International organisation for standardisation organisation internationale de normalisation

Non-normative: Encoder optimization, decoder speed improvement and cleanup, post filtering, loss concealment, rate control (1)

14.1.97.1.1.1.1.1.350JCTVC-P0059 Unifying HM and RExt Inter-Prediction Search [K. Sharman, N. Saunders, J. Gamei (Sony)]

See BoG report P0288 and related notes.

Further study was suggested to reduce losses in SCC cases.

7. Plenary Discussions and BoG Reports

   1. Project development

The VCEG and MPEG parent bodies held joint meetings with JCT-VC at 1600–1800 Monday, 1630–1800 Wednesday, and 1400–1500 Thursday.

Topics discussed in the joint discussion particularly included the following:

• 
  Liaison letter from SG 16 to WG 11 (WG 11 input document m31807)
  
  • 
    4:4:4 8b and 4:4:4 generally
    
  • 
    Screen content coding CfP
    
  • 
    FPA versioning
    
  • 
    extended gamut / high dynamic range
    
  • 
    interlaced source content
    
  • 
    medical applications
    
  • 
    general
    
• 
  RExt profiles
  
• 
  SEI / VUI / uses of auxiliary pictures development methodology
  
• 
  SHVC with non-HEVC base layer (so-called "hybrid" scalability)
  
• 
  SHVC with an interlaced-scan base layer
  
• 
  SHVC colour gamut and bit depth scalability
  
• 
  Field/frame issues in regard to scalability (for either AVC or HEVC base layers)
  
• 
  Frame packing SEI messages – with a versioning scheme agreed to be a reasonable approach (see additional information regarding SEI message development below)
  
• 
  New Call for Proposals on Screen Content Coding – issued jointly; technical work to be done in JCT-VC.
  
• 
  HEVC version 1 errata
  
  • 
    CPB removal delay
    
  • 
    Electro-optical transfer characteristics – esp. for BT.2020 (for which liaison input verified that there was a problem in the way this was specified)
    
  • 
    MinCR for high tier of Main and Main 10 profiles
    
  • 
    Desire for high visibility and rapid processing of corrections
    
  • 
    Plan to merge errata into Amd.1
    
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  3D-HEVC status (outside the scope of JCT-VC, moved forward for standardization)
  
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  Interlaced single-layer coding (esp. in re technical changes specifically for that) – study work ongoing in WG 11 parent body with preparation of draft Requirements and possible Call for Proposals
  
• 
  Extended colour-gamut / high dynamic range video coding – study work is ongoing in parent bodies
  
• 
  Colour-related SEI (for which there was no objection to JCT-VC proceeding with consideration of proposals such as those discussed in section 6.5.3)
  
• 
  Overlay auxiliary pictures (type code, carriage)
  
  • 
    Discussion 01-16: Rule for Aux pic type code: Five unaffiliated proponents and interop needed and achieved
    
• 
  Whether functionality of decoding 4:4:4 content with v1 decoders is relevant
  
  • 
    Discussion 01-16: Not currently of interest
    
• 
  Depth view packing SEI message
  
  • 
    Deferred to the next meeting
    
• 
  MFC with depth (similar approach to MVC+D, only texture uses MFC, proposal JCT3V-G0115)
  
  • 
    Deferred to further study
    
• 
  It was noted that there is a problem with the coding efficiency of the lossless coding of 16 b 4:4:4 in the design as of 2013-11.
  

In regard to issuing a Call for Proposals for Screen Content Coding, it was agreed that the parent bodies would issue this call jointly (as VCEG-AW90 and WG 11 N 14175, drafted based on joint meeting and joint BoG discussions during the meeting). An agreed timeline was established such that the deadline for submission of documents, bitstreams and executables would be 17 March. The parent bodies planned to charter the JCT-VC to begin the subsequent technical development work at the March/April meeting, upon review of the submitted proposals.

It was agreed to plan (and to call attention to the plan) to rapidly integrate the RExt, SHVC, and MV-HEVC extensions into a new edition of the complete HEVC standard upon completion of the development of these three texts rather than proceeding with publication of these texts as separate amendments.

