US 2020/0092576 A1Published application

Motion prediction coding with coframe motion vectors

AssigneeGoogle Inc.

InventorsBohan Li, Yaowu Xu, Jingning Han

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Abstract

Video coding may include generating, by a processor executing instructions stored on a non-transitory computer-readable medium, an encoded frame by encoding a current frame from an input bitstream, by generating a reference coframe spatiotemporally corresponding to the current frame, wherein the current frame is a frame from a sequence of input frames, wherein each frame from the sequence of input frames has a respective sequential location in the sequence of input frames, and wherein the current frame has a current sequential location in the sequence of input frames, and encoding the current frame using the reference coframe. Video coding may include including the encoded frame in an output bitstream and outputting the output bitstream.

Claims20

Dependent claims

A method comprising:

generating, by a processor executing instructions stored on a non-transitory computer-readable medium, a decoded frame by decoding a current frame from an encoded bitstream, wherein decoding includes:
identifying a current block from the current frame;
identifying a previously decoded block based on coding information for the current block;
determining whether motion information for the previously decoded block includes a coframe motion vector for the previously decoded block;
determining whether to identify a prediction block for decoding the current block based on a reference coframe;
in response to a determination to omit identifying the prediction block for decoding the current block based on the reference coframe:
in response to a determination that the motion information for the previously decoded block includes the coframe motion vector for the previously decoded block:
identifying an alignment block in the reference coframe based on a spatial location of the previously decoded block and the coframe motion vector for the previously decoded block;
determining a motion vector for the alignment block based on motion field information for the alignment block;
determining a motion vector prediction for the current block based on the motion vector for the alignment block and the coframe motion vector for the previously decoded block;
determining a motion vector for the current block based on the motion vector prediction for the current block;
and
identifying the prediction block based on a reference frame indicated by the motion vector for the current block;
in response to a determination to identify the prediction block for decoding the current block based on the reference coframe:
in response to a determination that the motion information for the previously decoded block includes the coframe motion vector for the previously decoded block:
determining a coframe motion vector prediction for the current block based on the coframe motion vector for the previously decoded block;
in response to a determination that the motion information for the previously decoded block omits the coframe motion vector for the previously decoded block:
identifying a forward motion vector from the motion information for the previously decoded block;
identifying a backward motion vector from the motion information for the previously decoded block;
determining a coframe motion vector prediction for the current block based on the forward motion vector and the backward motion vector;
determining a coframe motion vector for the current block based on the coframe motion vector prediction for the current block;
and
identifying the prediction block based on the reference coframe and the coframe motion vector for the current block;
generating a decoded block corresponding to the current block based on the prediction block;
and
including the decoded block in the decoded frame;
and
outputting a reconstructed frame based on the decoded frame.

25 more elements

A method comprising:

generating, by a processor executing instructions stored on a non-transitory computer-readable medium, an encoded frame by encoding a current frame from an input bitstream, wherein encoding includes:
identifying a current block from the current frame;
identifying a previously coded block;
determining whether motion information for the previously coded block includes a coframe motion vector for the previously coded block;
determining whether to identify a prediction block for encoding the current block based on a reference coframe;
in response to a determination to omit identifying the prediction block for encoding the current block based on the reference coframe:
in response to a determination that the motion information for the previously coded block includes the coframe motion vector for the previously coded block:
identifying an alignment block in the reference coframe based on a spatial location of the previously coded block and the coframe motion vector for the previously coded block;
determining a motion vector for the alignment block based on motion field information for the alignment block;
determining a motion vector prediction for the current block based on the motion vector for the alignment block and the coframe motion vector for the previously coded block;
and
including an indication of the motion vector prediction for the current block in an output bitstream;
and
in response to a determination to identify the prediction block for encoding the current block based on the reference coframe, determining a coframe motion vector prediction for the current block, wherein determining the coframe motion vector prediction for the current block includes:
in response to a determination that the motion information for the previously coded block includes the coframe motion vector for the previously coded block:
determining the coframe motion vector prediction for the current block based on the coframe motion vector for the previously coded block;
in response to a determination that the motion information for the previously coded block omits the coframe motion vector for the previously coded block:
identifying a forward motion vector from the motion information for the previously coded block;
identifying a backward motion vector from the motion information for the previously coded block;
and
determining the coframe motion vector prediction for the current block based on the forward motion vector and the backward motion vector;
and
including the indication of the coframe motion vector prediction for the current block in the output bitstream;
and
outputting the output bitstream.

22 more elements

A method comprising:

generating, by a processor executing instructions stored on a non-transitory computer-readable medium, an encoded frame by encoding a current frame from an input bitstream, wherein encoding includes:
generating a reference coframe spatiotemporally corresponding to the current frame, wherein the current frame is a frame from a sequence of input frames, wherein each frame from the sequence of input frames has a respective sequential location in the sequence of input frames, and wherein the current frame has a current sequential location in the sequence of input frames;
and
encoding the current frame using the reference coframe;
including the encoded frame in an output bitstream;
and
outputting the output bitstream.

4 more elements

Dependencies are inferred from the claim text.