Method and apparatus for encoding and decoding a video stream with subpictures
AssigneeCanon Kabushiki Kaisha
InventorsNaël Ouedraogo, Franck Denoual
Life of this patent
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Abstract
An encoding method comprising the encoding of information allowing the decoder to infer the splitting of CTBs located at the right, respectively the bottom of a subpicture, which width, respectively height, is not a multiple of the size of the CTBs, when the subpicture is not located at the right, respectively the bottom, of the image. Corresponding decoding methods for the generated bitstream are also proposed.
Claims19
A method of encoding video data comprising pictures into a bitstream, pictures being divided into subpictures each including one or more slices, the method comprising:
- encoding, in a sequence parameter set of the bitstream, a first flag indicating whether information of a subpicture is present;
- when a value of the first flag is 1, encoding, in the sequence parameter set of the bitstream, a second flag related to a constraint of subpictures;
- when a value of the second flag is 0, encoding, for a given subpicture in a picture, a third flag and a fourth flag in the sequence parameter set of the bitstream, the third flag indicating whether in-loop filtering operations across subpicture boundaries is enabled and the fourth flag indicating whether the given subpicture is treated as a picture in decoding process excluding in-loop filtering operations,
- wherein the third flag and the fourth flag are not encoded in the sequence parameter set of the bitstream when the value of the second flag is 1;
- and
- encoding coding tree blocks composing the pictures into the bitstream.
A non-transitory computer-readable storage medium storing instructions of a computer program for implementing a method, the method comprising:
- encoding, in a sequence parameter set of the bitstream, a first flag indicating whether information of a subpicture is present;
- when a value of the first flag is 1, encoding, in the sequence parameter set of the bitstream, a second flag related to a constraint of subpictures;
- when a value of the second flag is 0, encoding, for a given subpicture in a picture, a third flag and a fourth flag in the sequence parameter set of the bitstream, the third flag indicating whether in-loop filtering operations across subpicture boundaries is enabled and the fourth flag indicating whether the given subpicture is treated as a picture in decoding process excluding in-loop filtering operations,
- wherein the third flag and the fourth flag are not encoded in the sequence parameter set of the bitstream when the value of the second flag is 1;
- and
- encoding coding tree blocks composing the pictures into the bitstream.
A method of decoding a bitstream of video data comprising pictures, pictures being divided into subpictures each including one or more slices, the method comprising:
- decoding, from a sequence parameter set of the bitstream, a first flag indicating whether information of a subpicture is present;
- when a value of the first flag is 1, decoding, from the sequence parameter set of the bitstream, a second flag related to a constraint of subpictures;
- when a value of the second flag is 0, decoding, for a given subpicture in a picture, a third flag and a fourth flag from the sequence parameter set of the bitstream, the third flag indicating whether in-loop filtering operations across subpicture boundaries is enabled, and the fourth flag indicating whether the given subpicture is treated as a picture in decoding process excluding in-loop filtering operations,
- wherein the third flag and the fourth flag are not decoded from the sequence parameter set of the bitstream when the value of the second flag is 1;
- and
- decoding the bitstream at least based on the first flag.
A device for encoding video data comprising pictures into a bitstream, pictures being divided into subpictures each including one or more slices the device comprising a processor configured to execute:
- encoding, in a sequence parameter set of the bitstream, a first flag indicating whether information of a subpicture is present;
- when a value of the first flag is 1, encoding, in the sequence parameter set of the bitstream, a second flag related to a constraint of subpictures;
- when a value of the second flag is 0, encoding, for a given subpicture in a picture, a third flag and a fourth flag in the sequence parameter set of the bitstream, the third flag indicating whether in-loop filtering operations across subpicture boundaries is enabled and the fourth flag indicating whether the given subpicture is treated as a picture in decoding process excluding in-loop filtering operations,
- wherein the third flag and the fourth flag are not encoded in the sequence parameter set of the bitstream when the value of the second flag is 1;
- and
- encoding coding tree blocks composing the pictures into the bitstream.
A device for decoding a bitstream of video data comprising pictures, pictures being divided into subpictures each including one or more slices, the device comprising a processor configured for:
- decoding, from a sequence parameter set of the bitstream, a first flag indicating whether information of a subpicture is present;
- when a value of the first flag is 1, decoding, from the sequence parameter set of the bitstream a second flag related to a constraint of subpictures;
- when a value of the second flag is 0, decoding, for a given subpicture in a picture, a third flag and a fourth flag from the sequence parameter set of the bitstream, the third flag indicating whether in-loop filtering operations across subpicture boundaries is enabled, and the fourth flag indicating whether the given subpicture is treated as a picture in decoding process excluding in-loop filtering operations,
- wherein the third flag and the fourth flag are not decoded from the sequence parameter set of the bitstream when the value of the second flag is 1;
- and
- decoding the bitstream at least based on the first flag.
Dependencies are inferred from the claim text.