Methods and devices for reordered parallel entropy coding and decoding

An encoder for encoding an input sequence of symbols, the symbols belonging to a finite alphabet, the encoder comprising:

• a processor;
• a memory;
• and
• an encoding application stored in memory and containing instructions for configuring the processor to
• reorder the input sequence into groups of input bits in accordance with a predetermined reordering schedule;
• for each group of input bits,
• determine, in parallel, a context for each of the input bits in the group of input bits and associating a probability with that bit based on its context,
• wherein the context for each of the input bits in the group is different from the context of each of the other input bits in the group, and the context of each of the input bits in the group is determined independently from the other input bits in the group;
• and
• entropy encode the input bits to generate an encoded subsequence.

A decoder for decoding encoded data for decoding a bitstream of encoded data to reconstruct a sequence of symbols, the symbols belonging to a finite alphabet, the decoder comprising:

• a processor;
• a memory;
• and
• a decoding application stored in memory and containing instructions for configuring the processor to
• decode the bitstream of encoded data to produce decoded groups of bits, wherein, for each group of bits, the decoding to produce that group of bits includes determining a context for each bit in that group of bits and associating a probability with that bit based on its context, and wherein the context for each of the bits in that group of bits is different from the context of each of the other bits in that group, and the context of each of the bits in that group is determined independently from each of the other bits in that group;
• and
• reorder the bits of the groups of bits based on a predetermined reordering schedule to produce the reconstructed sequence of bits.