Microsoft Corporation
Parallelized decoding of variable-length prefix codes

Abstract:

Methods and systems are provided for decoding variable-length codes in a parallel process. A stream of variable-length code words is divided into fixed length words. A plurality of parallel sets of decoder circuits each receive, in parallel, a current fixed length word and a prior fixed length word. Each decoder circuit has a respective fixed leftover bit-count. Each decoder circuit generates a respective output that may include a decoded symbol and a new leftover bit-count. Each respective output is determined based on the respective current fixed length word, the respective prior fixed length word, and the respective fixed leftover bit-count. A set of selected decoder circuit outputs is generated for each set of the parallel sets of decoder circuits based on a set of first leftover bit-counts. One output from each set of selected decoder circuit outputs is selected as a final output based on a second prior leftover bit-count.