Method for reference picture processing in video coding
The present disclosure provides a computer-implemented method for video processing. The method includes deriving a total number by summing a number of reference picture list structures in sequence parameter set (SPS) and one; allocating memory for the total number of reference picture list structures in response to a reference picture list structure being signaled in a picture header of a current picture or a slice header of a current slice; and processing a current picture or a current slice using the allocated memory.
1. An apparatus for performing video data processing, the apparatus comprising:
a memory configured to store instructions; and
one or more processors configured to execute the instructions to cause the apparatus to perform:
signaling a first flag in a picture parameter set (PPS) to indicate whether a second flag and a first index are present in a picture header syntax or a slice header for a current picture referring to the PPS; wherein the second flag indicates whether reference picture list 1 is derived based on one of reference picture list structures associated with the reference picture list 1 signaled in a sequence parameter set (SPS) and the first index is an index, to a list of the reference picture list structures associated with the reference picture list 1 included in the SPS, of a reference picture list structure that is associated with the reference picture list 1 and that is used for derivation of the reference picture list 1;
determining whether the first index and a second index to be signaled, wherein the second index is an index, to a list of reference picture list structures associated with reference picture list 0 included in the SPS, of a reference picture list structure that is associated with the reference picture list 0 and that is used for derivation of the reference picture list 0;
in response to the second index not to be signaled, determining a value of the second index comprising:
when at most one reference picture list structure associated with the reference picture list 0 is included in the SPS, determining the value of the second index to be equal to 0;
in response to the first index not to be signaled, determining a value of the first index comprising:
when at most one reference picture list structure associated with the reference picture list 1 is included in the SPS, determining the value of the first index to be equal to 0; and
when the first flag is equal to 0 and the second flag is equal to 1, determining the value of the first index to be equal to the value of the second index;
deriving the reference picture list 1 based on the first index or the reference picture list 0 based on the second index; and
encoding the current picture based on the reference picture list 1 or the reference picture list 0.
2. A non-transitory computer readable medium that stores a bitstream of a video for processing according to a method comprising:
determining a value of a first flag indicating whether a second flag and a first index are present in a picture header syntax or a slice header for a current picture, wherein the second flag indicates whether reference picture list 1 is derived based on one of reference picture list structures associated with the reference picture list 1 signaled in a sequence parameter set (SPS) and the first index is an index, to a list of the reference picture list structures associated with the reference picture list 1 included in the SPS, of a reference picture list structure that is associated with the reference picture list 1 and that is used for derivation of the reference picture list 1;
determining whether the first index and a second index being present, wherein the second index is an index, to a list of reference picture list structures associated with reference picture list 0 included in the SPS, of a reference picture list structure associated with the reference picture list 0 that is used for derivation of the reference picture list 0;
in response to the second index being not present, determining a value of the second index comprising:
when at most one reference picture list structure associated with the reference picture list 0 is included in the SPS, determining the value of the second index to be equal to 0;
in response to the first index being not present, determining a value of the first index comprising:
when at most one reference picture list structure associated with the reference picture list 1 is included in the SPS, determining the value of the first index to be equal to 0; and
when the first flag is equal to 0 and the second flag is equal to 1, determining the value of the first index to be equal to the value of the second index; and
decoding a current picture based on the first index and the second index.
3. A computer-implemented method for decoding video, comprising:
receiving a video bitstream;
determining a value of a first flag indicating whether a second flag and a first index are present in a picture header syntax or a slice header for a current picture, wherein the second flag indicates whether reference picture list 1 is derived based on one of reference picture list structures associated with the reference picture list 1 signaled in a sequence parameter set (SPS) and the first index is an index, to a list of the reference picture list structures associated with the reference picture list 1 included in the SPS, of a reference picture list structure that is associated with the reference picture list 1 and that is used for derivation of the reference picture list 1;
determining values of the first index and a second index, wherein the second index is an index, to a list of reference picture list structures associated with reference picture list 0 included in the SPS, of a reference picture list structure that is associated with the reference picture list 0 and that is used for derivation of the reference picture list 0; and
decoding a current picture based on the first index and the second index,
wherein the second index is not present, and the value of the second index is determined to be:
equal to 0 when at most one reference picture list structure associated with the reference picture list 0 is included in the SPS;
wherein the first index is not present, and the value of the first index is determined to be:
equal to 0 when at most one reference picture list structure associated with the reference picture list 1 is included in the SPS; and
equal to the value of the second index when the first flag is equal to 0 and the second flag is equal to 1.