Method and apparatus for video coding
Method and decoder for reconstructing at least a sample of a block using an intra prediction angle determined from an intra prediction mode. The method includes decoding at least one syntax element from a coded video sequence. The at least one syntax element is indicative of an intra prediction mode. An intra prediction angle is determined that corresponds to the indicated intra prediction mode based on a stored relationship between a plurality of intra prediction modes and a plurality of intra prediction angles. At least one sample of a block is reconstructed using the intra prediction angle that is determined to correspond to the indicated intra prediction mode. The plurality of intra prediction modes in the stored relationship can include at least one of a first plurality of wide angle prediction modes and a second plurality of wide angle prediction modes. The first plurality of wide angle prediction modes is beyond a bottom left direction diagonal mode and the second plurality of wide angle prediction modes is beyond a top right direction diagonal mode.
1. A method for video decoding in a video decoder, the method comprising:
decoding at least one syntax element from a coded video sequence, the at least one syntax element indicative of an intra prediction mode;
determining an intra prediction angle that corresponds to the indicated intra prediction mode based on a stored relationship between a plurality of intra prediction modes and a plurality of intra prediction angles; and
reconstructing at least one sample of a block using the intra prediction angle that is determined to correspond to the indicated intra prediction mode, wherein
the plurality of intra prediction modes in the stored relationship includes at least one of a first plurality of wide angle prediction modes and a second plurality of wide angle prediction modes,
the first plurality of wide angle prediction modes is beyond a bottom left direction diagonal mode, and
the second plurality of wide angle prediction modes is beyond a top right direction diagonal mode.
2. The method as recited in claim 1 , wherein
the stored relationship is a look-up table.
3. The method as recited in claim 2 , wherein
the intra prediction angle corresponds to intraPredAngle and the intra prediction mode corresponds to predModeIntra, and
the stored relationship is in accordance with:
predModeIntra
−10
−9
−8
−7
−6
−5
−4
−3
−2
−1
2
3
4
5
6
7
8
intraPredAngle
114
93
79
68
60
54
49
45
39
35
32
29
26
23
21
19
17
predModeIntra
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
intraPredAngle
15
13
11
9
7
5
3
2
1
0
−1
−2
−3
−5
−7
−9
−11
predModeIntra
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
intraPredAngle
−13
−25
−017
−19
−21
−23
−26
−29
−32
−29
−26
−3
−21
−19
−17
−15
−13
predModeIntra
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
intraPredAngle
−11
−9
−7
−5
−3
−2
−1
0
1
2
3
5
7
9
11
13
15
predModeIntra
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
intraPredAngle
17
19
21
23
26
29
32
35
39
45
49
54
60
68
79
93
114.
4. The method as recited in claim 3 , wherein the reconstructing comprises:
reconstructing the at least one sample of a non-square block using the relationship between predModeIntra and intraPredAngle.
5. The method as recited in claim 1 , wherein the reconstructing comprises:
reconstructing the at least one sample of a non-square block using the stored relationship between the plurality of intra prediction modes and the plurality of intra prediction angles.
6. The method according to claim 1 , wherein
a number of the first plurality of wide angle prediction modes is ten; and
a number of the second plurality of wide angle prediction modes is ten.
7. The method according to claim 1 , wherein
the first plurality of wide angle prediction modes have integer values in a range of −1 to −10; and
the second plurality of wide angle prediction modes have integer values in a range of 67 to 76.
8. The method according to claim 7 , wherein
the plurality of intra prediction angles corresponding to each of the first and second plurality of wide angle prediction modes are in a range of 35 to 114.
9. The method according to claim 1 , wherein:
the first plurality of wide angle prediction modes go beyond mode 2 of the HEVC (High Efficiency Video Coding) standard; and
the second plurality of wide angle prediction modes go beyond mode 34 of the HEVC standard.
10. A video decoder for video decoding, comprising:
processing circuitry configured to:
decode at least one syntax element from a coded video sequence, the at least one syntax element indicative of an intra prediction mode;
determine an intra prediction angle that corresponds to the indicated intra prediction mode based on a stored relationship between a plurality of intra prediction modes and a plurality of intra prediction angles; and
reconstruct at least one sample of a block using the intra prediction angle that is determined to correspond to the indicated intra prediction mode, wherein
the plurality of intra prediction modes in the stored relationship includes at least one of a first plurality of wide angle prediction modes and a second plurality of wide angle prediction modes,
the first plurality of wide angle prediction modes is beyond a bottom left direction diagonal mode, and
the second plurality of wide angle prediction modes is beyond a top right direction diagonal mode.
