Motion vector range based on motion vector precision
AssigneesBeijing Bytedance Network Technology Co., Ltd., Bytedance Inc.
InventorsLi ZHANG, Kai ZHANG, Hongbin LIU, Jizheng XU, Yue WANG
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Abstract
A method for video processing is provided to include: determining a motion vector precision of one or more motion vectors related to a current video block of a video; selecting, based on the motion vector precision, a motion vector range; and performing, based on the motion vector range, a conversion between the current video block and a bitstream representation of the video.
Claims19
A method for processing video data, comprising:
- deriving, for a conversion between a current video block of a video and a bitstream of the video, at least one temporal collocated motion vector, wherein each of the at least one temporal collocated motion vector is derived at least based on a motion vector associated with a first block which has a temporal reference picture that is different from a target reference picture of the current video block;
- scaling each of the at least one temporal collocated motion vector based on a first picture order count difference between the target reference picture and a current picture including the current video block and a second picture order count difference between the temporal reference picture and a first picture including the first block;
- performing a first clipping operation on the at least one scaled temporal collocated motion vector to derive at least one clipped temporal collocated motion vector, wherein the clipping range of each component of the at least one clipped temporal collocated motion vector is [−(1<<(M−1)), (1<<(M−1))−1 ], M is greater than 16 and << is an arithmetic left shift operation;
- and
- performing the conversion based on the at least one clipped temporal collocated motion vector.
The method of claim 1, wherein the at least one clipped temporal collocated motion vector is further used to construct a motion candidate list, and at least one motion predictor derived based on the motion candidate list is used in the conversion directly, or is combined with at least one motion vector difference to derive a refined motion vector. 3 . The method of claim 2, wherein each component of the refined motion vector has a bit-depth M-bit.
An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions up on execution by the processor, cause the processor to:
- derive, for a conversion between a current video block of a video and a bitstream of the video, at least one temporal collocated motion vector, wherein each of the at least one temporal collocated motion vector is derived at least based on a motion vector associated with a first block which has a temporal reference picture that is different from a target reference picture of the current video block;
- scale each of the at least one temporal collocated motion vector based on a first picture order count difference between the target reference picture and a current picture including the current video block and a second picture order count difference between the temporal reference picture and a first picture including the first block;
- perform a first clipping operation on the at least one scaled temporal collocated motion vector to derive at least one clipped temporal collocated motion vector, wherein the clipping range of each component of the at least one clipped temporal collocated motion vector is [−(1<<(M−1)), (1<<(M−1))−1 ], M is greater than 16 and << is an arithmetic left shift operation;
- and
- perform the conversion based on the at least one clipped temporal collocated motion vector.
A non-transitory computer-readable storage medium storing instructions that cause a processor to:
- derive, for a conversion between a current video block of a video and a bitstream of the video, at least one temporal collocated motion vector, wherein each of the at least one temporal collocated motion vector is derived at least based on a motion vector associated with a first block which has a temporal reference picture that is different from a target reference picture of the current video block;
- scale each of the at least one temporal collocated motion vector based on a first picture order count difference between the target reference picture and a current picture including the current video block and a second picture order count difference between the temporal reference picture and a first picture including the first block;
- perform a first clipping operation on the at least one scaled temporal collocated motion vector to derive at least one clipped temporal collocated motion vector, wherein the clipping range of each component of the at least one clipped temporal collocated motion vector is [−(1<<(M−1)), (1<<(M−1))−1 ], M is greater than 16 and << is an arithmetic left shift operation;
- and
- perform the conversion based on the at least one clipped temporal collocated motion vector.
A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:
- deriving at least one temporal collocated motion vector, wherein each of the at least one temporal collocated motion vector is derived at least based on a motion vector associated with a first block which has a temporal reference picture that is different from a target reference picture of the current video block;
- scaling each of the at least one temporal collocated motion vector based on a first picture order count difference between the target reference picture and a current picture including the current video block and a second picture order count difference between the temporal reference picture and a first picture including the first block;
- performing a first clipping operation on the at least one scaled temporal collocated motion vector to derive at least one clipped temporal collocated motion vector, wherein the clipping range of each component of the at least one clipped temporal collocated motion vector is [−(1<<(M−1)), (1<<(M−1))−1 ], M is greater than 16 and << is an arithmetic left shift operation;
- and
- generating the bitstream based on the at least one clipped temporal collocated motion vector.
Dependencies are inferred from the claim text.