In regard to defect corrections for HEVC, it was agreed to call attention to the potential need to reduce the MinCR (minimum compression ratio) value in the High tier to 4 for levels 5.0 and higher to address problems encountered during implementation (see notes on JCTVC-P0044). It is important to determine whether the existing constraint can be modified or it may be necessary to define a new higher tier than the current High tier.

In consultation with the parent bodies, it was agreed to establish the following approach for consistency and coordination of the development of supplemental enhancement information (SEI) messsages and similar syntax features not affecting the normative decoding process:

1. 
   New messages may be added by consensus agreement;
   
2. 
   Proposed codepoint values within such messages are to be accepted subject to rules defined when a new codepoint type is defined;
   
3. 
   Such rules will include editorial quality and shall apply to the first specified codepoint values as well as to any later-proposed ones;
   
4. 
   An established such rule may later be agreed to be relaxed but not to be made more restrictive;
   
5. 
   Extensions of capability are to be established by creating new messages rather than modifying previously standardized messages.
   

In regard to hybrid codec scalability, it was planned to establish some profile for this, but the design was considered insufficiently mature for current specification. Further work in an AHG was planned to work out details. Regarding encapsulation – further study was planned and no action was taken. A candidate approach is the three-spec approach, which is essentially equivalent to establishing a system-level approach – e.g., the third spec would be a system mux spec that could specify the combination of the base layer with the enhancement layer in a manner that could be equivalent to forming an encapsulated bitstream if desirable. In regard to HEVC, the base layer would not be specified (for now) – just that a system supplies base layer picture arrays to reference by an enhancement-layer specification. An enhancement-only specification would be prohibited from having an ordinary HEVC base layer inside the same bitstream – formatted as an HEVC base layer (using base layer NUTs).

In regard to SHVC using an interlaced base layer (e.g. with sequence-level adaptation as in HEVC v1) – it seemed that no special awareness may be needed within the decoding process, and it was agreed to work on having high-level signalling to be incorporated in a manner that would be capable of indicating phase position alignments suitable for field-to-frame enhancement – but not specifically only useful for this purpose.

Regarding 4:4:4 profiles of RExt, the view of SG16 was expressed in m31807 and currently remains that the range extensions should specify a 4:4:4 8 bit profile. SG16 is operating under the presumption that the 4:4:4 profiles generally should be designed to perform as well as is feasible on the full variety of content expected to be encountered in 4:4:4 applications, which specifically includes "screen" and "mixed-source" content – provided that the complexity of supporting this capability is reasonable. SG 16 had not identified any elements of the current draft design as needing to be disabled in this profile on that basis. After joint discussion, the following plans were established:

• 
  Decision: Regarding 8 b 4:4:4 profile, the output draft output will say this is TBD, and not include such a profile definition.
  
• 
  Decision: Add 16 b 4:4:4 all-intra profile with 3 tiers
  
• 
  Wait until March/April to decide on what is in 4:4:4 profiles. The contention is primarily regarding intra block copy.
  
• 
  Decision: The output draft will identify all (6) identified features (transform skip rotation, transform skip context, intra block copy, implicit and explicit RDPCM, intra smoothing disabling, and large block-size transform skip) as TBD in the new profile, and whatever it said before for other 4:4:4 profiles
  

A summary of voting results on the SHVC ballot on ISO/IEC 23008-2:201X/PDAM 3 was received by WG 11 in its input document m32217 from the SC 29 secretariat. Japan requested that known issue(s) such as the Defect Report on 23008-2:201X should be fixed. The U.S. provided 23 comments. Comment responses were issued in WG 11 output document N 14229 consistent with outcomes recorded herein.

Decision: Regarding colour gamut / bit depth scalability – it was agreed for there to be such a profile specified in the output draft, with a maximum of 10 bit support with the bit depth of the enhancement layer required to be greater than or equal to the bit depth of the base layer when the enhancement layer is dependent on the base layer.

2. BoGs

14.1.97.1.1.1.1.1.351JCTVC-P0288 BoG report on Range Extensions [C. Rosewarne, K. Sharman]

See section 6.1.1.

14.1.97.1.1.1.1.1.352JCTVC-P0298 BoG report on Palette mode [C. Rosewarne]

See section 6.1.6.

14.1.97.1.1.1.1.1.353JCTVC-P0292 BoG Report on Colour Gamut Scalability (CGS) [A. Duenas]

See section 6.2.2.