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;
(b) selecting an intra direction mode for one of said coding units;
(c) 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 generate a first predictor for said intra direction mode;
(d) 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 generate a second predictor for said intra direction mode;
(e) 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;
(f) generating said first predictor for said intra direction mode from 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;
(g) generating said second predictor for said intra direction mode 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 first predictor is weighted according to a corresponding weight parameter.
3. The method of claim 2 further comprising wherein said second predictor is weighted according to a corresponding weight parameter.
4. The method of claim 1 further comprising wherein said second predictor is weighted according to a corresponding weight parameter.
5. The method of claim 1 further comprising wherein said first predictor is modified based on at least one shift conversion factor.
6. The method of claim 5 further comprising wherein said second predictor is modified based on at least one shift conversion factor.
7. The method of claim 1 further comprising wherein said second predictor is modified based on at least one shift conversion factor.
8. 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.
9. 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.