JVET-Q0751 AHG9: On mixed NAL unit [J. Samuelsson, S. Deshpande (Sharp), M. M. Hannuksela (Nokia), Hendry, S. Paluri (LGE)]
This contribution was discussed Thursday 16 January in Track A at 1200 (chaired by GJS).
This contribution provides candidate draft text for combined proposals developed in offline work.
This contribution relates to support for mixed NAL unit types in VVC. It is proposed to modify the text related to mixed_nalu_types_in_pic_flag to allow support for mixing bitstreams containing CRA pictures. This joint contribution is a combination of aspects from JVET-Q0206, JVET-Q0239, JVET-Q0261, JVET-Q0284, and JVET-Q0396.
Regarding whether the mixed indication should be a “one-way constraint” versus a requirement for mixed pictures to actually contain a mixture, this is not a one-way constraint, in order to make it easier to determine whether a picture is an IRAP or not.
Decision (cleanup): Adopt. This contains an additional aspect, which is to require that all VCL NAL units within one subpicture to have the same NAL unit type. It was commented that we need to check and clean up any text that may conflict with this (e.g., check 7.4.2.2, that any RASL shall precede RADL associated with the same IRAP), and the editors were given the discretion to make such corrections.
Any other aspects are for further study.