Entropy coding

A method for encoding a sequence of symbols, comprising

• assigning a number of parameters to each symbol of the sequence of symbols based on information comprised within previous symbols of the sequence of symbols;
• and
• forwarding each symbol to a selected one of a plurality of entropy encoders, the selection depending on the number of parameters assigned to the respective symbol, and each of the plurality of entropy encoders being configured to convert symbols forwarded to the respective entropy encoder into a respective bitstream, wherein each entropy encoder is a variable length coder configured to map symbol sequences to codewords shorter as, or as long as, a respective maximum bit length Lx,
• wherein the method further comprises,
• for each entropy encoder, buffering the respective bitstream of the respective entropy encoder in a respective individual buffer,
• reserving a sequence of tranche entries of respective bit length Nx for the plurality of entropy encoders in a global buffer in a sequential order depending on an order in which the reservations of the tranche entries for the plurality of entropy encoders are triggered;
• triggering a reservation of a tranche entry of bit length Nx for a respective one of the entropy encoders at times where the symbols of the sequence of symbols forwarded by the selector to the plurality of entropy encoders result in a beginning of a new symbol sequence to be mapped to a codeword at the respective entropy encoder, provided that at the respective time a number of bits currently reserved in the global buffer for the respective entropy encoder minus a number Mx of bits currently buffered in the individual buffer of the respective entropy encoder or the global buffer for the respective entropy encoder is not sufficient to accommodate an intended minimum number Cx of further codeword for the respective entropy encoder plus one, times the respective maximum bit length Lx, i.e. (Cx+1)·Lx,
• outputting buffered portions of the bitstreams from the codeword buffers to fill the respective reserved tranche entries in the global buffer, and
• removing filled tranche entries of the tranche entries in the sequential order to acquire a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner.

A decoder for reconstructing a sequence of symbols, comprising:

• a plurality of entropy decoders, each of which is configured to convert a respective bitstream into symbols;
• an assigner configured to assign a number of parameters to each symbol of a sequence of symbols to be reconstructed based on information comprised within previously reconstructed symbols of the sequence of symbols;
• and
• a selector configured to retrieve each symbol of the sequence of symbols to be reconstructed from a selected one of the plurality of entropy decoders, the selection depending on the number of parameters defined to the respective symbol,
• wherein each entropy decoder is a variable length decoder configured to map codewords shorter as, or as long as, a respective maximum bit length Lx, to symbol sequences,
• wherein the decoder further comprises global buffer configured to receive a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner, wherein the global buffer is configured to sequentially distribute the tranches from the global buffer to the plurality of entropy decoders depending on an order in which requests for the tranches occur,
• wherein each of the plurality of entropy decoders is configured to trigger a respective request for a tranche of respective bit length Nx of the respective bitstream from the global buffer at times where, among the symbols of the sequence of symbols to be reconstructed as retrieved by the selector from the plurality of entropy decoders, a symbol is encountered which forms a beginning of a new symbol sequence to be mapped from a new codeword within the respective bitstream by the respective entropy decoder, provided that at the respective time a number Mx of bits of the respective bitstream having been distributed to the respective entropy decoder by the global buffer, but not yet having been entropy decoded by the entropy decoder so far, including the new codeword, is less than an intended minimum number Cx of further codewords for the respective entropy decoder plus one, times the respective maximum bit length Lx, i.e. (Cx+1)·Lx.

A method for reconstructing a sequence of symbols, comprising:

• assigning a number of parameters to each symbol of a sequence of symbols to be reconstructed based on information comprised within previously reconstructed symbols of the sequence of symbols;
• and
• retrieving each symbol of the sequence of symbols to be reconstructed from a selected one of a plurality of entropy decoders, the selection depending on the number of parameters defined to the respective symbol, and each of the plurality of entropy decoders being configured to convert a respective bitstream into symbols, wherein each entropy decoder is a variable length decoder configured to map codewords shorter as, or as long as, a respective maximum bit length Lx, to symbol sequences,
• wherein the method further comprises
• receiving a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner, in a global buffer;
• sequentially distributing the tranches from the global buffer to the plurality of entropy decoders depending on an order in which requests for the tranches occur,
• for each of the plurality of entropy decoders, triggering a respective request for a tranche of respective bit length Nx of the respective bitstream from the global buffer at times where, among the symbols of the sequence of symbols to be reconstructed as retrieved by the selector from the plurality of entropy decoders, a symbol is encountered which forms a beginning of a new symbol sequence to be mapped from a new codeword within the respective bitstream by the respective entropy decoder, provided that at the respective time a number Mx of bits of the respective bitstream having been distributed to the respective entropy decoder by the global buffer, but not yet having been entropy decoded by the entropy decoder so far, including the new codeword is less than an intended minimum number Cx of further codewords for the respective entropy decoder plus one, times the respective maximum bit length Lx, i.e. (Cx+1)·Lx.

