Mismatch with spec on allow binary/ternary split process

[forayr]

In the specification, this processes use MaxBtSizeY, which is now variable. Whereas in the function canSplit in the VTM, the constant MAX_TB_SIZEY is used, instead of the variable value present in the sps.

[forayr]

MR: ​https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/merge_requests/805

[adamjw]

As far as I remember, this constraint is not really directly connected to the actual allowed MaxTbSize, but rather the VPDU size (which is fixed as 64, or MAX_TB_SIZEY). So I think the software actually represents the intended behavior and this should be fixed in the spec to match 64.
The canSplit function for TU_MAX_TR_SPLIT correctly respects the now variable maximal transform size, so if a block is larger than the maximal allowed transform size, it would be sub-split into smaller TUs. There is no reason to restrict BT/TT splits depending on maximal allowed transform size.

[bbross]

Changing the ticket to spec since the spec should be changed as follows:

In "6.4.2 Allowed binary split process", replace "MaxTbSizeY" with the VPDU size 64.

[adamjw]

Replying to bbross:

Changing the ticket to spec since the spec should be changed as follows:

In "6.4.2 Allowed binary split process", replace "MaxTbSizeY" with the VPDU size 64.

The same should be done "6.4.3 Allowed ternary split process"

[bbross]

This will be fixed JVET-P2001-vC.