be available.

We did see a prototype of a new cable, however, and it has now moved to a ribbon type. Since the connector and number of pins remains constant, it seems likely that one of the data lanes in the 2.0 spec has been reallocated to video. Representatives think a 5 m cable is reasonable and 15m possible. Compliance will be specified by an eye-diagram test.

Also new is support for dynamic metadata for HDR. This appears to be mainly a method to provide a place in the stream for the scene-by-scene or even frame-by-frame metadata and the signaling to notify the display device that the content has dynamic metadata.

The eARC feature provides supports for the most advanced audio formats such as object-based audio, and enables advanced audio signal control capabilities including device auto-detect. Up to 22.2 channels of audio are supported.

Meanwhile, the new Game Mode VRR features enables variable refresh rate, which allows a 3D graphics processor to display the image at the moment it is rendered for more fluid and better detailed gameplay, and for reducing or eliminating lag, stutter, and frame tearing. (The group couldn’t give us a lot of details, but said that it was ‘in the spirit of Freesync’ – Man. Ed.)

The new specification will be available to all HDMI 2.0 Adopters and they will be notified when it is released early in Q2 2017. – CC

Analyst Comment

The HDMI group created a forty slide presentation on HDMI 2.1 that can be downloaded. The new high res cable has not yet been named, but there will be a new name for cables with 48GB support. (BR)