JVET-AO0197 AHG9: DSC subpicture support using segment sets [J. Boyce, M. M. Hannuksela (Nokia)]

A backwards compatible approach is proposed for digital signing of sets of subpictures with the DSC SEI messages, with entire pictures also signed. A DSC signature is provided for segment sets of a substream, where a subpicture is a segment. A default segment set is defined that includes all segments in the picture, i.e. the default 0-th segment set contains the entire picture, and is always signed. Other segment sets which contain a subset of the segments are referred to as additional segment sets. Receiving systems are able to verify that entire pictures in a substream have not been modified, and can also verify that any additional signed segment sets in a substream have not been modified.

This could be an alternative to the current TuC subpictures design.

It was commented that using multiple dsci_id could also support backward compatibility using current approach. In current TuC one subpicture can only be assigned to one substream.

Does the proposed approach allow knowing in DSCI which subpictures are in which substream.

Answer: DSCI not currently, but yes in DSCS. But it can be added redundantly in DSCI.

Is SPS and PPS included or excluded in the signing for substreams in case of extraction? Answer: Initial thought is Parameter sets will be included in each substreams. Parameter sets can’t be rewritten as otherwise re-signing will be required.

It was asked if implicit association is no longer supported with the proposed approach.

There was some discussion regarding comparing overheads of the proposed approach and the TuC approach.

It was also suggested to consider harmonizing the proposed approach and the one in TuC.

Following options were discussed:

Option 1: Further study encouraged to harmonize proposed approach with the current TuC approach

Option 2: Add to TuC as an alternative option

Option 3: Add to TuC and remove the current approach in TuC

Option 1 was considered to be the preferred solution.

This was discussed on 23 January 2026 from 00:50-00:55 to consider a unified solution’s desirable characteristics: No specific ideas were clearly mentioned. The topic is for further study.