Joint Collaborative Team on Video Coding (jct-vc)

3.4Profile and level definitions and other requirements related topics

Joint discussions

Contributions in this area were initially discussed in a joint meeting with MPEG Requirements and VCEG at 4 p.m. Tue. 30th (GJS & J. Ostermann). At that time it was suggested for JCT-VC to identify a somewhat-reduced set of profiles relative to those proposed in JCTVC-N0191 for specification action at the current meeting, and for the remainder to be considered in further study.

The subject was then further discussed in JCT-VC on Wed. 31st (GJS).

Tentative conclusions for the output draft of this meeting were identified as follows:

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  Separate colour plane coding should be prohibited.
  
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  Aux pics (if specified) should not be profiled (at the moment).
  
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  Define the following new profiles:
  
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    4:4:4/10, 12
    
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    4:2:2/10, 12
    
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    4:2:0/12 (note that 8 and 10 bit profiles have already been specified)
    
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  Use one profile_idc for the syntax family, and use constraint flags for subset profiles within that.
  

It was remarked that intra-only is also very desirable to consider.

The subject was further discussed again in a joint discussion Thu. 1st at noon (GJS & J. Ostermann).

Additional aspects were agreed as follows:

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  The 4:2:2 and 4:4:4 cases should have 1.25 and 1.5 times the bit rate capability and half the minimum compression ratio MinCr requirement
  
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  The maximum CPB size should not be increased for the 4:2:2 and 4:4:4 cases – so, in these cases, the maximum CPB size will be less than a 1 second buffer at the max bit rate.
  
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  Separate colour plane mode should be prohibited.
  

The values will be studied and may be refined in the final version.

The naming of the profiles was left to the discretion of the editors.

Decision: Agreed as described above.

Other topics of joint discussion included the following:

• 
  JCTVC-N0050 (see section 6.5.1) also has aspects related to profile/level (for use of an AVC base layer in an SHVC video context). This was also the topic of a contribution to VCEG as VCEG-AV13. There remains an interest in enabling hybrid codec scalability, although some specifics need to be sorted out.
  
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  There is keen interest in further work on screen content coding (SCC) as a focus of development (versus designing a "generic" video coding standard intended to handle a broad range of applications). The WG 11 parent body developing a plan to issue a Call for Proposals for new work on the subject. Members of both parent bodies expressed an interest in this work, and potentially in conducting it jointly.
  
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  Work has been progressing in the WG 11 parent body regarding the potential benefit for modification of HEVC for improving the coding efficiency of coding interlaced video, and the study will be continued.
  
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  The potential use of the "tiled" frame packing arrangement with HEVC for stereoscopic video coding has been under discussion at the parent body level, and a suggestion under consideration in WG 11 was to specify such an indication in a separate SEI message rather than adding it to the existing frame packing arrangement SEI message.
  
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  A contribution VCEG-AV14 had been submitted to VCEG and been discussed, regarding still picture coding with HEVC. The response was as follows:
  
  • 
    Decision: It was agreed to move forward toward specification of a "level 8.5" with unlimited picture size, for which decoding is optional but normatively specified if decoded.
    
  • 
    Other aspects, including tiling constraints, are for further study.
    
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  "Best effort" decoding with degraded quality remains under investigation for potential action. See contribution N0291 and related notes.
  
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  3D and ultra-multiview video coding has been investigated in some recent work.
  
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  Input was received by the parent bodies regarding using a different sort of color representation for coded video content than has typically been used in past practice. This has sometimes been referred to as the coding of XYZ video content. A relevant contribution to VCEG was VCEG-AV11.
  
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  3GPP is evaluating the possibility of using HEVC and may request the specification of another tier/level of HEVC. Contribution N0237 was related to this and VCEG document VCEG-AV12.
  

JCTVC-N0178 HEVC profiles for medical imaging applications [P. Amon, A. Hutter, U.-E. Martin, N. Wirsz (Siemens)]

This document proposes HEVC profiles for medical imaging applications in the context of the Range Extensions currently standardized in the JCT-VC. The main requirements addressed by these proposed profiles are high bit-depth compression, lossless compression and signed coding. This results in the four proposed profiles High 12 Intra 4:0:0, High 12 4:0:0, High 16 Intra 4:0:0, and High 16 4:0:0.

JCTVC-N0191 AHG 5 and 18: Profiles for Range Extensions [K. Sharman, N. Saunders, J. Gamei, T. Suzuki, A. Tabatabai (Sony)]

A set of profiles are presented that propose to address the uses envisioned for HEVC Range Extensions. These proposed profiles are further refined, with the view to simplify encoder implementation and increase interoperability. This contribution proposes the following.

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  For JCT-VC (with its parent bodies) to specify all conformance points required by industry to avoid de-facto profiles defined outside this standardization body.
  
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  Two categories of profiles proposed to be defined:
  
  • 
    Main xxx profiles: No new RExt tools are included (intended for consumer applications)
    
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    High xxx profiles: Include new RExt tools and higher input bit-depths
    
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  Consideration of tools for non-camera captured content
  
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  Specification of a 4:2:0 12 bit profile
  

JCTVC-N0312 A proposal on HEVC 4:2:2 profile [S. Sekiguchi, A. Minezawa, H. Sakate (Mitsubishi)] [late]

This contribution proposes an HEVC profile supporting 4:2:2 chroma format. The proposed profile is an extension to the Main 10 profile.

JCTVC-N0237 HEVC version 1: Level 2.2 for support of WVGA@30fps [Y.-K. Wang (Qualcomm)]

(Reviewed at parent level Tue. 30th)

No immediate action was taken on this – parent bodies will liaise with 3GPP and determine appropriate action in future study.