Method and apparatus for history-based motion vector prediction with parallel processing

A video decoder for video decoding, comprising:

• processing circuitry configured to:
• acquire a current picture from a coded video bitstream, the current picture being segmented into a plurality of units, each unit divided into a plurality of blocks, the plurality of blocks in each unit being arranged as a first grid in each unit, and the plurality of units being arranged as a second grid in the current picture, the plurality of blocks being decoded in accordance with a parallel process,
• decode, for one of the units, a current block from the plurality of blocks using an entry from a history motion vector (HMVP) buffer,
• update the HMVP buffer with a motion vector of the decoded current block,
• determine a location of the current block in the current picture, and
• in response to a determination that the current block is located in a first column and a first row of a first unit of a row of the units in the second grid, reset the HMVP buffer.

A non-transitory computer readable medium having instructions stored therein, which when executed by a processor in a video decoder causes the processor to execute a method comprising:

• acquiring a current picture from a coded video bitstream, the current picture being segmented into a plurality of units, each unit divided into a plurality of blocks, the plurality of blocks in each unit being arranged as a first grid in each unit, and the plurality of units being arranged as a second grid in the current picture, the plurality of blocks being decoded in accordance with a parallel process;
• decoding, for one of the units, a current block from the plurality of blocks using an entry from a history motion vector (HMVP) buffer;
• updating the HMVP buffer with a motion vector of the decoded current block;
• determining a location of the current block in the current picture;
• and
• in response to determining that the current block is located in a first column and a first row of a first unit of a row of the units in the second grid, resetting the HMVP buffer.