Method and apparatus for digital data compression

In a system for processing a stream of digital bit sets, each related to a different subject in a passing array, said system including an arrangement for compressing said bit-sets in said stream and sending the results to utilization means, said arrangement also comprising:

• a preprocessing stage for distributing each said bit set in two parallel bit-compression paths, with all input sent to a common output buffer means, each said compression path being adapted to execute a prescribed first compression to ascertain "initial factors", and then execute a prescribed second compression to use a said initial factor with the second compression values being selected according to "word count" factors derived from results of the first compression;
• and provide a prescribed time-compressed output to said utilization means as "entropy encoded data";
• wherein said both said compressions are performed in real time, according to JPEG standards and using prescribed selected QM and Huffman table values, on a single two-pass stage of a Histogram/Compressor printed circuit board;
• wherein compression-control means is also provided to add "peripheral data", including "stuffed bytes", "restart codes" and "padding bytes" to each said compressed output;
• and
• wherein post processor means is also provided to accept said compressed data as 32-bit output and funnel it down to 16-bit output presented to said utilization means.