WO2015135174A1 - Codage de profondeur issue de la disparité simplifié en codage vidéo tridimensionnel (3d) - Google Patents

Codage de profondeur issue de la disparité simplifié en codage vidéo tridimensionnel (3d) Download PDF

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Publication number
WO2015135174A1
WO2015135174A1 PCT/CN2014/073358 CN2014073358W WO2015135174A1 WO 2015135174 A1 WO2015135174 A1 WO 2015135174A1 CN 2014073358 W CN2014073358 W CN 2014073358W WO 2015135174 A1 WO2015135174 A1 WO 2015135174A1
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Prior art keywords
depth
candidate list
motion parameter
current depth
parameter candidate
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PCT/CN2014/073358
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English (en)
Inventor
Hongbin Liu
Ying Chen
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Qualcomm Incorporated
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Priority to PCT/CN2014/073358 priority Critical patent/WO2015135174A1/fr
Publication of WO2015135174A1 publication Critical patent/WO2015135174A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/597—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding specially adapted for multi-view video sequence encoding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
    • H04N19/51—Motion estimation or motion compensation
    • H04N19/513—Processing of motion vectors
    • H04N19/517—Processing of motion vectors by encoding
    • H04N19/52—Processing of motion vectors by encoding by predictive encoding

Definitions

  • This disclosure relates to video encoding and decoding and, more particularly, three-dimensional (3D) video coding.
  • Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite radio telephones, so-called "smart phones," video teleconferencing devices, video streaming devices, and the like.
  • Digital video devices implement video compression techniques, such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4, Part 10, Advanced Video Coding (AVC), the High Efficiency Video Coding (HEVC) standard, and extensions of such standards.
  • AVC Advanced Video Coding
  • HEVC High Efficiency Video Coding
  • Video compression techniques perform spatial (intra-picture) prediction and/or temporal (inter-picture) prediction to reduce or remove redundancy inherent in video sequences.
  • a video slice i.e., a video frame or a portion of a video frame
  • Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same picture.
  • Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction with respect to reference samples in neighboring blocks in the same picture or temporal prediction with respect to reference samples in other reference pictures.
  • Spatial or temporal prediction results in a predictive block for a block to be coded.
  • Residual data represents pixel differences between the original block to be coded and the predictive block.
  • An inter-coded block is encoded according to a motion vector that points to a block of reference samples forming the predictive block, and the residual data indicates the difference between the coded block and the predictive block.
  • An intra-coded block is encoded according to an intra-coding mode and the residual data.
  • the residual data may be transformed from the pixel domain to a transform domain, resulting in residual coefficients, which then may be quantized.
  • the quantized coefficients initially arranged in a two-dimensional array, may be scanned in order to produce a one-dimensional vector of coefficients, and entropy coding may be applied to achieve even more compression.
  • a multiview coding bitstream may be generated by encoding views, e.g., from multiple perspectives.
  • Some three-dimensional (3D) video standards have been developed that make use of multiview coding aspects. For example, different views may transmit left and right eye views to support 3D video.
  • some 3D video coding processes may apply so-called multiview plus depth coding.
  • a 3D video bitstream may contain not only texture view components, but also depth view components. For example, each view may comprise one texture view component and one depth view component.
  • this disclosure describes techniques for simplifying depth motion prediction in a three-dimensional (3D) video coding process, such as 3D-HEVC.
  • the disclosure describes techniques for simplified derivation of disparity derived depth candidates for a motion parameter candidate list, e.g., a merging candidate list, for a current depth prediction unit (PU).
  • a motion parameter candidate list e.g., a merging candidate list
  • PU current depth prediction unit
  • a method for decoding multiview video data may include 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.
  • the method may further include deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block.
  • the method may further include deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list.
  • the method may further include decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video decoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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; derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block; derive a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video decoding device for decoding multiview video data may include 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.
  • the video decoding device may further include means for deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block.
  • the video decoding device may further include means for deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list.
  • the video decoding device may further include means for decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, may 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; derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block; derive a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a method for decoding multiview video data may include 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.
  • the method may further include deriving one or more candidates for the motion parameter candidate list based at least in part on a reference texture block.
  • the method may further include determining that a disparity motion vector associated with the reference texture block is available.
  • the method may further include, in response to the determination that the motion vector associated with the reference texture block is available, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based at least in part on the reference texture block.
  • DDD derived depth coding
  • the method may further include in response to the determination that the motion vector associated with the reference texture block is not available, determine not to derive the DDD candidate for the motion parameter candidate list.
  • the method may further include decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • a video decoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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; derive one or more candidates for the motion parameter candidate list based at least in part on a reference texture block; determine that a disparity motion vector associated with the reference texture block is available; in response to the determination that the motion vector associated with the reference texture block is available, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based at least in part on the reference texture block;
  • DDD derived depth coding
  • a video decoding device for decoding multiview video data may include 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.
  • the video decoding device may further include means for deriving one or more candidates for the motion parameter candidate list based at least in part on a reference texture block.
  • the video decoding device may further include means for determining that a disparity motion vector associated with the reference texture block is available.
  • the video decoding device may further include means for, in response to the
  • the video decoding device may further include means for, in response to the determination that the motion vector associated with the reference texture block is not available, determining not to derive the DDD candidate for the motion parameter candidate list.
  • the video decoding device may further include means for decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, may 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; derive one or more candidates for the motion parameter candidate list based at least in part on a reference texture block; determine that a disparity motion vector associated with the reference texture block is available; in response to the determination that the motion vector associated with the reference texture block is available, derive a derived depth coding (DDD) candidate for the motion parameter candidate list based at least in part on the reference texture block; in response to the determination that the motion vector associated with the reference texture block is not available, determine not to derive the DDD candidate for the motion parameter candidate list; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a method for decoding multiview video data may include 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.
  • the method may further include deriving a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode;
  • the method may further include decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video decoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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; derive a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • PU current depth prediction unit
  • DDD derived depth coding
  • a video decoding device for decoding multiview video data may include 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.
  • the video decoding device may further include means for deriving a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode.
  • the video decoding device may further include means for decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, may 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; derive a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a method for decoding multiview video data may include 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 current depth PU is coded with merge mode.
  • the method may further include determining whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU.
  • the method may further include in response to the
  • the method may further include decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video decoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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 current depth PU is coded with merge mode; determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU; in response to the determination that Inter SDC is applicable to the current depth PU, determine not to derive a derived depth coding (DDD) candidate for the motion parameter candidate list; in response to the determination that Inter SDC is not applicable to the current depth PU, derive a derived depth coding (DDD) candidate for the motion parameter candidate list; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • Inter SDC Inter prediction mode
  • a video decoding device for decoding multiview video data may include 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 current depth PU is coded with merge mode.
  • the video decoding device may further include means for determining whether Segment-wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU.
  • the video decoding device may further include means for, in response to the determination that Inter SDC is applicable to the current depth PU, determining not to derive a derived depth coding (DDD) candidate for the motion parameter candidate list.
  • the video decoding device may further include means for decoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, may 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 the current depth PU is coded with merge mode; determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU; in response to the determination that Inter SDC is applicable to the current depth PU, determine not to derive a derived depth coding (DDD) candidate for the motion parameter candidate list; and decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • Inter SDC Segment- wise DC coding for Inter prediction mode
  • a method for encoding multiview video data may include 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.
  • the method may further include deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block.
  • the method may further include deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list.
  • the method may further include encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video encoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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; derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block; derive a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video encoding device for encoding multiview video data may include 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.
  • the video encoding device may further include means for deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block.
  • the video encoding device may further include means for deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list.
  • the video encoding device may further include means for encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, may 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; derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block; derive a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a method for encoding multiview video data may include 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.
  • the method may further include deriving one or more candidates for the motion parameter candidate list based at least in part on a reference texture block.
  • the method may further include determining that a disparity motion vector associated with the reference texture block is available.
  • the method may further include, in response to the determination that the motion vector associated with the reference texture block is available, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based at least in part on the reference texture block.
  • DDD derived depth coding
  • the method may further include in response to the determination that the motion vector associated with the reference texture block is not available, determine not to derive the DDD candidate for the motion parameter candidate list.
  • the method may further include encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • a video encoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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; derive one or more candidates for the motion parameter candidate list based at least in part on a reference texture block; determine that a disparity motion vector associated with the reference texture block is available; in response to the determination that the motion vector associated with the reference texture block is available, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based at least in part on the reference texture block;
  • DDD derived depth coding
  • a video encoding device for encoding multiview video data may include 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.
  • the video encoding device may further include means for deriving one or more candidates for the motion parameter candidate list based at least in part on a reference texture block.
  • the video encoding device may further include means for determining that a disparity motion vector associated with the reference texture block is available.
  • the video encoding device may further include means for, in response to the
  • the video encoding device may further include means for, in response to the determination that the motion vector associated with the reference texture block is not available, determining not to derive the DDD candidate for the motion parameter candidate list.
  • the video encoding device may further include means for encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, may 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; derive one or more candidates for the motion parameter candidate list based at least in part on a reference texture block; determine that a disparity motion vector associated with the reference texture block is available; in response to the determination that the motion vector associated with the reference texture block is available, derive a derived depth coding (DDD) candidate for the motion parameter candidate list based at least in part on the reference texture block; in response to the determination that the motion vector associated with the reference texture block is not available, determine not to derive the DDD candidate for the motion parameter candidate list; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a method for encoding multiview video data may include 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.
  • the method may further include deriving a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode;
  • the method may further include encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video encoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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; derive a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • PU current depth prediction unit
  • DDD derived depth coding
  • a video encoding device for encoding multiview video data may include 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.
  • the video encoding device may further include means for deriving a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode.
  • the video encoding device may further include means for encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, may 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; derive a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a method for encoding multiview video data may include 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 current depth PU is coded with merge mode.
  • the method may further include determining whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU.
  • the method may further include in response to the
  • the method may further include encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a video encoding device may include a memory storing a coded video bitstream that includes multiview video data and one or more processors.
  • the one or more processors may be 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 current depth PU is coded with merge mode; determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU; in response to the determination that Inter SDC is applicable to the current depth PU, determine not to derive a derived depth coding (DDD) candidate for the motion parameter candidate list; in response to the determination that Inter SDC is not applicable to the current depth PU, derive a derived depth coding (DDD) candidate for the motion parameter candidate list; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • Inter SDC Inter prediction mode
  • a video encoding device for encoding multiview video data may include 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 current depth PU is coded with merge mode.
  • the video encoding device may further include means for determining whether Segment-wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU.
  • the video encoding device may further include means for, in response to the determination that Inter SDC is applicable to the current depth PU, determining not to derive a derived depth coding (DDD) candidate for the motion parameter candidate list.
  • the video encoding device may further include means for encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • a computer-readable storage medium may have instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, may 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 the current depth PU is coded with merge mode; determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU; in response to the determination that Inter SDC is applicable to the current depth PU, determine not to derive a derived depth coding (DDD) candidate for the motion parameter candidate list; and encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • Inter SDC Segment- wise DC coding for Inter prediction mode
  • FIG. 1 is a block diagram illustrating an example video coding system that may utilize the techniques described in this disclosure.
  • FIG. 2 is a conceptual diagram illustrating example spatially-neighboring and temporally- neighboring blocks.
  • FIG. 3 is a conceptual diagram illustrating an example multiview decoding order.
  • FIG. 4 is a conceptual diagram illustrating an example prediction structure for multiview coding.
  • FIG. 5 is a conceptual diagram illustrating an example derivation of inter- view predicted motion vector candidate.
  • FIG. 6 is a conceptual diagram illustrating an example derivation of a motion parameter inheritance (MPI) candidate.
  • MPI motion parameter inheritance
  • FIG. 7 is a conceptual diagram illustrating sub-prediction unit (PU) motion parameter inheritance (MPI).
  • PU sub-prediction unit
  • MPI motion parameter inheritance
  • FIG. 8 is a table indicating an example specification of lOCandldx
  • FIG. 9 is a block diagram illustrating an example video encoder that may implement the techniques described in this disclosure.
  • FIG. 10 is a block diagram illustrating an example video decoder that may implement the techniques described in this disclosure.
  • FIG. 11 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 12 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 13 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 14 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 15 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 16 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 17 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • FIG. 18 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the techniques described in this disclosure are generally related to three- dimensional (3D) video coding, e.g., the coding of two or more views. More particularly, the techniques are related to 3D video coding based on advanced codecs, including depth coding techniques. The techniques may be applied in a multiview plus depth process. In some examples, the techniques of this disclosure relate to
  • High-Efficiency Video Coding is a newly-developed video coding standard.
  • HEVC Draft 10 A recent draft of the HEVC standard, referred to as “HEVC Draft 10" is described in Bross et al., "High Efficiency Video Coding (HEVC) text specification draft 10 (for FDIS & Last Call),” Document: JCTVC-L1003_v34, Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC
  • 3D-HEVC is an extension of HEVC for 3D video data.
  • JCT-3V Joint Collaborative Team on 3D Video Coding Extension Development
  • a recent reference software "3D-HTM version 9.0" for 3D-HEVC can be downloaded from the following link:
  • 3D-HEVC provides for multiple views of the same scene from different viewpoints. Part of the standardization efforts for 3D-HEVC includes the
  • the techniques of this disclosure may be applied to a 3D-HEVC encoder-decoder (codec) in which multiview plus depth coding processes are used.
