Adaptive weighting of reference pictures in video encoding
A video decoder, encoder, and corresponding methods for processing video data for an image block and a particular reference picture index to predict the image block are disclosed that utilize adaptive weighting of reference pictures to enhance video compression, where a decoder includes a reference picture weighting factor unit for determining a weighting factor corresponding to the particular reference picture index; an encoder includes a reference picture weighting factor assignor for assigning a weighting factor corresponding to the particular reference picture index; and a method for decoding includes receiving a reference picture index with the data that corresponds to the image block, determining a weighting factor for each received reference picture index, retrieving a reference picture for each index, motion compensating the retrieved reference picture, and multiplying the motion compensated reference picture by the corresponding weighting factor to form a weighted motion compensated reference picture.
1. A method for video decoding, comprising:
receiving, in a bitstream, a signal indicative of a number of one or more reference pictures allowed to be used for predicting a plurality of image blocks of a picture;
receiving, in said bitstream, a signal indicative of a weighting factor for each slice or each picture of said one or more reference pictures, and said one or more reference pictures including a single reference picture for predicting an image block of said picture;
predicting said image block, using said single reference picture and the weighting factor received for said single reference picture; and
decoding said image block based on said predicted image block.
2. The method of claim 1 , said predicting comprising:
generating a motion compensated predictor for said image block using said single reference picture; and
weighting said motion compensated predictor using said weighting factor received for said single reference picture.
3. The method of claim 2 , said decoding comprising:
adding said weighted motion compensated predictor to residual data for said image block.
4. The method of claim 1 , wherein a plurality of reference pictures are used for predicting said plurality of image blocks of said picture, and wherein a reference picture index indicates which reference picture is used for predicting said image block.
5. The method of claim 1 , wherein said number of one or more reference pictures is included in a slice header.
6. An apparatus for video decoding, comprising:
at least one memory and one or more processors coupled to said at least one memory, wherein said one or more processors are configured to:
receive, in a bitstream, a signal indicative of a number of one or more reference pictures allowed to be used for predicting a plurality of image blocks of a picture;
receive, in said bitstream, a signal indicative of a weighting factor for each slice or each picture of said one or more reference pictures, and said one or more reference pictures including a single reference picture for predicting an image block of said picture;
predict said image block, using said single reference picture and the weighting factor received for said single reference picture; and
decode said image block based on said predicted image block.
7. The apparatus of claim 6 , wherein said one or more processors are configured to:
generate a motion compensated predictor for said image block using said single reference picture; and
weight said motion compensated predictor using said weighting factor received for said single reference picture.
8. The apparatus of claim 7 , wherein said one or more processors are further configured to:
add said weighted motion compensated predictor to residual data for said image block.
9. The apparatus of claim 6 , wherein a plurality of reference pictures are used for predicting said plurality of image blocks of said picture, and wherein a reference picture index indicates which reference picture is used for predicting said image block.
10. The apparatus of claim 6 , wherein said number of one or more reference picture is included in a slice header.
11. A non-transitory computer readable medium having computer readable program code embodied thereon, the computer readable program code comprising:
program code for receiving, in a bitstream, a signal indicative of a number of one or more reference pictures allowed to be used for predicting a plurality of image blocks of a picture;
program code for receiving, in said bitstream, a signal indicative of a weighting factor for each slice or each picture of said one or more reference pictures, and said one or more reference pictures including a single reference picture for predicting an image block of said picture;
program code for predicting said image block, using said single reference picture and the weighting factor received for said single reference picture; and
program code for decoding said image block based on said predicted image block.
12. The medium of claim 11 , said program code for predicting comprising:
program code for generating a motion compensated predictor for said image block using said single reference picture; and
program code for weighting said motion compensated predictor using said weighting factor received for said single reference picture.
13. The medium of claim 12 , said program code for decoding comprising:
program code for adding said weighted motion compensated predictor to residual data for said image block.
14. The medium of claim 11 , wherein a plurality of reference pictures are used for predicting said plurality of image blocks of said picture, and wherein a reference picture index indicates which reference picture is used for predicting said image block.
15. The medium of claim 11 , wherein said number of one or more reference pictures is included in a slice header.