Office Action 3: Notice of Allowance (2025-02-13)

CLAIMS:
AMENDMENTS TO THE CLAIMS:

This listing of claims will replace all prior versions, and listings, of claims in the application:

1-25. (Canceled).224

26\. (Currently Amended) A video decoder comprising:a microprocessor; and
a memory, the memory having program code that, when executed by the microprocessor, causes the video decoder to:
decode, from a video bitstream, a high-level flag which, when set to a first value,
indicates performing regular residual coding (RRC) for all coding units of a specific area of a current picture;determine, from the video bitstream, for a transform block (84), whether an inverse transform corresponding to the transform block is an identity transform or not;
when it is determined that the inverse transform is the identity transform and the high- level flag is set to a second value different from the first value, determine a first Rice parameter for a binarization of a residual transform coefficient of the transform block;
when it is determined that the inverse transform is not the identity transform or the high- level flag is set to the first value, determine a second Rice parameter for the binarization of the residual transform coefficient of the transform block; and
decode the residual transform coefficient of the transform block using the first or second Rice parameter.

27\. (Cancelled)

28\. (Cancelled)

29\. (Currently Amended) A video encoder comprising:a microprocessor; and

a memory, the memory having program code that, when executed by the microprocessor, causes the video encoder to:
encode, into a video bitstream, a high-level flag which, when set to a first value,
indicates performing regular residual coding (RRC) for all coding units of a specific area of a current picture;signal, in the video bitstream for a transform block, whether an inverse transform corresponding to the transform block is an identity transform;
when the inverse transform is the identity transform and the high-level flag is set to a second value different from the first value, determine a first Rice parameter for a binarization of a residual transform coefficient of the transform block;
when the inverse transform is not the identity transform or the high-level flag is set to the first value, determine a second Rice parameter for the binarization of the residual transform coefficient of the transform block; and
encode the residual transform coefficient of the transform block using the first or second Rice parameter.

30\. (Cancelled)

31\. (Cancelled)

32\. (Cancelled)

33\. (Previously Presented) The video encoder of claim 29, wherein the memory has program code that, when executed by the microprocessor, causes the video encoder to:determine that content for the video bitstream is camera-captured content; and
based on the determination that the content for the video bitstream is camera-captured content, set the high-level flag to the first value.

34\. (Previously Presented) The video encoder of claim 29, wherein the memory has program code that, when executed by the microprocessor, causes the video encoder to:determine that content for the video bitstream is screen content; and

based on the determination that content for the video bitstream is screen content, set the high-level flag to the second value.

35\. (Currently Amended) A method of video decoding, the method comprising:decoding, from a video bitstream, a high-level flag which, when set to a first value,
indicates performing regular residual coding (RRC) for all coding units of a specific area of a current picture;determining from the video bitstream, for a transform block, whether an inverse transform corresponding to the transform block is an identity transform;
when it is determined that the inverse transform is the identity transform and the high- level flag is set to a second value different from the first value, determining a first Rice parameter for a binarization of a residual transform coefficient of the transform block;
when it is determined that the inverse transform is not the identity transform or the high- level flag is set to the first value, determining a second Rice parameter for the binarization of the residual transform coefficient of the transform block; and
decoding the residual transform coefficient of the transform block using the first or second Rice parameter.

36\. (Cancelled)

37\. (Cancelled)

38\. (Currently Amended) A non-transitory, computer-readable storage medium storing computer program instructions, which when executed, cause a decoder to perform the steps of:
decoding, from a video bitstream, a high-level flag which, when set to a first value, indicates performing regular residual coding (RRC) for all coding units of a specific area of a current picture;determining from the video bitstream, for a transform block, whether an inverse transform corresponding to the transform block is an identity transform;

when it is determined that the inverse transform is the identity transform and the high- level flag is set to a second value different from the first value, determining a first Rice parameter for a binarization of a residual transform coefficient of the transform block;
when it is determined that the inverse transform is not the identity transform or the high- level flag is set to the first value, determining a second Rice parameter for the binarization of the residual transform coefficient of the transform block; and
decoding the residual transform coefficient of the transform block using the first or second Rice parameter.

