Joint Collaborative Team on Video Coding (jct-vc) of itu-t sg16 wp3 and iso/iec jtc1/SC29/WG11

6.7Non-normative: Encoder optimization, decoder speed improvement, post filtering, loss concealment, rate control

6.7.1Rate control

6.7.2Encoder optimization

JCTVC-N0372 HM Software modifications for interlaced coding [Zineb Agyo, Jerome Vieron, Jean Marc Thiesse] [late]

6.7.3Software development

JCTVC-N0043 On software complexity: real time and parallel SHVC video decoder [W. Hamidouche, M. Raulet, O. Déforges (??)]

6.8Withdrawn and unclear allocation

JCTVC-N0068 Withdrawn
JCTVC-N0166 Withdrawn
JCTVC-N0324 – re-registered as N0378.
JCTVC-N0345 Withdrawn

7Plenary Discussions and BoG Reports

7.1Project development

7.2BoGs

JCTVC-N0373 / JCT3V-E0306 BoG report on random access and cross-layer alignment of pictures types [J. Boyce]

Joint BoG.

(Reviewed Sun 28th Track A (GJS).)

BoG concerned N0244, N0065, N0084, N0121, N0066, N0090, N0147, and N0195 item 4.

• 
  IDRs will not be required to be aligned; to work out how to handle POC alignment between layers
  
  • 
    Current spec requires POC value alignment
    
  • 
    Alternative approach is layer-specific POC with alignment of POC differences
    
• 
  Specification of a layer-wise startup of the decoding process is needed
  
• 
  For TSA/STSA, if EL picture is a TSA/STSA, the corresponding base layer should also be a TSA/STSA
  
• 
  It was asked whether IDR/BLA in base layer but not in EL, the IDR in the BL causes marking of the EL pics as unused for reference (in other layers)? No, but need to figure out how/whether this is expressed in the text. (This is different than temporal sub-layer handling.) It was remarked that there may need to be some need to check/fix activation rules.
  

The track agreed with the BoG recommendations (some details remained open to be worked out).

BoG to further meet.

JCTVC-N0374 BoG report on SHVC/MV-HEVC HLS topics [J. Boyce]

J-BoG (J. Boyce) N0374 / E0306 [TBA]

(Reviewed Sun 28th Track A (GJS).)

The BoG met 27 July to review the following contributions:

• 
  6.4.4.5 Reference picture list construction (4)
  JCTVC-N0082, JCTVC-N0095, JCTVC-0216, JCTVC-0316
  
• 
  6.4.3.3 Efficient parameter set parameters signalling (3)
  JCTVC-N0162, JCTVC-N0200, JCTVC-N0212
  
• 
  6.6.2 Layer presence and dependency change SEI messages (2)
  JCTVC-N0173, JCTVC-N0174
  

The BoG recommended the following:

• 
  Adopt JCTVC-N0082, initialization process of reference picture lists for HEVC extensions.
  
• 
  Adopt JCTVC-N0371, scaling list prediction in SPS and PPS (harmonization of JCTVC-N0162 and JCTVC-N0200 variant 3).
  
• 
  Layer dependency change SEI message (which originated from JVT-S080) be removed from specification (since a new VPS could be sent to change the layer dependency). If the SEI message does remain, to adopt JCTVC-N0174 (with some editorial improvements).
  

There was some questioning about the 3rd recommendation. However, there was not a clear objection to the recommendation.

Decision: Agreed to BoG recommendations (pending 3V confirmation).

The BoG planned to meet again to revisit initialization of reference picture lists: Revision to JCT3V-D0220, and harmonization of JCTVC-N0095 and JCTVC-N0216, with experimental results compared to JCTVC-N0082

The BoG also met 28 July to review the following contributions:

• 
  6.4.4.3  General inter-layer RPS signalling and derivation
  
  • 
    N0059, N0081, N0118, N0154, N0195, N0217, N0131
    
• 
  Portions of 6.4.3.1 General
  
  • 
    N0130, N0195, N0217
    
• 
  6.4.4.6 Management of resampled or filtered inter-layer reference pictures
  
  • 
    N0128, N0282, N0056
    

Review of the outcome was conducted in plenary Mon. 29th.

Decision: Endorsed the BoG recommendations of the following:

1. 
   Adopt from JCTVC-N0057 second proposal, change decoding process to add condition that when SamplePredEnabledFlag equal to 1, don't include picture in the motion pred ref list.
   
2. 
   Adopt a condition on signaling inter_layer_pred_layer_idc[ i ], to avoid sending when NumDirectRefLayers equals NumActiveRefLayerPics, and instead infer values. From JCTVC-N0081, JCTVC-N0195 proposal 1, JCTVC-N0154, and JCTVC-N0217.
   
