Granted Patent B2

US 12,627,812 · App. 18/683,662 · Granted May 12, 2026

Inventors: Yue Yu (Palo Alto, CA); Haoping Yu (Palo Alto, CA); Vladyslav Zakharchenko (Palo Alto, CA)

Assignee: GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD.

H04N19/152H04N19/119H04N19/174H04N19/18H04N19/182H04N19/186H04N19/1883H04N19/197H04N19/436H04N19/70H04N19/96

Abstract

Claims (93)

1 . A method for decoding a video from a video bitstream, the method comprising:

accessing a binary string representing a partition of the video, the partition comprising a plurality of coding tree units (CTUs) forming one or more CTU rows;

for each CTU of the plurality of CTUs in the partition,

prior to decoding the CTU and in response to determining that parallel coding is enabled and that the CTU is the first CTU of a current CTU row, determining whether the current CTU row is the first CTU row in the partition;

in response to determining that the current CTU row is the first CTU row in the partition, setting a history counter for a color component for calculating Rice parameters to an initial value;

in response to determining that the current CTU row is not the first CTU row in the partition, setting the history counter for a color component to a value stored in a history counter storage variable;

decoding the CTU, comprising:

calculating the Rice parameters for transform units (TUs) in the CTU based on the value of the history counter;

decoding the binary string corresponding to the TUs in the CTU into coefficient values of the TUs based on the calculated Rice parameters; and

determining pixel values for the TUs in the CTU from the coefficient values; and

after decoding the CTU, in response to determining that parallel coding is enabled and that the CTU is the first CTU of the current CTU row, storing a current value of the history counter in the history counter storage variable.

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

3 . The method of claim 1 , wherein setting the history counter for a color component cIdx to an initial value comprises:

StatCoeff[ c Idx]=2*Floor(Log 2(BitDepth−10)),

wherein StatCoeff denotes the history counter, BitDepth specifies a bit depth of samples of luma and chroma arrays of the video, Floor(x) represents the largest integer less than or equal to x, and Log 2(x) is base-2 logarithm of x.

4 . The method of claim 1 , wherein calculating the Rice parameters for the TUs in the CTU based on the value of the history counter comprises:

determining a replacement variable HistValue based on the history counter;

calculating a local sum variable locSumAbs for a coefficient in a TU of the CTU using values of neighboring coefficients in a pre-determined neighborhood of the coefficient and the replacement variable HistValue; and

deriving a Rice parameter for the TU based on the local sum variable locSumAbs.

5 . The method of claim 4 , wherein calculating a local sum variable locSumAbs for a coefficient in a TU of the CTU comprises:

determining that a neighboring sample of a plurality of neighboring samples in the pre-determined neighborhood of the coefficient is outside the TU; and

using the replacement variable HistValue as a value of the neighboring sample outside the TU to calculate the local sum variable locSumAbs.

6 . The method of claim 1 , further comprising:

prior to decoding the CTU, in response to determining that the current CTU row is not the first CTU row in the partition, setting a replacement variable to a stored replacement variable value, wherein calculating the Rice parameters for TUs in the CTU based on the value of the history counter comprises calculating the Rice parameters for TUs in the CTU based on the replacement variable; and

after decoding the CTU, in response to determining that parallel coding is enabled and that the CTU is the first CTU of the current CTU row, storing a current value of the replacement variable.

7 . The method of claim 1 , wherein decoding the CTU further comprises updating the history counter by:

in response to determining that the first, non-zero, Golomb-Rice coded transform coefficient in a TU is coded as abs_remainder, updating the history counter for a color component cIdx as:

StatCoeff[ c Idx]=(StatCoeff[ c Idx]+Floor(Log 2(abs_remainder[ c Idx]))+2)>>1; and

in response to determining that the first, non-zero, Golomb-Rice coded transform coefficient in the TU is coded as dec_abs_level, updating the history counter for a color component cIdx as:

StatCoeff[ c Idx]=(StatCoeff[ c Idx]+Floor(Log 2(dec_abs_level[ c Idx])))>>1,

wherein StatCoeff denotes the history counter, Floor(x) represents the largest integer less than or equal to x, and Log 2(x is base-2 logarithm of x.