  • codec 3D-HEVC encoder-decoder
  • a multiview or 3D video sequence may include, for each access unit (i.e., with the same time instance), two or more pictures for each of two or more views, respectively.
  • two or more pictures may have the same time instance for purposes of defining an access unit, even in cases where the pictures are, in reality, displayed at different times. For instance, pictures may be displayed at different times when using active glasses that synchronize lens shuttering with a stereoscopic display, which rapidly alternates display of pictures of different views. Nevertheless, such pictures of different views may be defined as having the same time instance, and thus, included in a common access unit. Inter-view prediction may be allowed among pictures that are from different views, but in the same access unit or time instance.
  • each view may include both a texture picture (texture component) and a corresponding depth picture (depth component).
  • texture picture texture component
  • depth component depth component
  • each access unit contains multiple pictures, and pictures in each view have a unique view id, or view order index. However, the depth picture and texture picture of the same view may have different layer ids.
  • inter- view motion prediction based on the reconstructed view components from different views is enabled to improve coding efficiency.
  • inter- view motion prediction is similar to the motion compensation used in standard HEVC, and may utilize the same or similar syntax elements.
  • the video coder may use, as a source of motion information, a picture that is in the same access unit as the PU, but in a different view.
  • conventional motion compensation only uses pictures in different access units as reference pictures.
  • the motion parameters of a block in a dependent view may be predicted or inferred based on already-coded motion parameters in other views of the same access unit.
  • the techniques described in this disclosure are also related to constructing a list of motion parameter candidates for a current block of video data according to a motion parameter prediction mode, such as a merge mode, skip mode, or Advanced Motion Vector Prediction (AMVP) mode.
  • a motion parameter prediction mode such as a merge mode, skip mode, or Advanced Motion Vector Prediction (AMVP) mode.
  • AMVP Advanced Motion Vector Prediction
  • the video coder may generate a motion parameter candidate list, e.g., a merging candidate list or an AMVP candidate list. Both the video encoder and the video decoder construct the motion parameter candidate list in the same defined manner. If a candidate is selected from the list of motion parameter candidates, then the video coder may use motion parameters associated with the selected candidate to encode/decode a current video block.
  • a video encoder may signal, in an encoded bitstream of video data, an index value identifying the motion information candidate selected from the motion information candidate list constructed by the video encoder according to the defined process. Based on the index, the video decoder can identify the selected motion parameter candidate from the motion parameter candidate list constructed by the video decoder according to the defined process for decoding the current video block.
  • Merge mode is a video coding mode in which motion parameters (such as motion vectors, reference frame indexes, prediction directions, or other parameters) of a merging candidate are inherited for a current video block being coded.
  • a skip mode in which residual information is not coded, also utilizes the same merging candidate list construction process as used for merge mode. Accordingly, the motion parameter candidate, e.g., merging candidate, list construction techniques described herein may be applicable or a merge mode, a skip mode, or generally a merge/skip motion information prediction mode, which may be a merge mode and/or a skip mode.
  • both a video encoder and a video decoder construct a merging list of motion information candidates for a current video block (e.g., candidate motion parameters, such as reference pictures and motion vectors, for coding the current video block).
  • the candidates in the list may include spatial merging candidates (SMCs) derived from the motion information of spatial neighboring blocks, and a temporal merging candidate (TMC) derived from the motion information of a temporal neighboring block (from a reference picture at a different time instance than the current picture of the current video block).
  • the candidates in the merging candidate list may also include combined bi-predictive merging candidates, and zero motion vector merging candidates.
  • a video encoder signals the chosen motion information used to encode the current video block (i.e., the chosen candidate from the merging candidate list) by signaling an index into the candidate list. For the merge mode, once a video decoder decodes the index into the candidate list, all motion parameters of the indicated candidate are inherited by the current video block, and may be used by the video decoder to decode the current video block.
  • Video coders may also implement an AMVP mode that, similar to merge mode, includes expressing motion vectors as an index selecting one of a plurality of motion parameter candidates stored in a list of motion parameter candidates constructed in a defined manner.
  • AMVP mode like the merge mode, the motion vectors of reference blocks, e.g., spatially- and/or temporally-neighboring blocks, are used by video coders as motion parameter candidates.
  • a video encoder determines a motion vector difference (MVD) between a desired motion vector for coding the video block and the motion vector indicated by the motion information candidate selected from the motion parameter candidate list.
  • VMD motion vector difference
  • video coders employing the AMVP mode may also signal in the coded bitstream a reference picture index, and an inter-prediction direction for coding a particular video block according to the AMVP mode.
  • the candidate list may include an inter- view predicted motion vector candidate (IPMVC) in merging candidate lists and AMVP candidate lists.
  • IPMVC inter- view predicted motion vector candidate
  • the video coder may use an IPMVC in the same manner as other candidates in a candidate list.
  • An IPMVC specifies the motion parameters of a PU (i.e., a reference PU) of a disparity reference picture.
  • the disparity reference picture may be in the same access unit as a current PU, but in a different view than the current PU.
  • the video coder may perform a disparity vector construction process to determine a disparity vector for the current PU.
  • the disparity vector for the current PU may indicate a horizontal spatial displacement between a prediction block of the current PU and a location within the disparity reference picture.
  • the reference PU may be a PU of the disparity reference picture that covers the location indicated by the disparity vector.
  • a sub-PU motion parameter inheritance (MPI) candidate, inter- view motion prediction candidate, e.g., IPMVC, and derived depth coding (DDD) candidate are introduced in skip/merge mode coding of depth blocks, e.g., for 3D-HEVC.
  • MPI candidate e.g., sub-PU MPI candidate
  • the basic idea of the MPI candidate, e.g., sub-PU MPI candidate, is to exploit the similarity of the motion characteristics between the texture images and its associated depth images.
  • the inter- view motion prediction candidate may exploit the similarity of the motion characteristics between adjacent views.
  • the DDD candidate may exploit the correlation between disparity vector and depth value.
  • the techniques described in this disclosure generally relate to depth coding and, more particularly, relate to construction of a motion parameter candidate list, e.g., merge candidate list, for decoding or encoding a current depth PU.
  • the described techniques include 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, deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more for in the motion parameter candidate list, and decoding or encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • FIG. 1 is a block diagram illustrating an example video coding system 10 that may utilize the techniques of this disclosure.
  • video coder refers generically to both video encoders and video decoders.
  • video coding or “coding” may refer generically to video encoding or video decoding.
  • video coding system 10 includes a source device 12 and a destination device 14.
  • Source device 12 generates encoded video data. Accordingly, source device 12 may be referred to as a video encoding device or a video encoding apparatus.
  • Destination device 14 may decode the encoded video data generated by source device 12. Accordingly, destination device 14 may be referred to as a video decoding device or a video decoding apparatus.
  • Source device 12 and destination device 14 may be examples of video coding devices or video coding apparatuses.
  • Source device 12 and destination device 14 may comprise a wide range of devices, including desktop computers, mobile computing devices, notebook (e.g., laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called “smart" phones, televisions, cameras, display devices, digital media players, video gaming consoles, in-car computers, or the like.
  • desktop computers mobile computing devices
  • notebook (e.g., laptop) computers tablet computers
  • set-top boxes telephone handsets such as so-called “smart" phones
  • televisions cameras
  • display devices digital media players
  • video gaming consoles in-car computers, or the like.
  • Destination device 14 may receive encoded video data from source device 12 via a channel 16.
  • Channel 16 may comprise one or more media or devices capable of moving the encoded video data from source device 12 to destination device 14.
  • channel 16 may comprise one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in realtime.
  • source device 12 may modulate the encoded video data according to a communication standard, such as a wireless communication protocol, and may transmit the modulated video data to destination device 14.
  • the one or more communication media may include wireless and/or wired communication media, such as a radio frequency (RF) spectrum or one or more physical transmission lines.
  • RF radio frequency
  • the one or more communication media may form part of a packet-based network, such as a local area network, a wide-area network, or a global network (e.g., the internet).
  • the one or more communication media may include routers, switches, base stations, or other equipment that facilitate communication from source device 12 to destination device 14.
  • channel 16 may include a storage medium that stores encoded video data generated by source device 12.
  • destination device 14 may access the storage medium, e.g., via disk access or card access.
  • the storage medium may include a variety of locally-accessed data storage media such as Blu-ray discs, DVDs, CD-ROMs, flash memory, or other suitable digital storage media for storing encoded video data.
  • channel 16 may include a file server or another intermediate storage device that stores encoded video data generated by source device 12.
  • destination device 14 may access encoded video data stored at the file server or other intermediate storage device via streaming or download.
  • the file server may be a type of server capable of storing encoded video data and transmitting the encoded video data to destination device 14.
  • Example file servers include web servers (e.g., for a website), file transfer protocol (FTP) servers, network attached storage (NAS) devices, and local disk drives.
  • Destination device 14 may access the encoded video data through a standard data connection, such as an internet connection.
  • Example types of data connections may include wireless channels (e.g., Wi-Fi connections), wired connections (e.g., digital subscriber line (DSL), cable modem, etc.), or combinations of both that are suitable for accessing encoded video data stored on a file server.
  • the transmission of encoded video data from the file server may be a streaming transmission, a download transmission, or a combination of both.
  • the techniques of this disclosure are not limited to wireless applications or settings.
  • the techniques may be applied to video coding in support of a variety of multimedia applications, such as over-the-air television broadcasts, cable television transmissions, satellite television transmissions, streaming video transmissions, e.g., via the internet, encoding of video data for storage on a data storage medium, decoding of video data stored on a data storage medium, or other applications.
  • video coding system 10 may be configured to support one-way or two-way video transmission to support applications such as video streaming, video playback, video broadcasting, and/or video telephony.
  • FIG. 1 is merely an example and the techniques of this disclosure may apply to video coding settings (e.g., video encoding or video decoding) that do not necessarily include any data communication between the encoding and decoding devices.
  • data is retrieved from a local memory, streamed over a network, or the like.
  • a video encoding device may encode and store data to memory, and/or a video decoding device may retrieve and decode data from memory.
  • the encoding and decoding is performed by devices that do not communicate with one another, but simply encode data to memory and/or retrieve and decode data from memory.
  • source device 12 includes a video source 18, depth estimation unit 19, a video encoder 20, and an output interface 22.
  • output interface 22 may include a modulator/demodulator (modem) and/or a transmitter.
  • Video source 18 may include a video capture device, e.g., a video camera, a video archive containing previously-captured video data, a video feed interface to receive video data from a video content provider, and/or a computer graphics system for generating video data, or a combination of such sources of video data.
  • Video encoder 20 may encode video data from video source 18.
  • source device 12 directly transmits the encoded video data to destination device 14 via output interface 22.
  • the encoded video data may also be stored onto a storage medium or a file server for later access by destination device 14 for decoding and/or playback.
  • destination device 14 includes an input interface 28, a video decoder 30, depth image based rendering (DIBR) unit 31, and a display device 32.
  • input interface 28 includes a receiver and/or a modem.
  • Input interface 28 may receive encoded video data over channel 16.
  • Video decoder 30 may decode encoded video data.
  • Display device 32 may display the decoded video data.
  • Display device 32 may be integrated with or may be external to destination device 14.
  • Display device 32 may comprise a variety of display devices, such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.
  • LCD liquid crystal display
  • OLED organic light emitting diode
  • Video encoder 20 and video decoder 30 each may be implemented as any of a variety of suitable circuitry, such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware, or any combinations thereof. If the techniques are implemented partially in software, a device may store instructions for the software in a suitable, non-transitory computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Any of the foregoing (including hardware, software, a combination of hardware and software, etc.) may be considered to be one or more processors. Each of video encoder 20 and video decoder 30 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined encoder/decoder (CODEC) in a respective device.
  • CODEC combined encoder/decoder
  • Video source 18 of source device 12 may include a video capture device, such as a video camera, a video archive containing previously captured video, and/or a video feed interface to receive video from a video content provider.
  • video source 18 may generate computer graphics-based data as the source video, or a combination of live video, archived video, and computer-generated video.
  • source device 12 and destination device 14 may form so-called camera phones or video phones.
  • the techniques described in this disclosure may be applicable to video coding in general, and may be applied to wireless and/or wired applications.
  • the captured, pre-captured, or computer-generated video may be encoded by video encoder 20.
  • the encoded video information may then be output by output interface 22 onto a computer- readable medium 16.
  • Video source 18 may provide multiple views of video data to video encoder 20.
  • video source 18 may correspond to an array of cameras, each having a unique horizontal position relative to a particular scene being filmed.
  • video source 18 may generate video data from disparate horizontal camera perspectives, e.g., using computer graphics.
  • Depth estimation unit 19 may be configured to determine values for depth pixels corresponding to pixels in a texture image.
  • depth estimation unit 19 may represent a Sound Navigation and Ranging (SONAR) unit, a Light Detection and Ranging (LIDAR) unit, or other unit capable of directly determining depth values substantially simultaneously while recording video data of a scene.
  • SONAR Sound Navigation and Ranging
  • LIDAR Light Detection and Ranging
  • depth estimation unit 19 may be configured to calculate depth values indirectly by comparing two or more images that were captured at substantially the same time from different horizontal camera perspectives. By calculating horizontal disparity between substantially similar pixel values in the images, depth estimation unit 19 may approximate depth of various objects in the scene.
