Wavelet transforms in a digital video tape recorder (DVTR)

The primary aim of the project is to record CCIR 601 digital video data compressed by factors in the range of 4:1 to 8:1 onto a video tape recorder. The starting point was the JPEG still picture transmission specification using the 3 basic compression element pairs: a decorrelator/correlator (in JPEG this is the DCT/IDCT combination), a linear quantiser/dequantiser which removes less visible picture information, and an entropy coder/decoder. Of these, the first-third element pairs are lossless and fully reversible, whilst the second elemental is so-called 'visually lossless', meaning that the errors introduced are not normally visible. The correlator element (the IDCT) introduced, as a result of the errors created by the quantiser/dequantiser pair, some objectionable artifacts at 4:1 compression. This paper, concentrates specifically on the decorrelator/correlator process and, in particular, the use of wavelet filter banks with ideal characteristics.