| CPC H04N 19/513 (2014.11) [H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/70 (2014.11)] | 11 Claims |
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1. A method for decoding an inter-predicted video block, the method comprising:
receiving, by a device comprising a memory storing instructions and a processor in communication with the memory, a coded video bitstream;
extracting, by the device from the coded video bitstream, an inter-predication mode and a joint delta motion vector (MV) (joint_delta_mv) for a current block in a current frame;
extracting, by the device from the coded video bitstream, a flag (joint_mvd_flag) indicating whether a first delta MV for a first reference frame in a reference list 0 and a second delta MV for a second reference frame in a reference list 1 are jointly signaled;
when the flag indicates that the first delta MV and the second delta MV are jointly signaled, deriving, by the device, the first delta MV corresponding to the reference list 0 and the second delta MV corresponding to the reference list 1 based on the joint delta MV, the first delta MV in conjunction with a first reference MV to obtain a first MV corresponding to the first reference frame in the reference list 0, and the second delta MV in conjunction with a second reference MV to obtain a second MV corresponding to the second reference frame in the reference list 1; and
decoding, by the device, the current block in the current frame based on the first delta MV and the second delta MV wherein:
the inter-predication mode of the current block is NEW_NEWMV; and
the deriving the first delta MV and the second delta MV based on the joint delta MV comprises:
when a first absolute POC distance between the first reference frame and the current frame is equal to a second absolute POC distance between the second reference frame and the current frame:
determining the first delta MV as the joint delta MV,
when a direction relationship of the first reference frame and the second reference frame relative to the current frame is same: determining the second delta MV as the joint delta MV, and
when the direction relationship of the first reference frame and the second reference frame relative to the current frame is opposite: determining the second delta MV as the joint delta MV multiplied by −1.
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