  • Depth estimation unit 19 may be functionally integrated with video source 18, in some examples. For example, when video source 18 generates computer graphics images, depth estimation unit 19 may provide actual depth maps for graphical objects, e.g., using z-coordinates of pixels and objects used to render texture images.
  • display device 32 may comprise a device capable of displaying two or more views simultaneously or substantially simultaneously, e.g., to produce a 3D visual effect for a viewer.
  • DIBR unit 31 of destination device 14 may render synthesized views using texture and depth information of decoded views received from video decoder 30. For example, DIBR unit 31 may determine horizontal disparity for pixel data of texture images as a function of values of pixels in
  • DIBR unit 31 may then generate a synthesized image by offsetting pixels in a texture image left or right by the determined horizontal disparity.
  • display device 32 may display one or more views, which may correspond to decoded views and/or synthesized views, in any combination.
  • video decoder 30 may provide original and updated precision values for depth ranges and camera parameters to DIBR unit 31, which may use the depth ranges and camera parameters to properly synthesize views.
  • video encoder 20 which may be a video encoder and/or a video decoder, such as video encoder 20 and video decoder 30.
  • This disclosure may generally refer to video encoder 20 "signaling" certain information to another device, such as video decoder 30.
  • the term “signaling” may generally refer to the communication of syntax elements and/or other data used to decode the compressed video data. Such communication may occur in real- or near-real-time.
  • such communication may occur over a span of time, such as might occur when storing syntax elements to a computer-readable storage medium in an encoded bitstream at the time of encoding, which then may be retrieved by a decoding device at any time after being stored to this medium.
  • video encoder 20 and video decoder 30 operate according to a video compression standard, such as ISO/IEC MPEG-4 Visual and ITU-T H.264 (also known as ISO/IEC MPEG-4 AVC), including its Scalable Video Coding (SVC) extension, Multiview Video Coding (MVC) extension, and MVC -based 3DV extension.
  • SVC Scalable Video Coding
  • MVC Multiview Video Coding
  • MVC -based 3DV extension MVC -based 3DV extension.
  • any bitstream conforming to the MVC-based 3DV extension of H.264/ AVC always contains a sub-bitstream that is compliant to the MVC extension of H.264/ AVC.
  • 3DV three-dimensional video
  • video encoder 20 and video decoder 30 may operate according to ITU-T H.261, ISO/IEC MPEG-1 Visual, ITU-T H.262 or ISO/IEC MPEG-2 Visual, and ITU-T H.264, ISO/IEC Visual.
  • video encoder 20 and video decoder 30 may operate according to the HEVC standard, the multi-view video coding extension of HEVC (MV-HEVC), and/or the 3D video coding extension of HEVC (3D-HEVC), discussed above.
  • a video sequence typically includes a series of pictures. Pictures may also be referred to as "frames.”
  • a picture may include three sample arrays, denoted S L , Sc b , and Sc r - S L is a two-dimensional array (i.e., a block) of luma samples.
  • Sc b is a two-dimensional array of Cb chrominance samples.
  • Sc r is a two-dimensional array of Cr chrominance samples.
  • Chrominance samples may also be referred to herein as "chroma" samples.
  • a picture may be monochrome and may only include an array of luma samples.
  • video encoder 20 may generate a set of coding tree units (CTUs).
  • Each of the CTUs may comprise a coding tree block of luma samples, two corresponding coding tree blocks of chroma samples, and syntax structures used to code the samples of the coding tree blocks.
  • a CTU may comprise a single coding tree block and syntax structures used to code the samples of the coding tree block.
  • a coding tree block may be an NxN block of samples.
  • a CTU may also be referred to as a "tree block” or a "largest coding unit” (LCU).
  • the CTUs of HEVC may be broadly analogous to the macroblocks of other standards, such as H.264/AVC. However, a CTU is not necessarily limited to a particular size and may include one or more coding units (CUs).
  • a slice may include an integer number of CTUs ordered consecutively in a raster scan order.
  • video encoder 20 may recursively perform quad-tree partitioning on the coding tree blocks of a CTU to divide the coding tree blocks into coding blocks, hence the name "coding tree units."
  • a coding block is an NxN block of samples.
  • a CU may comprise a coding block of luma samples and two corresponding coding blocks of chroma samples of a picture that has a luma sample array, a Cb sample array, and a Cr sample array, and syntax structures used to code the samples of the coding blocks.
  • a CU may comprise a single coding block and syntax structures used to code the samples of the coding block.
  • Video encoder 20 may partition a coding block of a CU into one or more prediction blocks.
  • a prediction block is a rectangular (i.e., square or non-square) block of samples on which the same prediction is applied.
  • a prediction unit (PU) of a CU may comprise a prediction block of luma samples, two corresponding prediction blocks of chroma samples, and syntax structures used to predict the prediction blocks. In monochrome pictures or pictures having three separate color planes, a PU may comprise a single prediction block and syntax structures used to predict the prediction block.
  • Video encoder 20 may generate predictive luma, Cb, and Cr blocks for luma, Cb, and Cr prediction blocks of each PU of the CU.
  • Video encoder 20 may use intra prediction or inter prediction to generate the predictive blocks for a PU. If video encoder 20 uses intra prediction to generate the predictive blocks of a PU, video encoder 20 may generate the predictive blocks of the PU based on decoded samples of the picture associated with the PU.
  • video encoder 20 may generate the predictive blocks of the PU based on decoded samples of one or more pictures other than the picture associated with the PU.
  • Inter prediction may be uni-directional inter prediction (i.e., uni-prediction) or bi-directional inter prediction (i.e., bi-prediction).
  • video encoder 20 may generate a first reference picture list (RefPicListO) and a second reference picture list (RefPicListl) for a current slice.
  • Each of the reference picture lists may include one or more reference pictures.
  • video encoder 20 may search the reference pictures in either or both RefPicListO and RefPicListl to determine a reference location within a reference picture. Furthermore, when using uni- prediction, video encoder 20 may generate, based at least in part on samples
  • the predictive sample blocks for the PU are corresponding to the reference location, the predictive sample blocks for the PU.
  • video encoder 20 may generate a single motion vector that indicates a spatial displacement between a prediction block of the PU and the reference location.
  • a motion vector may include a horizontal component specifying a horizontal displacement between the prediction block of the PU and the reference location and may include a vertical component specifying a vertical displacement between the prediction block of the PU and the reference location.
  • video encoder 20 may determine a first reference location in a reference picture in RefPicListO and a second reference location in a reference picture in RefPicListl. Video encoder 20 may then generate, based at least in part on samples corresponding to the first and second reference locations, the predictive blocks for the PU. Moreover, when using bi-prediction to encode the PU, video encoder 20 may generate a first motion vector indicating a spatial displacement between a sample block of the PU and the first reference location and a second motion vector indicating a spatial displacement between the prediction block of the PU and the second reference location.
  • a reference picture list construction for the first or the second reference picture list (e.g., RefPicListO or RefPicListl) of a B picture includes two steps:
  • the reference picture list initialization is an explicit mechanism that puts the reference pictures in the reference picture memory (also known as decoded picture buffer) into a list based on the order of POC (Picture Order Count, aligned with display order of a picture) values.
  • the reference picture list reordering mechanism can modify the position of a picture that was put in the list during the reference picture list initialization to any new position, or put any reference picture in the reference picture memory in any position even the picture doesn't belong to the initialized list. Some pictures after the reference picture list reordering (modification) may be put in a very further position in the list.
  • a reference index to a reference picture list can be used to identify any reference picture included in the reference picture list.
  • video encoder 20 may generate a luma residual block for the CU.
  • Each sample in the luma residual block of the CU indicates a difference between a luma sample in one of the predictive luma blocks of the CU and a corresponding sample in the original luma coding block of the CU.
  • video encoder 20 may generate a Cb residual block for the CU.
  • Each sample in the CU's Cb residual block may indicate a difference between a Cb sample in one of the CU's predictive Cb blocks and a corresponding sample in the CU's original Cb coding block.
  • Video encoder 20 may also generate a Cr residual block for the CU.
  • Each sample in the CU's Cr residual block may indicate a difference between a Cr sample in one of the CU's predictive Cr blocks and a corresponding sample in the CU's original Cr coding block.
  • video encoder 20 may use quad-tree partitioning to decompose the luma, Cb, and Cr residual blocks of a CU into one or more luma, Cb, and Cr transform blocks.
  • a transform block is a rectangular (e.g., square or non-square) block of samples on which the same transform is applied.
  • a transform unit (TU) of a CU may comprise a transform block of luma samples, two corresponding transform blocks of chroma samples, and syntax structures used to transform the transform block samples.
  • each TU of a CU may be associated with a luma transform block, a Cb transform block, and a Cr transform block.
  • the luma transform block associated with the TU may be a sub-block of the CU's luma residual block.
  • the Cb transform block may be a sub-block of the CU's Cb residual block.
  • the Cr transform block may be a sub-block of the CU's Cr residual block.
  • a TU may comprise a single transform block and syntax structures used to transform the samples of the transform block.
  • Video encoder 20 may apply one or more transforms to a luma transform block of a TU to generate a luma coefficient block for the TU.
  • a coefficient block may be a two-dimensional array of transform coefficients.
  • a transform coefficient may be a scalar quantity.
  • Video encoder 20 may apply one or more transforms to a Cb transform block of a TU to generate a Cb coefficient block for the TU.
  • Video encoder 20 may apply one or more transforms to a Cr transform block of a TU to generate a Cr coefficient block for the TU.
  • video encoder 20 may quantize the coefficient block. Quantization generally refers to a process in which transform coefficients are quantized to possibly reduce the amount of data used to represent the transform coefficients, providing further compression.
  • video encoder 20 may entropy encode syntax elements indicating the quantized transform coefficients. For example, video encoder 20 may perform Context- Adaptive Binary Arithmetic Coding (CAB AC) on the syntax elements indicating the quantized transform coefficients.
  • CAB AC Context- Adaptive Binary Arithmetic Coding
  • Video encoder 20 may output a bitstream that includes a sequence of bits that forms a representation of coded pictures and associated data.
  • the bitstream may comprise a sequence of network abstraction layer (NAL) units.
  • NAL unit is a syntax structure containing an indication of the type of data in the NAL unit and bytes containing that data in the form of a raw byte sequence payload (RBSP) interspersed as necessary with emulation prevention bits.
  • Each of the NAL units includes a NAL unit header and encapsulates a RBSP.
  • the NAL unit header may include a syntax element that indicates a NAL unit type code.
  • the NAL unit type code specified by the NAL unit header of a NAL unit indicates the type of the NAL unit.
  • a RBSP may be a syntax structure containing an integer number of bytes that is encapsulated within a NAL unit. In some instances, an RBSP includes zero bits.
  • NAL units may encapsulate different types of RBSPs.
  • a first type of NAL unit may encapsulate an RBSP for a picture parameter set (PPS)
  • a second type of NAL unit may encapsulate an RBSP for a coded slice
  • a third type of NAL unit may encapsulate an RBSP for SEI messages, and so on.
  • NAL units that encapsulate RBSPs for video coding data (as opposed to RBSPs for parameter sets and SEI messages) may be referred to as video coding layer (VCL) NAL units.
  • VCL video coding layer
  • Video decoder 30 may receive a bitstream generated by video encoder 20.
  • video decoder 30 may parse the bitstream to obtain syntax elements from the bitstream.
  • Video decoder 30 may reconstruct the pictures of the video data based at least in part on the syntax elements obtained from the bitstream.
  • the process to reconstruct the video data may be generally reciprocal to the process performed by video encoder 20. For instance, video decoder 30 may use motion vectors of PUs to determine predictive blocks for the PUs of a current CU.
  • video decoder 30 may inverse quantize coefficient blocks associated with TUs of the current CU. Video decoder 30 may perform inverse transforms on the coefficient blocks to reconstruct transform blocks associated with the TUs of the current CU.
  • Video decoder 30 may reconstruct the coding blocks of the current CU by adding the samples of the predictive blocks for PUs of the current CU to corresponding samples of the transform blocks of the TUs of the current CU. By reconstructing the coding blocks for each CU of a picture, video decoder 30 may reconstruct the picture.
  • video encoder 20 may signal the motion parameters of a PU (for inter prediction) using merge mode or advanced motion vector prediction (AMVP) mode.
  • AMVP advanced motion vector prediction
  • Motion parameter prediction may comprise the determination of motion parameters of a video unit (e.g., a PU) based on motion parameters of one or more other video units.
  • the motion parameters of a PU may include motion vector(s) of the PU and reference index(s) of the PU.
  • video encoder 20 When video encoder 20 signals the motion parameters of a current PU using merge mode, video encoder 20 generates a merge candidate list.
  • video encoder 20 may perform a merge candidate list construction process.
  • the merge candidate list includes a set of merge candidates that indicate the motion parameters of PUs that spatially or temporally neighbor the current PU. That is, in the merge mode, a candidate list of motion parameters (e.g., reference indexes, motion vectors, etc.) is constructed where a candidate can be from reference blocks, e.g., spatial and temporal neighboring blocks.
  • a candidate list of motion parameters e.g., reference indexes, motion vectors, etc.
  • video encoder 20 may select a merge candidate from the merge candidate list and may use the motion parameters indicated by the selected merge candidate as the motion parameters of the current PU.
  • Video encoder 20 may signal the position in the merge candidate list of the selected merge candidate. For instance, video encoder 20 may signal the selected motion parameters by transmitting an index into the candidate list.