8 . A system comprising:

a processing device; and

a non-transitory computer-readable medium communicatively coupled to the processing device, wherein the processing device is configured to execute program code stored in the non-transitory computer-readable medium and thereby perform operations comprising:

accessing a binary string representing a partition of a video, the partition comprising a plurality of coding tree units (CTUs) forming one or more CTU rows;

for each CTU of the plurality of CTUs in the partition,

prior to decoding the CTU and in response to determining that parallel coding is enabled and that the CTU is the first CTU of a current CTU row, determining whether the current CTU row is the first CTU row in the partition;

in response to determining that the current CTU row is the first CTU row in the partition, setting a history counter for a color component for calculating Rice parameters to an initial value;

in response to determining that the current CTU row is not the first CTU row in the partition, setting the history counter for a color component to a value stored in a history counter storage variable;

decoding the CTU, comprising:

calculating the Rice parameters for transform units (TUs) in the CTU based on the value of the history counter;

decoding the binary string corresponding to the TUs in the CTU into coefficient values of the TUs based on the calculated Rice parameters; and

determining pixel values for the TUs in the CTU from the coefficient values; and

after decoding the CTU, in response to determining that parallel coding is enabled and that the CTU is the first CTU of the current CTU row, storing a current value of the history counter in the history counter storage variable.

9 . The system of claim 8 , wherein setting the history counter for a color component cIdx to an initial value comprises:

StatCoeff[ c Idx]=2*Floor(Log 2(BitDepth−10)),

wherein StatCoeff denotes the history counter, BitDepth specifies a bit depth of samples of luma and chroma arrays of the video, Floor(x) represents the largest integer less than or equal to x, and Log 2(x) is base-2 logarithm of x.

10 . The system of claim 8 , wherein calculating the Rice parameters for the TUs in the CTU based on the value of the history counter comprises:

determining a replacement variable HistValue based on the history counter;

calculating a local sum variable locSumAbs for a coefficient in a TU of the CTU using values of neighboring coefficients in a pre-determined neighborhood of the coefficient and the replacement variable HistValue; and

deriving a Rice parameter for the TU based on the local sum variable locSumAbs.

11 . The system of claim 8 , further comprising:

prior to decoding the CTU, in response to determining that the current CTU row is not the first CTU row in the partition, setting a replacement variable to a stored replacement variable value, wherein calculating the Rice parameters for TUs in the CTU based on the value of the history counter comprises calculating the Rice parameters for TUs in the CTU based on the replacement variable; and

after decoding the CTU, in response to determining that parallel coding is enabled and that the CTU is the first CTU of the current CTU row, storing a current value of the replacement variable.

12 . The system of claim 8 , wherein decoding the CTU further comprises updating the history counter by:

in response to determining that the first, non-zero, Golomb-Rice coded transform coefficient in a TU is coded as abs_remainder, updating the history counter for a color component cIdx as:

StatCoeff[cIdx]=(StatCoeff[ c Idx]+Floor(Log 2(abs_remainder[ c Idx]))+2)>>1; and

in response to determining that the first, non-zero, Golomb-Rice coded transform coefficient in the TU is coded as dec_abs_level, updating the history counter for a color component cIdx as:

StatCoeff[ c Idx]=(StatCoeff[ c Idx]+Floor(Log 2(dec_abs_level[ c Idx])))>>1,

wherein StatCoeff denotes the history counter, Floor(x) represents the largest integer less than or equal to x, and Log 2(x) is base-2 logarithm of x.

