Opened 5 years ago
Closed 5 years ago
#452 closed defect (fixed)
Mismatch on subclause 8.4.3 (Derivation process for chroma intra prediction mode)
Reported by: | hmjang | Owned by: | |
---|---|---|---|
Priority: | minor | Milestone: | |
Component: | spec | Version: | VVC D6 vE |
Keywords: | Cc: | ksuehring, bbross, XiangLi, fbossen, jvet@… |
Description
There is a mismatch on 8.4.3.
In order to align the Spec. to SW, the specification should be changed from
In this process, the chroma intra prediction mode IntraPredModeC[ xCb ][ yCb ] is derived. The corresponding luma intra prediction mode lumaIntraPredMode is derived as follows: – If intra_mip_flag[ xCb ][ yCb ] is equal to 1, lumaIntraPredMode is set equal to INTRA_PLANAR. – Otherwise, if CuPredMode[ 0 ][ xCb ][ yCb ] is equal to MODE_IBC or MODE_PLT, lumaIntraPredMode is set equal to INTRA_DC. – Otherwise, lumaIntraPredMode is set equal to IntraPredModeY[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ]. The chroma intra prediction mode IntraPredModeC[ xCb ][ yCb ] is derived using cclm_mode_mode_flag, cclm_mode_idx, intra_chroma_pred_mode and lumaIntraPredMode as specified in Table 8 2.
to
The corresponding luma intra prediction mode lumaIntraPredMode is derived as follows: – If intra_mip_flag[ xCb + cbWidth / 2 xCb ][ yCb + cbHeight / 2 yCb ] is equal to 1, lumaIntraPredMode is set equal to INTRA_PLANAR. – Otherwise, if CuPredMode[ 0 ][ xCb + cbWidth / 2 xCb ][ yCb + cbHeight / 2 yCb ] is equal to MODE_IBC or MODE_PLT, lumaIntraPredMode is set equal to INTRA_DC. – Otherwise, lumaIntraPredMode is set equal to IntraPredModeY[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ]. The chroma intra prediction mode IntraPredModeC[ xCb ][ yCb ] is derived using cclm_mode_mode_flag, cclm_mode_idx, intra_chroma_pred_mode and lumaIntraPredMode as specified in Table 8 2.
Additionally, one editorial suggestion could be considered.
In 8.4.2 process, intra_mip_flag[ xCb ][ yCb ] is refered. it could lead misinterpretation about its behavior. for example, DUAL_TREE_CHROMA case, intra_mip_flag is not signaled. it mean intra_mip_flag[ xCb ][ yCb ] is 0 for chroma component.
I suggest that the clear description. It could be changed that "intra_mip_flag[ xCb ][ yCb ] of the corresponding luma coding block" instead of "intra_mip_flag[ xCb ][ yCb ]".
Change history (1)
comment:1 Changed 5 years ago by bbross
- Resolution set to fixed
- Status changed from new to closed
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Good catch! Thanks!
Fixed it in a document we are preparing to be submitted as an editorial input
to the 16th JVET meeting.