  • Video decoder 30 may obtain, from the bitstream, the index into the candidate list (i.e., a candidate list index).
  • video decoder 30 may generate the same merge candidate list using the same list construction processor as the video encoder, and may determine, based on the indication of the position of the selected merge candidate, the selected merge candidate.
  • Video decoder 30 may then use the motion information of the selected merge candidate to generate predictive blocks for the current PU. That is, video decoder 30 may determine, based at least in part on the merge candidate list index, a selected candidate in the candidate list, wherein the selected candidate specifies the motion vector for the current PU. In this way, at the decoder side, once the index is decoded, all motion parameters of the corresponding block where the index points may be inherited by the current PU.
  • Skip mode is similar to merge mode.
  • video encoder 20 and video decoder 30 generate and use a merge candidate list in the same way that video encoder 20 and video decoder 30 use the merge candidate list in merge mode.
  • video encoder 20 signals the motion parameters of a current PU using skip mode
  • video encoder 20 does not signal any residual data for the current PU.
  • video decoder 30 may determine, without use of residual data, a predictive block for the PU based on a reference block indicated by the motion parameters of a selected candidate in the merge candidate list.
  • AMVP mode is similar to merge mode in that video encoder 20 may generate a candidate list and may select a candidate from the candidate list.
  • video encoder 20 may signal a RefPicListX motion vector difference (MVD) for the current PU and a RefPicListX reference index for the current PU in addition to signaling a RefPicListX MVP flag for the current PU.
  • the RefPicListX MVP flag for the current PU may indicate the position of a selected AMVP candidate in the AMVP candidate list.
  • the RefPicListX MVD for the current PU may indicate a difference between a RefPicListX motion vector of the current PU and a motion vector of the selected AMVP candidate.
  • video encoder 20 may signal the RefPicListX motion information of the current PU by signaling a RefPicListX motion vector predictor (MVP) flag, a RefPicListX reference index value, and a RefPicListX MVD.
  • MVP RefPicListX motion vector predictor
  • the data in the bitstream representing the motion vector for the current PU may include data representing a reference index, an index to a candidate list, and an MVD.
  • video decoder 30 may obtain, from the bitstream, a MVD for a current PU and a MVP flag. Video decoder 30 may generate the same AMVP candidate list using the same list construction process as the video encoder, and may determine, based on the MVP flag, the selected AMVP candidate. Video decoder 30 may recover a motion vector of the current PU by adding the MVD to the motion vector indicated by the selected AMVP candidate. That is, video decoder 30 may determine, based on a motion vector indicated by the selected AMVP candidate and the MVD, the motion vector of the current PU. Video decoder 30 may then use the recovered motion vector or motion vectors of the current PU to generate predictive blocks for the current PU.
  • FIG. 2 is a conceptual diagram illustrating example spatially-neighboring and temporally-neighboring PUs relative to a current PU 40.
  • video decoder 30 may derive one or more motion parameter candidates based on the motion parameters of spatially-neighboring PUs that cover locations that spatially neighbor the current PU.
  • the spatially-neighboring PUs may be PUs that cover the locations indicated as A 0 , A l5 B 0 , B l5 and B 2 .
  • a PU may cover a location when a prediction block of the PU includes the location.
  • a video coder may also include a candidate in a merge candidate list or an AMVP candidate list that is based on the motion information of a PU that temporally neighbors a current PU (i.e., a PU that is in a different time instance, and thus access unit, than the current PU).
  • a temporal motion parameter candidate may be referred to as a temporal merging candidate (TMC).
  • TMC temporal merging candidate
  • a video coder may need to access the motion vector of a picture from a different access unit in a reference picture list.
  • a video coder may identify a reference picture that includes a PU that is co-located with the current PU. In other words, the video coder may identify a co-located picture. If the current slice of the current picture is a B slice (i.e., a slice that is allowed to include bi-directionally inter predicted PUs), video encoder 20 may signal, in a slice header, a syntax element (e.g.,
  • collocated_from_10_flag that indicates whether the co-located picture is from
  • RefPicListO or RefPicListl when the use of TMVPs is enabled for a current slice, and the current slice is a B slice (e.g., a slice that is allowed to include bi- directionally inter predicted PUs), video encoder 20 may signal a syntax element (e.g., collocated_from_10_flag) in a slice header to indicate whether the co-located picture is in RefPicListO or RefPicListl.
  • a syntax element e.g., collocated_from_10_flag
  • video decoder 30 may use another syntax element (e.g.,
  • collocated_ref_idx which may be signaled in a slice header, to identify a picture (i.e., the co-located picture) in the identified reference picture list. That is, after a reference picture list is identified, collocated_ref_idx, signaled in a slice header is used to identify the picture in the reference picture list.
  • the video coder may identify a co-located PU by checking the co-located picture.
  • the TMC may indicate either the motion parameters of a right-bottom PU of the CU containing the co-located PU, illustrated by block Ti in FIG. 2, or the motion parameters of the right-bottom PU within the center PUs of the CU containing this PU, illustrated by block T 2 in FIG. 2.
  • block Ti the motion parameters of the right-bottom PU within the center PUs of the CU containing this PU
  • T 2 in FIG. 2
  • the positions of blocks Ti and T 2 illustrate how they are co-located with current PU 40, while they have a dashed border to illustrate that they are not located in a different temporal reference picture (in a different access unit) then current PU 40.
  • the right-bottom PU of the CU containing the co-located PU may be a PU that covers a location immediately below and right of a bottom- right sample of a prediction block of the PU.
  • the right-bottom PU within the center PUs of the CU containing the co-located PU e.g., block T 2 in FIG. 2 may be a PU that covers a location that covers a location at or near the center of the current PU.
  • the TMC may indicate the motion information of a PU that is in the reference picture and that covers a location that is co-located with a bottom right corner of the current PU, or the TMVP may indicate the motion information of a PU that is in the reference picture and that covers a location that is co-located with a center of the current PU.
  • the video coder may scale the motion vectors based on the temporal location (reflected by POC value). For instance, a video coder may increase the magnitude of a motion vector by greater amounts when a difference between the POC values of a current picture and a reference picture is greater than when a difference between the POC values of the current picture and the reference picture is less.
  • a “view component” may be a coded representation of a view in a single access unit.
  • a “view” may refer to a sequence of view components associated with the same view identifier.
  • Multiview coding supports inter-view prediction.
  • Inter- view prediction is similar to the inter prediction used in HEVC and may use the same syntax elements.
  • video encoder 20 may use, as a reference picture, a picture that is in the same access unit as the current video unit, but in a different view.
  • conventional inter prediction only uses pictures in different access units as reference pictures.
  • a view may be referred to as a "base view” if a video decoder (e.g., video decoder 30) can decode pictures in the view without reference to pictures in any other view.
  • a video coder (such as video encoder 20 or video decoder 30) may add a picture into a reference picture list if the picture is in a different view but within a same time instance (i.e., access unit) as the picture that the video coder is currently coding.
  • the video coder may insert an inter- view prediction reference picture at any position of a reference picture list.
  • FIG. 3 is a conceptual diagram illustrating an example multiview decoding order.
  • the multiview decoding order may be a bitstream order.
  • each square corresponds to a view component.
  • Columns of squares correspond to access units.
  • Each access unit may be defined to contain the coded pictures of all the views of a time instance.
  • Rows of squares correspond to views.
  • the access units are labeled TO...T8 and the views are labeled SO...S7.
  • pictures in an access unit may in reality be displayed at the same time or at different times, based on the type of 3D display being used.
  • An auto stereoscopic display or a stereoscopic display that is associated with passive filtering glasses may display each of the pictures (view components) of a common access unit, e.g., pictures 0 - 7 of access unit TO, at the same time, whereas a stereoscopic display that is associated with active glasses may display each of the pictures at different times.
  • a stereoscopic display that is associated with active glasses may display each of the pictures at different times. Because each view component of an access unit is decoded before any view component of the next access unit, the decoding order of FIG. 3 may be referred to as time-first coding.
  • the decoding order of access units may not be identical to the output or display order of the views.
  • Multiview coding may support inter-view prediction.
  • Inter-view prediction is similar to temporal inter prediction used in H.264/AVC, HEVC, or other video coding specifications, and may use the same syntax elements.
  • a video coder may use, as a reference picture, a picture that is in the same access unit as the current video unit, but in a different view.
  • conventional temporal inter prediction only uses pictures in different access units of the same view as reference pictures.
  • a view may be referred to as a "base view" if a video decoder (e.g., video decoder 30) can decode pictures in the view without reference to pictures in any other view.
  • a video coder may add a picture into a reference picture list (e.g., RefPicListO or RefPicListl) if the picture is in a different view but within a same time instance (i.e., access unit) as the picture that the video coder is currently coding.
  • the video coder may insert an inter- view prediction reference picture at any position of a reference picture list.
  • FIG. 4 is a conceptual diagram illustrating an example prediction structure for multiview coding.
  • the multiview prediction structure of FIG. 4 includes temporal and inter- view prediction.
  • each square corresponds to a view component.
  • the access units are labeled TO...Tl 1 and the views are labeled SO...S7.
  • Squares labeled "I” are intra predicted view components.
  • Squares labeled "P” are uni-directionally inter predicted view components.
  • Squares labeled "B” and “b” are bi-directionally inter predicted view components. Squares labeled "b” may use squares labeled "B" as reference pictures.
  • An arrow that points from a first square to a second square indicates that the first square is available in inter prediction (either temporal inter-prediction or inter- view prediction) as a reference picture for the second square.
  • inter prediction either temporal inter-prediction or inter- view prediction
  • view components in different views of the same access unit may be available as reference pictures.
  • the use of one view component of an access unit as a reference picture for another view component of the same access unit may be referred to as inter-view prediction.
  • inter-view prediction may be performed among pictures in different views of the same access unit (i.e., with the same time instance) to remove correlation between views.
  • a picture may be added into a reference picture list, if the picture is in a different view but with a same time instance.
  • An inter-view prediction reference picture can be put in any position of a reference picture list, just like any inter prediction reference picture.
  • motion vectors there are two kinds of motion vectors.
  • One kind of motion vector is a normal motion vector that points to a temporal reference picture.
  • the type of inter prediction corresponding to a normal, temporal motion vector may be referred to as motion-compensated prediction (MCP).
  • MCP motion-compensated prediction
  • the corresponding motion vector is referred to as a "disparity motion vector.”
  • a disparity motion vector points to a picture in a different view (i.e., an inter- view reference picture).
  • DCP derivative-compensated prediction
  • 3D-HEVC may improve coding efficiency using inter- view motion prediction.
  • a video coder may determine (i.e., predict) the motion information of a current PU based on the motion information of a PU in a different view than (but within the same access unit as) the current PU.
  • a video coder may determine disparity vectors for video units (e.g., PUs, CUs, etc.). In general, a disparity vector is used as an estimator of the displacement between two views.
  • a video coder may use a disparity vector for a video unit either to locate a reference block in another view for inter- view motion prediction, or the video coder may convert the disparity vector to a disparity motion vector for inter-view motion prediction. That is, the disparity vector may be used either to locate the corresponding block in the other view for inter- view motion prediction or be converted to a disparity motion vector for inter- view motion prediction.
  • An implicit disparity vector is a disparity vector of a spatially- or temporally-neighboring PU that is coded using inter- view prediction.
  • An IDV may be generated when a PU employs inter-view motion parameter prediction, e.g., the candidate for AMVP or merge modes is derived from a reference block in the other view with the help of a disparity vector.
  • Such a disparity vector is referred to as an IDV.
  • An IDV may be stored to the PU for the purpose of disparity vector derivation.
  • an IDV is derived by converting a depth value, e.g., depth value 128, to the disparity between current depth view and the reference depth view directly.
  • Depth value 128 refers to a specific depth value, i.e., the middle depth value, assuming the depth value is to be represented by eight bits and the depth value can range from 0 to 255. Conversion from depth value to disparity may be as follows.
  • vps_cp_inv_off_plus_off are coded in the video parameter set (VPS), or a set of camera parameters cp_scale, cp_off, cp_inv_scale_plus_scale, and cp_inv_off_plus_off are coded in slice segment header.
  • the syntax for the set of camera parameters are coded in the video parameter set (VPS), or a set of camera parameters cp_scale, cp_off, cp_inv_scale_plus_scale, and cp_inv_off_plus_off are coded in slice segment header.
  • vps_cp_inv_off_plus_off is shown in Table 1, below. Semantics for the set of camera parameters included in Table 1 follows Table 1. The syntax for set of camera
  • Table 1 Video parameter set extension 2 syntax
  • cp_precision specifies the precision of vps_cp_scale[ i ][ j ], vps_cp_off[ i ][ j ], vps_cp_inv_scale_plus_scale[ i ][ j ], and vps_cp_inv_off _plus_off[ i ][ j ] in the VPS and cp_scale[ j ], cp_off[ j ], cp_inv_scale_plus_scale[ j ], and cp_inv_off_plus_off[ j ] in the slice segment header.
  • the value of cp_precision shall be in the range of 0 to 5, inclusive.
  • vps_cp_scale[ i ][ j ], vps_cp_off[ i ][ j ], vps_cp_inv_scale_plus_scale[ i ][ j ], and vps_cp_inv_off _plus_off[ i ][ j ] are present in the VPS or that cp_scale[ j ], cp_off[ j ], cp_inv_scale_plus_scale[ j ], and cp_inv_off _plus_off [ j ] are present in slice segment headers with nuh_layer_id equal to layerld and VpsViewIdx[ layerld ] equal to i.
