As Hollywood adepts know, the next phase in picture quality beyond HD is something called 4k. Although the name suggests 4k (perhaps 4096) pixels in the vertical or horizontal direction, its resolution is actually 3840 × 2160, i.e., twice the pixels of HD in both horizontal and vertical directions.
4k is the highest quality of image actually captured by digital cinematography right now. The question is, how will it be delivered to consumers, in what timeframe, and how will it be protected?
Those of us who attended the Anti-Piracy and Content Protection Summit in LA last week learned that the answer to the latter question is unknown as yet. Spencer Stephens, CTO of Sony Pictures, gave a brief presentation explaining what 4k is and outlining his studio’s wish list for 4k content protection. He said that it was an opportunity to start fresh with a new design, compared to the AACS content protection technology for Blu-ray discs, which is 10 years old.
This is interesting on a couple of levels. First, it implies that the studios have not predetermined a standard for 4k content protection; in contrast, Blu-ray discs were introduced in the market about three years after AACS was designed. Second, Stephens’s remarks had the flavor of a semi-public appeal to the community of content protection vendors — some of which were in the audience at this conference — for help in designing DRM schemes for 4k that met his requirements.
Stephens’s wish list included such elements as:
- Title-by-title diversity, so that a technique used to hack one movie title doesn’t necessarily apply to another
- Requiring players to authenticate themselves online before playback, which enables hacked players to be denied but makes it impossible to play 4k content without an Internet connection
- The use of HDCP 2.2 to protect digital outputs, since older versions of HDCP have been hacked
- Session-based watermarking, so that each 4k file is marked with the identity of the device or user that downloaded it (a technique used today with early-window HD content)
- The use of trusted execution environments (TEE) for playback, which combine the security of hardware with the renewability of software
From time to time I hear from startup companies that claim to have designed better technologies for video content protection. I tell them that getting studio approval for new content protection schemes is a tricky business. You can get studio technology executives excited about your technology, but they don’t actually “approve” it such that they guarantee they’ll accept it if it’s used in a content service. Instead, they expect service providers to propose the technology in the context of the overall service, and the studios will consider providing licenses to their content in that broader context. And of course the studios don’t actually pay for the technology; the service providers or consumer device makers do.
In other words, studios “bless” new content protection technologies, but otherwise the entire sales process takes place at arms’ length from the studios. In that sense, the studios act somewhat like a regulatory agency does when setting guidelines for compliance with a regulation such as HIPAA and GLB (for information privacy in healthcare and financial services respectively). The resulting technology often meets the letter but not the spirit of the regulations.
In this respect, Stephens’s remarks were a bit of fresh air. They are an invitation to more open dialog among vendors, studios, and service providers about the types of content protection that they may be willing to implement when it comes time to distribute 4k content to consumers.
In the past, such discussions often happened behind closed doors, took the form of unilateral “unfunded mandates,” and/or resulted in implementations that plainly did not work. As technology gets more sophisticated and the world gets more complex, Hollywood is going to have to work more closely with downstream entities in the content distribution chain if it wants its content protected. Spencer Stephens’s presentation was a good start in that direction.