JPEG 2000 - Computer Definition
A standard for compressing still images from the Joint Photographic Experts Group. Introduced in 2000, JPEG 2000 uses wavelet compression and provides greater compression ratios than the discrete cosine (DCT) method used in regular JPEG. It also takes more processing power to decode the images. JPEG 2000 supports both lossy and lossless modes, and it is noted for its "visually lossless" appearance, whereby lossy images look so good that they appear to have been compressed with a lossless method. The millions of JPEG images on the Web are regular JPEG, not JPEG 2000. Smart Decoding A significant feature of JPEG 2000 is that images can be decoded into different resolutions, allowing, for example, a viewer to quickly render a low-resolution image from a gigantic file that would otherwise take considerably longer. Smart decoding enables the same image file to serve multiple uses. Motion JPEG 2000 Motion JPEG 2000 is the video version of JPEG 2000. However, unlike other movie formats, which use interframe coding to compress multiple frames, each JPEG 2000 frame is compressed independently. Motion JPEG 2000 is the standard for the d-cinema format for digital movie theaters and is commonly referred to as simply "JPEG 2000." JPEG 2000's smart decoding is also a major advantage for digital cinema. For example, although the movie may have been mastered in 4K resolution, it can be decoded and projected at 2K without having to decode into 4K first and then downconvert into 2K afterwards. This enables the same source file to be used in different theaters. See JPEG, MPEG, wavelet compression and digital cinema.