  • cp_present_flag[ i ] indicates that camera parameters are not present.
  • cpRequiredFlag[ layerld ] When, for any value of layerld, cpRequiredFlag[ layerld ] is equal to 1, the value of cp_present_flag[ VpsViewIdx[ layerld ] ] shall be equal to 1. When not present, the value of cp_present_flag[ i ] is inferred to be equal to 0.
  • cp_in_slice_segment_header_flag[ i ] 1 specifies that the syntax elements vps_cp_scale[ i ][ j ], vps_cp_off[ i ][ j ], vps_cp_inv_scale_plus_scale[ i ][ j ], and vps_cp_inv_off_plus_off[ i ][ j ] are not present in the VPS and that the syntax elements cp_scale[ j ], cp_off[ j ], cp_inv_scale_plus_scale[ j ], and
  • cp_inv_off_plus_off[ j ] are present in slice segment headers with nuh_layer_id equal to layerld and VpsViewIdx[ layerld ] equal to i.
  • cp_in_slice_segment_header_flag 0 specifies that the vps_cp_scale[ i][ j ], vps_cp_off[ i][ j ],
  • vps_cp_inv_scale_plus_scale[ i ][ j ][ j ] syntax elements are present in the VPS and that the syntax elements cp_scale[ j ], cp_off[ j ], cp_inv_scale_plus_scale[ j ], and cp_inv_off _plus_off [ j ] are not present in slice segment headers with nuh_layer_id equal to layerld and VpsViewIdx[ layerld ] equal to i.
  • the value of cp_in_slice_segment_header_flag[ i ] is inferred to be equal to 0.
  • vps_cp_inv_scale_plus_scale[ i ][ j ] specify conversion parameters for converting a depth value to a disparity value and might be used to infer the values of cp_scale[ j ], cp_off[ j ], cp_inv_scale_plus_scale[ j ], and cp_inv_off_plus_off[ j ] for the i-th view specified in VPS.
  • the conversion parameters are associated with the texture view.
  • cp_inv_off_plus_off[ j ] specify conversion parameters for converting a depth value to a disparity value.
  • cp_inv_scale_plus_scale[ j ] are inferred to be equal to vps_cp_scale[ Viewldx ][ j ], vps_cp_off[ Viewldx ][ j ],
  • the array DepthToDisparityB[ j ][ d ] specifying the disparity between the current view and the view with Viewldx equal j corresponding to the depth value d in the view with Viewldx equal to j and the array DepthToDisparityF[ j ][ d ] specifying the disparity between the view with Viewldx equal j and the current view corresponding to the depth value d in the current view is derived as specified in the following:
  • variable log2Div is set equal to BitDepthy - 1 + cp_precision.
  • DepthToDisparityF[ j ][ d ] ( invScale * d + invOffset ) » log2DivHere, BitDepthy is the bit depth of luma component of depth pixel.
  • DepthToDisparityB[j] is used to convert the depth value to the disparity between the current view and the view with Viewldx (view index) equal to j.
  • Inter SDC Inter prediction mode
  • 3D-HEVC Segment- wise DC coding for Inter prediction mode
  • Inter SDC Inter prediction mode
  • 3D-HEVC provides an alternative residual coding method for depth Inter mode coding, in which only one DC residual value is coded for each PU and is used as residual for all samples within the PU. Transform and quantization are skipped, and no transform tree is coded. Whether Inter SDC is used is signaled in the general coding unit parameters at CU level.
  • Inter SDC mode To decrease the signaling bits on Inter SDC mode, only non-skipped CU may be allowed to apply Inter SDC. Furthermore, to avoid possible overlap between Inter SDC mode and skip mode, Inter SDC mode may be applied only when DC residual of each PU within the CU is non-zero. DC residual of a PU may be calculated as the average of the difference between original sample value and prediction sample value of all samples with the PU.
  • a video coder may add an inter-view motion parameter candidate, e.g., the inter-view Predicted Motion Vector Candidate (IPMVC), if available, to the motion parameter candidate lists for AM VP and skip/merge modes.
  • IPMVC inter-view Predicted Motion Vector Candidate
  • the IPMVC if available, is a temporal motion vector. Since skip mode has the same motion vector derivation process as merge mode, all techniques described in this document may apply to both merge and skip modes.
  • a video coder may derive the IPMVC candidate for a current block as follows:
  • a corresponding block of the current PU/CU in a reference view of the same access unit is located by the disparity vector, e.g., the IDV derived as described above.
  • the corresponding block is not intra-coded and not inter- view predicted and its reference picture has a POC value equal to that of one entry in the same reference picture list of current PU/CU, its motion parameters (prediction direction, reference pictures, and motion vectors), after converting the reference index based on POC, are derived to be the IPMVC.
  • a video coder may denote a luma location ( xP, yP ) of the top-left luma sample of the current prediction unit relative to the top-left luma sample of the current picture.
  • the values nPSW and nPSH denote the width and height of the current prediction unit, respectively. Additional values for identification of the corresponding block include the reference view order index refViewIdx, and a disparity vector mvDisp.
  • the video coder may then set the corresponding block as the prediction unit that covers the luma location ( xRef, yRef ) in the view component with Viewldx equal to refViewIdx.
  • FIG. 5 is a conceptual diagram illustrating an example derivation of an IPMVC for merge/skip mode.
  • FIG. 5 shows an example of the derivation process of the inter- view predicted motion vector candidate.
  • a current PU 50 occurs in view VI at a time instance Tl.
  • a reference PU 52 for current PU 50 occurs in a different view than current PU 50 (i.e., view V0) and at the same time instance as current PU (i.e., time instance Tl).
  • a video coder e.g., video encoder 20 or video decoder 30, may identify reference PU 52 based on a disparity vector 51, e.g., IDV, derived for current PU 50, as described above.
  • reference PU 52 is bi-directionally inter predicted. Hence, reference PU 52 has a first motion vector 54 and a second motion vector 56.
  • Motion vector 54 indicates a position in a reference picture 58. Reference picture 58 occurs in view V0 and in time instance TO.
  • Motion vector 56 indicates a position in reference picture 60. Reference picture 60 occurs in view V0 and in time instance T3.
  • the video coder may generate, based on the motion information of reference PU 52, an IPMVC for inclusion in a merge candidate list of current PU 50.
  • the IPMVC may have a first motion vector 62 and a second motion vector 64.
  • Motion vector 62 matches motion vector 54 and motion vector 64 matches motion vector 56.
  • the video coder generates the IPMVC such that a first reference index of the IPMVC indicates a position in RefPicListO for current PU 50 of a reference picture (i.e., reference picture 66) occurring in the same time instance as reference picture 58 (i.e., time instance TO).
  • a reference picture i.e., reference picture 66
  • reference picture 66 occurs in the first position (i.e., RefO) in RefPicListO for current PU 50. Furthermore, the video coder generates the IPMVC such that a second reference index of the IPMVC indicates a position in RefPicListl for current PU 50 of a reference picture (i.e., reference picture 68) occurring in the same time instance as reference picture 60. Thus, in the example of FIG. 5, the RefPicListO reference index of the IPMVC may be equal to 0. In the example of FIG.
  • a reference picture 70 occurs in the first position (i.e., RefO) in RefPicListl for current PU 50 and reference picture 68 occurs in the second position (i.e., Refl) in RefPicListl for current PU 50.
  • the RefPicListl reference index of the IPMVC may be equal to 1.
  • FIG. 6 is a conceptual diagram illustrating an example derivation of a motion parameter inheritance (MPI) candidate for depth coding.
  • MPI motion parameter inheritance
  • a video coder may derive one or more additional motion parameter candidates for inclusion in a motion parameter candidate list of a depth PU based on MPI.
  • MPI may exploit the similarity of the motion characteristics between the texture images and its associated depth images.
  • a MPI candidate reuses the motion parameters, e.g., motion vectors and reference indices, of the already coded corresponding texture block, if it is available.
  • FIG. 6 shows an example of the derivation process of the MPI candidate where the corresponding texture block is selected as the 4x4 block located to the right bottom of the center of the current PU.
  • FIG. 6 illustrates a current depth PU 80 within the depth component 82, i.e., depth picture 82, of the current access unit.
  • a video coder may identify a reference sample location 88 in the texture component 86.
  • the video coder may identify reference sample location 88 in texture component 86 based on the location and size of the current depth PU 80, as well as a desired reference block relative to the location and size of the current depth PU.
  • Reference texture block 84 is a block in texture component 86 that covers reference sample location 88.
  • the video coder identifies reference sample location 88 such that reference texture block 84 is selected as the 4x4 block located to the right bottom of the center of the current depth PU 80.
  • the video coder may derive an MPI candidate for inclusion in the motion parameter candidate list for current depth PU 80 as being the motion parameters of reference texture block 84.
  • motion vectors with integer precision are used in depth coding while quarter precision of motion vectors is utilized for texture coding. Therefore, the motion vector of the reference texture block shall be scaled before using as an MPI candidate.
  • the current PU may correspond to a reference area (with the same size as the current PU) in the reference picture that is larger than the reference block.
  • the reference area corresponding to the current PU may have plentiful motion information.
  • FIG. 7 is a conceptual diagram illustrating sub-prediction unit (PU) MPI.
  • PU sub-prediction unit
  • a video coder generates a set of motion parameters for each sub-PU. Meanwhile, the video coder also generates a Representative set of Motion Parameters (RMP) for pruning the sub-PU MPI candidate with other candidates, such as an IPMVC, TMC, or spatial candidates.
  • RMP Motion Parameters
  • a video coder may derive the sub-PU MPI candidate as follows:
  • the video coder has divided current depth PU 90 of depth component 92 into four sub-PUs 96A-96D
  • a block in the corresponding texture picture that covers (xRefSub, yRefSub) is used as the reference texture block for the current sub-PU.
  • the video coder has identified reference sample locations 97A-97D (collectively, “reference sample locations 97") for each of sub-PUs 96A-96D, respectively.
  • the video coder has identified reference blocks 98A-98D (collectively, “reference blocks 98") as the blocks in texture component 94 that cover reference sample locations 97A-97D, respectively. o For each of the identified reference blocks,
  • each of reference texture blocks 98A-98D was inter coded, and respectively include motion parameters including motion vectors 99A-99D (collectively, "motion vectors 99").
  • Sub-PU MPI results in each of sub-PUs 96 inheriting the respective motion parameters of reference texture blocks 98, including the respective motion vectors 99.
  • a video coder derives a sub-PU MPI candidate for current depth PU 90 based on the motion parameters inherited by sub-PUs 96.
  • the video coder may derive the sub-PU MPI candidate for inclusion in the motion parameter candidate list to be the RMP, which is determined as described above.
  • the video coder inserts the sub-PU MPI, if available, into the merge candidate list before all other motion parameter candidates. It should be noted that motion vectors with integer precision are used in depth coding while quarter precision of motion vectors is utilized for texture coding. Therefore, the video coder should scale the motion vector of the corresponding texture block before using the motion vector as a sub-PU MPI candidate. Additionally, a video coder may apply different sub-PU block sizes, such as 4x4, 8x8, and 16x16.
  • a syntax element may be present in VPS to indicate the sub-PU size.
  • Detailed semantics of such a syntax element are as follows: log2_sub_pb_mpi_size_minus3 specifies the value of the variable SubPbSizeMPI that is used in the decoding of prediction units using the sub prediction block based texture merging candidate.
  • the value of log2_sub_pb_mpi_size_minus3 shall be in the range of 0 to 3, inclusive.
  • SubPbSizeMPI is derived as specified in the following:
  • SubPbSizeMPI 1 « ( log2_sub_pb_mpi_size_minus3 + 3 ) (H-6) This syntax element is coded with ue(v).
  • sub-PU MPI is identical to MPI.
  • a motion parameter candidate that a video coder, e.g., video encoder 20 or video decoder 30, may include in a motion parameter candidate list for inter coding a depth block is the disparity derived depth (DDD) candidate.
  • DDD disparity derived depth
  • the basic concept of a DDD candidate is that disparity vector can be converted to depth value and therefore used to predict a depth PU. For the DDD candidate, all pixels within the depth PU are predicted by one single depth value.
  • a video coder inserts DDD candidate into the motion parameter candidate list after the sub-PU MPI candidate and before the IPMVC candidate and the spatial or temporal candidates.
  • DDD candidate The basic concept of disparity derived depth (DDD) candidate is that disparity vector can be converted to depth value and therefore used to predict depth PU.
  • DDD candidate all pixels within the depth PU are predicted by one single depth value.
  • DDD candidate is inserted after the sub-PU MPI candidate and before the IPVMC candidate and the spatial or temporal candidates.
  • the single depth value (denoted as ddep) is derived from the disparity motion vector, if available, (denoted as TexDv) of the reference texture block of the current depth PU.
  • ddep the disparity motion vector, if available, denote the size of current PU by nPSW x nPSH and denote coordination of its top left sample relative to the top left sample of the depth picture by (xP, yP), the block in the corresponding texture picture that covers (xP + nPSW/2, yP + nPSH/2) is used as the reference texture block for current depth PU.
  • a video coder derives the single depth value (denoted as ddep) from the disparity motion vector, if available, (denoted as TexDv) of the co-located texture block of the current depth PU.