An encoder for encoding a sequence of symbols, comprising

• an assigner configured to assign a number of parameters to each symbol of the sequence of symbols based on information comprised within previous symbols of the sequence of symbols;
• a plurality of entropy encoders each of which is configured to convert the symbols forwarded to the respective entropy encoder into a respective bitstream;
• and
• a selector configured to forward each symbol to a selected one of the plurality of entropy encoders, the selection depending on the number of parameters assigned to the respective symbol,
• wherein each entropy encoder is a variable length coder configured to map symbol sequences to codewords.
• wherein the encoder comprises, for each entropy encoder, an individual buffer for buffering the respective bitstream of the respective entropy encoder, and a global buffer, wherein the global buffer is configured to reserve a sequence of tranche entries for the plurality of entropy encoders in a sequential order depending on an order in which the reservations of the tranche entries for the plurality of entropy encoders are triggered;
• wherein the plurality of entropy encoders and the respective individual buffers cooperate to trigger a reservation of a tranche entry of bit length Nx for a respective one of the entropy encoders at times where the symbols of the sequence of symbols forwarded by the selector to the plurality of entropy encoders result in a beginning of a new symbol sequence to be mapped to a codeword at the respective entropy encoder, provided that at the respective time a difference between a number of bits currently reserved in the global buffer for the respective entropy encoder and a number Mx of bits currently buffered in the individual buffer of the respective entropy encoder or the global buffer for the respective entropy encoder does not fulfill a predetermined criterion,
• wherein the individual buffers of the plurality of entropy encoders are configured to output buffered portions of the bitstreams to fill the respective reserved tranche entries in the global buffer, and the global buffer is configured to remove filled tranche entries of the tranche entries in the sequential order to acquire a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner,
• wherein
• the individual buffers are configured to output buffered portions of the bitstreams to fill the respective reserved tranche entries in the global buffer in units of tranche entries;
• the global buffer is configured to, at the times of the triggering of a respective reservation by any of the plurality of entropy encoders and the respective individual buffers,
• finish the removal of the filled tranche entries of the tranche entries in the sequential order from the least recently reserved, already having been filled tranche entry, inclusively, if any, up to the least recently reserved, not yet filled tranche entry, exclusively, then
• check as to whether a number of bits in the global buffer covered by the reserved tranche entries plus a bit length Nx of the requested tranche entry for the respective reservation-triggering entropy encoder is greater than a maximum buffer delay D, and,
• if not
• reserve a respective new tranche entry of bit length Nx for the respective reservation-triggering entropy encoder, but
• if so,
• cause the entropy encoder for which the least recently reserved, not yet filled tranche entry is reserved, to extend symbols forwarded to it by the selector, which have not yet been entropy encoded, if any, to a valid symbol sequence, and map the valid symbol sequence to a codeword so as to be buffered by the corresponding individual buffer, and then
• check as to whether the number Mx of bits currently buffered in the individual buffer of the entropy encoder for which the least recently reserved, not yet filled tranche entry is reserved, is smaller than the bit length Nx for this entropy encoder, and if so, append Nx-Mx bits to the Mx bits currently buffered, and then
• output Nx buffered bits out of the individual buffer of the entropy encoder for which the least recently reserved, not yet filled tranche entry is reserved, into the least recently reserved, not yet filled tranche entry in order to fill same, with leaving potentially additionally buffered bits beyond the Nx buffered bits output, in the individual buffer.

