| JCTVC-O0168 On derivation of slice information and motion information for inter-layer reference picture in SHVC [X. Xiu, Y. Ye, Y. He, Y.-W. He (InterDigital)]
This contribution proposes to simplify the derivation of slice information and motion information for inter-layer reference picture in SHVC. Firstly, it is proposed to always associate an inter-layer reference picture with a single slice. Secondly, it is proposed that in the case when reference layer picture is coded with multiple slices and at least two slices have different slice information, the slice associated with the inter-layer reference picture is set to I-Slice and all 16x16 motion blocks of the inter-layer reference picture are set to MODE_INTRA.
Problem was reported in N0334 (O0216 is a follow-up)
JCTVC-O0216 On slice level information derivation and motion field mapping for resampled interlayer reference picture [J. Chen, V. Seregin, X. Li, K. Rapaka, M. Karczewicz (Qualcomm)]
This contribution reported that inter-layer motion prediction in the current SHVC does not work properly when there are multiple slices in the reference layer picture. Two solutions are proposed to solve the issue.
-
Solution 1: generate one single slice for the resampled picture and copy the slice type and reference picture lists information from the first slice of the reference layer picture; in addition, impose a bit-stream conformance constraint that, when there are multiple slices in the reference layer picture and those slices have different slice type or reference picture lists, the inter-layer motion prediction from that reference layer picture is disallowed for the current particular picture.
-
Solution 2: generate a single slice for the resampled picture with new reference picture lists to include all the reference pictures derived from the corresponding reference picture lists of all slices in the reference layer picture. During motion mapping, reference indices of the reference blocks are adjusted to be referring to the reference picture with the same POC as in the reference layer picture.
O0168 and both solutions from O0216 have as common ground to generate only one slice for the ILR picture
O0168 and O0216 solution 1 in principle disable TMVP from ILR picture, which seems to be the most viable and simple solution due to the fact that the compression gain by inter-layer motion prediction is low. It should be applied in cases of multiple slices of different types.
Proponents of O0168 and O0216 solution 1 were asked to summarize commonalities and differences of their solutions and suggest the most simple approach.
This was further discussed Thu 21st pm (GJS). It was agreed that the method in O0216-v3 solution 1 is best since it does not require decoder awareness of the characteristics of the slice information in multiple slices of the reference layer. Decision: Adopt.
Dostları ilə paylaş: | 