  • j the view index of the reference view that Texdv pointing to and denote TexDvx as the horizontal component of TexDv
  • DDDInvScale[j] DDDInvOffset[j] and DDDShift[j] are derived by using the pseudo-code in Table 3, where cp_scale, cp_offset and BitDepthy are defined in a set of camera parameters provided in a VPS or slice segment header as described above with respect to Table 1 and Table 2.
  • AbsScale abs(cp_scale[ j ])
  • MinError abs(AbsScale *256 - TargetV)
  • RoundingDir Sign(TargetV -AbsScale * BestD)
  • DDDInvScale[j] (BestD «(BitDepth Y +cp_precision-l ))*Sign(cp_scale[ j ])
  • DDDInvOffset[i] -Sign(cp_scale[ j ])* BestD*( cp_off[ j ] « BitDepth Y )+ DDDShift[i]-l)) + DDDShift[i]-4))* RoundingDir
  • a video coder e.g., video encoder 20 and/or video decoder 30, may construct a merging candidate list, as an example of a motion parameter candidate list, for a current depth PU as follows.
  • the video coder may first derive a disparity vector for the current depth PU as described above.
  • the merging candidate list construction process for depth views in 3D-HEVC can be defined as follows:
  • Sub-PU MPI is derived by the procedure described above. If it is available, it is inserted to the merge list.
  • DDD is derived by the procedure described above. If it is available, it is inserted to the merge list.
  • An IPMVC is derived by the procedure described above. If the IPMVC is available and is not same with the RMP generated in the sub-PU MPI candidate derivation process, it is inserted to the merge list.
  • Constrained pruning is performed by the following procedures:
  • Bo is added to the candidate list.
  • a 0 is added to the candidate list.
  • B 2 is added to the candidate list.
  • the target reference picture index of the temporal merging candidate may be changed instead of fixing to be 0.
  • the target reference index is changed to another index which corresponds to the first entry of inter- view reference picture in the reference picture list.
  • the target reference index is changed to another index which corresponds to the first entry of temporal reference picture in the reference picture list.
  • FIG. 8 is a table indicating an example specification of lOCandldx and HCandldx in 3D-HEVC. The relationship among combldx, lOCandldx and HCandldx are defined in the table of FIG. 8.
  • a merge index is signaled in the general prediction unit parameters at PU level.
  • the current derivation process of a disparity derived depth (DDD) candidate may potentially have the following issue:
  • motion information i.e., motion vector/disparity motion vector and reference indices
  • the current derivation process of a DDD candidate does not use the already-fetched motion information.
  • the current derivation process of a DDD candidate may include fetching additional motion information from a reference texture block that was not assessed in the derivation process of the sub-PU MPI candidate.
  • this may increase the worst case of number of motion information (in reference texture blocks) needed to assess by 1.
  • the current derivation process of a DDD candidate may be less efficient.
  • the derivation of the depth value in DDD mode may be based only on accessing a co-located texture region, which may be a reference texture block that may already need to be accessed for deriving other merging candidates, such as a reference texture block accessed for deriving the sub-PU MPI candidate. More specifically, the DDD merging candidate may access a center block of the co-located texture region, which is already required to be accessed in deriving the sub-PU MPI candidate.
  • the reference texture block is set to be the corresponding texture block of the first sub-PU of current depth PU in raster scan order. In another example, the reference texture block is set to be a corresponding texture block of any sub-PU (within current depth PU) involved in sub-PU MPI candidate derivation process. Alternatively, if disparity motion vector associated with the reference texture block is unavailable, the DDD candidate is considered as unavailable and is not inserted to the depth merge list.
  • a DDD candidate may only be inserted into the merge list for one or more specific PU partition modes for the depth PU.
  • a DDD candidate may be inserted to the merge list only when the depth PU is coded with partition mode 2Nx2N, and is not inserted to the merge list for depth PU coded with other partition modes, i.e., 2NxN, 2NxnU, 2NxnD, Nx2N, nLx2N, nRx2N and NxN.
  • a DDD candidate may be inserted to the merge list only when the depth PU is coded with partition mode 2Nx2N, 2NxN and Nx2N, and is not inserted to the merge list for depth PU coded with other partition modes, i.e., 2NxnU, 2NxnD, nLx2N, nRx2N and NxN.
  • the concept of a DDD merging candidate may be combined with inter SDC in a way that the residual of the SDC mode can be predicted from the difference between the depth value as derived during the DDD merge candidate generation and the average depth values of the prediction block(s) of the current PU. More specifically, when the inter SDC applies for the current PU, the DC residual may or may not, based on a flag indicator, be predicted from the difference between the depth value derived from DDD merge candidate derivation process and the average of the depth values of the prediction block(s) of the current PU.
  • the DC residual may always predicted from the difference between the depth value derived from DDD merge candidate derivation process and the average of the depth values of the prediction block(s) of the current PU.
  • a DC residual predictor may be calculated differently, e.g., with corner pixels of the prediction block.
  • DDD merging candidate is not inserted to the depth merge list of the PU. Any or all of the techniques described in this disclosure may be implemented separately or in conjunction with each other.
  • FIG. 9 is a block diagram illustrating an example video encoder 20 that may implement the techniques of this disclosure.
  • FIG. 9 is provided for purposes of explanation and should not be considered limiting of the techniques as broadly exemplified and described in this disclosure.
  • This disclosure describes video encoder 20 in the context of HEVC coding and, more particularly, 3D-HEVC coding, e.g., as described in 3D-HEVC WD and as further modified as described in this disclosure.
  • the techniques of this disclosure may be applicable to other coding standards or methods.
  • the techniques of this disclosure may be applicable to other coding standards or methods.
  • video encoder 20 includes a prediction processing unit 100, video data memory 101, a residual generation unit 102, a transform processing unit 104, a quantization unit 106, an inverse quantization unit 108, an inverse transform processing unit 110, a reconstruction unit 112, a filter unit 114, a decoded picture buffer 116, and an entropy encoding unit 118.
  • Prediction processing unit 100 includes an inter-prediction processing unit 120 and an intra-prediction processing unit 126.
  • Inter- prediction processing unit 120 includes a motion estimation (ME) unit 122 and a motion compensation (MC) unit 124.
  • video encoder 20 may include more, fewer, or different functional components.
  • Video data memory 101 may store video data to be encoded by the components of video encoder 20.
  • the video data stored in video data memory 101 may be obtained, for example, from video source 18.
  • Decoded picture buffer 116 may be a reference picture memory that stores reference video data for use in encoding video data by video encoder 20, e.g., in intra- or inter-coding modes.
  • Video data memory 101 and decoded picture buffer 116 may be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices.
  • Video data memory 101 and decoded picture buffer 116 may be provided by the same memory device or separate memory devices.
  • texture and depth encoding may be performed by the same components of prediction processing unit 100 or different components within prediction processing unit 100.
  • separate texture and depth encoders may be provided in some implementations.
  • multiple texture and depth encoders may be provided to encode multiple views, e.g., for multiview plus depth coding.
  • Video encoder 20 may receive video data. Video encoder 20 may encode each CTU in a slice of a picture of the video data. Each of the CTUs may be associated with equally-sized luma coding tree blocks (CTBs) and corresponding CTBs of the picture. As part of encoding a CTU, prediction processing unit 100 may perform quad-tree partitioning to divide the CTBs of the CTU into progressively- smaller blocks. The smaller blocks may be coding blocks of CUs. For example, prediction processing unit 100 may partition a CTB associated with a CTU into four equally-sized sub-blocks, partition one or more of the sub-blocks into four equally-sized sub-sub-blocks, and so on.
  • CTBs luma coding tree blocks
  • Video encoder 20 may encode CUs of a CTU to generate encoded
  • prediction processing unit 100 may partition the coding blocks associated with the CU among one or more PUs of the CU. Thus, each PU may be associated with a luma prediction block and corresponding chroma prediction blocks.
  • Video encoder 20 and video decoder 30 may support PUs having various sizes. As indicated above, the size of a CU may refer to the size of the luma coding block of the CU and the size of a PU may refer to the size of a luma prediction block of the PU.
  • video encoder 20 and video decoder 30 may support PU sizes of 2Nx2N or NxN for intra prediction, and symmetric PU sizes of 2Nx2N, 2NxN, Nx2N, NxN, or similar for inter prediction.
  • Video encoder 20 and video decoder 30 may also support asymmetric partitioning for PU sizes of 2NxnU, 2NxnD, nLx2N, and nRx2N for inter prediction.
  • Inter-prediction processing unit 120 may generate predictive data for a PU by performing inter prediction on each PU of a CU.
  • the predictive data for the PU may include predictive blocks of the PU and motion information for the PU.
  • Inter-prediction processing unit 120 may perform different operations for a PU of a CU depending on whether the PU is in an I slice, a P slice, or a B slice. In an I slice, all PUs are intra predicted. Hence, if the PU is in an I slice, inter-prediction processing unit 120 does not perform inter prediction on the PU.
  • motion estimation unit 122 may search the reference pictures in a list of reference pictures (e.g., "RefPicListO") for a reference region for the PU.
  • the reference region for the PU may be a region, within a reference picture, that contains samples that most closely correspond to the prediction blocks of the PU.
  • Motion estimation unit 122 may generate a reference index that indicates a position in RefPicListO of the reference picture containing the reference region for the PU.
  • motion estimation unit 122 may generate a motion vector that indicates a spatial displacement between a coding block of the PU and a reference location associated with the reference region.
  • the motion vector may be a two- dimensional vector that provides an offset from the coordinates in the current picture to coordinates in a reference picture.
  • Motion estimation unit 122 may output the reference index and the motion vector as the motion information of the PU.
  • Motion compensation unit 124 may generate the predictive blocks of the PU based on actual or interpolated samples at the reference location indicated by the motion vector of the PU.
  • motion estimation unit 122 may perform uni-prediction or bi-prediction for the PU. To perform uni-prediction for the PU, motion estimation unit 122 may search the reference pictures of RefPicListO or a second reference picture list ("RefPicListl") for a reference region for the PU. Motion estimation unit 122 may output, as the motion information of the PU, a reference index that indicates a position in RefPicListO or RefPicListl of the reference picture that contains the reference region, a motion vector that indicates a spatial displacement between a prediction block of the PU and a reference location associated with the reference region, and one or more prediction direction indicators that indicate whether the reference picture is in
  • Motion compensation unit 124 may generate the predictive blocks of the PU based at least in part on actual or interpolated samples at the reference location indicated by the motion vector of the PU.
  • motion estimation unit 122 may search the reference pictures in RefPicListO for a reference region for the PU and may also search the reference pictures in RefPicListl for another reference region for the PU.
  • Motion estimation unit 122 may generate reference indexes that indicate positions in RefPicListO and RefPicListl of the reference pictures that contain the reference regions.
  • motion estimation unit 122 may generate motion vectors that indicate spatial displacements between the reference locations associated with the reference regions and a prediction block of the PU.
  • the motion information of the PU may include the reference indexes and the motion vectors of the PU.
  • Motion compensation unit 124 may generate the predictive blocks of the PU based at least in part on actual or interpolated samples at the reference locations indicated by the motion vectors of the PU.
  • Intra-prediction processing unit 126 may generate predictive data for a PU by performing intra prediction on the PU.
  • the predictive data for the PU may include predictive blocks for the PU and various syntax elements.
  • Intra-prediction processing unit 126 may perform intra prediction on PUs in I slices, P slices, and B slices.
  • intra-prediction processing unit 126 may use multiple intra prediction modes to generate multiple sets of predictive blocks for the PU.
  • intra- prediction processing unit 126 may generate predictive blocks for the PU using a particular set of samples from neighboring blocks.
  • the neighboring blocks may be above, above and to the right, above and to the left, or to the left of the prediction blocks of the PU, assuming a left-to-right, top-to-bottom encoding order for PUs, CUs, and CTUs.
  • Intra-prediction processing unit 126 may use various numbers of intra prediction modes, e.g., 33 directional intra prediction modes. In some examples, the number of intra prediction modes may depend on the size of the prediction blocks of the PU.
  • Prediction processing unit 100 may select the predictive data for PUs of a CU from among the predictive data generated by inter-prediction processing unit 120 for the PUs or the predictive data generated by intra-prediction processing unit 126 for the PUs. In some examples, prediction processing unit 100 selects the predictive data for the PUs of the CU based on rate/distortion metrics of the sets of predictive data. The predictive blocks of the selected predictive data may be referred to herein as the selected predictive blocks.
  • Residual generation unit 102 may generate, based on the luma, Cb and Cr coding block of a CU and the selected predictive luma, Cb and Cr blocks of the PUs of the CU, luma, Cb and Cr residual blocks of the CU. For instance, residual generation unit 102 may generate the residual blocks of the CU such that each sample in the residual blocks has a value equal to a difference between a sample in a coding block of the CU and a corresponding sample in a corresponding selected predictive block of a PU of the CU.
  • Transform processing unit 104 may perform quad-tree partitioning to partition the residual blocks of a CU into transform blocks associated with TUs of the CU.
  • a TU may be associated with a luma transform block and two corresponding chroma transform blocks.
  • the sizes and positions of the luma and chroma transform blocks of TUs of a CU may or may not be based on the sizes and positions of prediction blocks of the PUs of the CU.