3. 
   Adopt an Inter Layer Reference Picture (ILRP) presence flag in the VPS, conditioning the presence of ILRP syntax elements in the slice segment header, similar to JCTVC-N0195 proposal 2.
   
4. 
   Change order of sorting of inter-layer reference pictures to be in descending rather than ascending order, from JCTVC-N0131 Proposal 4.
   
5. 
   Add constraint when splitting_flag is used, that the sum of the lengths be less than or equal to 6, from JCTVC-N0195 5^th proposal.
   

Decision (Ed): Endorsed the BoG recommendation that the editors consider the following:

1. 
   A text bug fix identified in JCTVC-N0059, in which motion resampling is currently only invoked when alt collocated idc flag is equal to 1, while it should be invoked whenever inter-layer motion prediction is performed and the current and reference layer differ in resolution.
   
2. 
   Add an editorial note for SHVC encoders to avoid use of TMVP when the inter-layer reference picture is the only one in the list.
   

The BoG suggested to the Track that:

1. 
   JCTVC-N0128 Proposal 2 be reviewed in the track, as the topic was difficult to address in the BoG.
   
2. 
   The Track revisit the concept of sending IL RPS candidates in VPS with slice indication, as in JCTVC-N0118and JCTVC-N0081.
   

When the BoG meets again, to revisit JCTVC-N0217 Proposals 4.1.1 and 4.1.2.

JCTVC-N0374 BoG report on SHVC/MV-HEVC HLS topics [J. Boyce]
BoG (A Segall), investigate sequence, test conditions, etc. for colour gamut scalability.

(not yet ready for review Mon. 29th)

JCTVC-N0375 BoG report on arbitrary scalability ratios support in SHVC [E. François]

(Outcome reviewed in plenary Mon. 29th.)

The BoG on arbitrary scalability ratios support addresses the following topics.

1. 
   Definition of test conditions (test material, downsampler) for the upcoming investigation,
   
2. 
   Selection of an initial set of upsampling filter coefficients as a comparison point.
   

The BoG met first on 27 July. The status of the current discussions as of Mon 29th was as follows:

1. 
   It is preferred to use for test condidions one (or a limited set of) spatial scalability ratio(s) enabling to test as many different phases as possible. Further analysis is being made to identify such ratio(s).
   
2. 
   It is preferred to use the JSVM downsampler with phase offset set to 0. Further analysis of the JSVM downsampler is being made to evaluate the amount of changes required in the software.
   
3. 
   It is recommended to select a set of upsampling filter coefficients which ensures the SHM behaviour unchanged for common test conditions.
   

The BoG met again on July 29. The resulting recommendations are listed in the document.
The BoG came up with the following recommendations:

To set-up an SCE on arbitrary spatial scalability ratio.

Test conditions

• 
  Spatial scalability ratios
  
  • 
    Use the existing 1.5x and 2x spatial ratios
    
  • 
    Use the following additional ratios, depending on sequences resolution:
    
    • 
      Class A – horizontal: 2560 / 1456 – vertical: 1600 / 912
      
    • 
      Class B – horizontal: 1080 / 616 – vertical: 1920 / 1096
      
• 
  Downsampler
  
  • 
    Use JSVM downsampler (with phase offset set to 0)
    
  • 
    Generate new anchors for 1.5x, 2x and the new arbitrary ratios to be tested
    
  • 
    Base layer sequences to be uploaded on the site used for HEVC, with downsampler source code and md5
    
    • 
      Software developped by Qualcomm, sent to Samsung who will generate and upload the Base Layer sequences + md5 + software package
      
    • 
      When – software 2 weeks after meeting ends, sequences and md5 data 3 weeks after meeting ends
      
• 
  The detailed test conditions will be refined off-line for the CE (if there is a CE) definition
  

Initial set of upsampling filter coefficients as a comparison point

• 
  The filters for currently defined phase positions are not changed
  
• 
  Use as the starting point for the missing positions the following filters :
  
  • 
    Pick-up coefficients from N0219
    
  • 
    except for luma 6/16 phases, picked-up from N0273
    
• 
  these filters will be used to generate the anchor as a comparison point
  

The recommendations listed above were agreed upon, and open issues were further discussed in JCT plenary on Monday evening.

• 
  Which software for filters coefficients?
  
  • 
    put in the SHM software, enabled by macro, such that the same filters can also be used e.g. for related investigations of AHG
    
• 
  What will be investigated in the CE ?
  
  • 
    the 2 proposals N0219 and N0273 related to arbitrary spatial scalability
    

Non-RCE2 BoG (R. Joshi)