JVET-AN0067 AHG9: Comments on Neural-network Post-filter in VSEI V4 and V3 [S. Deshpande (Sharp)]

JVET-AN0067 also relates to the NNPF SEI messages

Following asserted bug-fix is proposed related to neural-network post-filter in VSEI V4 and V3:

• Proposal 1: It is asserted that for certain value of y that can occur, the function InpSampleVal( y, x, picHeight, picWidth, croppedPic, cIdx ) does not specify what the sampleVal should be when nnpfc_padding_type is equal to 3. An else clause is proposed to be added to provide a valid value for sampleVal under those conditions.

Additionally following bug-fix and typo-fix are proposed related to neural-network post-filter in VSEI V4:

• Item 1: When TemporalExtrapolationFlag is equal to 1, equation 79 for computation of numPicsInOutputTensor should use the signalled syntax element nnpfc_extrapolated_pics_minus1.
• Item 2: The missing descriptor of u(1) is specified for the syntax element nnpfa_no_foll_clvs_flag in neural-network post-filter activation SEI message
• Item 3: In Figure 12, on the right side the value “16” should be changed to the value “15” to correspond to the value on the left side. (Also applies to VSEI V3)

For proposal 1, it was suggested to use wrapping instead of clipping for the x component.

Adopt proposal 1 modified to use wrapping for the x component. A -v2 version of the document to be uploaded with this modification.

Delegate all editorial improvements to the editors.

JVET-AN0067 AHG9: Comments on Neural-network Post-filter in VSEI V4 and V3