A decoder for reconstructing a sequence of symbols, comprising:

• a plurality of entropy decoders, each of which is configured to convert a respective bitstream into symbols;
• an assigner configured to assign a number of parameters to each symbol of a sequence of symbols to be reconstructed based on information comprised within previously reconstructed symbols of the sequence of symbols;
• and
• a selector configured to retrieve each symbol of the sequence of symbols to be reconstructed from a selected one of the plurality of entropy decoders, the selection depending on the number of parameters defined to the respective symbol,
• wherein each entropy decoder is a variable length decoder configured to map codewords to symbol sequences,
• wherein the decoder further comprises global buffer configured to receive a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner, wherein the global buffer is configured to sequentially distribute the tranches from the global buffer to the plurality of entropy decoders depending on an order in which requests for the tranches occur,
• wherein each of the plurality of entropy decoders is configured to trigger a respective request for a tranche of the respective bitstream from the global buffer at times where, among the symbols of the sequence of symbols to be reconstructed as retrieved by the selector from the plurality of entropy decoders, a symbol is encountered which forms a beginning of a new symbol sequence to be mapped from a new codeword within the respective bitstream by the respective entropy decoder, provided that at the respective time a number Mx of bits of the respective bitstream having been distributed to the respective entropy decoder by the global buffer, but not yet having been entropy decoded by the entropy decoder so far, including the new codeword, is less than a predetermined number,
• wherein the decoder is configured to
• log, for each entropy decoder, a number of bits distributed from the global buffer to the plurality of entropy decoders up to the distribution of a least recently distributed tranche distributed from the global buffer to the respective entropy decoder,
• determine, each time a respective request for a tranche of a respective bit length Nx is triggered, as to whether a difference between a global number of bits distributed from the global buffer to the plurality of entropy decoders up to the respective request on the one hand, and a minimum logged number of bits on the other hand, is greater than a maximum buffer delay D, and, if so,
• discard the least recently distributed tranche distributed from the global buffer to the entropy decoder for which the minimum logged number has been logged, and any symbols not yet having been retrieved from the entropy decoder for which the minimum logged number has been logged by the selector.

An encoder for encoding a sequence of symbols, comprising

• an assigner configured to assign a number of parameters to each symbol of the sequence of symbols based on information comprised within previous symbols of the sequence of symbols;
• a plurality of entropy encoders each of which is configured to convert the symbols forwarded to the respective entropy encoder into a respective bitstream;
• and
• a selector configured to forward each symbol to a selected one of the plurality of entropy encoders, the selection depending on the number of parameters assigned to the respective symbol,
• wherein each entropy encoder is a variable length coder configured to map symbol sequences to codewords.
• wherein the encoder comprises, for each entropy encoder, an individual buffer for buffering the respective bitstream of the respective entropy encoder, and a global buffer, wherein the global buffer is configured to reserve a sequence of tranche entries for the plurality of entropy encoders in a sequential order depending on an order in which the reservations of the tranche entries for the plurality of entropy encoders are triggered;
• wherein the plurality of entropy encoders and the respective individual buffers cooperate to trigger a reservation of a tranche entry of bit length Nx for a respective one of the entropy encoders at times where the symbols of the sequence of symbols forwarded by the selector to the plurality of entropy encoders result in a beginning of a new symbol sequence to be mapped to a codeword at the respective entropy encoder, provided that at the respective time a difference between a number of bits currently reserved in the global buffer for the respective entropy encoder and a number Mx of bits currently buffered in the individual buffer of the respective entropy encoder or the global buffer for the respective entropy encoder does not fulfill a predetermined criterion,
• wherein the individual buffers of the plurality of entropy encoders are configured to output buffered portions of the bitstreams to fill the respective reserved tranche entries in the global buffer, and the global buffer is configured to remove filled tranche entries of the tranche entries in the sequential order to acquire a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner,
• the encoder further comprising a fragmentizer configured to fragmentize the single stream of tranches into chunks with accompanying each chunk with information as to how the tranches of the plurality of entropy encoders are distributed over the respective chunk so as to acquire a sequence of chunks.

