New compression paradigms in JPEG 2000

The JPEG2000 still image compression standard has adopted a new compression paradigm: 'Encode once, decode many.' JPEG2000 architecture allows the codestream to be decoded differently for different application needs. The codestream can be decoded to produce lossless and lossy images, specific spatial regions of the image or images with different quality and resolution. The syntax contains pointers and length fields which allow relevant coded data to be identified without the entropy coder or transforms. Consequently, the codestream can be 'parsed' to create different codestreams without transcoding. For example, such parsing operation can create a new codestream which contains a lower resolution image (e.g. thumbnail) of the original codestream. If a codestream is produced appropriately, it can also be converted to codestreams of lower quality images, or images containing only a specific spatial region. This feature is very useful for many applications, especially on the internet.