Level information for sub-picture tracks

1. A method for processing video data comprising:

determining a level indicator for a set of subpictures in one or more subpicture tracks, wherein the level indicator is included in a sample group carrying information for the set of subpictures, and wherein the level indicator is contained in a sample entry of the sample group; and

performing a conversion between a visual media data and a media data file based on the level indicator.

2. The method of claim 1 , wherein a name of the sample group that includes ‘spli’ indicates the level indicator is included in the sample group.

3. The method of claim 2 , wherein the sample group is a subpicture level information sample group.

4. The method of claim 1 , wherein the subpicture tracks are included in a subpicture entity group.

5. The method of claim 4 , wherein the sample entry of the sample group contains an indication of a grouping type of the subpicture entity group.

6. The method of claim 4 , wherein a grouping type parameter (grouping_type_parameter) of the sample group contains an indication of a grouping type of the subpicture entity group.

7. The method of claim 4 , wherein a rule requires all sample to group boxes (SampleToGroupBoxes) for subpictures to contain a grouping type parameter (grouping_type_parameter) indicating a grouping type of the subpicture entity group.

8. The method of claim 7 , wherein one bit of the grouping_type_parameter is a subpicture common group flag (subpic_common_group_flag) that indicates the grouping type of the subpicture entity group.

9. The method of claim 4 , wherein a group identifier of an entity to group box (EntityToGroupBox) associated with the subpicture entity group is further contained in the sample entry of the sample group.

10. An apparatus for processing video data comprising:

a processor; and

a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:

determine a level indicator for a set of subpictures in one or more subpicture tracks, wherein the level indicator is included in a sample group carrying information for the set of subpictures, and wherein the level indicator is contained in a sample entry of the sample group; and

perform a conversion between a visual media data and a media data file based on the level indicator.

11. The apparatus of claim 10 , wherein a name of the sample group that includes ‘spli’ indicates the level indicator is included in the sample group.

12. The apparatus of claim 11 , wherein the sample group is a subpicture level information sample group.

13. The apparatus of claim 10 , wherein the subpicture tracks are included in a subpicture entity group.

14. A non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to:

determine a level indicator for a set of subpictures in one or more subpicture tracks, wherein the level indicator is included in a sample group carrying information for the set of subpictures, and wherein the level indicator is contained in a sample entry of the sample group; and

perform a conversion between a visual media data and a media data file based on the level indicator.

15. The non-transitory computer readable medium of claim 14 , wherein a name of the sample group that includes ‘spli’ indicates the level indicator is included in the sample group.

16. The non-transitory computer readable medium of claim 15 , wherein the sample group is a subpicture level information sample group.

17. The non-transitory computer readable medium of claim 14 , wherein the subpicture tracks are included in a subpicture entity group.

18. The method of claim 1 , wherein the conversion includes encoding the visual media data into the media data file.

19. The method of claim 1 , wherein the conversion includes decoding the visual media data from the media data file.