CWG-G089: Missing constraints

CWG-G089 introduces the constraints listed below.

These were integrated into the specification but not yet integrated into the AVM.

Constraints

OLK Constraint It is a requirement of bitstream conformance that if long_term_frame_id_bits is greater than 0, the OrderHint of an OLK shall be less than (1 << OrderHintBits).

Note: This constraint ensures that the OrderHint of an OLK is equal to the value of order_hint in the bitstream (i.e., no modular wrap-around has occurred) when long-term reference frames are in use. This guarantees that the relative distance and ordering between an OLK and its long-term reference frames are the same whether decoding is sequential or initiated at the OLK as a random access point. Encoders may select an appropriate value for order_hint_bits_minus_1 when addressing this constraint.

RAS Constraint It is a requirement of bitstream conformance that if long_term_frame_id_bits is greater than 0, the OrderHint of a RAS frame with restricted_prediction_switch equal to 0 shall be less than (1 << OrderHintBits).

Note: This constraint ensures that the OrderHint of a RAS frame is equal to the value of order_hint in the bitstream (i.e., no modular wrap-around has occurred) when long-term reference frames are in use. This guarantees that the relative distance and ordering between a RAS frame and its long-term reference frames are the same whether decoding is sequential or initiated at the RAS frame as a random access point. Encoders may select an appropriate value for order_hint_bits_minus_1 when addressing this constraint.