JVET-AC0335 Non-EE2: Content adaptive OBMC enabling [K. Cui, Z. Zhang, V. Seregin, M. Karczewicz (Qualcomm)] [late]

This contribution proposes a method to adaptively control OBMC based on hash block hit percentage. It reports {-0.02%, -0.02%, -0.03%} YUV BD-rate gains for Class F and {-1.28%, -0.80%, -0.69%} YUV BD-rate gains for Class TGM under RA configuration.

Decision is done on basis of first frame for entire sequence. It is noted that JVET-0190 also includes one non-normative method of disabling OBMC for screen content by sequence-level flag, but not using an automatic setting of that flag as in this contribution.

This is an encoder-only method, for information only.

It was asked if the method reliably recognizes screen content. In class F, OBMC is not turned off for two sequences with mixed content. It was reported that turning OBMC off for entire class F would result in 0.45% loss for that class.

It is asserted that this is a straightforward approach to automatically disable OBMC without class-dependent settings. This is a non-normative encoder change. As an EE is planned for disabling OBMC at block level, it is also interesting to use this method as an anchor.

Decision (SW): Adopt JVET-AC0335. Investigate during ECM8 software integration if it has any impact on camera-captured content. If not, it does not need to made configurable (but should be possible to be disabled by macro). If it would have negative impact on camera-captured content, it should be made configurable, and in CTC only be enabled for classes F and TGM.

High-level syntax (HLS) and related proposals (28)

AHG9: SEI messages on neural-network post filter (22)

Contributions in this area were initially discussed in session 5 at 1300–1515 UTC on Thursday 12 Jan. 2023 (chaired by JRO) – the notes and decisions from that session (based on the summary related to items 1-8 and 10 as listed in JVET-AC0208. These notes were later included in the BoG report JVET-AC0324 for simplicity. All other reviews, as well as possible refinements related to the aforementioned items were conducted in BoG JVET-AC0324 (G. Sullivan)