Sub-prediction unit temporal motion vector prediction (sub-PU TMVP) for video coding

A video coding apparatus for processing a current prediction unit (PU) with a sub-PU temporal motion vector prediction (TMVP) mode, comprising circuitry configured to:

• receive the current PU including sub-PUs;
• determining a main collocated picture;
• determine an initial motion vector for said sub-PUs that is a motion vector of a spatial neighboring block of the current PU;
• determine collocated sub-PUs in the main collocated picture according to the initial motion vector;
• and
• obtain collocated motion information of the collocated sub-PUs in the main collocated picture for deriving motion vectors of the sub-PUs of the current PU.

A non-transitory computer-readable medium storing instructions which, when executed by a processor, cause the processor to perform a video coding method for processing a current prediction unit (PU) with a sub-PU temporal motion vector prediction (TMVP) mode, the method comprising:

• receiving the current PU including sub-PUs;
• determining a main collocated picture;
• determining an initial motion vector for said sub-PUs;
• determining collocated sub-PUs in the main collocated picture based on the initial motion vector;
• and
• obtaining collocated motion information of the collocated sub-PUs in the main collocated picture for deriving motion vectors of the sub-PUs of the current PU.