Entropy coding for signal enhancement coding

Patent metadata

Field	Value
Publication number	US-12556746-B2
Application number	US-202318161566-A
Country	US
Kind code	B2
Filing date	Jan 30, 2023
Priority date	Aug 3, 2018
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

There is provided a method of encoding a video signal, the method comprising: receiving an input frame; processing the input frame to generate at least one set of residuals data, the residuals data enabling a decoder to reconstruct the input frame from a reference reconstructed frame; and, applying a run-length coding operation to the set of residuals data, wherein the run-length coding operation comprises generating a run-length encoded bytestream comprising a set of symbols representing non-zero data values of the residuals data set and counts of consecutive zero values of the residuals data set. In certain embodiments the method comprises apply a Huffman coding operation to the set of symbols. A method of decoding is also provided as well as apparatuses and a computer readable medium.

First claim

The invention claimed is:

1 . A method of encoding a video signal, the method comprising:
receiving an input frame; processing the input frame to generate residual data, the residual data enabling a decoder to reconstruct the input frame from a reference reconstructed frame; applying a modified run-length coding operation to the residual data where each value in the residual data is sent as a value and where each zero in the residual data is sent as a run of multiple consecutive zeros, wherein the modified run-length coding operation comprises generating a run-length encoded bytestream comprising a set of symbols representing non-zero data values of the residual data and counts of consecutive zero values of the residual data; applying a Huffman coding operation to the set of symbols to generate Huffman encoded data comprising a set of codes representing the run-length encoded bytestream; and in response to a determination that a number of the non-zero data values exceeds a threshold, selecting a header type that is structured to include bits representing a difference between a code length of one of the symbols in the set of symbols and a minimum length of a code used to encode the one symbol, where said code is included in the set of codes.

2 . A method according to claim 1 , wherein the modified run-length coding operation comprises:
encoding non-zero data values of the residual data into at least a first type of symbol; and encoding counts of consecutive zero values into a second type of symbol, such that the residual data is encoded as a sequence of symbols of different types.

3 . A method according to claim 1 , wherein the modified run-length coding operation comprises:
encoding data values of the residual data into a first type of symbol and a third type of symbol, the first and third types of symbol each comprising a part of a data value, such that the parts can be combined at a decoder to reconstruct the data value.

4 . A method according to claim 3 , wherein the modified run-length coding operation comprises:
comparing a size of each data value of the residual data to be encoded to a second threshold; and encoding each data value into the first type of symbol if the size is below the second threshold and encoding a part of each data value into the first type of symbol and a part of each data value into the third type of symbol if the size is above the second threshold.

5 . A method according to claim 4 , further comprising:
if the size is above the second threshold, setting a flag in the symbol of the first type of symbol indicating a part of the represented data value is encoded into a further symbol of the third type of symbol.

6 . A method according to claim 2 , further comprising:
inserting a flag in each symbol indicating a type of symbol encoded next in the run-length encoded bytestream.

7 . A method according to claim 1 , wherein the Huffman coding operation is a canonical Huffman coding operation, such that the Huffman encoded data comprises a code length for each unique symbol of the set of symbols, the code length representing a length of a code used to encode a corresponding symbol.

8 . A method according to claim 1 , further comprising:
comparing a data size of at least a portion of the run-length encoded bytestream to a data size of at least a portion of the Huffman encoded data; and outputting the run-length encoded bytestream or the Huffman encoded data in an output bitstream based on the comparison.

9 . A method according to claim 8 , further comprising:
adding a flag to configuration metadata accompanying the output bitstream indicating if the bitstream represents the run-length encoded bytestream or the Huffman encoded data.

10 . A method according to claim 1 , wherein the Huffman coding operation comprises:
generating a separate frequency table for symbols of the first type of symbol and symbols of the second type of symbol.

11 . A method according to claim 7 , further comprising:
generating a particular stream header, which is included among said stream headers, wherein generating the particular stream header includes generating an indication of a plurality of code lengths, such that a decoder can derive code lengths and respective corresponding symbols for a canonical Huffman decoding operation.

12 . A method according to claim 11 , wherein the particular stream header is a first type of stream header, and wherein an indication of the symbol associated with a respective code length of the plurality of code lengths is provided.

13 . A method according to claim 11 , wherein the particular stream header is a second type of stream header and the method further comprises ordering the plurality of code lengths in the stream header based on a predetermined order of symbols corresponding to each of the code lengths, such that the code lengths can be associated with a corresponding symbol at the decoder.

14 . A method according to claim 13 , wherein the second type of stream header further comprises a flag indicating a symbol in the predetermined order of the possible set of symbols does not exist in the set of symbols in the run-length encoded bytestream.

15 . A method according to claim 1 , wherein the modified run-length coding operation comprises:
encoding the non-zero data values of the residual data into at least a first type of symbol; encoding the counts of the consecutive zero values of the residual data into a second type of symbol, such that the residual data is encoded as a sequence of symbols of different types; and inserting a flag in each symbol of the second type of symbol indicating whether a subsequent symbol of the set of symbols comprises the first type of symbol or the second type of symbol.

16 . An encoding apparatus configured to:
receive an input frame; process the input frame to generate residual data, the residual data enabling a decoder to reconstruct the input frame from a reference reconstructed frame; apply a modified run-length coding operation to the residual data where each value in the residual data is sent as a value and where each zero in the residual data is sent as a run of multiple consecutive zeros, wherein the modified run-length coding operation comprises generating a run-length encoded bytestream comprising a set of symbols representing non-zero data values of the residual data and counts of consecutive zero values of residual data; apply a Huffman coding operation to the set of symbols to generate Huffman encoded data comprising a set of codes representing the run-length encoded bytestream; and in response to a determination that a number of the non-zero data values exceeds a threshold, select a header type that is structured to include bits representing a difference between a code length of one of the symbols in the set of symbols and a minimum length of a code used to encode the one symbol, where said code is included in the set of codes.

17 . A non-transitory computer readable medium comprising instructions that are executable by one or more processors cause the one or more processors to:
receive an input frame; process the input frame to generate residual data, the residual data enabling a decoder to reconstruct the input frame from a reference reconstructed frame; apply a modified run-length coding operation to the residual data where each value in the residual data is sent as a value and where each zero in the residual data is sent as a run of multiple consecutive zeros, wherein the modified run-length coding operation comprises generating

Assignees

• V Nova Int Ltd

Inventors

• Meardi Guido

Classifications

• H04N19/60

  using transform coding · CPC title

• H04N19/44

  Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder · CPC title

• H04N19/36

  Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability · CPC title

• H04N19/33 Primary

  in the spatial domain · CPC title

• H04N19/136

  Incoming video signal characteristics or properties · CPC title