A decoder for reconstructing a sequence of symbols, comprising:

• a plurality of entropy decoders, each of which is configured to convert a respective bitstream into symbols;
• an assigner configured to assign a number of parameters to each symbol of a sequence of symbols to be reconstructed based on information comprised within previously reconstructed symbols of the sequence of symbols;
• and
• a selector configured to retrieve each symbol of the sequence of symbols to be reconstructed from a selected one of the plurality of entropy decoders, the selection depending on the number of parameters defined to the respective symbol,
• wherein each entropy decoder is a variable length decoder configured to map codewords to symbol sequences,
• wherein the decoder further comprises
• a defragmentizer configured to defragmentize and distribute tranches of the bitstreams to the entropy decoders from a sequence of chunks where each chunk has accompanied therewith information as to how the tranches of the bitstreams for the plurality of entropy decoders are distributed over the respective chunk.

A method for encoding a sequence of symbols, comprising

• assigning a number of parameters to each symbol of the sequence of symbols based on information comprised within previous symbols of the sequence of symbols;
• forwarding each symbol to a selected one of a plurality of entropy encoders, the selection depending on the number of parameters assigned to the respective symbol, each of the plurality of entropy encoders being configured to convert the symbols forwarded to the respective entropy encoder into a respective bitstream,
• wherein each entropy encoder is a variable length coder configured to map symbol sequences to codewords.
• for each entropy encoder, buffering the respective bitstream of the respective entropy encoder in an individual buffer, and
• reserving a sequence of tranche entries for the plurality of entropy encoders in a global buffer in a sequential order depending on an order in which the reservations of the tranche entries for the plurality of entropy encoders are triggered;
• triggering a reservation of a tranche entry of bit length Nx for a respective one of the entropy encoders at times where the symbols of the sequence of symbols forwarded by the selector to the plurality of entropy encoders result in a beginning of a new symbol sequence to be mapped to a codeword at the respective entropy encoder, provided that at the respective time a difference between a number of bits currently reserved in the global buffer for the respective entropy encoder and a number Mx of bits currently buffered in the individual buffer of the respective entropy encoder or the global buffer for the respective entropy encoder does not fulfill a predetermined criterion,
• output buffered portions of the bitstreams from the individual buffers of the plurality of entropy encoders to fill the respective reserved tranche entries in the global buffer,
• removing filled tranche entries of the tranche entries in the sequential order from the global buffer to acquire a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner,
• wherein
• output buffered portions of the bitstreams from the individual buffers to fill the respective reserved tranche entries in the global buffer in units of tranche entries;
• at the times of the triggering of a respective reservation by any of the plurality of entropy encoders and the respective individual buffers,
• finishing the removal of the filled tranche entries of the tranche entries in the sequential order from the least recently reserved, already having been filled tranche entry, inclusively, if any, up to the least recently reserved, not yet filled tranche entry, exclusively, then
• checking as to whether a number of bits in the global buffer covered by the reserved tranche entries plus a bit length Nx of the requested tranche entry for the respective reservation-triggering entropy encoder is greater than a maximum buffer delay D, and,
• if not
• reserving a respective new tranche entry of bit length Nx for the respective reservation-triggering entropy encoder, but
• if so,
• causing the entropy encoder for which the least recently reserved, not yet filled tranche entry is reserved, to extend symbols forwarded to it by the selector, which have not yet been entropy encoded, if any, to a valid symbol sequence, and map the valid symbol sequence to a codeword so as to be buffered by the corresponding individual buffer, and then
• checking as to whether the number Mx of bits currently buffered in the individual buffer of the entropy encoder for which the least recently reserved, not yet filled tranche entry is reserved, is smaller than the bit length Nx for this entropy encoder, and if so, appending Nx-Mx bits to the Mx bits currently buffered, and then
• outputting Nx buffered bits out of the individual buffer of the entropy encoder for which the least recently reserved, not yet filled tranche entry is reserved, into the least recently reserved, not yet filled tranche entry in order to fill same, with leaving potentially additionally buffered bits beyond the Nx buffered bits output, in the individual buffer.

