Method and apparatus of high-level signaling for weighted prediction
The present disclosure provides an encoding method, wherein the method comprises: determining syntax elements to be coded, wherein the syntax elements include a reference picture list structure and at least one high-level syntax (HLS) weighted prediction parameters; coding the at least one HLS weighted prediction parameters; and after coding the at least one HLS weighted prediction parameters, coding the reference picture list structure. The syntax elements are reordered such that coding the reference picture list structure can be based on values of the at least one HLS weighted prediction parameters.
1 . An encoding method, comprising:
determining syntax elements to be coded, wherein the syntax elements include a reference picture list structure (ref_pic_list_struct) and at least one high-level syntax (HLS) weighted prediction parameter;
coding the at least one HLS weighted prediction parameter; and
after coding the at least one HLS weighted prediction parameter, coding the reference picture list structure, wherein the reference picture list structure is presented in a sequence parameter set (SPS) or in a slice header,
wherein coding the reference picture list structure comprises restricting a binarization of at least a part of the reference picture list structure, including, when a sequence parameter set flag for weighted uni-prediction is set to 0, coding a modified delta picture order count (POC) value for an element of a reference picture list, wherein the modified delta POC value is less than a delta POC value being used in coding process.
2 . The encoding method of claim 1 , wherein a reference picture list derived from the reference picture list structure comprises reference pictures, each reference picture having same picture order count (POC) parameter.
3 . The encoding method of claim 1 , wherein the at least one HLS weighted prediction parameter comprises at least one of a sequence parameter set flag for weighted uni-prediction or a sequence parameter set flag for weighted bi-prediction.
4 . A decoding method, comprising:
receiving a bitstream;
decoding the bitstream to obtain syntax elements comprising a reference picture list structure (ref_pic_list_struct) and at least one high level syntax (HLS) weighted prediction parameter, wherein the at least one HLS weighted prediction parameter is decoded prior to the reference picture list structure, wherein the reference picture list structure is presented in a sequence parameter set (SPS) or in a slice header;
performing prediction based on the obtained syntax elements to obtain a prediction block;
reconstructing a reconstructed block based on the prediction block; and
obtaining a decoded picture based on the reconstructed block,
wherein performing prediction based on the obtained syntax elements to obtain the prediction block comprises:
obtaining a value of delta picture order count (POC) based on the at least one HLS weighted prediction parameter and a syntax element in the reference picture list structure; and
performing prediction based on the value of delta POC, wherein
the syntax element in the reference picture list structure is abs_delta_poc_st;
the value of delta POC is obtained as follows:
if(sps_weighted_pred_flag || sps_weighted_bipred_flag)
AbsDeltaPocSt[listIdx][rplsIdx][i]=abs_delta_poc_st[listIdx][rplsIdx][i]else
AbsDeltaPocSt[listIdx][rplsIdx][i]=abs_delta_poc_st[listIdx][rplsIdx][i]+1
wherein AbsDeltaPocSt[listIdx][rplsIdx][i] is the absolute value of delta POC, abs_delta_poc_st[listIdx][rplsIdx][i] is the syntax element in the reference picture list structure.
5 . The method of claim 4 , wherein the at least one HLS weighted prediction parameter includes at least one of a sequence parameter set flag for weighted uni-prediction or a sequence parameter set flag for weighted bi-prediction.
6 . The method of claim 4 , wherein decoding the bitstream to obtain the syntax elements is performed by entropy decoding.
7 . The method of claim 4 , wherein obtaining the value of delta POC comprises:
determining, based on a value of the at least one HLS weighted prediction parameter, whether the value of delta POC is allowed to have a value of 0;
when it is determined that the value of delta POC is not allowed to have a value of 0, restoring the value of delta POC using an incremented value of the syntax element in the reference picture list structure.
8 . A decoder, comprising:
at least one processor; and
one or more memories coupled to the at least one processor and storing programming instructions, which when executed by the at least one processor, cause the decoder to:
receive a bitstream;
decode the bitstream to obtain syntax elements comprising a reference picture list structure (ref_pic_list_struct) and at least one high level syntax (HLS) weighted prediction parameter, wherein the at least one HLS weighted prediction parameter is decoded prior to the reference picture list structure, wherein the reference picture list structure is presented in a sequence parameter set (SPS) or in a slice header;
perform prediction based on the obtained syntax elements to obtain a prediction block;
reconstructing a reconstructed block based on the prediction block; and
obtain a decoded picture based on the reconstructed block, where the prediction is performed by:
obtaining a value of delta picture order count (POC) based on the at least one HLS weighted prediction parameter and a syntax element in the reference picture list structure; and
performing prediction based on the value of delta POC, wherein
the syntax element in the reference picture list structure is abs_delta_poc_st;
the value of delta POC is obtained as follows:
if (sps_weighted_pred_flag || sps_weighted_bipred_flag)
AbsDeltaPocSt [listIdx][rplsIdx][i]=abs_delta_poc_st[listIdx][rplsIdx][i]else
AbsDeltaPocSt[listIdx][rplsIdx][i]=abs_delta_poc_st[listIdx][rplsIdx][i]+1
wherein AbsDeltaPocSt[listIdx][rplsIdx][i] is an absolute value of delta POC, abs_delta_poc_st[listIdx][rplsIdx][i] is the syntax element in the reference picture list structure.
9 . The decoder of claim 8 , wherein the at least one HLS weighted prediction parameter includes at least one of a sequence parameter set flag for weighted uni-prediction or a sequence parameter set flag for weighted bi-prediction.
10 . The decoder of claim 8 , wherein the decoding of the bitstream to obtain syntax elements is performed by entropy decoding.
11 . The decoder of claim 8 , wherein the programming instructions, which when executed by the at least one processor, further cause the decoder to:
determine, based on a value of the at least one HLS weighted prediction parameter, whether the value of delta POC is allowed to have a value of 0;
when it is determined that the value of delta POC is not allowed to have a value of 0, restore the value of delta POC using an incremented value of the syntax element in the reference picture list structure.
12 . An encoding device, comprising:
at least one processor; and
one or more memories coupled to the at least one processor and storing programming instructions, which when executed by the at least one processor, cause the encoding device to:
determine syntax elements to be coded, wherein the syntax elements include a reference picture list structure ref_pic_list_struct and at least one high-level syntax (HLS) weighted prediction parameter;
code the at least one HLS weighted prediction parameter; and
after coding the at least one HLS weighted prediction parameter, code the reference picture list structure, wherein the reference picture list structure is presented in a sequence parameter set (SPS) or in a slice header; and
a non-transitory machine-readable medium to store coded video data from the encoding device in a form of a bitstream,
wherein the coding of the reference picture list structure comprises a restriction on a binarization of at least a part of the reference picture list structure, including, when a sequence parameter set flag for weighted uni-prediction is set to 0, code a modified delta picture order count (POC) value for an element of a reference picture list, wherein the modified delta POC value is less than a delta POC value being used in coding process.
13 . The encoding device of claim 12 , wherein a reference picture list derived from the reference picture list structure comprises reference pictures, each reference picture having a same picture order count (POC) parameter.
14 . The encoding device of claim 12 , wherein the at least one HLS weighted prediction parameter comprises at least one of a sequence parameter set flag for weighted uni-prediction or a sequence parameter set flag for weighted bi-prediction.