A.2.2 Decoded Texture Signal Constraints
26.1183GPPRelease 17TSVirtual Reality (VR) profiles for streaming applications
A.2.2.1 General
Due to the restrictions to use a single decoder, the decoded texture signals require to follow the profile and level constraints of the decoder. Generally, this requires a careful balance of the permitted frame rates, stereo modes, spatial resolutions, and usage of region wise packing for different resolutions and coverage restrictions. Details on preferred settings such as frame rates and spatial resolutions are for example discussed in TR 26.918 [2].
This clause provides a summary of restrictions for the different operation points defined in the present document.
A.2.2.2 Constraints for Main and Flexible H.265/HEVC Operation Point
The profile and level constraints of H.265/HEVC Main-10 Profile Main Tier Profile Level 5.1 require careful balance of the permitted frame rates, stereo modes, spatial resolutions, and usage of region wise packing for different resolutions and coverage restrictions. If the decoded texture signal is beyond the Profile and Level constraints, then a careful adaptation of the signal is recommended to fulfil the constraints.
This clause provides a brief overview of potential signal constraints and possible adjustments.
Table A.2-1 provides selected permitted combinations of spatial resolutions, frame rates and stereo modes assuming full coverage and no region-wise packing applied. Note that fractional frame rates are excluded for better readability. Note that the Main H.265/HEVC Operation Point only allows frame rates up to 60 Hz.
Table A.2-1: Selected permitted combinations of spatial resolutions and frame rates
|
Spatial resolution per eye |
Stereo |
Permitted Frame Rates in Hz |
|
4096 × 2048 |
None |
24; 25; 30; 50; 60 |
|
3840 × 1920 |
None |
24; 25; 30; 50; 60 |
|
3072 × 1536 |
None |
24; 25; 30; 50; 60; 90; 100 |
|
2880 × 1440 |
None |
24; 25; 30; 50; 60; 90; 100; 120 |
|
2048 × 1024 |
None |
24; 25; 30; 50; 60; 90; 100; 120 |
|
2880 × 1440 |
TaB |
24; 25; 30; 50; 60 |
|
2048 × 1024 |
TaB |
24; 25; 30; 50; 60; 90; 100; 120 |
Table A.2-2 provides the maximum percentage of high-resolution area that can be encoded assuming that the low-resolution area is encoded in 2k resolution covering the full 360 degree area, i.e. using 2048 × 1024 or 1920 × 960 and full coverage is provided for different frame rates. Note also that a viewport typically covers about 12-25% of a full 360 video. Note that fractional frame rates are excluded for better readability.
Table A.2-2: Maximum Percentage of high-resolution area when assuming that the low-resolution area is encoded in 2k resolution, i.e. using 2048 × 1024 or 1920 × 960 and full coverage is provided for different frame rates
|
Spatial resolution |
Spatial resolution |
Stereo |
Frame Rates in Hz |
|||||||
|
24 |
25 |
30 |
50 |
60 |
90 |
100 |
120 |
|||
|
6144 × 3072 |
2048 × 1024 |
None |
9.29% |
9.29% |
9.29% |
9.29% |
9.29% |
5.24% |
4.43% |
3.21% |
|
4096 × 2048 |
2048 × 1024 |
None |
21.67% |
21.67% |
21.67% |
21.67% |
21.67% |
12.22% |
10.33% |
7.50% |
|
3840 × 1920 |
1920 × 960 |
None |
100.00% |
100.00% |
100.00% |
100.00% |
100.00% |
74.12% |
63.38% |
47.26% |
|
6144 × 3072 |
2048 × 1024 |
TaB |
3.21% |
3.21% |
3.21% |
3.21% |
3.21% |
1.19% |
0.79% |
0.18% |
|
4096 × 2048 |
2048 × 1024 |
TaB |
7.50% |
7.50% |
7.50% |
7.50% |
7.50% |
2.78% |
1.83% |
0.42% |
|
3840 × 1920 |
1920 × 960 |
TaB |
47.26% |
47.26% |
47.26% |
47.26% |
47.26% |
20.40% |
15.02% |
6.96% |
Table A.2-3 provides the maximum percentage of coverage area that can be encoded assuming that the remaining pixels are not encoded for different frame rates. Note that fractional frame rates are excluded for better readability.
