Method for signaling virtual boundary signaling with subpictures in coded video stream

1. A method, executable by a processor, the method comprising:

receiving video data comprising a base layer, and one or more enhancement layers that correspond to one or more subpictures, the one or more subpictures having one or more virtual boundaries;

signaling, in a sequence parameter set, a syntax element sps_virtual_boundaries_enabled_flag specifying whether virtual boundaries are enabled for the video data;

when the syntax element sps_virtual_boundaries_enabled_flag equals 1, specifying that virtual boundaries are enabled, signaling, in a picture parameter set or a picture header, a second syntax element pps_virtual_boundaries_present_flag specifying whether information of the one or more virtual boundaries is signaled in the picture parameter set, and a third syntax element ph_virtual_boundaries_present_flag specifying whether information of the one or more virtual boundaries is signaled in the picture header;

when the information specifies that the information of the one or more virtual boundaries is signaled in the picture parameter set or the picture header, signaling, in the picture parameter set or the picture header associated with the received video data, information corresponding to a number of the one or more virtual boundaries; and

decoding the video data based on the signaled information corresponding to the virtual boundaries.

2. The method of claim 1 , wherein based on a virtual boundary being detected, in-loop filtering is disabled across the virtual boundary.

3. The method of claim 2 , wherein the in-loop filtering comprises one or more from among a deblocking filter, a sample adaptive offset filter, and an adaptive loop filter.

4. The method of claim 1 , further comprising:

reorganizing the one or more subpictures; and

updating the information specifying whether the one or more virtual boundaries are present at a picture level.

5. The method of claim 1 , wherein a distance between two vertical boundaries is specified to be greater than or equal to a size corresponding to a luma sample associated with the received video data.

6. The method of claim 1 , wherein the information specifying whether the one or more virtual boundaries are present is signaled in the picture parameter set when not signaled in the sequence parameter set.

7. The method of claim 1 , wherein the sequence parameter set includes a signal of the number of vertical virtual boundaries and the number of horizontal virtual boundaries.

8. The method of claim 1 , wherein the picture parameter set includes a signal of the number of vertical virtual boundaries and the number of horizontal virtual boundaries.

9. The method of claim 1 , wherein the picture header includes a signal of the number of vertical virtual boundaries and the number of horizontal virtual boundaries.

10. A computer system for coding video data, the computer system comprising:

one or more computer-readable non-transitory storage media configured to store computer program code; and

one or more computer processors configured to access said computer program code and operate as instructed by said computer program code, said computer program code including:

receiving code configured to cause the one or more computer processors to receive video data comprising a base layer, and one or more enhancement layers that correspond to one or more subpictures, the one or more subpictures having one or more virtual boundaries;

first signaling code configured to cause the one or more computer processors to signal, in a sequence parameter set, a syntax element sps_virtual_boundaries_enabled_flag specifying whether virtual boundaries are enabled for the video data;

second signaling code configured to cause the one or more computer processors to, when the syntax element sps_virtual_boundaries_enabled_flag equals 1, specifying that virtual boundaries are enabled, signal, in, a picture parameter set or a picture header, a second syntax element pps_virtual_boundaries_present_flag specifying whether information of the one or more virtual boundaries is signaled in, the picture parameter set, and a third syntax element ph_virtual_boundaries_present_flag specifying whether information of the one or more virtual boundaries is signaled on the picture header;

third signaling code configured to cause the one or more computer processors to, when the information specifies that the information of the one or more virtual boundaries is signaled in, the picture parameter set or the picture header, signal, in, the picture parameter set or the picture header associated with the received video data, information corresponding to a number of the one or more virtual boundaries; and

decoding code configured to cause the one or more computer processors to decode the video data based on the signaled information corresponding to the virtual boundaries.

11. The computer system of claim 10 , wherein based on a virtual boundary being detected, in-loop filtering is disabled across the virtual boundary.

12. The computer system of claim 11 , wherein the in-loop filtering comprises one or more from among a deblocking filter, a sample adaptive offset filter, and an adaptive loop filter.

13. The computer system of claim 10 , further comprising:

reorganizing code configured to cause the one or more computer processors to reorganize the one or more subpictures and

updating code configured to cause the one or more computer processors to update the information specifying whether the one or more virtual boundaires are present at a picture level.

14. The computer system of claim 10 , wherein a distance between two vertical boundaries is specified to be greater than or equal to a size corresponding to a luma sample associated with the received video data.

15. The computer system of claim 10 , wherein the information specifying whether the one or more virtual boundaries are present is signaled in the picture parameter set when not signaled in the sequence parameter set.

16. A non-transitory computer readable medium having stored thereon a computer program for coding video data, the computer program configured to cause one or more computer processors to:

receive video data comprising a base layer, and one or more enhancement layers that correspond to one or more subpictures, the one or more subpictures having one or more virtual boundaries;

signaling, in a sequence parameter set, a syntax element sps_virtual_boundaries_enabled_flag specifying whether virtual boundaries are enabled for the video data;

when the syntax element sps_virtual_boundaries_enabled_flag equals 1, specifying that virtual boundaries are enabled, signaling, in, a picture parameter set or a picture header, a second syntax element pps_virtual_boundaries_present_flag specifying whether information of the one or more virtual boundaries is signaled in, the picture parameters set, and a third syntax element ph_virtual_boundaries_present_flag specifying whether information of the one or more virtual boundaries is signaled in the picture header;

when the information specifies that the information of the one or more virtual boundaries is signaled in, the picture parameter set or the picture header, signaling, in, the picture parameter set or the picture header associated with the received video data, information corresponding to a number of the one or more virtual boundaries; and

decode the video data based on the signaled information corresponding to the virtual boundaries.

17. The computer readable medium of claim 16 , wherein based on a virtual boundary being detected, in-loop filtering is disabled across the virtual boundary.

18. The computer readable medium of claim 17 , wherein the in-loop filtering comprises one or more from among a deblocking filter, a sample adaptive offset filter, and an adaptive loop filter.

19. The computer readable medium of claim 16 , further comprising:

reorganizing code configured to cause the one or more computer processors to reorganize the one or more subpictures and

updating code configured to cause the one or more computer processors to update the information specifying whether the one or more virtual boundaries are present at a picture level.

20. The computer readable medium of claim 16 , wherein a distance between two vertical boundaries is specified to be greater than or equal to a size corresponding to a luma sample associated with the received video data.