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17th Meeting: Brussels, January 2020 2019-12-30 23:35
On level definitions
Authors: Ye-Kui Wang ByteDance Yong He InterDigital Ping Wu ZTE
Abstract
This contribution proposes a few changes to the level definitions text in the latest VVC draft text, summarized as follows:
Meeting Notes
JVET-Q0112 On level definitions [Y.-K. Wang (Bytedance), Y. He (InterDigital), P. Wu (ZTE)]

See also the AHG8 report, which describes relevant email reflector discussion.

This was presented Thursday 16 January 1815–1945 (chaired by FJB).

This contribution proposes a few changes to the level definitions text in the latest VVC draft text, summarized as follows:

  1. The equation for the derivation of the variable MaxDpbSize is updated to use the maximum picture size among pictures within a CLVS instead of using the variable PicSizeInSamplesY, and a value of MaxDpbSize is derived for each layer.
  2. For each layer, a constraint is specified to require the value of a specific instance of the max_dec_pic_buffering_minus1[ ] syntax element plus one shall be less than or equal to the value of MaxDpbSize of the layer. Furthermore, a constraint on the overall DPB size for an OLS containing multiple layers is specified.
  3. The definitions of the constraints on picture size, picture width, and picture height use the maximum picture size, picture width, and picture height instead of the variable PicSizeInSamplesY and the syntax elements pic_width_in_luma_samples and pic_height_in_luma_samples. Furthermore, the constraints are specified separately for each of the SPSs referenced by the layers.
  4. The definitions of several constraints for an AU on the CPB removal time, the nominal CPB removal time, the DPB output time, and the sum of the NumBytesInNalUnit variables use the sum of the picture size of all pictures in an AU instead of the variable PicSizeInSamplesY.
  5. Instead of specifying a limit on the maximum number of slices per picture for each level and using the limit in specifying some constraints for an AU on CPB removal times, a limit on the maximum number of slices per AU is specified and used in specifying those constraints.

The exact proposed text changes are included in Section 3 of this contribution.

It is asserted that the first item (using the global maximum picture size to determine the DPB size) is required following the adoption of JVET-Q0814. Decision (cleanup): Agreed (item of JVET-Q0112).

The second item has been obsoleted by the adoption of JVET-Q0814.

It is asserted that the first part of the third item (using the global maximum picture size in computing limits instead of current picture size) is required following the adoption of JVET-Q0814. Decision (cleanup): Agreed (item of JVET-Q0112).

The second part of the third item has been obsoleted by the adoption of JVET-Q0814.

The fourth item proposes to use the cumulative worst-case picture size for all pictures in an AU to derive constraints on CPB removal time, etc. Decision (cleanup): Agreed (item of JVET-Q0112).

The fifth item proposes to have a limit on the number of slices per AU instead of per picture. This aspect and the actual numbers for the limits were planned for further study.

Cited:
JVET-AA0003 JVET-AQ0003 JVET-Q2001 JVET-R0002 JVET-R0003 JVET-R0060 JVET-R0081 JVET-R0082 JVET-R0141 JVET-R0142 JVET-R0208 JVET-R0218 JVET-R0219 JVET-R0305 JVET-R0350 JVET-R0370 JVET-R0392 JVET-R0481 JVET-R2001 JVET-S0003 more than 20
PATENTS:
4154524 0.34 WO/2024/015638 0.33 WO/2022/206988 0.32 WO/2022/206991 0.31 WO/2022/214063 0.30 WO/2022/214056 0.28 WO/2022/214047 0.27 WO/2022/214046 0.26
ARCHIVE v1 :
JVET-Q0112-v1.docx
Decisions
The fifth item proposes to have a limit on the number of slices per AU instead of per picture. This aspect and the actual numbers for the limits were planned for further study.
Citation