OFFICE ACTION:
DETAILED ACTION
Notice of Pre-AIA  or AIA  Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114 was filed in this application after appeal to the Patent Trial and Appeal Board, but prior to a decision on the appeal. Since this application is eligible for continued examination under 37 CFR 1.114 and the fee set forth in 37 CFR 1.17(e) has been timely paid, the appeal has been withdrawn pursuant to 37 CFR 1.114 and prosecution in this application has been reopened pursuant to 37 CFR 1.114. Applicant’s submission filed on 21 October 2024 has been entered.
Response to Arguments
Applicant’s arguments, see Response to Final Office Action mailed 8 May 2024, filed 21 October 2024, with respect to Claim Rejections under 35 USC §102 and §103 have been fully considered and are persuasive.  The Claim Rejections under 35 USC §102 and §103 of Claims 26, 29, 33-35, and 38 has been withdrawn.
Allowable Subject Matter
Claims 26, 29, 33-35, and 38 are allowed.
The following is an examiner’s statement of reasons for allowance: While the prior art shows setting a high level flag to indicate RRC or not along with transform skip (see, Karczewicz et al. (US 2021/0112279 A1): ¶ [0069], [0083], and [0085]) as well as determining the rice parameter based on whether transform skip is used (see, Yoo et al. (US 2021/0385478 A1): ¶ [0171]), the requirement of transform skip and the high-level flag at a specific setting for determination of the Rice parameter along with all other limitations has not been found in the prior art.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee.  Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Conclusion

