Adaptive unequal weight planar prediction
A method of decoding JVET video includes receiving a bitstream that includes encoded video data that includes encoded video data. From the encoded data, a horizontal predictor and a vertical predictor for a pixel in the current coding block may be interpolated. A coding block size may be identified to determine whether to use equal weight or unequal weights to apply to each of the horizontal and vertical predictors for calculating a final planar prediction value P(x,y) by comparing the coding block size to a coding block size threshold.
1. A method of decoding a bitstream, including a plurality of frames, by a decoder, comprising:
(a) receiving said bitstream indicating how a coding tree unit was partitioned into coding units according to a quad tree plus multi tree structure that allows a coding block to be split in half in both horizonal and vertical directions, wherein one of said partitioned blocks to be split is further based upon one selected from a group consisting of,
(i) a symmetric binary partitioning that splits one of said partitioned blocks in half in either a horizontal direction or a vertical direction resulting in two blocks that are the same size, and
(ii) an asymmetric partitioning that splits one of said partitioned blocks in either a horizontal direction or a vertical direction resulting in a plurality of blocks that are different sizes;
(b) where a first one of said coding units has a first width and a first height, wherein said first width is different than said first height;
(c) where a second one of said coding units has a second width and a second height, wherein said second width is different than said second height;
(d) where said first width is different than said second width, and said first height is different than said second height;
(e) calculating a first prediction to predict pixel values for said first coding unit and calculating a second prediction to predict pixel values for said second coding unit;
(f) determining a first predictor based upon a plurality of pixels drawn from a first horizontal array of pixels and drawn from a first vertical array of pixels for a pixel in said first coding unit;
(g) determining a second predictor based upon a plurality of pixels drawn from a second horizontal array of pixels and drawn from a second vertical array of pixels for a pixel in said second coding unit;
(h) where said first horizontal array of pixels is different than said second horizontal array of pixels, and said first vertical array of pixels is different than said second vertical array of pixels;
(i) where a set of available first horizontal array of pixels and available first vertical array of pixels for said first coding unit is based upon said first height and said first width, respectively;
(j) where a set of available second horizontal array of pixels and available second vertical array of pixels for said second coding unit is based upon said second height and said second width, respectively;
(k) decoding said first coding unit based upon said first prediction for said predicted pixel of said first coding unit which is based upon said first predictor, and decoding said second coding unit based upon said second planar prediction for said predicted pixel of said second coding unit which is based upon said second predictor.
2. The method of claim 1 , wherein unequal weights A(x,y) and B(x,y) are assigned for prediction of each pixel within the first coding unit.
3. The method of claim 1 , wherein unequal weights A(x,y) and B(x,y) are each assigned to a distance ratio from a reliable neighboring pixel for the first predictor.
4. The method of claim 1 , wherein a block size of said first coding unit also determines whether to apply dimension based weight such that P(x,y) is determined as
P
(
W
,
H
)
=
W
*
R
(
W
,
-
1
)
+
H
*
R
(
-
1
,
H
)
H
+
W
,
where R(x, y) denotes the intensity value of the reconstructed neighboring pixel at (x, y) coordinate.
5. The method of claim 1 , wherein the coding block size of said first coding unit is indicated by information in the bitstream.
6. The method of claim 5 , wherein the information in the bitstream includes at least one of: the first coding unit size, a slice type associated with the first coding unit, and/or a number of non-zero quantized coefficients associated with the first coding unit.
7. The method of claim 6 , wherein the information in the bitstream is signaled via a flag.
8. The method of claim 7 , wherein the information in the bitstream is signaled in at least one of a sequence parameter set (SPS), a picture parameter set (PPS), and/or a slice header.
9. A method of decoding a bitstream by a decoder, comprising:
(a) receiving said bitstream indicating how a coding tree unit was partitioned into coding units according to a quad tree plus multi tree structure that allows a coding block to be split in half in both horizonal and vertical directions, wherein one of said partitioned blocks to be split is further based upon one selected from a group consisting of,
(i) a symmetric binary partitioning that splits one of said partitioned blocks in half in either a horizontal direction or a vertical direction resulting in two blocks that are the same size, and
(ii) an asymmetric partitioning that splits one of said partitioned blocks in either a horizontal direction or a vertical direction resulting in a plurality of blocks that are different sizes;
(b) where a first one of said coding units has a first width and a first height, wherein said first width is different than said first height;
(c) where a second one of said coding units has a second width and a second height, wherein said second width is different than said second height;
(d) where said first width is different than said second width, and said first height is different than said second height;
(e) using a first single directional index to predict a first pixel of said first coding unit which identifies a plurality of pixels drawn from a first reference pixel in a position above said first coding unit in array of pixels and a second reference pixel at a position to the left of said first coding unit in array of pixels;
(f) using a second single directional index to predict a first pixel of said second coding unit which identifies a plurality of pixels drawn from a third reference pixel in a position above said second coding unit in array of pixels and a fourth reference pixel at a position to the left of said second coding unit in array of pixels;
(g) where said first single directional index is different than said second single directional index;
(h) where a set of available first indexes from which said first single directional index is selected based upon said first height and/or said first width of said first coding unit;
(i) where a set of available second indexes from which said second single directional index is selected based upon said second height and/or said second width of said first coding unit;
(j) decoding said first coding unit based upon said first pixel prediction for said first pixel of said first coding unit, and decoding said second coding unit based upon said second pixel prediction for said first pixel of said second coding unit;
(k) wherein said first set of available first indexes refers to directional predicational angles including values greater then 45 degrees and/or less than −135 degrees;
(l) wherein said second set of available first indexes refers to directional predicational angles including values greater then 45 degrees and/or less than −135 degrees.