3DTV Over the Air?

ATSC stands for Advanced Television Systems Committee, and about 20 years ago, this group developed the standard that became the basis for our digital terrestrial TV broadcasts. (Remember all that confusion about the digital transition two years ago?) The standard is due for updating, and the group has been hard at work on ATSC 2.0 already. At their annual meeting this week, the committee talked about some of the changes that could come with a revised standard.

One of the key changes would be a provision that supports the transmission of stereoscopic 3DTV content in high definition. This could seem to be a major challenge, especially given the current battles over the broadcast spectrum that has been assigned to terrestrial television stations. The fact is, however, that 3DTV could be accomodated within the existing bandwidth. The current digital broadcast standard is based on MPEG2 compression technology, which is the form that was used for DVDs. We now routinely use MPEG4 for video compression, including Blu-ray and satellite TV transmissions. This newer approach can be roughly twice as efficient as MPEG2, which means that two frames — left and right — could be sent in the same bandwidth currently required for a single frame.

There are other ways that the data stream could be condensed even further. For example, there is no difference in the appearance of distant objects between the two stereoscopic views. As a result, that data only needs to be sent once. The right hand frame could be sent in its entirety, followed by the data that is different for the left frame. This has the added advantage of maintaining backward compatibility with 2D sets; they could just ignore the second frame if they do not have 3D capabilities.

In order to get to this point, we need a standard for the broadcaster and television manufacturers to use. And we’d probably need external adapters for legacy sets, but that would probably be a low-cost addition.

ATSC is reportedly exploring other additions to the standard, including the ability to deliver data files in the background of the signal transmission, interactive features, audience measurement tools, and advanced program guide information.

This is not going to happen any time soon — remember that it took more than 15 years to implement the first ATSC standard — so don’t hold your breath. But it is entirely possible that broadcast television will get the chance to keep up with some of the other program distribution choices.