  • Transform processing unit 104 may generate transform coefficient blocks for each TU of a CU by applying one or more transforms to the transform blocks of the TU. Transform processing unit 104 may apply various transforms to a transform block associated with a TU. For example, transform processing unit 104 may apply a discrete cosine transform (DCT), a directional transform, or a conceptually-similar transform to a transform block. In some examples, transform processing unit 104 does not apply transforms to a transform block. In such examples, the transform block may be treated as a transform coefficient block.
  • DCT discrete cosine transform
  • Quantization unit 106 may quantize the transform coefficients in a coefficient block. The quantization process may reduce the bit depth associated with some or all of the transform coefficients. For example, an ra-bit transform coefficient may be rounded down to an m-bit transform coefficient during quantization, where n is greater than m.
  • Quantization unit 106 may quantize a coefficient block associated with a TU of a CU based on a quantization parameter (QP) value associated with the CU.
  • QP quantization parameter
  • Video encoder 20 may adjust the degree of quantization applied to the coefficient blocks associated with a CU by adjusting the QP value associated with the CU. Quantization may introduce loss of information, thus quantized transform coefficients may have lower precision than the original ones.
  • Inverse quantization unit 108 and inverse transform processing unit 110 may apply inverse quantization and inverse transforms to a coefficient block, respectively, to reconstruct a residual block from the coefficient block.
  • Reconstruction unit 112 may add the reconstructed residual block to corresponding samples from one or more predictive blocks generated by prediction processing unit 100 to produce a reconstructed transform block associated with a TU. By reconstructing transform blocks for each TU of a CU in this way, video encoder 20 may reconstruct the coding blocks of the CU.
  • Filter unit 114 may perform one or more deblocking operations to reduce blocking artifacts in the coding blocks associated with a CU.
  • Decoded picture buffer 116 may store the reconstructed coding blocks after filter unit 114 performs the one or more deblocking operations on the reconstructed coding blocks.
  • Inter-prediction processing unit 120 may use a reference picture that contains the reconstructed coding blocks to perform inter prediction on PUs of other pictures.
  • intra-prediction processing unit 126 may use reconstructed coding blocks in decoded picture buffer 116 to perform intra prediction on other PUs in the same picture as the CU.
  • Entropy encoding unit 118 may receive data from other functional components of video encoder 20. For example, entropy encoding unit 118 may receive coefficient blocks from quantization unit 106 and may receive syntax elements from prediction processing unit 100. Entropy encoding unit 118 may perform one or more entropy encoding operations on the data to generate entropy-encoded data.
  • entropy encoding unit 118 may perform a context-adaptive variable length coding (CAVLC) operation, a CAB AC operation, a variable-to-variable (V2V) length coding operation, a syntax -based context- adaptive binary arithmetic coding (SBAC) operation, a Probability interval Partitioning Entropy (PIPE) coding operation, an Exponential- Golomb encoding operation, or another type of entropy encoding operation on the data.
  • Video encoder 20 may output a bitstream that includes entropy-encoded data generated by entropy encoding unit 118.
  • Video encoder 20 is an example of a video encoder configured to perform any of the techniques described in this disclosure. Additional 3D processing components may also be included within video encoder 20. In accordance with one or more techniques of this disclosure, one or more units within video encoder 20 may perform the techniques described herein as part of a video encoding process. For example, inter- prediction processing unit 120, including motion estimation unit 122 and motion compensation unit 124, may be configured to perform the techniques described herein as part of a video encoding process.
  • Video encoder 20, e.g., inter-prediction processing unit 120 may be configured to use techniques described herein to construct a motion parameter candidate list, e.g., merge candidate list, for encoding a current depth PU. More particularly, video encoder 20, e.g., inter-prediction processing unit 120, may be configured to use the techniques described herein to generate a derived depth coding (DDD) candidate for the motion parameter candidate list based on a co-located texture region, wherein the co-located texture region is a reference texture block that is already needed to be accessed for deriving other candidates in the motion parameter candidate list
  • DDD derived depth coding
  • a device including video encoder 20 is an example of a video encoding device comprising a memory storing a coded video bitstream that includes multiview video data, and one or more processors.
  • the one or more processors are configured to generate a derived depth coding (DDD) candidate for the motion parameter candidate list based on a co-located texture region, wherein the co-located texture region is a reference texture block that is already needed to be accessed for deriving other candidates in the motion parameter candidate list.
  • the one or more processors are further configured to encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • a device including video encoder 20 is also an example of a video encoding device comprising a memory storing a coded video bitstream that includes multiview video data, and one or more processors.
  • the one or more processors are 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, derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list.
  • the one or more processors are further configured to encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • FIG. 10 is a block diagram illustrating an example video decoder 30 that is configured to implement the techniques of this disclosure.
  • FIG. 10 is provided for purposes of explanation and is not limiting on the techniques as broadly exemplified and described in this disclosure.
  • This disclosure describes video decoder 30 in the context of HEVC coding and, in particular, 3D-HEVC coding.
  • the techniques of this disclosure may be applicable to other coding standards or methods.
  • video decoder 30 includes an entropy decoding unit 150, video data memory 151, a prediction processing unit 152, an inverse quantization unit 154, an inverse transform processing unit 156, a reconstruction unit 158, a filter unit 160, and a decoded picture buffer 162.
  • Prediction processing unit 152 includes a motion compensation unit 164 and an intra-prediction processing unit 166.
  • video decoder 30 may include more, fewer, or different functional
  • Video data memory 151 may store video data, such as an encoded video bitstream, to be decoded by the components of video decoder 30.
  • the video data stored in video data memory 151 may be obtained, for example, from computer-readable medium 16, e.g., from a local video source, such as a camera, via wired or wireless network communication of video data, or by accessing physical data storage
  • Video data memory 151 may form a coded picture buffer (CPB) that stores encoded video data from an encoded video bitstream.
  • Decoded picture buffer 162 may be a reference picture memory that stores reference video data for use in decoding video data by video decoder 30, e.g., in intra- or inter-coding modes.
  • Video data memory 151 and decoded picture buffer 162 may be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices.
  • Video data memory 151 and decoded picture buffer 162 may be provided by the same memory device or separate memory devices.
  • prediction processing unit 152 are described as performing both texture decoding and depth decoding.
  • texture and depth decoding may be performed by the same components of prediction processing unit 152 or different components within prediction processing unit 152.
  • separate texture and depth decoders may be provided in some implementations.
  • multiple texture and depth decoders may be provided to decode multiple views, e.g., for multiview plus depth coding.
  • prediction processing unit 152 may be configured to intra- or inter-decode texture data and depth data as part of a 3D coding process, such as a 3D-HEVC process.
  • a coded picture buffer (CPB) 151 may receive and store encoded video data (e.g., NAL units) of a bitstream.
  • Entropy decoding unit 150 may receive NAL units from CPB 151 and parse the NAL units to obtain syntax elements from the bitstream.
  • Entropy decoding unit 150 may entropy decode entropy-encoded syntax elements in the NAL units.
  • Prediction processing unit 152, inverse quantization unit 154, inverse transform processing unit 156, reconstruction unit 158, and filter unit 160 may generate decoded video data based on the syntax elements extracted from the bitstream.
  • the NAL units of the bitstream may include coded slice NAL units.
  • entropy decoding unit 150 may extract and entropy decode syntax elements from the coded slice NAL units.
  • Each of the coded slices may include a slice header and slice data.
  • the slice header may contain syntax elements pertaining to a slice.
  • video decoder 30 may perform a decoding operation on a CU. By performing the decoding operation on a CU, video decoder 30 may reconstruct coding blocks of the CU.
  • inverse quantization unit 154 may inverse quantize, i.e., de-quantize, coefficient blocks associated with TUs of the CU.
  • Inverse quantization unit 154 may use a QP value associated with the CU of the TU to determine a degree of quantization and, likewise, a degree of inverse quantization for inverse quantization unit 154 to apply. That is, the compression ratio, i.e., the ratio of the number of bits used to represent original sequence and the
  • compressed one may be controlled by adjusting the value of the QP used when quantizing transform coefficients.
  • the compression ratio may also depend on the method of entropy coding employed.
  • inverse transform processing unit 156 may apply one or more inverse transforms to the coefficient block in order to generate a residual block associated with the TU.
  • inverse transform processing unit 156 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotational transform, an inverse directional transform, or another inverse transform to the coefficient block.
  • KLT Karhunen-Loeve transform
  • intra-prediction processing unit 166 may perform intra prediction to generate predictive blocks for the PU.
  • Intra-prediction processing unit 166 may use an intra prediction mode to generate the predictive luma, Cb, and Cr blocks for the PU based on the prediction blocks of spatially-neighboring PUs.
  • Intra-prediction processing unit 166 may determine the intra prediction mode for the PU based on one or more syntax elements decoded from the bitstream.
  • Prediction processing unit 152 may construct a first reference picture list
  • RefPicListO a second reference picture list
  • RefPicListl a second reference picture list
  • entropy decoding unit 150 may obtain motion information for the PU.
  • Motion compensation unit 164 may determine, based on the motion information of the PU, one or more reference regions for the PU. Motion compensation unit 164 may generate, based on samples at the one or more reference blocks for the PU, predictive luma, Cb, and Cr blocks for the PU.
  • Reconstruction unit 158 may use the residual values from the luma, Cb, and Cr transform blocks associated with TUs of a CU and the predictive luma, Cb, and Cr blocks of the PUs of the CU, i.e., either intra-prediction data or inter-prediction data, as applicable, to reconstruct the luma, Cb, and Cr coding blocks of the CU.
  • reconstruction unit 158 may add samples of the luma, Cb, and Cr transform blocks to corresponding samples of the predictive luma, Cb, and Cr blocks to reconstruct the luma, Cb, and Cr coding blocks of the CU.
  • Filter unit 160 may perform a deblocking operation to reduce blocking artifacts associated with the luma, Cb, and Cr coding blocks of the CU.
  • Video decoder 30 may store the luma, Cb, and Cr coding blocks of the CU in decoded picture buffer 162.
  • Decoded picture buffer 162 may provide reference pictures for subsequent motion compensation, intra prediction, and presentation on a display device, such as display device 32 of FIG. 1.
  • video decoder 30 may perform, based on the luma, Cb, and Cr blocks in decoded picture buffer 162, intra prediction or inter prediction operations on PUs of other CUs.
  • video decoder 30 may extract, from the bitstream, transform coefficient levels of the significant luma coefficient block, inverse quantize the transform coefficient levels, apply a transform to the transform coefficient levels to generate a transform block, generate, based at least in part on the transform block, a coding block, and output the coding block for display.
  • Video encoder 30 is an example of a video decoder configured to perform any of the techniques described in this disclosure. Additional 3D processing components may also be included within video encoder 30. In accordance with one or more techniques of this disclosure, one or more units within video decoder 30 may perform the techniques described herein as part of a video decoding process. For example, motion compensation unit 164 may be configured to perform the techniques described herein as part of a video decoding process.
  • Video decoder 30, e.g., motion compensation unit 164 may be configured to use techniques described herein to construct a motion parameter candidate list, e.g., merge candidate list, for decoding a current depth PU. More particularly, video decoder 30, e.g., motion compensation unit 164, may be configured to use the techniques described herein to generate a derived depth coding (DDD) candidate for the motion parameter candidate list based on a co-located texture region, wherein the co-located texture region is a reference texture block that is already needed to be accessed for deriving other candidates in the motion parameter candidate list
  • DDD derived depth coding
  • a device including video decoder 30 is an example of a video decoding device comprising a memory storing a coded video bitstream that includes multiview video data, and one or more processors.
  • the one or more processors are 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, derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block, deriving a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list.
  • the one or more processors are further configured to decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • FIG. 11 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 11 may be performed by a video coder, e.g., video encoder 20 and/or video decoder 30, such as the inter-prediction processing unit 120, motion compensation unit 124, and/or motion compensation unit 164 thereof, as part of a depth encoding and/or depth decoding process. More particularly, a video coder may perform the example method of FIG. 11 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1102).
  • the video coder may further derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block (1104).
  • the one or more candidates may include a Sub-PU MPI candidate, a IPMVC candidate, and the like.
  • the video coder may further derive a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list (1106).
  • DDD derived depth coding
  • the reference texture block that is already accessed by the video coder for deriving other candidates in the motion parameter candidate list may also be referred to as a co-located texture block.
  • Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list.
  • the video coder may further decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1108)
  • deriving the one or more candidates for the motion parameter candidate list may include deriving a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block, and deriving the DDD candidate may include deriving the DDD candidate based on a center block of the reference texture block that is used to derive the sub-PU MPI candidate for the motion parameter candidate list.
  • the reference texture block may be a corresponding texture block of a first sub-PU for the current depth PU in raster scan order.
  • the reference texture block may be a corresponding texture block of any sub-PU within the current depth PU involved in a sub-PU MPI candidate derivation process.
  • the video coder may determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU.
  • the video coder may, in response to determining that Inter SDC is applicable to the current depth PU, predict a DC residual of the Inter SDC for the current depth PU based at least in part on the difference between a depth value derived during generating the DDD candidate and an average of depth values of one or more prediction blocks of the current depth PU.
  • the average of depth values of one or more prediction blocks of the current depth PU may include an average of intensities of corner pixels of the one or more prediction blocks of the current depth PU.
