The British way to decompress

Tuesday, February 6, 2001

The demand for digital video has been expanding beyond simple Internet data streaming, to include mobile phones, video conferencing, online games, medical imaging, CCTV and remote monitoring, cable TV, and more.

As people apply digital video beyond entertainment into business-critical applications, the demand is rising for compression and transmission (download) technologies that are more reliable and secure.

Now a British professor has devised a wavelet algorithm that may replace current industry standards MPEG and M-JPEG. Don Monro, a professor at Bath University (Bath, UK), has founded XiWave plc (www.xiwave.com), a company that will commercialize the discovery.

The new algorithm is called Xi-2, defined by the company as "a dynamically scalable software codec (coder-decoder)." As opposed to compressing data in 8x8 pixel blocks, like MPEG and M-JPEG, XI-2 compresses digital file size by removing the least important information first-such as adjacent pixels of similar color, which XiWave calls "redundant."

The result is that XI-2 avoids "block artifacts" caused by those 8x8 pixel packages. It also allows the user to download digital video at any rate below its compression rate, as opposed to the current burden of creating high-speed and low-speed versions. Finally, it handles data errors well, and provides higher security, the company says.

Meanwhile, MPEG (Moving Pictures Experts Group) has advanced to MPEG-4, a next-generation version that uses audio/video objects (AVOs) instead of a continuous stream. Those AVOs can be manipulated independently, giving users far greater flexibility, as well as improved security. M-JPEG (Motion-Joint Photographic Experts Group) is another, less-sophisticated, option.