Missing a default/inferred value for alf_cc_cb/cr_filters_signalled_minus1

[swong10]

The value of alf_cc_cb/cr_filters_signalled_minus1 Syntax Element shall be in the range of 0 to 3. It is used to parse alf_ctb_cc_cb/cr_idc[ ][ ].

If alf_cc_cb/cr_filter_signal_flag is set to 0, alf_cc_cb/cr_filters_signalled_minus1 is not present in the bitstream.

The VVC spec semantic does not provide an inferred or default value for alf_cc_cb/cr_filters_signalled_minus1. But in the VTM, it is effectively assumed a value of 3 when it is not present (i.e. alf_cc_cb/cr_filters_signalled = 3+1 = 4). Because there is a line in the following code segment (
"ccAlfFilterCount[0] = ccAlfFilterCount[1] = MAX_NUM_CC_ALF_FILTERS;" which is equal to 4). These 2 VTM variables are not inferred or defaulted to 0 as we would expect.

In AlfParameter.h:

struct CcAlfFilterParam
{

bool ccAlfFilterEnabled[2];
bool ccAlfFilterIdxEnabled[2][MAX_NUM_CC_ALF_FILTERS];
uint8_t ccAlfFilterCount[2];
short ccAlfCoeff[2][MAX_NUM_CC_ALF_FILTERS][MAX_NUM_CC_ALF_CHROMA_COEFF];
int newCcAlfFilter[2];
int numberValidComponents;
CcAlfFilterParam()
{

reset();

}
void reset()
{

std::memset( ccAlfFilterEnabled, false, sizeof( ccAlfFilterEnabled ) );
std::memset( ccAlfFilterIdxEnabled, false, sizeof( ccAlfFilterIdxEnabled ) );
std::memset( ccAlfCoeff, 0, sizeof( ccAlfCoeff ) );
ccAlfFilterCount[0] = ccAlfFilterCount[1] = MAX_NUM_CC_ALF_FILTERS;
numberValidComponents = 3;
newCcAlfFilter[0] = newCcAlfFilter[1] = 0;

}

The choice of this inferred/default value does affect the CABAC decoding of a bitstream that has alf_cc_cb/cr_filter_signal_flag set to 0.

Please confirm if this is a conformance case, and if a default/inferred value should be specified in the VVC spec to match that of the VTM?