#903 closed defect (fixed)

Issues in Subpicture sub-bitstream extraction process

Reported by: vdrugeon Owned by:
Priority: minor Milestone:
Component: spec Version:
Keywords: Cc: ksuehring, bbross, XiangLi, fbossen, jvet@…

Description

In C.7 Subpicture sub-bitstream extraction process, the variable SubpicIdList is used, but never defined. At first, I thought that the variable SubpicIdVal was meant instead, but this is unlikely, since SubpicIdVal converts a subpicture index into a subpicture ID, whereas the variable SubpicIdList seems to convert a subpicture ID into a subpicture index, which is the opposite. So I believe that SubpicIdList derivation is needed and currently missing.

Furthermore, the process contains the following: "Rewrite the value of the pic_width_max_in_luma_samples and pic_height_max_in_luma_samples in all referred to SPS NAL units and the value of pic_width_in_luma_samples and pic_height_in_luma_samples in all referred to PPS NAL units to be equal to subpic_width_minus1[ SubpicIdList[ subPicId ] ] and subpic_height_minus1[ SubpicIdList[ subPicId ] ]." This seems wrong, because subpic_width_minus1 and subpic_height_minus1 are in units of CtbSizeY, whereas pic_width_max_in_luma_samples and pic_height_max_in_luma_samples are in units of luma samples.

Change history (1)

comment:1 Changed 17 months ago by vdrugeon

  • Resolution set to fixed
  • Status changed from new to closed

Fixed by decisions taken during the 18th JVET meeting

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