Image encoding/decoding method and apparatus, and recording medium storing bitstream

1 . An image decoding method comprising:

obtaining a stream including subpicture information of a plurality of subpictures;

selecting a first subpicture to be extracted from among the plurality of subpictures;

obtaining a sub stream for the first subpicture from the stream, by removing or using at least one piece of subpicture information included in the stream; and

decoding the sub stream for the first subpicture,

wherein the subpicture information comprises at least one of sequence parameter set (SPS) information or picture parameter set (PPS) information,

wherein the sub stream is obtained without changing at least one piece of subpicture information of the first subpicture, and

wherein the unchanged subpicture information comprises information indicating whether to treat a subpicture as a picture.

2 . The image decoding method of claim 1 , wherein the subpicture information comprises a non-Video Coding Layer Network Abstraction Layer (non-VCL NAL) unit and a Video Coding Layer Network Abstraction Layer (VCL NAL) unit for the plurality of subpictures.

3 . The image decoding method of claim 1 , wherein the sub stream is obtained by removing a VCL NAL unit for a subpicture which is not the first subpicture.

4 . The image decoding method of claim 1 , wherein the sub stream is obtained, by setting top left coding tree unit (CTU) coordinates of the first subpicture are set to (0, 0).

5 . The image decoding method of claim 1 , wherein the sub stream is obtained by changing information indicating a total number of subpictures to be extracted.

6 . The image decoding method of claim 1 , wherein the sub stream is obtained by removing subpicture information for a subpicture which is not the first subpicture.

7 . The image decoding method of claim 1 ,

wherein the subpicture information comprises at least one of a video parameter set (VPS) NAL unit, an end of bitstream (EOB) NAL unit, an access unit delimiter (AUD) NAL unit or a supplemental enhancement information (SEI) NAL unit, and

wherein at least one of the VPS NAL unit, the EOB NAL unit, the AUD NAL unit or the SEI NAL unit is not removed from the stream.

8 . An image encoding method comprising:

partitioning a picture into a plurality of subpictures;

obtaining a stream containing encoded data for the plurality of subpictures, the stream including subpicture information of the plurality of subpictures, wherein the subpicture information is used for extracting, from the stream, a sub stream for a first subpicture among the plurality of subpictures;

wherein the subpicture information comprises at least one of sequence parameter set (SPS) information or picture parameter set (PPS) information,

wherein at least one piece of subpicture information of the first subpicture is unchanged when the sub stream for the first subpicture is extracted from the stream, and

wherein the unchanged subpicture information comprises information indicating whether to treat a subpicture as a picture.

9 . The image encoding method of claim 8 , wherein the subpicture information comprises a non-Video Coding Layer Network Abstraction Layer (non-VCL NAL) unit and a Video Coding Layer Network Abstraction Layer (VCL NAL) unit for the plurality of subpictures.

10 . The image encoding method of claim 9 , wherein the sub stream is obtained, by removing a VCL NAL unit for a sub picture which is not the first subpicture.

11 . A method for transmitting a bitstream comprising encoded video data, the method comprising:

generating the bitstream for an image; and

transmitting the bitstream,

wherein generating the bitstream for the image comprises:

partitioning a picture into a plurality of subpictures;

obtaining a stream containing encoded data for the plurality of subpictures, the stream including subpicture information of the plurality of subpictures, wherein the subpicture information is used for extracting, from the stream, a sub stream for a first subpicture among the plurality of subpictures;

wherein the subpicture information comprises at least one of sequence parameter set (SPS) information or picture parameter set (PPS) information,

wherein at least one piece of subpicture information of the first subpicture is unchanged when the sub stream for the first subpicture is extracted from the stream, and

wherein the unchanged subpicture information comprises information indicating whether to treat a subpicture as a picture.