Table A.2-3: Maximum Percentage of coverage area for different frame rates
|
Spatial resolution |
Stereo |
Frame Rates in Hz |
|||||||
|
24 |
25 |
30 |
50 |
60 |
90 |
100 |
120 |
||
|
6144 × 3072 |
None |
47.22% |
47.22% |
47.22% |
47.22% |
47.22% |
31.48% |
28.33% |
23.61% |
|
4096 × 2048 |
None |
100.00% |
100.00% |
100.00% |
100.00% |
100.00% |
70.83% |
63.75% |
53.13% |
|
3840 × 1920 |
None |
100.00% |
100.00% |
100.00% |
100.00% |
100.00% |
80.59% |
72.53% |
60.44% |
|
6144 × 3072 |
TaB |
23.61% |
23.61% |
23.61% |
23.61% |
23.61% |
15.74% |
14.71% |
11.81% |
|
4096 × 2048 |
TaB |
53.13% |
53.13% |
53.13% |
53.13% |
53.13% |
35.42% |
31.88% |
26.56% |
|
3840 × 1920 |
TaB |
60.44% |
60.44% |
60.44% |
60.44% |
60.44% |
40.30% |
36.27% |
30.22% |
A.2.2.2a Constraints for Main 8K H.265/HEVC Operation Point
The profile and level constraints of H.265/HEVC Main-10 Profile Main Tier Profile Level 6.1 require careful balance of the permitted frame rates, stereo modes, spatial resolutions, and usage of region wise packing for different resolutions and coverage restrictions. If the decoded texture signal is beyond the Profile and Level constraints, then a careful adaptation of the signal is recommended to fulfil the constraints.
This clause provides a brief overview of potential signal constraints and possible adjustments.
Table A.2a-1 provides selected permitted combinations of spatial resolutions, frame rates and stereo modes assuming full coverage and no region-wise packing applied. Note that fractional frame rates are excluded for better readability. Note that the Main 8K H.265/HEVC Operation Point only allows frame rates up to 60 Hz.
Table A.2a-1: Selected permitted combinations of spatial resolutions and frame rates
|
Spatial resolution per eye |
Stereo |
Permitted Frame Rates in Hz |
|
8192 × 4096 |
None |
24; 25; 30; 50; 60 |
|
7680 × 3840 |
None |
24; 25; 30; 50; 60 |
|
6144 × 3072 |
None |
24; 25; 30; 50; 60; 90; 100 |
|
5760 × 2880 |
None |
24; 25; 30; 50; 60; 90; 100; 120 |
|
4096 × 2048 |
None |
24; 25; 30; 50; 60; 90; 100; 120 |
|
5760 × 2880 |
TaB |
24; 25; 30; 50; 60 |
|
4096 × 2048 |
TaB |
24; 25; 30; 50; 60; 90; 100; 120 |
Table A.2a-2 provides the maximum percentage of coverage area that can be encoded assuming that the remaining pixels are not encoded for different frame rates. Note that fractional frame rates are excluded for better readability.
Table A.2a-2 Maximum Percentage of coverage area for different frame rates
|
Spatial resolution |
Stereo |
Frame Rates in Hz |
|||||||
|
24 |
25 |
30 |
50 |
60 |
90 |
100 |
120 |
||
|
12288 × 6144 |
None |
47.22% |
47.22% |
47.22% |
47.22% |
47.22% |
31.48% |
28.33% |
23.61% |
|
8192 × 4096 |
None |
100.00% |
100.00% |
100.00% |
100.00% |
100.00% |
70.83% |
63.75% |
53.13% |
|
7680 × 3840 |
None |
100.00% |
100.00% |
100.00% |
100.00% |
100.00% |
80.59% |
72.53% |
60.44% |
|
12288 × 6144 |
TaB |
23.61% |
23.61% |
23.61% |
23.61% |
23.61% |
15.74% |
14.71% |
11.81% |
|
8192 × 4096 |
TaB |
53.13% |
53.13% |
53.13% |
53.13% |
53.13% |
35.42% |
31.88% |
26.56% |
|
7680 × 3840 |
TaB |
60.44% |
60.44% |
60.44% |
60.44% |
60.44% |
40.30% |
36.27% |
30.22% |