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39th Meeting: Daejeon, KR, March 2025 2025-03-19 21:55
AHG9: Substream dependency signalling in the DSCI SEI message
Authors: Ye-Kui Wang ByteDance Yun Li SJTU K. Yang SJTU Jizheng Xu ByteDance Y. Xu SJTU
Abstract
This document contains the draft text for changes to the versatile supplemental enhancement information messages for coded video bitstreams (VSEI) standard (Rec. ITU-T H.274 | ISO/IEC 23002-7), to specify 15 additional SEI messages, namely 1) SEI processing order, 2) processing order nesting, 3) encoder optimization information, 4) source picture timing information, 5) object mask information, 6) modality information, 7) text description information, 8) digitally signed content initialization, 9) digitally signed content selection, 10) digitally signed content verification, 11) generative face video, 12) generative face video enhancement, 13) AI usage restrictions, 14) packed regions information, and 15) image format metadata. The changes also include updates to some of the existing SEI messages, including the two neural-network post-filter (NNPF) SEI messages, as well as some corrections to the previous version of the VSEI standard.
Meeting Notes
JVET-AL0115 AHG9: Substream dependency signalling in the DSCI SEI message [Y.-K. Wang (Bytedance), Y. Li, K. Yang (SJTU), J. Xu (Bytedance), Y. Xu (SJTU)]

It is asserted that the substream dependency signalling in the DSCI SEI message though the two loops of the reference substream flag syntax element has redundancy. For example, if substream ss2 depends on substream ss1, and substream ss3 depends on ss2, then it is known that ss3 depends on ss1 and thus that dependency does not need to be signalled but can be inferred.

This contribution proposes a change to the DSCI SEI message syntax to avoid such redundancy, through a derived variable flag to condition the presence of the reference substream flag syntax element.

The detailed proposed text changes are provided in an attachment to this contribution. The changes are marked relative to the spec text provided in JVET-AL0103, which includes asserted purely editorial changes to the DSC SEI messages based on JVET-AK2006-v1.

The goal of the proposal is to save bits. No data is provided on the amount of bitrate savings.

It was suggested that the proposed change would require more analysis of dependencies to parse the SEI message.

In was suggested that in HLS designs we often try to avoid signalling redundancies.

No action was taken on this.

ARCHIVE :
JVET-AL0115-v1.docx JVET-AL0115_vseiSpecText-v1.docx
Decisions
No action was taken on this.
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