Method for decoding and encoding video with history-based Rice parameter derivations, and non-transitory computer-readable medium

Patent metadata

Field	Value
Publication number	US-12532035-B2
Application number	US-202218697350-A
Country	US
Kind code	B2
Filing date	Oct 5, 2022
Priority date	Oct 6, 2021
Publication date	Jan 20, 2026
Grant date	Jan 20, 2026

Abstract

A method for decoding a video comprises accessing a binary string representing a partition of the video, the partition comprising multiple CTUs; decoding each CTUs in the partition, decoding the CTU comprising decoding a transform unit (TU) of the CTU by: updating a history counter StatCoeff for a color component for calculating Rice parameters based on a first non-zero quantized level in the TU; prior to calculating a next Rice parameter, updating a replacement variable HistValue based on the updated history counter StatCoeff, calculating the Rice parameters for the TU based on the updated replacement variable HistValue; decoding the binary string corresponding to the TU into coefficient values of the TU based on the calculated Rice parameters; and determining pixel values for the TU in the CTU from the coefficient values; and outputting a decoded partition of the video comprising the decoded multiple CTUs in the partition.

First claim

The invention claimed is:

1 . A method for decoding a video, the method comprising:
accessing a binary string representing a partition of the video, the partition comprising a plurality of coding tree units (CTUs); decoding each CTU of the plurality of CTUs in the partition, decoding the CTU comprising decoding a transform unit (TU) of the CTU by:
updating a history counter StatCoeff for a color component for calculating Rice parameters based on a first non-zero quantized level in the TU;
prior to calculating a next Rice parameter, updating a replacement variable HistValue based on the updated history counter StatCoeff;
calculating the Rice parameters for the TU based on the updated replacement variable HistValue;
decoding the binary string corresponding to the TU into coefficient values of the TU based on the calculated Rice parameters; and
determining pixel values for the TU in the CTU from the coefficient values; and
outputting a decoded partition of the video comprising the decoded plurality of CTUs in the partition; wherein updating the history counter StatCoeff for a color component cIdx as:

StatCoeff
[
cIdx
]

=

(

StatCoeff
[
cIdx
]

+

Floor
(

Log
2

(

abs
⁡
(
level
)

)

)

)

>>
1

,

wherein Floor(x) represents the largest integer less than or equal to x, Log 2 (x) is base-2 logarithm of x, abs(x) represent an absolute value of x, and level represents the first non-zero quantized level in the TU.

2 . The method of claim 1 , wherein the partition is a frame, a slice, or a tile.

3 . The method of claim 1 , further comprising, for a first CTU in the partition, setting the replacement variable HistValue to an initial value based on an initial value of the history counter StatCoeff as

HistValue
=

sps_persistent
⁢
_rice
⁢
_adaptation
⁢
_enabled
⁢

_flag

?

1

⁢

<<

StatCoeff
[
cIdx
]

:
0

wherein sps_persistent_rice_adaptation_enabled_flag indicates whether a history-based Rice parameter derivation is enabled.

4 . The method of claim 1 , wherein updating a replacement variable HistValue based on the history counter StatCoeff comprises updating the replacement variable Hist Value for a color component cIdx by calculating:

HistValue

[
cIdx
]

=

1
⁢

<<

StatCoeff
[
cIdx
]

.

5 . The method of claim 1 , wherein calculating the Rice parameters for the TU in the CTU based on the replacement variable HistValue comprises:
calculating a local sum variable locSumAbs for a coefficient in the TU of the CTU using values of neighboring coefficients in a pre-determined neighborhood of the coefficient and the replacement variable HistValue; and deriving the Rice parameters for the TU based on the local sum variable locSumAbs.

6 . A non-transitory computer-readable medium having program code and a bitstream that are stored thereon, the program code, when executed by one or more processing devices, causes the one or more processing devices to perform a method for encoding a video to generate the bitstream, the method comprising:
accessing a partition of the video, the partition comprising a plurality of coding tree units (CTUs); processing the partition of the video to generate a binary representation of the partition, the processing comprising:
encoding each CTU of the plurality of CTUs in the partition, encoding the CTU comprising encoding a transform unit (TU) of the CTU by:
updating a history counter StatCoeff for a color component for calculating Rice parameters based on a first non-zero quantized level in the TU;
prior to calculating a next Rice parameter, updating a replacement variable HistValue based on the updated history counter StatCoeff;
calculating the Rice parameters for the TU based on the updated replacement variable HistValue; and
encoding coefficient values of the TU into a binary representation corresponding to the TU in the CTU based on the calculated Rice parameters; and

encoding the binary representation of the partition into the bitstream of the video; wherein updating the history counter StatCoeff for a color component cIdx as:

StatCoeff
[
cIdx
]

=

(

StatCoeff
[
cIdx
]

+

Floor
(

Log
2

(

abs
⁡
(
level
)

)

)

)

>>
1

,

Assignees

• Guangdong Oppo Mobile Telecommunications Corp Ltd

Inventors

• Yu Yue
• Yu Haoping

Classifications

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/18

  the unit being a set of transform coefficients · CPC title

• H04N19/119

  Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/91

  Entropy coding, e.g. variable length coding [VLC] or arithmetic coding · CPC title