Joint Video Experts Team (jvet) of itu-t sg 6 wp and iso/iec jtc 1/sc 29/wg 11

12.6List of actions taken affecting Draft 2 of VVC, VTM 2, BTM and 360Lib

The following is a summary, in the form of a brief list, of the actions taken at the meeting that affect the text of the VVC draft text, VTM or 360Lib description. Both technical and editorial issues are included. This list is provided only as a summary – details of specific actions are noted elsewhere in this report and the list provided here may not be complete and correct. The listing of a document number only indicates that the document is related, not that it was adopted in whole or in part.

12.6.1Encoder only or CTC/software changes

Implement VTM/BMS SW software as for the original HEVC deblocking, with filtering on an 8x8 grid as the minimum filtered boundary grid size.

(Nno spec text on deblocking.).

JVET-K0185: Fast encoder for affine from 4.1.5c in combination with normative adoption 4.1.3c

JVET-K0367: Affine encoder optimization by SIMD

JVET-K0154: enable FULL_NBIT macro by default

JVET-K0157: “long-term reference + no-output picture”

JVET-K0206: Perceptual quantizer

Increase chroma QP by 1 when trees are separate

JVET-K0238: Encoder side grouping of CTUs for SAO parameter derivation

JVET-K0352/JVET-K0198: Encoder optimization for merge

JVET-K0390: Rate control

JVET-K0220: Segmentation optimization with speedups

Some more from JVET-K0562, e.g. metric calculation, tool usage statistics and visualization, cleanups, …

As a general rule, sophisticated speedups such as dedicated SIMD optimization need final approval, to be made at the discretion of software coordinators

12.6.2Syntax/semantics/decoding process changes VTM/WD

General: QT/BT/TT as per VTM 1 is no longer considered a “placeholder”.

JVET-K0351 (test c): Partitioning: Keep only the TT restriction (preventing binary split with same orientation in center partition of the ternary split) in VTM at both encoder and decoder

JVET-K0554: Partitioning: Implicit splitting at picture boundaries

JVET-K0307/JVET-K0237/JVET-K0369/JVET-K0232/JVET-K0315: Deblocking bugfix: Perform deblocking at boundaries of TUs with any size >=64

Implement VTM/BMS SW as the original HEVC deblocking, filtering on an 8x8 grid as minimum size (no spec text on deblocking).

JVET-K0371/JVET-K0564: ALF (based on subtest 2.4.1.4c, 4x4 classification based on Laplacian for luma only, 7x7 luma, 5x5 chroma filters); disable prediction of adaptive filters from fixed filter set; disable temporal prediction; put filter parameters into slice header; Enabling flag at CTU level.

JVET-K0063: PDPC

JVET-K0190: 4.1.8 CCLM only

JVET-K0052: Affine merge bug fix

JVET-K0184: Affine MC (CE4.1.1a 4x4 fixed subblock size).

JVET-K0337: Affine MC coding and models (4.1.3a, affine MVP list construction, and 4.1.3b, MV difference coding, and 4.1.3c, 4/6 parameter model, no slice level switch).

JVET-K0565: Specification text of affine MC package

JVET-K0367/JVET-K0052/JVET-K0103: Restriction of affine merge mode to CU sizes >= 8x8

JVET-K0357: AMVR (4.3.3a) from BMS to VTM

Transform: Adopt AMT (both intra and inter, each controlled by an SPS flag) as follows (providing approximately AI 3.3%, RA 2.0%, LB 1.3%):

• 
  No 64-length DST7 and DCT8 (no AMT syntax sent when either dimension is larger then 32)
  
• 
  No 128-length DCT2
  
• 
  Only DCT2, DST7 and DCT8
  
• 
  All transforms are to have 10 bit coefficients
  
• 
  Uses the syntax that has been in the BMS. AMT is applied only for luma. There are separate enabling flags for intra and inter at SPS level. When AMT is enabled, then
  
  • 
    If CBF=1, then
    
    • 
      A flag for DCT2 in both directions; if not then
      
      • 
        If (intra and the number of nonzero coefficients is greater than two) or inter (regardless of the number of nonzero coefficients)
        
        • 
          Flag for horizontal is DST7 vs. DCT8
          
        • 
          Flag for vertical is DST7 vs. DCT8
          
      • 
        Otherwise (intra block with only 1 or 2 nonzero coefficients), DST7 is used both horizontally and vertically
        
• 
  Rather than AMT, the suggested name is multiple transform selection (MTS)
  
• 
  JVET-K0346: 8x8 motion vector storage for (A)TMVP [Note: High precision 1/16 pel according to plenary decision]
  

JVET-K0251: Increase max QP from 51 to 63.

JVET-K0230/K0556: Separate trees for intra slices (without multiple intra chroma direct modes) with an implicit split to 64x64; prohibit ternary split (for both intra and inter) of anything bigger than 64 in width or height (and not send the bit to indicate ternary type at that level). There should be a high-level (e.g., SPS) flag to enable or disable the use of separate trees.

JVET-K0122: DC prediction bug fix (use only the longer side to compute the average for non-square blocks)

JVET-K0368 with modifications tested in JVET-K0529: TU binarization, intra modes from BMS, 3 MPM, extended by JVET-K0500: Wide angles in the expansion of the number of angles (85 angles, 87 intra prediction modes total)

ATMVP from BMS to VTM, with modifications from JVET-K0346:

• 
  One fixed collocated picture is used to derive temporal motion information.
  
• 
  Slice level adaptive sub-block switching, 8x8 or 4x4.
  
• 
  Constrain the region from where ATMVP motion is derived to the collocated CTU plus one 4x4 block column outside the collocated CTU at the right hand side, the same region for HEVC TMVP.
  
• 
  JVET-K0566: Specification text of ATMVP/AMVP
  

JVET-K0071: Dependent quantization/

JVET-K0072: Modified entropy coding supporting and dependent quantization

JVET-K0310: Sign data hiding (for use when dependent quantization is disabled)

JVET-K0325: Simple high-level syntax

12.6.3BMS

All modifications from VTM

JVET-K0248: Generalized B prediction to BMS

JVET-K0076: 8.2.2 Current picture referencing

JVET-K0217 (variant 9.2.9l) bi-directional template matching, along with the method from JVET-K0199 (9.1.1.a) that refined vectors are not used to predict MVs from neighbour blocks, and not for deblocking

JVET-K0485: BIO (speeded-up variant)

12.6.4Changes in 360Lib

JVET-K0131: Modified cubemap projection

This does not have normative status – to be used as reference in CE13 as a best-known solution that would not affect the decoding loop.