Reference Picture Management in Video Coding

A method of decoding a coded video bitstream implemented by a video decoder, the method comprising:

• decoding, by the video decoder, a previous picture including all slices thereof to obtain a previous decoded picture;
• storing, by the video decoder, the previous decoded picture in a decoded picture buffer (DPB) after the decoding;
• marking, by the video decoder, the previous decoded picture as used for short-term reference after all the slices of the previous decoded picture have been decoded;
• and
• decoding, by the video decoder, a first slice of a current picture, the decoding of the first slice of the current picture comprising:
• obtaining, by the video decoder, a first reference picture list of the first slice and a second reference picture list of the first slice;
• re-marking, by the video decoder, the previous decoded picture as used for long-term reference when the previous decoded picture is referred to by a long-term reference picture (LTRP) entry in the first reference picture list or the second reference picture list;
• and
• re-marking, by the video decoder, the previous decoded picture as unused for reference when the previous decoded picture is not referred to in the first reference picture list or the second reference picture list.

A coding device, comprising:

• a receiver configured to receive a coded video bitstream;
• a memory coupled to the receiver, the memory storing instructions;
• and
• a processor coupled to the memory, the processor configured to execute the instructions stored in the memory to cause the processor to:
• obtain a first reference picture list of a current slice and a second reference picture list of the current slice;
• mark a status of a reference picture in a decoded picture buffer (DPB) based on the first reference picture list and the second reference picture list when the current slice is a first slice in a current picture to which the current slice belongs, wherein the status of the reference picture in the decoded picture buffer is one of used for short-term reference, used for long-term reference, or unused for reference;
• and
• use the reference picture in a reconstructing process of the current picture when the status of the reference picture is used for short-term reference or used for long-term reference.

A coding device, comprising:

• a receiver configured to receive a coded video bitstream;
• a memory coupled to the receiver, the memory storing instructions;
• and
• a processor coupled to the memory, the processor configured to execute the instructions stored in the memory to cause the processor to:
• decode a previous picture including all slices thereof to obtain a first decoded picture;
• store the first decoded picture in a decoded picture buffer (DPB) after the decoding;
• mark the previous decoded picture as used for short-term reference after all the slices of the previous decoded picture have been decoded;
• and
• decode a first slice of a current picture, which further causes the processor to:
• obtain a first reference picture list of the first slice and a second reference picture list of the first slice;
• re-mark the previous decoded picture as used for long-term reference when the previous decoded picture is referred to by a long-term reference picture (LTRP) entry in the first reference picture list or the second reference picture list;
• and
• re-mark the previous decoded picture as unused for reference when the previous decoded picture is not referred to in the first reference picture list or the second reference picture list.