Panasonic develops 3D standard for BD disc
Panasonic has submitted a proposal that describes a way of storing 3D content on conventional Blu-ray discs to the Blu-ray Disc Association (BDA). The Japanese vendor intends to make an early contribution to the standardisation process in order to avoid potential format wars – and, of course, to promote its own interests. According to Nikkei Electronics Asia, Panasonic is also thinking about submitting a corresponding 3D extension to the HDMI standard. The BDA plans to discuss the proposals before the end of the year and hopes to present first commercial results in 2010.
Panasonic's proposal closely follows well-established standard technologies and avoids proprietary methods. The images are to be encoded with the two-channel encoder already part of MPEG-4. The second channel will only contain the differential signal of the first channel, which considerably reduces the data volume. Panasonic estimates that this approach creates 1.5 times instead of twice the amount of 3D signal data and in addition, it allows the 3D discs to be played in 2D on conventional BD players. The video tracks for the right and left eye each offer the full HD resolution of 1920 × 1080 pixels. The data is to be transferred to the display via HDMI, and the stereoscopic images for the right and left eye are to alternate in each frame. Finally, a flag in the MPEG-4 stream is to indicate that the material is 3D and tell the respective hardware how to handle the images.
At the Ceatec show in Japan in October, Panasonic presented a plasma display with full HD resolution and capable of rendering 3D images using the proposed technology. The 103 inch plasma display received 120 frames – 60 each for the right and the left eye – per second from a modified Blu-ray player and alternated the frames accordingly. Active shutter goggles were used to align the stereoscopic images with the viewer's respective eye, which created a 3D impression. A similar stereoscopic approach is also used in digital 3D cinema, although 3D movies more often tend to use passive polarising goggles – which are dramatically cheaper.
Using polarising filters has another advantage over more primitive colour-separated 3D, used in cinemas from the 1950s. These used glasses with one red and one green lens, each almost completely blocking the light passing through the other, so that each eye saw a different image – an 3D anaglyph image. However, this dramatically restricts the range of colours that can be shown, which was acceptable in the days of black and white films, but is not today. Since the human eye is almost completely unable to detect the polarisation of light – unlike the eyes of some invertebrates, including mantis shrimp, cephalopods and most insects – to humans, polarising spectacles appeal completely clear, enabling full-colour 3D film projection.
(lghp)
