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18th Meeting: Teleconference, April 2020 2020-04-09 09:36
AHG15: On scaling list prediction
Authors: Adarsh Krishnan Ramasubramonian Qualcomm Bappaditya Ray Qualcomm G. van der Auwera Qualcomm Marta Karczewicz Qualcomm
Abstract
This document proposes changes to the derivation of scaling list reference ID when the chroma scaling lists are not signalled. Scaling lists may be explicitly signalled, copied or predicted from other scaling lists - the scaling list used for copying or predicting is referred to as the reference scaling list. The current specification allows luma scaling lists to be copied or predicted from lists that correspond to chroma scaling lists even when the chroma lists are absent; it is asserted that this behaviour is undesirable. The document proposes to modify the reference scaling list ID derivation by skipping the absent chroma lists. It is asserted that the proposed method fixes the issue of referring absent lists; due to the small bit savings, the proposed method is argued to be preferable compared to explicit constraints or inferring default lists.
Meeting Notes
JVET-R0127 AHG15: On scaling list prediction [A. K. Ramasubramonian, B. Ray, G. Van der Auwera, M. Karczewicz (Qualcomm)]

This document proposes changes to the derivation of scaling list reference ID when the chroma scaling lists are not signalled. Scaling lists may be explicitly signalled, copied or predicted from other scaling lists – the scaling list used for copying or predicting is referred to as the reference scaling list. The current specification allows luma scaling lists to be copied or predicted from lists that correspond to chroma scaling lists even when the chroma lists are absent; it is asserted that this behaviour is undesirable. The document proposes to modify the reference scaling list ID derivation by skipping the absent chroma lists. It is asserted that the proposed method fixes the issue of referring absent lists; due to the small bit savings, the proposed method is argued to be preferable compared to explicit constraints or inferring default lists.

Also related to ticket #926. Another method is proposed that disallows prediction from chroma scaling list when it is not present. This would also require a syntax change, reducing the range of code words to only allowing reference to luma values.

See further notes under JVET-R0326.

Cited:
JVET-R0015
PATENTS:
CA2951517C 0.34 2023-01-24 20210281843 0.34 WO/2024/151462 0.33 CA2952460C 0.32 2023-03-07 4115616 0.32 WO/2021/178664 0.31 TW201444341A 0.30 2014-11-16 WO/2024/086604 0.30
ARCHIVE v2 :
JVET-R0127.docx JVET-R0127.pdf
Decisions
See further notes under JVET-R0326.
Citation