When the UHD Alliance — a consortium of consumer electronics manufacturers, major studios, distributors and tech companies — unveiled its specs for 4K UHD displays and content at this year’s Consumer Electronics Show (CES), it was a who’s who of the CE industry behind the effort.

Panasonic, Sony, Samsung, TCL, Sharp, LG Electronics and more grouped together to help set standards for resolution, peak luminance, high dynamic range (HDR), black levels and wide color gamut, and unveiling an “Ultra HD Premium” logo for UHD devices, content and services that meet the standards.

But one notable CE company was missing from the parade: Vizio, one of the largest flat-panel sellers in the U.S. And now the company is speaking out as to why.

“Vizio sees value in the industry specifying a premium experience for consumers but the ‘Premium 4K’ certification program proposed by the UHDA falls short and has serious problems,” a company spokesman said in an emailed statement. “The UHDA program does not sufficiently detail how to measure for or specify items like peak brightness or black level and as a result, certifies some products that we don’t believe should qualify for a UHD Premium certification and would ignore other products that should be certified.”

Vizio is specifically calling out the UHD Alliance’s requirement that sets the peak brightness for sets at in excess of 1,000 nits (a measurement of bright a TV set can be). The CE company argues that the UHD Alliance’s testing requirement only measures “the center brightness point of a test pattern and does not measure how the surrounding black level is affected.”

Vizio is also displeased with this dynamic range spec of the UHD Alliance’s certification, saying that despite Vizio’s Reference Series UHD sets having an 800,000:1 contrast ratio, it wouldn’t meet the UHD Alliance’s Premium 4K spec, due to the Alliance’s peak brightness vs. black level spec of 1,000 nit brightness with 0.05 nits black level.

“As a result, Vizio remains focused on the Dolby Vision format at this time, as we feel it is technologically superior and has substantially better picture quality resulting from a proper implementation of high dynamic range and extended color gamut,” the spokesman wrote. Dolby Vision is that company’s proprietary high-dynamic range technology. Dolby is a member of the UHD Alliance.

But the UHD Alliance isn’t having any of it, with a statement from the group dismissing Vizio concerns, and pointing out “had Vizio participated in the Alliance’s efforts, their contributions would have been welcome.”

“The UHD Alliance respectfully rejects the premise of its Vizio colleagues,” an emailed statement reads. “The full UHDA specification and testing protocols — developed collaboratively by the world’s leading television manufacturers, technology companies and major Hollywood studios — are made available only to testing centers and licensees, and the assertions and assumptions with regard to UHDA testing are inaccurate.”

The statement noted that the Ultra HD Premium spec is format agnostic, “making a television’s specific implementation of HDR technology irrelevant to Ultra HD Premium certification.” The UHD Alliance said its specs don’t dictate what technology CE companies use in their sets, and that its certification program was developed with the input of CE, technology and content creators.

For more information on the UHD Alliance, click here.