APPLICANT REBUTTAL: REMARKS Reconsideration and allowance are respectfully requested. Novelty Claims 26, 29, 35, and 38 stand rejected under 35 U.S.C. §102 as allegedly being anticipated by newly-cited Yoo (US 2021/0385478)1. This rejection is respectfully traversed. The independent claims 26, 29, 35, and 38 are amended to recite "indicates performing regular residual coding (RRC) for all coding units of a specific area of a current picture." Claim 26 requires among other features: decode, from a video bitstream, a high-level flag which, when set to a first value, indicates performing regular residual coding (RRC) for a specific area of a current picture; determine, from the video bitstream, for a transform block (84), whether an inverse transform corresponding to the transform block is an identity transform or not; when it is determined that [1] the inverse transform is the identity transform and [2] the high-level flag is set to a second value different from the first value, determine a first Rice parameter for a binarization of a residual transform coefficient of the transform block; when it is determined that the inverse transform is not the identity transform or the high-level flag is set to the first value, determine a second Rice parameter for the binarization of the residual transform coefficient of the transform block; and decode the residual transform coefficient of the transform block using the first or second Rice parameter. To reject claim 26, the FOA cites paragraphs [0116] and [0171] of Yoo quoted below with emphasis added. [0116] as shown in Table 8, residual coding may be divided according to a value of the syntax element transform_skipjflag of the transform skip flag. That is, a different syntax element may be used for residual coding based on the value of the transform skip flag (based on whether the transform is skipped). Residual coding 1 Yoo is a continuation of a PCT application that was filed after the priority date for the instant application. Unfortunately, the FOA did not provide a copy of the Yoo provisional application or identify where there is support in the Yoo provisional application for each of the cited paragraphs in Yoo in the FOA. If a rejection is maintained based on Yoo, the above are requested to be provided. used when the transform skip is not applied (that is, when the transform is applied) may be called regular residual coding (RRC), and residual coding used when the transform skip is not applied (that is, when the transform is not applied) may be called transform skip residual coding (TSRC). Table 9 above may show a syntax element of residual coding when a value of transform-skip_flag is 0, that is, when the transform is applied, and Table 20 above may show a syntax element of residual coding when the value of transformskip_flag is 1, that is, when the transform is not applied. [emphasis added] [0171] Alternatively, for example, the rice parameter cRiceParam may be determined based on whether a transform skip is applied to a current block. That is, if a transform is not applied to a current TB including a current CG [coefficient group of a transform block], in other words, if the transform skip is applied to the current TB including the current CG, the rice parameter cRiceParam may be derived to be 1. Alternatively, if the transform is applied to the current TB including the current CG, in other words, if the transform skip is not applied to the current TB including the current CG, the rice parameter cRiceParam for the abs_remainder[n] to be currently coded as described above may be derived to be the same value as cRiceParam for abs_remainder[n] previously coded. [emphasis added] These paragraphs do not disclose decoding the claimed "high-level flag." Thus, they also fail to disclose "when it is determined that the inverse transform is the identity transform and the high-level flag is set to a second value different from the first value, determin[ing] a first Rice parameter for a binarization of a residual transform coefficient of the transform block." The Rice parameter is not disclosed as also being based on a "high level flag" as required by claim 26. Paragraph [0171] states "the rice parameter cRiceParam may be determined based on whether a transform skip is applied to a current block." There is no disclosure that the determination of cRiceParam is also based on a determination of both: the inverse transform is the identity transform and the high-level flag is set to a second value different from the first value. According to claim 26, even if transform-skip is applied, which corresponds to the claimed "inverse transform is the identity transform," the claimed Rice parameter further depends on the high-level flag. For example, if transform skip is applied and the high-level flag is the second value, then the "first Rice parameter" is determined. If transform skip is applied and the high-level flag is the first value, then "the second Rice parameter" is determined. In both cases, transform skip is applied, but the flag is different (second value and first value) and so the Rice parameter is different (first Rice parameter and second Rice parameter). In contrast, the Rice parameter in Yoo only depends on transform skip. Thus, Yoo does not disclose all of the features recited in claim 