HDMI Licensing Group Releases 3D HDMI Spec to Public

HDMI Licensing, LLC, the agent responsible for licensing the High-Definition Multimedia Interface (HDMI) specification, last week announced, on behalf of the HDMI Founders, that it has released the 3D portion of the HDMI Specification Version 1.4. The purpose of this document is to provide public access to the Specification, while not requiring an executed HDMI Adopter Agreement. The document available for download is extracted from version 1.4 of the HDMI Specification. The HDMI Consortium intends to release a 1.4a version of the HDMI Specification shortly, which will include updates to the 3D portion of the Specification, including a mandated 3D format for broadcast content. As soon as the 1.4a version of the Specification is published to Adopters, an update to the 3D portion of the document, available for public download, will also be published. Additional 3D video formats will be specified in a future version.

"The HDMI Consortium recognizes the importance of standardized 3D formats for movies, gaming and broadcast content and the need for non-adopter companies and organizations to have access to that portion of the HDMI Specification," said Steve Venuti, president of HDMI Licensing, LLC. "As the mainstream adoption of 3D is gaining momentum and content providers define and expand their 3D roadmaps, HDMI is ready to support this major market development."

HDMI 1.3 topped out at 2 x 1080i, as it did not provide the bandwidth to handle two 1080p pictures at 60fps. The 1.4 version provides support for up to 2 x 1080p, and addresses several framing aspects of the HDMI interface pertaining to the delivery of 3D content. It is format-agnostic, providing support for seven video-format configurations called "3D structures," and leaving room for nine more in the future. The supported resolutions are 480p, 720p, 1080i and 1080p. Both rectilinear and quincunx (checkerboard) sampling are supported; with quincunx, the sub-sampling position interchanges on every line of the original full left and right pictures. Metadata is also included to provide parallax information.

The difference between some of the 3D structures is all about timing. The structures are:

- "frame packing" (alternating left/right frames @ 1v x 1h)
- "field alternative" (alternating left/right interlace fields @ 1v x 1h)
- "line alternative" (alternating left/right lines @ 2v x 1h)
- "side-by-side (full)" (left and right frames @ 1v x 2h)
- "side-by-side (half)" (left and right frames @ 1v x 1h)
- "left + depth" (left frame plus depth information)
- "left + depth + graphics + graphics-depth"
- (future use)

The public release of the 3D section of HDMI 1.4 now makes it easier for more companies to get access to the specification, which should in principle facilitate the development of both content and products. Together with the recent BDA specification for 3D Blu-Ray players, the media and interface technologies provide the necessary ecosystem for 3D home content to proliferate. Expect more silicon solutions to appear quickly for both interfaces and processing gear in the coming months.

By Aldo Cugnini, DisplayDaily