Content for  TS 26.118  Word version:  18.0.0

This operation targets enhanced 360 video decoding and rendering of H.265/HEVC video for VR applications. Among others, this operation point supports among others rendering of:

• 8K mono video at up to 60 Hz frame rates for full coverage
• 6K stereoscopic video at up to 60 Hz frame rates for full coverage
• 4K mono video at up to 120 Hz frame rates for full coverage
• Higher than 8K resolutions for restricted coverage
• Extended colour space, and SDR and HDR transfer characteristics

A Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation point shall conform to the requirements in the remainder of clause 5.1.7. A Receiver conforming to the 3GPP VR Main 8K H.265/HEVC Operation point shall support decoding and rendering a Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation point. Detailed receiver requirements are provided in the remainder of clause 5.1.7.

A Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation point

• shall conform to H.265/HEVC Main-10 Profile Main Tier Profile Level 6.1 [6], i.e. for a Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation,
  • the general_profile_idc shall be set to 2 indicating the Main10 profile.
  • the general_tier_flag shall be set to 0 indicating the Main tier.
  • the value of level_idc shall not be greater than 183 (corresponding to the Level 6.1) and should indicate the lowest level to which the Bitstream conforms.
• shall have general_progressive_source_flag equal to 1,
• shall have general interlaced_source_flag equal to 0,
• shall have general_frame_only_constraint_flag equal to 1
• shall conform to following further limitations:
  • if frame rate 60 fps is used, then the maximum luma picture size in samples of 33,554,432 is not exceeded,
  • the maximum VCL Bit Rate is constrained to be 80 Mbps with CpbVclFactor and CpbNalFactor being fixed to be 1000 and 1100, respectively.

Bitstreams conforming to the 3GPP VR Main 8K H.265/HEVC Operation point shall be encoded with 10-bit precision:

• bit_depth_luma_minus8 = 2 (10 bits)
• bit_depth_chroma_minus8 = bit_depth_luma_minus8

Receivers conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall support 10-bit precision.

Due to the options provided in this operation point, additional original format may be considered that can then be decoded and rendered by a Receiver conforming to this operation point. Recommended original formats beyond those specified in clause 5.1.4.3 for equirectangular projection (ERP) are:

• Mono formats: 8192 × 4096, 7680 × 3840, 6144 × 3072, 5760 × 2880
• Stereo formats with resolution for each eye: 6144 × 3072, 5860 × 2880, 4096 × 2048, 3840 × 1920, 2880 × 1440, 2048 × 1024

The distribution formats are more flexible as additional VR metadata as defined in the remainder of clause 5.1.7 may be used. However, for the distribution formats, all requirements of H.265/HEVC Main-10 Profile Main Tier Profile Level 6.1 [5] shall apply to the decoded texture signal. According to H.265/HEVC Main-10 Profile Main Tier Profile Level 6.1 [6], the maximum luminance width and height does not exceed 16,888 pixels. In addition to the H.265/HEVC Main-10 Profile Main Tier Profile Level 6.1 [6] constraints, a Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation point, the decoded texture signal shall in addition:

• not exceed the luminance width of 16,384 pixels, and
• not exceed the luminance height of 16,384 pixels.

A Receiver conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall be capable of decoding and rendering Bitstreams with a decoded texture signal of maximum luminance width of 16,384 pixels, a maximum luminance height of 16,384 pixels and the overall profile/level constraints.

A Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall use either Recommendation ITU-R BT.709 [3] colorimetry or Recommendation ITU-R BT.2020 [4] colorimetry in non-constant luminance for standard dynamic range (SDR). For Perceptual Quantization (PQ) High Dynamic Range (HDR), BT.2020 [4] colorimetry in non-constant luminance and PQ electro-optical transfer function (EOTF) as defined in Recommendation ITU-R BT.2100 [11] are used. For Hybrid Log-Gamma (HLG) High Dynamic Range (HDR), BT.2020 [4] colorimetry in non-constant luminance and the HLG opto-electronic transfer function (OETF) as defined in Recommendation ITU-R BT.2100 [11] are used. Specifically, in the VUI, the colour parameter information shall be present, i.e.:

• video_signal_type_present_flag value and colour_description_present_flag value shall be set to 1.
• If BT.709 [3] is used, it shall be signalled by setting colour_primaries to the value 1, transfer_characteristics to the value 1 and matrix_coeffs to the value 1.
• If BT.2020 [4] and SDR is used, it shall be signalled by setting colour_primaries to the value 9, transfer_characteristics to the value 14 and matrix_coeffs to the value 9,
• the chroma_loc_info_present_flag should be equal to 1, and if set the chroma_sample_loc_type_top_field and chroma_sample_loc_type_bottom_field shall both be equal to 2.
• If BT.2020 [4] and ITU-R BT.2100 [11] are used in HDR, it shall be signalled by setting colour_primaries to the value 9 and matrix_coeffs to the value 9. The chroma_sample_loc_type_top_field shall be set to 2.
  • If the PQ EOTF is used, transfer_characteristics shall be set to the value 16.
  • If the HLG OETF is used, transfer_characteristics shall be set to either the value 18 or 14. In the latter case, the Bitstream shall also contain the alternative_transfer_characteristics SEI message. The alternative_transfer_characteristics SEI message shall be inserted at each RAP, and its parameter preferred_transfer_characteristics shall be set to the value 18.
  • the chroma_loc_info_present_flag should be equal to 1, and if set, the chroma_sample_loc_type_top_field and chroma_sample_loc_type_bottom_field shall both be equal to 2.

A Receiver conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall be capable of decoding and rendering according to any of the above configurations. SEI messages for HDR metadata signalling may be used. The requirements and recommendations for Bitstreams and Receivers, as documented in clause 4.5.5.7 of TS 26.116, also apply for the 3GPP VR Main 8K H.265/HEVC Operation Point.

A Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall have one of the following frame rates: 24; 25; 30; 24/1001; 30/1001; 50; 60; 60/1001; 90; 100; 120; 120/1001 Hz. Selected combinations of frame rates with other source parameters are provided in Annex A.2.2.2a. In the VUI, the timing information may be present:

• If the timing information is present, i.e. the value of vui_timing_info_present_flag is set to 1, then the values of vui_num_units_in_tick and vui_time_scale shall be set according to the frame rates allowed in this clause. The timing information present in the video Bitstream should be consistent with the timing information signalled at the system level.
• The frame rate shall not change between two RAPs. fixed_frame_rate_flag value, if present, shall be set to 1.

There are no requirements on output timing conformance for H.265/HEVC decoding (Annex C of [6]). The Hypothetical Reference Decoder (HRD) parameters, if present, should be ignored by the Receiver. A Receiver conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall be capable of decoding and rendering Bitstreams that use frame rates according to the bitstream requirements documented above.

The same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.7 apply.

Receivers conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall satisfy the same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.8.

The same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.9 apply.

Bitstreams conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall satisfy the same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.10.

The same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.11 apply. However, the region-wise packing SEI message (payloadType equal to 155) shall only be used for restricted coverage signalling (in contrast to 3GPP VR Main H.265/HEVC Operation Point, where region-wise packing SEI message is used for signalling both restricted coverage and viewport-optimized content). When the video does not cover the entire sphere, for each picture, there shall be a region-wise packing SEI message present in the bitstream that applies to the picture. Furthermore, the following restrictions apply:

• num_packed_regions shall be set to 1.
• rwp_guard_band_flag[0] shall be equal to 0.
• rwp_transform_type[0] shall be equal to 0.
• The value of packed_region_width[0] shall be equal to proj_region_width[0].
• The value of packed_region_height[0] shall be equal to proj_region_height[0].

Bitstreams and receivers conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall satisfy the same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.13.

For a Bitstream conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point:

• the equirectangular projection SEI message (payloadType equal to 150) with erp_guard_band_flag not set to 0 shall not be present,
• the sphere rotation SEI message (payloadType equal to 154) shall not be present.
• the region-wise packing SEI message (payloadType equal to 155) not conforming to the restrictions stated in clause 5.1.7.11 shall not be present.

Receivers conforming to the 3GPP VR Main 8K H.265/HEVC Operation Point shall satisfy the same requirements as those defined for 3GPP VR Main H.265/HEVC Operation Point in clause 5.1.5.15.