Japan’s NHK Science & Technology Research Laboratories has demonstrated a new dual-stream Hybridcast process for transmitting full-resolution (1080p) 3-D video data via terrestrial broadcast and a separate broadband Internet connection to home television sets.
Using commercially available active-shutter 3-D glasses, the Japanese broadcaster conducted the Hybridcast demo in late May. The new technology was developed in collaboration with Nippon Telegraph and Telephone (NTT).
Video for one of the right and left eyes was transmitted to a home television by broadcast airwaves, and video for the other eye is transmitted by a broadband connection. As a result, it became possible to transmit full HD-equivalent video for each of the right and left eyes.
Currently, the most common methods used for most 3-D broadcasts are the side-by-side and top-and-bottom schemes. Both compress the dual images by about 50 percent (in terms of the amount of visual data) and stores both of them in one frame of full HD video. Then, they are decompressed at the 3-D compatible TV.
In such cases, most people would agree that the 3-D video resolution is lower than full HD (1080 horizontal lines). The new NHK Hybridcast method does not reduce resolution, according to NHK, allowing the full resolution to be seen.
This new 3-D video transmission method that streams two signals to the television had to overcome a synchronization problem, according to engineers at NHK. Normally, signals transmitted via an Internet connection lag behind the airwaves. This required the timing to be precisely aligned.
The company exhibited the new technology as one of the applications of the Hybridcast, a service that combines broadcast and broadband. It transmits metadata to tablet computers such as the iPad based on content being broadcast for televisions. The core technology of the service uses presentation time stamp (PTS) for synchronization synthesis of data being transmitted via different channels.
The demonstration used Panasonic’s model TH-P54VT2 54in 3-D TV as a display, but it’s not clear whether NHK had to reconfigure the television in any way.