A method for reconstructing a sequence of symbols using a plurality of entropy decoders, each of which is configured to convert a respective bitstream into symbols, the method comprising:

• assigning a number of parameters to each symbol of a sequence of symbols to be reconstructed based on information comprised within previously reconstructed symbols of the sequence of symbols;
• and
• retrieving each symbol of the sequence of symbols to be reconstructed from a selected one of the plurality of entropy decoders, the selection depending on the number of parameters defined to the respective symbol,
• wherein each entropy decoder is a variable length decoder configured to map codewords to symbol sequences,
• wherein the method further comprises
• receiving a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner, in a global buffer,
• sequentially distributing the tranches from the global buffer to the plurality of entropy decoders depending on an order in which requests for the tranches occur,
• for each of the plurality of entropy decoders, triggering a respective request for a tranche of the respective bitstream from the global buffer at times where, among the symbols of the sequence of symbols to be reconstructed as retrieved by the selector from the plurality of entropy decoders, a symbol is encountered which forms a beginning of a new symbol sequence to be mapped from a new codeword within the respective bitstream by the respective entropy decoder, provided that at the respective time a number Mx of bits of the respective bitstream having been distributed to the respective entropy decoder by the global buffer, but not yet having been entropy decoded by the entropy decoder so far, including the new codeword, is less than a predetermined number,
• wherein the method further comprises
• logging, for each entropy decoder, a number of bits distributed from the global buffer to the plurality of entropy decoders up to the distribution of a least recently distributed tranche distributed from the global buffer to the respective entropy decoder,
• determining, each time a respective request for a tranche of a respective bit length Nx is triggered, as to whether a difference between a global number of bits distributed from the global buffer to the plurality of entropy decoders up to the respective request on the one hand, and a minimum logged number of bits on the other hand, is greater than a maximum buffer delay D, and, if so,
• discarding the least recently distributed tranche distributed from the global buffer to the entropy decoder for which the minimum logged number has been logged, and any symbols not yet having been retrieved from the entropy decoder for which the minimum logged number has been logged by the selector.

A method for encoding a sequence of symbols, comprising

• assigning a number of parameters to each symbol of the sequence of symbols based on information comprised within previous symbols of the sequence of symbols;
• forwarding each symbol to a selected one of a plurality of entropy encoders, the selection depending on the number of parameters assigned to the respective symbol, wherein each of the plurality of entropy encoders is configured to convert the symbols forwarded to the respective entropy encoder into a respective bitstream;
• wherein each entropy encoder is a variable length coder configured to map symbol sequences to codewords.
• wherein the method comprises
• for each entropy encoder, buffering the respective bitstream of the respective entropy encoder in an individual buffer, and
• reserving a sequence of tranche entries for the plurality of entropy encoders in a global buffer in a sequential order depending on an order in which the reservations of the tranche entries for the plurality of entropy encoders are triggered;
• triggering a reservation of a tranche entry of bit length Nx for a respective one of the entropy encoders at times where the symbols of the sequence of symbols forwarded by the selector to the plurality of entropy encoders result in a beginning of a new symbol sequence to be mapped to a codeword at the respective entropy encoder, provided that at the respective time a difference between a number of bits currently reserved in the global buffer for the respective entropy encoder and a number Mx of bits currently buffered in the individual buffer of the respective entropy encoder or the global buffer for the respective entropy encoder does not fulfill a predetermined criterion,
• outputting buffered portions of the bitstreams from the individual buffers of the plurality of entropy encoders to fill the respective reserved tranche entries in the global buffer, with removing filled tranche entries of the tranche entries in the sequential order from the global buffer to acquire a single stream of tranches of the bitstreams of the plurality of bitstreams, interspersed into the single stream of tranches in an interleaved manner,
• the method further comprising
• fragmentizing the single stream of tranches into chunks with accompanying each chunk with information as to how the tranches of the plurality of entropy encoders are distributed over the respective chunk so as to acquire a sequence of chunks.

A method for reconstructing a sequence of symbols by a plurality of entropy decoders, each of which is configured to convert a respective bitstream into symbols, the method comprising

• assigning a number of parameters to each symbol of a sequence of symbols to be reconstructed based on information comprised within previously reconstructed symbols of the sequence of symbols;
• and
• retrieving each symbol of the sequence of symbols to be reconstructed from a selected one of the plurality of entropy decoders, the selection depending on the number of parameters defined to the respective symbol,
• wherein each entropy decoder is a variable length decoder configured to map codewords to symbol sequences,
• wherein the method further comprises
• defragmentizing and distributing tranches of the bitstreams to the entropy decoders from a sequence of chunks where each chunk has accompanied therewith information as to how the tranches of the bitstreams for the plurality of entropy decoders are distributed over the respective chunk.