MPEG s compression efficiency comes from its predictive abilities. Where you really save with compression is looking from one picture to the next. The reason IP streaming is really good is that there are algorithms that provide a lot more compression with the same video quality as MPEG-2 does for use today. We can take a wavelet algorithm and keep the same video quality and use 1 Mbps for a very nice high-quality movie that would take us over 3 Mbps today. Rather than creating 8 x 8 blocks to compress, wavelets decompose the original signal into subbands, explained Gordon.
Wavelets also are localized functions, which is important at the edges of images.
With MPEG s DCT algorithm, the 8 x 8 blocks can lose their crisp edges, whereas with wavelets, the edges still are well defined. Many wavelets are available, so you also can pick the one that s best suited to the picture you re compressing, she added. There s yet another compression method being developed fractals, which are based on quadratic equations. But fractals have not been as widely deployed as wavelets. There are drawbacks to wavelets, especially in terms of computational time required.