26. Analogous distinguishing features are recited in claims 29, 35, and 38. The anticipation rejection based on Yoo should be withdrawn. Nonobviousness Claims 33 and 34 stand rejected under 35 U.S.C. §103 as allegedly being unpatentable over Yoo further in view of Ma. This rejection is respectfully traversed. Ma also does not disclose the subject matter of claim 26 and the other independent claims. For example, Ma does not disclose or suggest the claimed high-level flag. Claim 33 recites: wherein the memory has program code that, when executed by the microprocessor, causes the video encoder to: determine that content for the video bitstream is camera-captured content; and based on the determination that the content for the video bitstream is camera-captured content, set the high-level flag to the first value. For claim 33, the FOA refers to paragraph [0053] of Yoo and states: "The IBC [intra block copy] prediction mode or palette mode may be used for content image/video coding of a game or the like, for example, screen content coding." Even assuming that Ma discloses flags for IBC prediction mode and palette mode, such flags are not the claimed high-level flag because coding tools for prediction are typically decided at the coding unit level, which is not high-level signaling. The term "high-level" in video coding has a commonly accepted definition known to the person of ordinary skill in the art (POSA). See, for example, The High-Level Syntax of the Versatile Video Coding (VVC) Standard, IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 31, NO. 10, OCTOBER 2021, pp. 3779-3800, which explains "The structuring of the bitstream into NAL units and all of the syntax outside the slice data, including the headers that precede the slice data within the VCL NAL units and all of the syntax in the non-VCL NAL units, is considered the high-level syntax (HLS)." The left column of page 3780 (Emphasis added). The right column of page 3780 states: For VVC, the HLS specifically includes the NAL unit syntax (including the NAL unit header), decoding capability information (DCI), operating point information (OPI), video parameter set (VPS), sequence parameter set (SPS), picture parameter set (PPS), adaptation parameter set (APS), video usability information (VUI), supplemental enhancement information (SEI), access unit delimiter (AUD), picture header (PH), slice header (SH), end of sequence (EOS), end of bitstream (EOB), etc. CTU-level and lower-level coding tool syntax are not considered HLS. (Emphasis added). Furthermore, the proposed combination of Yoo and Ma fails to disclose or suggest that the Rice parameter is determined based on either the IBC prediction mode or the palette mode coding tools disclosed by Yoo and Ma. The FOA acknowledges that Yoo does not teach "based on the determination that the content for the video bitstream is camera-captured content, set the high-level flag to the first value" and cites section 1 of Ma. Section 1 of Ma describes low-level signaling of TSRC/RRC (coding unit level and transform unit level) for each coding unit whether RRC or TSRC is to be used. Section 1 does not disclose high-level signaling or flags which "enable" or "allow" the selection of TSRC or RRC. Section 2 mentions "Two high-level syntax, one PPS and one slice level, are signaled to indicate the selection of TSRC/RRC is enabled." What is meant is that a CU level flag is signaled if a flag in the PPS enables the signaling. Alternatively, Ma states "[a] TB level syntax is signaled if PPS is enabled." In both cases, the signaling of TSRC/RRC is a low-level flag (CU coding unit or TB transform block). However, the two high-level syntax in section 2 of Ma do not indicate "performing regular residual coding (RRC) for a specific area of a current picture" as recited in the independent claims. Similar arguments apply to claim 34. The obviousness rejection should be withdrawn. The application is in condition for allowance. An early notice to that effect is requested. By responding only to particular positions asserted in the office action, Applicant does not acquiesce in other positions that have not been explicitly addressed. Applicant's arguments for the patentability of a claim should not be understood as implying that no other reasons for the patentability of that claim exist. Nothing in this response should be construed as an intent to concede any issue regarding any claim, except as specifically stated in this response, and the amendment of any claim does not necessarily signify concession of unpatentability of the claim prior to its amendment. Nothing stated or unstated in this response should be interpreted as an explicit or implicit admission regarding the applicability of art applied or cited or that there is any compatibility between disparate references. The Commissioner is hereby authorized to charge any deficiency, or credit any overpayment, in the fee(s) filed, or asserted to be filed, or which should have been filed herewith (or with any paper hereafter filed in this application by this firm) to Deposit Account No. 14-1140. Respectfully submitted, NIXON & VANDERHYE P.C. By: /John R. Lastova/ John R. Lastova Reg. No. 33,149JRL: 901 North Glebe Road, 11th Floor Arlington, VA 22203-1808 Telephone: (703) 816-4000 Facsimile: (703) 816-4100


