Lack of 3-D Captioning Standard Stymies Development

As more content is being produced in 3-D, the need for captioning, now mandated by the U.S. government, has been brought to the forefront. While all of the vendors in this category are aware of the need to do it, very few customers have asked for it, which holds back development.

“We certainly have the capability to produce captions in 3-D space, but we’re not investing a lot in R&D until there is customer demand and a standard specification for how to do it,” said José M. Salgado, president and CEO of Los Angeles-based SoftNI, a veteran captioning and subtitling software provider.

To be clear, the issue has to do with closed-captioning, not necessarily “subtitling.” 3-D subtitling is typically predetermined by the content producer and is inserted into a plane (below, on the side or on top of the screen) that’s most aesthetically pleasing to the eye. Because subtitles are simply a part of the picture, there is no need for new technology to transmit or display them.

Closed-captioning, on the other hand, serves a greater need and must be done uniformly. This data is sent as text with timing information by a broadcaster or program provider and turned on or off at the TV set by the consumer. There is a method for doing this in 2-D (called CEA-708) that’s standardized by the Consumer Electronics Association. Every TV set sold in the United States must be able to recognize this code and display it when required. In that code, you can still control the positioning of the captioning but not the 3-D depth. The result is that the 3-D experience is often not the best it could be.

“Captions are still transmitted in 2-D, even for 3-D content, but there is no way yet to make use of 3-D depth in the captions,” said Jason Livingston, product manager at Computer Prompting & Captioning (CPC). “All of the 3-D TV sets sold today can only decode 2-D caption information. It’s a problem that people are starting to be aware of, but we’re a long ways from having an industrywide agreement.”

Currently, captioning material is sent to 3-D TV sets in the same manner as 2-D HDTV. Captioners can control the 2-D placement of the captions, just like they do now. As long as the captioner does a good job, it will not obscure anything important, and the portion that is obscured will be the same regardless of whether the video is 2-D or 3-D.

This has frustrated some viewers because all of the work that goes into framing a 3-D scene and the depth perception is lost when a caption box covers it. With no standard way of accommodating multiple layers within a scene, there’s no control over space and depth.

“You’ll still see closed-captions appearing where people are used to seeing them, but there’s no code for ensuring a pleasing 3-D viewer experience,” Livingston said. “As soon as the CEA and FCC establish a technical standard for how to transmit 3-D closed-captions, then it will be in our software. From a manufacturer’s perspective, it does not make sense to do it until the technical standards have been decided and published.”

For the time being, Livingston recommends that his customers produce closed-captioning in the same way they currently do for 2-D content.

“Captioning vendors don’t have any say in how the industry will ultimately decide how to handle 3-D closed-captions, and we can’t tell the TV set manufacturers, ‘This is the code we want you to use,’ because they won’t implement it until the CEA establishes an industry standard.” Livingston said. “So, we’re all waiting and doing a few tests until then.”

Unlike closed-captioning, which is transmitted separately from the picture and can be turned on and off, subtitles are burned into the picture and cannot be turned off by the viewer. But, captioning companies such as CPC and SoftNI are ready to offer 3-D subtitles in their software today.

“We’re just waiting for demand,” SoftNI’s Salgado said.

SoftNI offers its Subtitler Suite and Digital Suite software products for subtitle burn-in and metadata insertion into HD and SD digital files. CPC’s MacCaption (for Apple computers) or Caption Maker (for PCs) has the ability to encode closed-captioning and burn-in subtitles as well. Other vendors include Cheetah International and service providers National Captioning Institute and Boston public TV station WGBN.

“We’ve had some viewers ask about 3-D subtitling, but we have not much interest from content creators yet,” CPC’s Livingston said. “The basic structure is there in our products for doing it, but we’re still working on the user interface and trying to understand what tools content creators want.”

The fact that captioning is done in software bodes well for these captioning companies, because as soon as a standard is announced, the software can be easily upgraded via a free download to accommodate 3-D captions — and it can be done in a matter of weeks.

Adding to the issue, the government recently signed the Twenty-first Century Communications and Video Accessibility Act (S. 3304), which mandates captioning for Web-delivered content that has also appeared on traditional broadcast TV. The legislation also states that all CE receiving devices large enough for video must be equipped to support captioning functionality. So, a new set of concerns will become apparent in 2011 because there are a number of Web display formats that don’t support closed-captioning at all, and those that do use a number of incompatible standards

However, a number of vendors, including the ones mentioned here, support the Described and Captioned Media Program (DCMP) and can help add captions to Web-based video. For a list, visit this link.

By Michael Grotticelli, Broadcast Engineering