Opened 4 years ago
Closed 4 years ago
#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 4 years ago by vdrugeon
- Resolution set to fixed
- Status changed from new to closed
Fixed by decisions taken during the 18th JVET meeting