13 . A method for encoding a video, the method comprising:

accessing a partition of the video, the partition comprising a plurality of coding tree units (CTUs) forming one or more CTU rows;

processing the partition of the video to generate a binary representation of the partition, the processing comprising:

for each CTU of the plurality of CTUs in the partition,

prior to encoding the CTU and in response to determining that parallel coding is enabled and that the CTU is the first CTU of a current CTU row, determining whether the current CTU row is the first CTU row in the partition;

in response to determining that the current CTU row is the first CTU row in the partition, setting a history counter for a color component for calculating Rice parameters to an initial value;

in response to determining that the current CTU row is not the first CTU row in the partition, setting the history counter for a color component to a value stored in a history counter storage variable; and

encoding the CTU, comprising:

calculating the Rice parameters for transform units (TUs) in the CTU based on the value of the history counter, and

encoding coefficient values of the TUs into a binary representation corresponding to the TUs in the CTU based on the calculated Rice parameters; and

after encoding the CTU, in response to determining that parallel coding is enabled and that the CTU is the first CTU of the current CTU row, storing a current value of the history counter in the history counter storage variable; and

encoding the binary representation of the partition into a bitstream of the video.

14 . The method of claim 13 , wherein the partition is a frame, a slice, or a tile.

15 . The method of claim 13 , wherein setting the history counter for a color component cIdx to an initial value comprises:

StatCoeff[ c Idx]=2*Floor(Log 2(BitDepth−10)),

wherein StatCoeff denotes the history counter, BitDepth specifies a bit depth of samples of luma and chroma arrays of the video, Floor(x) represents the largest integer less than or equal to x, and Log 2(x) is base-2 logarithm of x.

16 . The method of claim 13 , wherein calculating the Rice parameters for the TUs in the CTU based on the value of the history counter comprises:

determining a replacement variable HistValue based on the history counter;

calculating a local sum variable locSumAbs for a coefficient in a TU of the CTU using values of neighboring coefficients in a pre-determined neighborhood of the coefficient and the replacement variable HistValue; and

deriving a Rice parameter for the TU based on the local sum variable locSumAbs.

17 . The method of claim 16 , wherein calculating a local sum variable locSumAbs for a coefficient in a TU of the CTU comprises:

determining that a neighboring sample of a plurality of neighboring samples in the pre-determined neighborhood of the coefficient is outside the TU; and

using the replacement variable HistValue as a value of the neighboring sample outside the TU to calculate the local sum variable locSumAbs.

18 . The method of claim 13 , further comprising:

prior to encoding the CTU, in response to determining that the current CTU row is not the first CTU row in the partition, setting a replacement variable to a stored replacement variable value, wherein calculating the Rice parameters for TUs in the CTU based on the value of the history counter comprises calculating the Rice parameters for TUs in the CTU based on the replacement variable; and

after encoding the CTU, in response to determining that parallel coding is enabled and that the CTU is the first CTU of the current CTU row, storing a current value of the replacement variable.

19 . The method of claim 13 , wherein encoding the CTU further comprises updating the history counter by:

in response to determining that the first, non-zero, Golomb-Rice coded transform coefficient in a TU is coded as abs_remainder, updating the history counter for a color component cIdx as:

StatCoeff[ c Idx]=(StatCoeff[ c Idx]+Floor(Log 2(abs_remainder[ c Idx]))+2)>>1; and

in response to determining that the first, non-zero, Golomb-Rice coded transform coefficient in the TU is coded as dec_abs_level, updating the history counter for a color component cIdx as:

StatCoeff[ c Idx]=(StatCoeff[ c Idx]+Floor(Log 2(dec_abs_level[ c Idx])))>>1,

wherein StatCoeff denotes the history counter, Floor(x) represents the largest integer less than or equal to x, and Log 2(x is base-2 logarithm of x.

20 . A non-transitory computer-readable storage medium, having a computer program and a bitstream stored thereon, wherein the computer program, when executed by a processor, enables the processor to perform the method of claim 13 to generate the bitstream.

Assignments (2)

Continuity (4)

References Cited (63)