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Dolby Spec Anticipates Mix of 2D and 3D Material

SAN FRANCISCO: Dolby released its Open Specification for Frame Compatible 3D systems recently. It proposes a method of optimizing the performance 3D and 2D content because both formats are likely to be used side by side, Dolby said.

“Optimizing for 2D content in a frame-compatible 3D system has value, because some content, including interstitial material such as commercials, will be available in 2D format only,” the document stated. “Current specifications refer only to static 3D operation and do not consider dynamic 2D to 3D transitions--or vice versa. This is appropriate, as it takes existing 3D televisions one to three seconds to change between 2D and 3D display modes.”

Besides commercials, 3D will likely be used creatively as well, similar to the way color was used in films like “Schindler’s List” and “The Wizard of Oz,” Dolby said.

The spec takes into account established consensus regarding frame-decimation video compression methods. E.g., that quincunx decimation is less bit-rate efficient than column or line decimation; and that HDTV interlace formats must use column interleave decimation and side-by-side packing for the vertical resolution to be adequate.

Dolby’s spec concludes that the interlace scheme should be adopted for implementing frame-compatible 3D for progressive as well as interlaced systems. It says a “complementary left-eye/right-eye decimation structure should be adopted” for higher resolution 3D images as well as full-resolution 3D images.

The development of Dolby’s open 3D spec was announced at the NAB Show in April. The document is available from Dolby: “Dolby Open Specification for Frame-Compatible 3D Systems.”
-- Deborah D. McAdams