CITED REFERENCE SUMMARIES: Ref US20210112279A1: Claims:
A method of decoding video data, the method comprising: receiving, from a video bitstream, one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block of video data coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain; determining a type of coding scheme to apply to the residual values based on the one or more syntax elements; determining the residual values based on the determined type of coding scheme; and reconstructing the block based on the determined residual values and the prediction block.
receiving, from a video bitstream, one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block of video data coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain;
determining a type of coding scheme to apply to the residual values based on the one or more syntax elements;
determining the residual values based on the determined type of coding scheme; and
reconstructing the block based on the determined residual values and the prediction block.
The method of claim 1 , wherein the first type of coding scheme is a transform coefficient coding (TRCC) scheme, and the second type of coding scheme is a transform skip residual coding (TSRC) scheme.
The method of claim 2 , wherein, in the TRCC scheme, information indicative of a position of a last significant value is parsed, and wherein, in the TSRC scheme, information indicative of the position of the last significant value is not parsed.
The method of claim 2 , wherein, in the TRCC scheme, a number of flags indicating whether a residual value of the residual values is greater than a threshold value is different than a number of flags indicating whether the residual value of the residual values is greater than the threshold value in the TSRC scheme.
The method of claim 1 , wherein determining the residual values comprises determining the residual values without applying an inverse transform to the residual values.
The method of claim 1 , wherein receiving the one or more syntax elements comprises receiving a flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied to the residual values of the block coded with transform skip.
The method of claim 1 , further comprising: receiving a first flag indicating whether transform skip is enabled, wherein receiving the one or more syntax elements comprises parsing a second flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied based on the first flag indicating that transform skip is enabled.
receiving a first flag indicating whether transform skip is enabled,
wherein receiving the one or more syntax elements comprises parsing a second flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied based on the first flag indicating that transform skip is enabled.
The method of claim 1 , wherein receiving the one or more syntax elements comprises receiving the one or more syntax elements based on a quantization parameter (QP) being less than or equal to a threshold value.
A method of encoding video data, the method comprising: determining residual values based on a difference between a block of video data that is to be coded with transform skip and a prediction block, wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain; determining a type of coding scheme between a first type of coding scheme and a second type of coding scheme to apply to the residual values; encoding the residual values based on the determined type of coding scheme; and signaling, into a video bitstream, one or more syntax elements of the video data indicative of whether the first type of coding scheme or the second type of coding scheme is applied to the residual values.
determining residual values based on a difference between a block of video data that is to be coded with transform skip and a prediction block, wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain;
determining a type of coding scheme between a first type of coding scheme and a second type of coding scheme to apply to the residual values;
encoding the residual values based on the determined type of coding scheme; and
signaling, into a video bitstream, one or more syntax elements of the video data indicative of whether the first type of coding scheme or the second type of coding scheme is applied to the residual values.
The method of claim 9 , wherein the first type of coding scheme is a transform coefficient coding (TRCC) scheme, and the second type of coding scheme is a transform skip residual coding (TSRC) scheme.
The method of claim 9 , wherein signaling the one or more syntax elements comprises signaling a flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied to the residual values.
The method of claim 9 , wherein signaling the one or more syntax elements comprises signaling the one or more syntax elements based on a quantization parameter (QP) being less than or equal to a threshold value.
A device for decoding video data, the device comprising: memory configured to store video data; and processing circuitry coupled to the memory and configured to: receive, from a video bitstream, one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block of video data coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain; determine a type of coding scheme to apply to the residual values based on the one or more syntax elements; determine the residual values based on the determined type of coding scheme; and reconstruct the block based on the determined residual values and the prediction block.
memory configured to store video data; and
processing circuitry coupled to the memory and configured to: receive, from a video bitstream, one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block of video data coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain; determine a type of coding scheme to apply to the residual values based on the one or more syntax elements; determine the residual values based on the determined type of coding scheme; and reconstruct the block based on the determined residual values and the prediction block.
receive, from a video bitstream, one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block of video data coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain;
determine a type of coding scheme to apply to the residual values based on the one or more syntax elements;
determine the residual values based on the determined type of coding scheme; and
reconstruct the block based on the determined residual values and the prediction block.
The device of claim 13 , wherein the first type of coding scheme is a transform coefficient coding (TRCC) scheme, and the second type of coding scheme is a transform skip residual coding (TSRC) scheme.
The device of claim 14 , wherein, in the TRCC scheme, information indicative of a position of a last significant value is parsed, and wherein, in the TSRC scheme, information indicative of the position of the last significant value is not parsed.
The device of claim 14 , wherein, in the TRCC scheme, a number of flags indicating whether a residual value of the residual values is greater than a threshold value is different than a number of flags indicating whether the residual value of the residual values is greater than the threshold value in the TSRC scheme.
The device of claim 13 , wherein to determine the residual values, the processing circuitry is configured to determine the residual values without applying an inverse transform to the residual values.
The device of claim 13 , wherein to receive the one or more syntax elements, the processing circuitry is configured to receive a flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied to the residual values of the block coded with transform skip.
The device of claim 13 , wherein the processing circuitry is configured to: receive a first flag indicating whether transform skip is enabled, wherein to receive the one or more syntax elements, the processing circuitry is configured to parse a second flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied based on the first flag indicating that transform skip is enabled.
receive a first flag indicating whether transform skip is enabled,
wherein to receive the one or more syntax elements, the processing circuitry is configured to parse a second flag in a slice header indicating whether the first type of coding scheme or the second type of coding scheme is applied based on the first flag indicating that transform skip is enabled.
The device of claim 13 , wherein to receive the one or more syntax elements, the processing circuitry is configured to receive the one or more syntax elements based on a quantization parameter (QP) being less than or equal to a threshold value.
