Simplified sub-prediction unit (sub-PU) motion parameter inheritance (MPI)

A method for encoding multiview video data, the method comprising:

• generating a motion parameter candidate list for a first depth prediction unit (PU) in a depth component of a current view of the multiview video data, wherein generating the motion parameter candidate list for the first depth PU comprises:
• dividing the first depth PU into a first plurality of sub-PUs;
• identifying a first co-located texture block to a representative block of the first depth PU, wherein a location of the first co-located texture block in a texture component of the current view corresponds to a location of the representative block of the first depth PU, wherein the representative block of the first depth PU is a first-occurring sub-PU of the first plurality of sub-PUs in raster scan order of the first depth PU or a center sub-PU of the first plurality of sub-PUs;
• determining whether motion parameters of the first co-located texture block are unavailable;
• and
• in response to the determination that motion parameters of the first co-located texture block are unavailable, determining that a first sub-PU motion parameter inheritance candidate is unavailable for inclusion in the motion parameter candidate list for the first depth PU;
• encoding motion information for the first depth PU based on the motion parameter candidate list for the first depth PU without the first sub-PU motion parameter inheritance candidate;
• generating a motion parameter candidate list for a second depth PU in the depth component of the current view, wherein generating the motion parameter candidate list for the second depth PU comprises:
• dividing the second depth PU into a second plurality of sub-PUs;
• identifying a second co-located texture block, wherein a location of the second co-located texture block in the texture component of the current view corresponds to a location of a representative block of the second depth PU, wherein the representative block of the second depth PU is a first-occurring sub-PU of the second plurality of sub-PUs in raster scan order of the second depth PU or a center sub-PU of the second plurality of sub-PUs;
• determining whether motion parameters of the second co-located texture block are unavailable;
• and
• in response to determining that the motion parameters of the second co-located texture block are available, generating a second sub-PU motion parameter inheritance candidate for inclusion in the motion parameter candidate list for the second depth PU, wherein the second sub-PU motion parameter inheritance candidate comprises a respective set of motion parameters for each sub-PU of the second plurality of sub-PUs;
• and
• encoding motion information for the second depth PU based on the motion parameter candidate list for the second depth PU, wherein the motion parameter candidate list for the second depth PU includes the second sub-PU motion parameter inheritance candidate.

A video coding device comprising:

• a memory storing a coded video bitstream that includes multiview video data;
• and
• one or more processors configured to:
• generate a motion parameter candidate list for a current depth prediction unit (PU) in a depth component of a current view of the multiview video data, wherein the one or more processors are configured such that, as part of generating the motion parameter candidate list for the depth PU, the one or more processors:
• divide the current depth PU into a plurality of sub-PUs;
• identify a co-located texture block, wherein a location of the co-located texture block in a texture component of the current view corresponds to a location of a representative block of the current depth PU, wherein the representative block of the current depth PU is a first-occurring sub-PU of the plurality of sub-PUs in raster scan order of the current depth PU or a center sub-PU of the plurality of sub-PUs;
• determine whether motion parameters of the co-located texture block are unavailable;
• in response to the determination that motion parameters of the co-located texture block are unavailable, determine that a sub-PU motion parameter inheritance candidate is unavailable for inclusion in the motion parameter candidate list for the current depth PU;
• and
• in response to determining that the motion parameters of the co-located texture block are available, generate the sub-PU motion parameter inheritance candidate, wherein the sub-PU motion parameter inheritance candidate comprises a respective set of motion parameters for each sub-PU of the plurality of sub-PUs;
• and
• code motion information for the current depth PU based on the motion parameter candidate list for the current depth PU, wherein the motion parameter candidate list for the current depth PU does not include the sub-PU motion parameter inheritance candidate when the sub-PU motion parameter inheritance candidate is unavailable and the motion parameter candidate list for the current depth PU includes the sub-PU motion parameter inheritance candidate when the motion parameters of the co-located texture block are available.

A video coding device for coding multiview video data, the video coding device comprising:

• means for generating a motion parameter candidate list for a current depth prediction unit (PU) in a depth component of a current view of the multiview video data, wherein the means for generating the motion parameter candidate list for the current depth PU comprises:
• means for dividing the current depth PU into a plurality of sub-PUs;
• means for identifying a co-located texture block to a representative block of the current depth PU, wherein a location of the co-located texture block in a texture component of the current view corresponds to a location of the representative block of the current depth PU, wherein the representative block of the current depth PU is a first-occurring sub-PU of the plurality of sub-PUs in raster scan order of the current depth PU or a center sub-PU of the plurality of sub-PUs;
• means for determining whether motion parameters of the co-located texture block are unavailable;
• means for, in response to the determination that motion parameters of the co-located texture block are unavailable, determining that a sub-PU motion parameter inheritance candidate is unavailable for inclusion in the motion parameter candidate list for the current depth PU;
• and
• means for generating, in response to determining that the motion parameters of the co-located texture block are available, the sub-PU motion parameter inheritance candidate, wherein the sub-PU motion parameter inheritance candidate comprises a respective set of motion parameters for each sub-PU of the plurality of sub-PUs;
• and
• means for coding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU, wherein the motion parameter candidate list for the current depth PU does not include the sub-PU motion parameter inheritance candidate when the sub-PU motion parameter inheritance candidate is unavailable and the motion parameter candidate list for the current depth PU includes the sub-PU motion parameter inheritance candidate when the motion parameters of the co-located texture block are available.

A computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video coding device for coding multiview video data, cause the one or more processors to:

• generate a motion parameter candidate list for a current depth prediction unit (PU) in a depth component of a current view of the multiview video data, wherein as part of causing the one or more processors to generate the motion parameter candidate list for the current depth PU, execution of the instructions causes the one or more processors to:
• divide the current depth PU into a plurality of sub-PUs;
• identify a co-located texture block to a representative block of the current depth PU, wherein a location of the co-located texture block in a texture component of the current view corresponds to a location of the representative block of the current depth PU, wherein the representative block of the current depth PU is a first-occurring sub-PU of the plurality of sub-PUs in raster scan order of the current depth PU or a center sub-PU of the plurality of sub-PUs;
• determine whether motion parameters of the co-located texture block are unavailable;
• in response to the determination that motion parameters of the co-located texture block are unavailable, determine that a sub-PU motion parameter inheritance candidate is unavailable for inclusion in the motion parameter candidate list for the current depth PU;
• and
• in response to determining that the motion parameters of the co-located texture block are available, generate the sub-PU motion parameter inheritance candidate, wherein the sub-PU motion parameter inheritance candidate comprises a respective set of motion parameters for each sub-PU of the plurality of sub-PUs;
• and
• code motion information for the current depth PU based on the motion parameter candidate list for the current depth PU, wherein the motion parameter candidate list for the current depth PU does not include the sub-PU motion parameter inheritance candidate when the sub-PU motion parameter inheritance candidate is unavailable and the motion parameter candidate list for the current depth PU includes the sub-PU motion parameter inheritance candidate when the motion parameters of the co-located texture block are available.