Method for output layer set signaling in scalable video stream

A device for encoding video data, the device comprising:

• at least one memory configured to store program code;
• and
• at least one processor configured to read the program code and operate as instructed by the program code, the program code including:
• first obtaining code configured to cause the at least one processor to obtain video data;
• processing code configured to cause the at least one processor to obtain the video data to determine a plurality of output layer sets;
• first determining code configured to cause the at least one processor to determine a first flag indicating whether each output layer set of the plurality of output layer sets includes more than one layer;
• second determining a second flag indicating that all of layers included in the plurality of output layer sets are independently coded,
• third determining code configured to cause the at least one processor to, based on the first flag indicating that the each output layer set includes more than the one layer and the second flag indicating that the all of the layers included in the plurality of output layer sets are independently coded, determine a an output layer set mode;
• selecting code configured to cause the at least one processor to select at least one layer from among the layers included in the plurality of output layer sets as at least one output layer based on the output layer set mode;
• setting code configured to cause the at least one processor to, set, for each unselected layer that is not selected as the at least one output layer, a third flag indicating whether a respective unselected layer is a direct reference layer for the selected at least one output layer;
• and
• generating code configured to cause the at least one processor to generate an encoded video bitstream based on the first flag, the second flag, and the plurality of output layer sets.

A non-transitory computer-readable medium storing instructions, the instructions comprising:

• one or more instructions that, when executed by one or more processors of a device for encoding video data, cause the one or more processors to:
• obtain video data;
• process the video data to determine a plurality of output layer sets;
• determine a first flag indicating whether each output layer set of the plurality of output layer sets includes more than one layer;
• determine a second flag indicating that all of layers included in the plurality of output layer sets are independently coded;
• based on the first flag indicating that the each output layer set includes more than the one layer and the second flag indicating that the all of the layers included in the plurality of output layer sets are independently coded, determine an output layer set mode;
• select at least one layer from the among layers included in the plurality of output layer sets as at least one output layer based on the output layer set mode;
• set, for each unselected layer that is not selected as the at least one output layer, a third flag indicating whether a respective unselected layer is a direct reference layer for the selected at least one output layer;
• and
• generate an encoded video bitstream based on the first flag, the second flag, and the plurality of output layer sets.