The device of claim 13 , further comprising a display configured to display a picture that includes the reconstructed block.
The device of claim 13 , wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, a set-top box, or a wireless communication device.
A computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to: receive, from a video bitstream, one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block of video data coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain; determine a type of coding scheme to apply to the residual values based on the one or more syntax elements; determine the residual values based on the determined type of coding scheme; and reconstruct the block based on the determined residual values and the prediction block.
A device for decoding video data, the device comprising: means for receiving one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain; means for determining a type of coding scheme to apply to the residual values based on the one or more syntax elements; means for determining the residual values based on the determined type of coding scheme; and means for reconstructing the block based on the determined residual values and the prediction block.
means for receiving one or more syntax elements of the video data indicative of whether a first type of coding scheme or a second type of coding scheme is applied to residual values of a block coded with transform skip, wherein the residual values are indicative of a difference between the block and a prediction block, and wherein, in transform skip, the residual values are not transformed from a sample domain to a frequency domain;
means for determining a type of coding scheme to apply to the residual values based on the one or more syntax elements;
means for determining the residual values based on the determined type of coding scheme; and
means for reconstructing the block based on the determined residual values and the prediction block.
Ref US20210385478A1: Claims:
An image decoding method performed by a decoding apparatus, comprising: receiving residual information for a current block; deriving a context model for a sign flag of a current residual coefficient in a current sub-block of the current block; decoding the sign flag based on the context model; deriving the current residual coefficient based on the sign flag; deriving a residual sample based on the current residual coefficient; and generating a reconstructed picture based on the residual sample, wherein the context model for the sign flag is derived based on a sign flag of a residual coefficient decoded prior to the current residual coefficient in the current sub-block.
receiving residual information for a current block;
deriving a context model for a sign flag of a current residual coefficient in a current sub-block of the current block;
decoding the sign flag based on the context model;
deriving the current residual coefficient based on the sign flag;
deriving a residual sample based on the current residual coefficient; and
generating a reconstructed picture based on the residual sample,
wherein the context model for the sign flag is derived based on a sign flag of a residual coefficient decoded prior to the current residual coefficient in the current sub-block.
The image decoding method of claim 1 , wherein, when a value of the sign flag of the residual coefficient decoded prior to the current residual coefficient is 0, the context model for the sign flag of the current residual coefficient is derived as a context model 0, and wherein, when the value of the sign flag of the residual coefficient decoded prior to the current residual coefficient is 1, the context model for the sign flag of the current residual coefficient is derived as a context model 1.
wherein, when a value of the sign flag of the residual coefficient decoded prior to the current residual coefficient is 0, the context model for the sign flag of the current residual coefficient is derived as a context model 0, and
wherein, when the value of the sign flag of the residual coefficient decoded prior to the current residual coefficient is 1, the context model for the sign flag of the current residual coefficient is derived as a context model 1.
The image decoding method of claim 1 , further comprising determining whether the sign flag is decoded based on the context model, by comparing a specific value and the number of non-zero residual coefficients in the current sub-block.
The image decoding method of claim 3 , wherein the sign flag is bypass-decoded when the number of non-zero residual coefficients is less than the specific value, and wherein the sign flag is decoded based on the context model when the number of non-zero residual coefficients is greater than or equal to the specific value.
wherein the sign flag is bypass-decoded when the number of non-zero residual coefficients is less than the specific value, and
wherein the sign flag is decoded based on the context model when the number of non-zero residual coefficients is greater than or equal to the specific value.
The image decoding method of claim 3 , wherein the specific value is derived based on a size of the current block.
The image decoding method of claim 5 , wherein the specific value is derived as 5 when the size of the current block is an 8Ã8 size, and wherein the specific value is derived as 4 when the size of the current block is a 4Ã4 size.
wherein the specific value is derived as 5 when the size of the current block is an 8Ã8 size, and
wherein the specific value is derived as 4 when the size of the current block is a 4Ã4 size.
The image decoding method of claim 3 , wherein the specific value is derived based on a size of the current block and a position of the current sub-block in the current block.
The image decoding method of claim 7 , wherein the specific value is derived as 5 when the size of the current block is an 8Ã8 size and the current sub-block is a bottom-right sub-block of the current block, and wherein the specific value is derived as 4 when the size of the current block is the 8Ã8 size and the current sub-block is a top-left block of the current block.
wherein the specific value is derived as 5 when the size of the current block is an 8Ã8 size and the current sub-block is a bottom-right sub-block of the current block, and
wherein the specific value is derived as 4 when the size of the current block is the 8Ã8 size and the current sub-block is a top-left block of the current block.
The image decoding method of claim 3 , wherein the specific value is derived based on a size of the current block, a position of the sub-block in the current block, and a prediction mode of the current block.
The image decoding method of claim 9 , wherein the specific value is derived as 5 when the size of the current block is the 8Ã8 size, the current sub-block is a bottom-right sub-block of the current block, and the prediction mode of the current block is an intra prediction mode, and wherein the specific value is derived as 0 when the size of the current block is the 8Ã8 size, the current sub-block is a top-left sub-block of the current block, and the prediction mode of the current block is the intra prediction mode.
wherein the specific value is derived as 5 when the size of the current block is the 8Ã8 size, the current sub-block is a bottom-right sub-block of the current block, and the prediction mode of the current block is an intra prediction mode, and
wherein the specific value is derived as 0 when the size of the current block is the 8Ã8 size, the current sub-block is a top-left sub-block of the current block, and the prediction mode of the current block is the intra prediction mode.
The image decoding method of claim 1 , wherein the context model for the sign flag is derived as one of a plurality of context models based on sign flags of a plurality of residual coefficients decoded prior to the current residual coefficient in the current sub-block.
An image encoding method performed by an encoding apparatus, comprising: deriving a current residual coefficient in a current sub-block of a current block; deriving a context model for a sign flag of the current residual coefficient; encoding the sign flag based on the context model; and generating a bitstream including the sign flag, wherein the context model for the sign flag is derived based on a sign flag of a residual coefficient encoded prior to the current residual coefficient in the current sub-block.
deriving a current residual coefficient in a current sub-block of a current block;
deriving
[Truncated to input limit]