System for variable-length-coding and variable-length-decoding digital data for compressing transmission data

A variable-length-coding apparatus for variable-length-coding digital data which is divided into a block unit of a predetermined size, the apparatus comprising:

• input terminals for inputting quantization coefficients of said digital data to the block units;
• a plurality of coefficient storing units for respectively storing quantization coefficients input through said input terminals;
• means for outputting different scan addresses to a plurality of said coefficient storing units;
• a plurality of run level coders for transforming coefficients which are stored in a plurality of said coefficient storing units, into symbols according to the scanning patterns with input respective scan addresses;
• a plurality of variable length coders for respectively variable-length-coding the data output from a plurality of said run level coders;
• a plurality of buffers for separately storing variable-length-coded data output from a plurality of said variable length coders;
• accumulators for separately accumulating the lengths of variable-length-coded data output from the plurality of said variable length coders;
• a minimum selector for selecting a minimum value among accumulated lengths output respectively from a plurality of said accumulators;
• means for selecting a predetermined buffer among the plurality of said buffers according to a designated selecting signal input from said minimum selector;
• and
• means for outputting both scanning pattern data which represents a scanning pattern corresponding to a minimum value selected from said minimum selector and variable-length-coded data which are output from the selected buffer in said buffer selector, to transmission channels.