7.7Non-normative: Encoder optimization, decoder speed improvement and cleanup, post filtering, loss concealment, rate control (0)
7.7.1Rate control
7.7.2Encoder optimization
See notes on JCTVC-Q0077 (effectiveness of the HM Inter Search for Screen Content) and JCTVC-Q0147 (fast inter search method for screen content coding) and JCTVC-Q0148 (RExt Quantization rounding for RDPCM) and JCTVC-Q0056 (weighted prediction parameter optimization).
JCTVC-Q0078, Items 3 b, 3 c and 4, clarifying which pictures in an output layer sets are applied the values of general_progressive_source_flag, general_interlaced_source_flag, general_non_packed_constraint_flag and general_frame_only_constraint_flag.
Decision (Ed.): The BoG suggested, and the JCT-VC endorsed, delegating the following to the editors:
Several editorial issues regarding HRD operation from JCTVC-Q0055. Review text modifications with contribution author.
Editorial improvements are needed for the association of NAL units within an access unit and access unit boundary detection. Language in JCTVC-0091 may be useful to study.
JCTVC-Q0146, proposal 1.2, consider adding a NOTE and check if usage of HandleCraAsBlaFlag and EOS behavior is clearly described, and proposal 1.3 specification bug fix
JCTVC-Q0054 proposal #2, bug fix in the semantics of vps_profile_present_flag[ ]
JCTVC-Q0116, consider adding a note regarding how random accessibility is affected by the recovery point SEI message
The BoG recommended the following activities to take place:
To discuss JCTVC-Q0166 in track, "On scaled reference layer offset"
A high-level question raised by this is whether to allow changes of the region of the reference layer that is enhanced by the EL – in regard to both the positioning and the resampling ratio.
It was remarked that the per-picture adjustment flexibility needed for the interlace phase adjustment already imposes some of the same kind of requirement on the decoder as this flexibility would.
It was agreed in principle that it would be desirable to enable this functionality – although details need to be worked out and examined for suitability. Revisit after offline study.
To discuss JVTVC-Q0170 in track, "Resampling need for a scalable layer"
This contribution proposes a two-bit indicator per layer to indicate whether resampling or position adjustment is needed or not for decoding an EL. An alternative indicator could be provided as scalability mask information. It was remarked that bit depth difference is also not indicated. No action was taken on this.
To discuss JCTVC-Q0090 in track, "Redundant picture SEI message"
Further study was encouraged on this topic, but no immediate action was planned. This would be for consideration beyond the scope of the current phase of work.
To discuss JCTVC-Q0105 in track, "On temporal enhancement layers and diagonal inter-layer prediction". See notes on that contribution.
To discuss aspects of JCTVC-Q0078 in track, "On additional layer sets, rewriting of simulcast layers, and profile-tier-level indication for auxiliary picture layers". See notes on that contribution. Revisit.
To discuss JCTVC-Q0115 in track, "On indication of decoding process". TBP. (Related to Q0078)
Some additional items remained to be addressed or were identified as out of scope for this BoG. Revisit.
TBP that can be covered if further discussion: Q0161, Q0162, Q0164, Q0167
JCTVC-Q0234 BoG report on SHVC upsampling process and phase offset [J. Boyce]
The BoG met on 3rd meeting day (29 March). The outcome was discussed in JCT-VC later on 29 March and in the morning of 30 March (GJS).
The BoG recommended that the following activities take place:
Discussion within the track of whether the phase adjustment should use explicit signalling of phases vs. the current method which derives phases based upon flags for interlace indication and cross-layer phase position? Mixed opinions were expressed in review. Addressing the needs for the next topic listed below may affect the desired outcome on this.
Side activity among proponents to consider a general solution for explicit signaling of related parameters to address multiple issues, including 540p->720p, ROI scalability, field-to-frame, and other phase adjustment issues, and revisit this meeting. The 540p->720p case could be handled by using the conformance cropping window to derive the scaling factor. Revisit for consideration of the general issue.
The BoG plans to meet again (Tues) to revisit:
Any new contributions based upon side activity discussion
Revisit phase adjustment
Revisit improving coding efficiency for 540p -> 720p scalability (as if this is treated with an inaccurate scaling ratio, the coding efficiency loss reported in Q0104 is substantial – e.g., 9%).
JCTVC-Q0236 BoG report for Non-CfP SCC and related documents [R. Cohen] JCTVC-Q0239 BoG report on summary of objective performance and tools for SCC CfP responses [R. Joshi, R. Cohen, H. Yu]
JCTVC-Q0244 BoG report on screen content coding reference model (SCM) [R. Cohen]
