Weighted angular prediction for intra coding
A method of decoding JVET video, comprising receiving a bitstream indicating how a coding tree unit was partitioned into coding units according to a partitioning structure that allows nodes to be split according to a partitioning technique. An intra direction mode for a coding unit may be selected, as well as one or more of the plurality of reference lines to generate at least one predictor for the intra direction mode. A predictor may be generated from reference samples within each selected reference line by combining predicted pixel values based on a projected position on a main reference line in combination with predicted pixel values based on a projected position on a side reference line. The predicted pixel values are weighted according to a weight parameter, wherein the weight parameter is determined based on a shift conversion factor.
1. A method for decoding video data comprising one or more processors, the method comprising:
(a) receiving a bitstream indicating how a coding tree unit was partitioned into a plurality of coding units according to a partitioning structure that allows nodes to be split according to a partitioning technique that includes rectangular coding units, wherein said bitstream includes at least one B-slice;
(b) selecting a first one of a plurality of main reference lines, where said first one of said plurality of main reference lines is selected from a set that comprises (i) a first main reference line next adjacent to said coding unit above said coding unit, and (ii) a second main reference line next adjacent to said first main reference line above said coding unit, to determine a predictor for said coding unit;
(c) selecting a second one of a plurality of side reference lines, where said second one of said plurality of side reference lines is selected from a set that comprises (i) a first side reference line next adjacent to said coding unit left of said coding unit, and (ii) a second side reference line next adjacent to said first side reference line left of said coding unit, to further determine said predictor for said coding unit;
(d) wherein, (i) a combination of said first main reference line next adjacent to said coding unit above said coding unit and said second side reference line next adjacent to said first side reference line left of said coding unit is not permitted, and (ii) a combination of said second main reference line next adjacent to said first main reference line above said coding unit and said first side reference line next adjacent to said coding unit left of said coding unit is not permitted;
(e) selectively generating said predictor for said coding unit either from a group comprising (i) one or more of a plurality of main reference samples within said selected first one of said plurality of main reference lines based on a projected position on said selected first one of said plurality of main reference lines or, (ii) from one or more of a plurality of side reference samples within said selected second one of said plurality of side reference lines based on a projected position on said selected second one of said plurality of side reference lines.
2. The method of claim 1 further comprising wherein said predictor is used to form a weighted prediction.
3. The method of claim 1 further comprising wherein said predictor is derived based upon a shift operation.
4. The method of claim 1 further comprising said plurality of main reference lines is selected from a set that also comprises a Nth reference line that is not a third main reference line next adjacent to said second main reference line above said coding unit.
5. The method of claim 1 further comprising said plurality of side reference lines is selected from a set that also comprises a Nth reference line that is not a third side reference line next adjacent to said second side reference line left of said coding unit.
6. The method of claim 4 further comprising said plurality of side reference lines is selected from a set that also comprises a Nth reference line that is not a third side reference line next adjacent to said second side reference line left of said coding unit.
7. A bitstream of compressed video data for decoding by a decoder, including a computer readable storage medium storing the compressed video data, the bitstream comprising:
(a) said bitstream containing data indicating how a coding tree unit was partitioned into a plurality of coding units according to a partitioning structure that allows nodes to be split according to a partitioning technique that includes rectangular coding units, wherein said bitstream includes at least one B-slice;
(b) wherein said bitstream is configured for selecting a first one of a plurality of main reference lines, where said first one of said plurality of main reference lines is selected from a set that comprises (i) a first main reference line next adjacent to said coding unit above said coding unit, and (ii) a second main reference line next adjacent to said first main reference line above said coding unit, to determine a predictor for said coding unit;
(c) wherein said bitstream is configured for selecting a second one of a plurality of side reference lines, where said second one of said plurality of side reference lines is selected from a set that comprises (i) a first side reference line next adjacent to said coding unit left of said coding unit, and (ii) a second side reference line next adjacent to said first side reference line left of said coding unit, to further determine said predictor for said coding unit;
(d) wherein, (i) a combination of said first main reference line next adjacent to said coding unit above said coding unit and said second side reference line next adjacent to said first side reference line left of said coding unit is not permitted, and (ii) a combination of said second main reference line next adjacent to said first main reference line above said coding unit and said first side reference line next adjacent to said coding unit left of said coding unit is not permitted;
(e) wherein said bitstream is configured for selectively generating said predictor for said coding unit either from a group comprising (i) one or more of a plurality of main reference samples within said selected first one of said plurality of main reference lines based on a projected position on said selected first one of said plurality of main reference lines or, (ii) from one or more of a plurality of side reference samples within said selected second one of said plurality of side reference lines based on a projected position on said selected second one of said plurality of side reference lines.
8. A method of encoding a bitstream of compressed video data by an encoder, comprising:
(a) providing said bitstream indicating how a coding tree unit was partitioned into a plurality of coding units according to a partitioning structure that allows nodes to be split according to a partitioning technique that includes rectangular coding units, wherein said bitstream includes at least one B-slice;
(b) wherein said bitstream is configured for selecting a first one of a plurality of main reference lines, where said first one of said plurality of main reference lines is selected from a set that comprises (i) a first main reference line next adjacent to said coding unit above said coding unit, and (ii) a second main reference line next adjacent to said first main reference line above said coding unit, to determine a predictor for said coding unit;
(c) wherein said bitstream is configured for selecting a second one of a plurality of side reference lines, where said second one of said plurality of side reference lines is selected from a set that comprises (i) a first side reference line next adjacent to said coding unit left of said coding unit, and (ii) a second side reference line next adjacent to said first side reference line left of said coding unit, to further determine said predictor for said coding unit;
(d) wherein, (i) a combination of said first main reference line next adjacent to said coding unit above said coding unit and said second side reference line next adjacent to said first side reference line left of said coding unit is not permitted, and (ii) a combination of said second main reference line next adjacent to said first main reference line above said coding unit and said first side reference line next adjacent to said coding unit left of said coding unit is not permitted;
(e) wherein said bitstream is configured for selectively generating said predictor for said coding unit either from a group comprising (i) one or more of a plurality of main reference samples within said selected first one of said plurality of main reference lines based on a projected position on said selected first one of said plurality of main reference lines or, (ii) from one or more of a plurality of side reference samples within said selected second one of said plurality of side reference lines based on a projected position on said selected second one of said plurality of side reference lines.