Value ranges for syntax elements in video coding

A device for encoding video data, comprising:

• a memory configured to store a plurality of pictures obtained from a bitstream, the plurality of pictures including a current picture and one or more reference pictures;
• and
• at least one processor operably coupled to the memory and configured to determine a reference picture set (RPS) for the current picture based at least in part on the one or more reference pictures;
• determine a picture order count (POC) value of each reference picture of the one or more reference pictures in the RPS;
• identify at least one of a number of long-term reference pictures and a number of short-term reference pictures within the RPS;
• apply constraints to the number of long-term pictures and the number of short-term pictures in the RPS, the constraints being based on the POC value and a maximum decoded picture buffer size minus one, if a video sequence parameter (VPS) extension is in use;
• if the plurality of pictures comprises a base layer of video data, constrain a sum of a number of negative pictures, a number of positive pictures, number of long-term pictures derived based on candidate long term reference pictures specified in an active sequence parameter set (SPS), and a number of long-term pictures directly signaled in a slice header of the current picture to a value that is less than or equal to a maximum decoded picture buffer size identified in the active SPS minus one;
• generate at least one syntax element identifying the RPS based on the constraints;
• encode the current picture based on the RPS and the at least one syntax element.

A method for decoding video data, comprising:

• obtaining a picture order count (POC) of a current picture and POC values for one or more reference pictures from a bitstream;
• determining a reference picture set (RPS) having the one or more reference pictures based on the POC values of the current picture and the POC values of the one or more reference pictures;
• identifying the one or more reference pictures in the RPS as at least one of a
• number of long-term pictures and a number of short-term pictures, the number of long-term pictures and the number of short-term pictures being based on constraints, the constraints being based on the POC value and a maximum decoded picture buffer size minus one, if a video parameter set (VPS) extension is in use;
• wherein if the current picture is in a base layer, a sum of a number of negative pictures, a number of positive pictures, a number of long-term pictures derived based on candidate long term reference pictures specified in an active sequence parameter set (SPS), and a number of long-term pictures directly signaled in a slice header of the current picture is constrained to a value that is less than or equal to a maximum decoded picture buffer size identifies in the active SPS minus one;
• and
• decoding the current picture based on the RPS.

A device for decoding video data, comprising:

• a memory configured store a current picture, a picture order count (POC) of a current picture, and POC values for one or more reference pictures, the POC values and the current picture being obtained from a bitstream;
• and
• a processor operably coupled to the memory and configured to determine a reference picture set (RPS) having the one or more reference pictures based on the POC values of the current picture and the POC values of the
• one or more reference pictures, identify the one or more reference pictures in the RPS as at least one of a number of long-term pictures and a number of short-term pictures, the number of long-term pictures and the number of short-term pictures being based on constraints, the constraints being based on the POC value and a maximum decoded picture buffer size minus one, if a video parameter set (VPS) extension is in use, and
• wherein if the current picture is in a base layer, a sum of a number of negative pictures, a number of positive pictures, a number of long-term pictures derived based on candidate long term reference pictures specified in an active sequence parameter set (SPS), and a number of long-term pictures directly signaled in a slice header of the current picture is constrained to a value that is less than or equal to a maximum decoded picture buffer size identified in the active SPS minus one, and
• decode the current picture based on the RPS.