11. The video decoder recited in claim 10 , wherein the processing circuitry is configured to store the relationship in a look-up table.
12. The video decoder recited in claim 11 , wherein:
the intra prediction angle corresponds to intraPredAngle and the intra prediction mode corresponds to predModeIntra, and
the processing circuitry is configured to store the relationship as:
predModeIntra
−10
−9
−8
−7
−6
−5
−4
−3
−2
−1
2
3
4
5
6
7
8
intraPredAngle
114
93
79
68
60
54
49
45
39
35
32
29
26
23
21
19
17
predModeIntra
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
intraPredAngle
15
13
11
9
7
5
3
2
1
0
−1
−2
−3
−5
−7
−9
−11
predModeIntra
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
intraPredAngle
−13
−25
−17
−19
−21
−23
−26
−29
−32
−29
−26
−23
−21
−19
−17
−15
−13
predModeIntra
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
intraPredAngle
−11
−9
−7
−5
−3
−2
−1
0
1
2
3
5
7
9
11
13
15
predModeIntra
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
intraPredAngle
17
19
21
23
26
29
32
35
39
45
49
54
60
68
79
93
114.
13. The video decoder recited in claim 12 , wherein the processing circuitry is configured to reconstruct the at least one sample of a non-square block using the relationship between predModeIntra and intraPredAngle.
14. The video decoder recited in claim 10 , wherein the processing circuitry is configured to reconstruct the at least one sample of a non-square block using the stored relationship between the plurality of intra prediction modes and the plurality of intra prediction angles.
15. The video decoder recited in claim 10 , wherein:
a number of the first plurality of wide angle prediction modes is ten; and
a number of the second plurality of wide angle prediction modes is ten.
16. The video decoder recited in claim 10 , wherein:
the first plurality of wide angle prediction modes have integer values in a range of −1 to −10; and
the second plurality of wide angle prediction modes have integer values in a range of 67 to 76.
17. The video decoder recited in claim 16 , wherein
the plurality of intra prediction angles corresponding to each of the first and second plurality of wide angle prediction modes are in a range of 35 to 114.
18. The video decoder recited in claim 10 , wherein:
the first plurality of wide angle prediction modes go beyond mode 2 of the HEVC (High Efficiency Video Coding) standard; and
the second plurality of wide angle prediction modes go beyond mode 34 of the HEVC standard.
19. A non-transitory computer-readable medium storing instructions which when executed by a computer for video decoding cause the computer to perform:
decoding at least one syntax element from a coded video sequence, the at least one syntax element indicative of an intra prediction mode;
determining an intra prediction angle that corresponds to the indicated intra prediction mode based on a stored relationship between a plurality of intra prediction modes and a plurality of intra prediction angles; and
reconstructing at least one sample of a block using the intra prediction angle that is determined to correspond to the indicated intra prediction mode, wherein
the plurality of intra prediction modes in the stored relationship includes at least one of a first plurality of wide angle prediction modes and a second plurality of wide angle prediction modes,
the first plurality of wide angle prediction modes is beyond a bottom left direction diagonal mode, and
the second plurality of wide angle prediction modes is beyond a top right direction diagonal mode.
20. The medium as recited in claim 19 , wherein
the intra prediction angle corresponds to intraPredAngle and the intra prediction mode corresponds to predModeIntra, and
the stored relationship is in accordance with:
predModeIntra
−10
−9
−8
−7
−6
−5
−4
−3
−2
−1
2
3
4
5
6
7
8
intraPredAngle
114
93
79
68
60
54
49
45
39
35
32
29
26
23
21
19
17
predModeIntra
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
intraPredAngle
15
13
11
9
7
5
3
2
1
0
−1
−2
−3
−5
−7
−9
−11
predModeIntra
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
intraPredAngle
−13
−25
−17
−19
−21
−23
−26
−29
−32
−29
−26
−23
−21
−19
−17
−15
−13
predModeIntra
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
intraPredAngle
−11
−9
−7
−5
−3
−2
−1
0
1
2
3
5
7
9
11
13
15
predModeIntra
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
intraPredAngle
17
19
21
23
26
29
32
35
39
45
49
54
60
68
79
93
114.