Sub-band coding of composite video for data compression in a solid state recorder

The compression of images has been a world-wide topic of research for many years with a prolific number of publications on many aspects. Applications essentially fall into the areas of transmission or storage with a wide range of differing quality requirements dependent on the specific use. Interest has been motivated by the need to record NTSC programme material in the studio with the resultant stringent requirements for high image quality and full editing capabilities. The storage medium is solid-state random access memory (RAM) so that compressing the video signal has substantial benefits in increasing the storage time. A suitable compression algorithm was investigated and developed by theoretical studies and simulations and, subsequently, a hardware prototype of the resultant scheme was built and evaluated. The starting point of the investigation was the well established transform and entropy coding approach as specified, for example, in the JPEG baseline proposal. During the development a number of objectives and factors were considered, many of which are driven by the broadcast requirements of the final product