  • FIG. 12 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 12 may be performed by a video coder, e.g., video encoder 20 and/or video decoder 30, such as the inter-prediction processing unit 120, motion compensation unit 124, and/or motion compensation unit 164 thereof, as part of a depth encoding and/or depth decoding process. More particularly, a video coder may perform the example method of FIG. 12 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1202).
  • the video coder may further derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block (1203).
  • the one or more candidates may include a Sub-PU MPI candidate, a IPMVC candidate, and the like.
  • the video coder may further determine whether a disparity motion vector associated with the reference texture block accessed to derived the one or more candidates is available (1204). If the video coder determines that the disparity motion vector associated with the reference texture block is not available, video coder may determine not to derive a DDD candidate for the motion parameter candidate list (1206).
  • video coder may derive a DDD candidate for the motion parameter candidate list based at least in part on the disparity motion vector associated with the reference texture block (1208). Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list. The video coder may further decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1210).
  • FIG. 13 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 13 may be performed by a video coder, e.g., video encoder 20 and/or video decoder 30, such as the inter-prediction processing unit 120, motion compensation unit 124, and/or motion compensation unit 164 thereof, as part of a depth encoding and/or depth decoding process. More particularly, a video coder may perform the example method of FIG. 13 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1302).
  • the video coder may further determine whether the partition mode of the current depth PU is of a specified partition mode (1304). If the video coder determines the current depth PU is not of a specified partition mode, video coder may determine not to derive a DDD candidate for the motion parameter candidate list (1306). Alternatively, if the video coder determines that the current depth PU is of a specified partition mode, video coder may derive a DDD candidate for the motion parameter candidate list (1308). In one example, the video coder may only derive a DDD candidate if the partition mode of the current depth PU is 2Nx2N.
  • the video coder may only derive a DDD candidate if the partition mode of the current depth PU is either 2Nx2N, 2NxN, or Nx2N. Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list. The video coder may further decode motion
  • FIG. 14 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 14 may be performed by a video coder, e.g., video encoder 20 and/or video decoder 30, such as the inter-prediction processing unit 120, motion compensation unit 124, and/or motion compensation unit 164 thereof, as part of a depth encoding and/or depth decoding process. More particularly, a video coder may perform the example method of FIG. 14 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1402).
  • the video coder may further determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU (1404). If the video coder determines that Inter SDC is applicable to the current depth PU, video coder may determine not to derive a DDD candidate for the motion parameter candidate list (1406). Alternatively, if the video coder determines that Inter SDC is not applicable to the current depth PU, video coder may derive a DDD candidate for the motion parameter candidate list (1408). Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list. The video coder may further decode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1410).
  • Inter SDC Inter prediction mode
  • FIG. 15 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 15 may be performed by a video coder, e.g., video encoder 20 or units thereof such as the inter-prediction processing unit 120 and motion compensation unit 124, as part of a depth encoding process. More particularly, a video coder may perform the example method of FIG. 15 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1502).
  • the video coder may further derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block (1504).
  • the one or more candidates may include a Sub-PU MPI candidate, a IPMVC candidate, and the like.
  • the video coder may further derive a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list (1506).
  • DDD derived depth coding
  • the reference texture block that is already accessed by the video coder for deriving other candidates in the motion parameter candidate list may also be referred to as a co-located texture block.
  • Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list.
  • the video coder may further encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1508)
  • deriving the one or more candidates for the motion parameter candidate list may include deriving a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block, and deriving the DDD candidate may include deriving the DDD candidate based on a center block of the reference texture block that is used to derive the sub-PU MPI candidate for the motion parameter candidate list.
  • the reference texture block may be a corresponding texture block of a first sub-PU for the current depth PU in raster scan order.
  • the reference texture block may be a corresponding texture block of any sub-PU within the current depth PU involved in a sub-PU MPI candidate derivation process.
  • the video coder may determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU.
  • the video coder may, in response to determining that Inter SDC is applicable to the current depth PU, predict a DC residual of the Inter SDC for the current depth PU based at least in part on the difference between a depth value derived during generating the DDD candidate and an average of depth values of one or more prediction blocks of the current depth PU.
  • the average of depth values of one or more prediction blocks of the current depth PU may include an average of intensities of corner pixels of the one or more prediction blocks of the current depth PU.
  • FIG. 16 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 16 may be performed by a video coder, e.g., video encoder 20 or units thereof such as the inter-prediction processing unit 120 and motion compensation unit 124, as part of a depth encoding process. More particularly, a video coder may perform the example method of FIG. 16 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1602).
  • the video coder may further derive one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block (1603).
  • the one or more candidates may include a Sub-PU MPI candidate, a IPMVC candidate, and the like.
  • the video coder may further determine whether a disparity motion vector associated with the reference texture block accessed to derived the one or more candidates is available (1604). If the video coder determines that the disparity motion vector associated with the reference texture block is not available, video coder may determine not to derive a DDD candidate for the motion parameter candidate list (1606).
  • video coder may derive a DDD candidate for the motion parameter candidate list based at least in part on the disparity motion vector associated with the reference texture block (1608). Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list. The video coder may further encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1610).
  • FIG. 17 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 17 may be performed by a video encoder, e.g., video encoder 20 or units thereof such as inter-prediction processing unit 120 and motion compensation unit 124, as part of a depth encoding process. More particularly, a video coder may perform the example method of FIG. 17 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1702). The video coder may further determine whether the partition mode of the current depth PU is of a specified partition mode (1704). If the video coder determines the current depth PU is not of a specified partition mode, video coder may determine not to derive a DDD candidate for the motion parameter candidate list (1706). Alternatively, if the video coder determines that the current depth PU is of a specified partition mode, video coder may derive a DDD candidate for the motion parameter candidate list (1708). In one example, the video coder may only derive a DDD candidate if the partition mode of the current depth PU is 2Nx2N.
  • the video coder may only derive a DDD candidate if the partition mode of the current depth PU is either 2Nx2N, 2NxN, or Nx2N. Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list. The video coder may further encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1710).
  • FIG. 18 is a flow diagram illustrating an example method for simplified derivation of disparity derived depth candidates for a motion parameter candidate list.
  • the example method of FIG. 18 may be performed by a video encoder, e.g., video encoder 20 or units thereof such as the inter-prediction processing unit 120 and motion compensation unit 124 as part of a depth encoding process. More particularly, a video coder may perform the example method of FIG. 18 as part of a motion parameter candidate list, e.g., merge candidate list, generation process for motion parameter prediction, e.g., according to the merge mode, of a current depth PU.
  • a motion parameter candidate list e.g., merge candidate list
  • generation process for motion parameter prediction e.g., according to the merge mode, of a current depth PU.
  • the video coder may generate a motion parameter candidate list for a current depth PU. (1802).
  • the video coder may further determine whether Segment- wise DC coding for Inter prediction mode (Inter SDC) is applicable to the current depth PU (1804). If the video coder determines that Inter SDC is applicable to the current depth PU, video coder may determine not to derive a DDD candidate for the motion parameter candidate list (1806). Alternatively, if the video coder determines that Inter SDC is not applicable to the current depth PU, video coder may derive a DDD candidate for the motion parameter candidate list (1808). Deriving the DDD candidate may include inserting the DDD candidate into the motion parameter candidate list.
  • the video coder may further encode motion information for the current depth PU based on the motion parameter candidate list for the current depth PU (1710).
  • a method for decoding multiview video data comprising:
  • a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list;
  • deriving the one or more candidates for the motion parameter candidate list comprises deriving a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block; and
  • MPI sub-PU motion parameter inheritance
  • deriving the DDD candidate for the motion parameter candidate list comprises deriving the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • a video decoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • processors configured to:
  • DDD derived depth coding
  • MPI motion parameter inheritance
  • derive the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • a video decoding device for decoding multiview video data 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; means for deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block;
  • PU current depth prediction unit
  • a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list;
  • the means for deriving the one or more candidates for the motion parameter candidate list comprises means for deriving a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block; and
  • MPI motion parameter inheritance
  • the means for deriving the DDD candidate for the motion parameter candidate list comprises means for deriving the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, cause the one or more processors to:
  • DDD derived depth coding
  • MPI motion parameter inheritance
  • derive the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • Clause 23 The computer-readable storage medium of any of clauses 19-22, further comprising:
  • Inter SDC Inter prediction mode
  • a method for decoding multiview video data comprising:
  • DDD derived depth coding
  • a video decoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • processors configured to:
  • DDD derived depth coding
  • a video decoding device for decoding multiview video data comprising:
  • PU current depth prediction unit
  • DDD derived depth coding
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding 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;
  • PU current depth prediction unit
  • DDD derived depth coding
  • a method for decoding multiview video data comprising:
  • Clause 30 The method of clause 29, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 31 The method of clause 29, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a video decoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • processors configured to:
  • 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 derive a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and
  • DDD derived depth coding
  • Clause 33 The video decoding device of clause 32, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 34 The video decoding device of clause 32, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a video decoding device for decoding multiview video data comprising:
  • DDD derived depth coding
  • Clause 36 The video decoding device of clause 35, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 37 The video decoding device of clause 35, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, cause the one or more processors to:
  • DDD derived depth coding
  • Clause 39 The computer-readable storage medium of clause 38, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 40 The computer-readable storage medium of clause 38, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a method for decoding multiview video data comprising:
  • a video decoding device comprising: a memory storing a coded video bitstream that includes multiview video data; and
  • processors configured to:
  • a video decoding device for decoding multiview video data comprising:
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video decoding device for decoding multiview video data, cause the one or more processors to:
  • a method for encoding multiview video data comprising:
  • 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 deriving one or more candidates for the motion parameter candidate list based at least in part on accessing a reference texture block;
  • a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list;
  • deriving the one or more candidates for the motion parameter candidate list comprises deriving a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block; and
  • MPI sub-PU motion parameter inheritance
  • deriving the DDD candidate for the motion parameter candidate list comprises deriving the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • Clause 50 The method of any of clauses 45-49, wherein the average of depth values of one or more prediction blocks of the current depth PU includes an average of intensities of corner pixels of the one or more prediction blocks of the current depth PU.
  • a video encoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • processors configured to:
  • DDD derived depth coding
  • Clause 52 The video encoding device of clause 51, wherein the one or more processors are further configured to: derive a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block; and
  • MPI motion parameter inheritance
  • derive the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • Clause 55 The video encoding device of any of clauses 51-54, wherein the one or more processors are further configured to:
  • Inter SDC Inter prediction mode
  • a video encoding device for encoding multiview video data comprising:
  • PU current depth prediction unit
  • a derived depth coding (DDD) candidate for the motion parameter candidate list based only on the reference texture block that is already accessed for deriving the one or more candidates for the motion parameter candidate list;
  • the means for deriving the one or more candidates for the motion parameter candidate list comprises means for deriving a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block; and
  • MPI motion parameter inheritance
  • the means for deriving the DDD candidate for the motion parameter candidate list comprises means for deriving the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • Clause 62 The video encoding device of any of clauses 57-61, wherein the average of depth values of one or more prediction blocks of the current depth PU includes an average of intensities of corner pixels of the one or more prediction blocks of the current depth PU.
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, cause the one or more processors to:
  • DDD derived depth coding
  • Clause 64 The computer-readable storage medium of clause 63, further comprising:
  • a sub-PU motion parameter inheritance (MPI) candidate for the motion parameter candidate list based at least in part on accessing the reference texture block; and derive the DDD candidate for the motion parameter candidate list comprises based on a center block of the reference texture block used to derive the sub-PU MPI candidate.
  • MPI motion parameter inheritance
  • Clause 65 The computer-readable storage medium of clause 63 or 64, wherein the reference texture block is a corresponding texture block of a first sub-PU for the current depth PU in raster scan order.
  • Clause 66 The computer-readable storage medium of clause 63 or 64, wherein the reference texture block is a corresponding texture block of any sub-PU within the current depth PU involved in a sub-PU MPI candidate derivation process.
  • Clause 67 The computer-readable storage medium of any of clauses 63-66, further comprising:
  • Clause 68 The computer-readable storage medium of any of clauses 63-67, wherein the average of depth values of one or more prediction blocks of the current depth PU includes an average of intensities of corner pixels of the one or more prediction blocks of the current depth PU.
  • a method for encoding multiview video data comprising:
  • DDD derived depth coding
  • a video encoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • processors configured to:
  • DDD derived depth coding
  • a video encoding device for encoding multiview video data comprising:
  • PU current depth prediction unit
  • DDD derived depth coding
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, cause the one or more processors to:
  • DDD derived depth coding
  • a method for encoding multiview video data comprising:
  • a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and encoding motion information for the current depth PU based on the motion parameter candidate list for the current depth PU.
  • DDD derived depth coding
  • Clause 74 The method of clause 73, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 75 The method of clause 73, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a video encoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • processors configured to:
  • 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 derive a derived depth coding (DDD) candidate for the motion parameter candidate list only if a partition mode of the current depth PU is of a specified partition mode; and
  • DDD derived depth coding
  • Clause 77 The video encoding device of clause 76, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 78 The video encoding device of clause 76, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a video encoding device for encoding multiview video data comprising:
  • DDD derived depth coding
  • Clause 80 The video encoding device of clause 79, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 81 The video encoding device of clause 79, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, cause the one or more processors to:
  • DDD derived depth coding
  • Clause 83 The computer-readable storage medium of clause 82, wherein the specified partition mode is a 2Nx2N partition mode.
  • Clause 84 The computer-readable storage medium of clause 82, wherein the specified partition mode is one of: a 2Nx2N partition mode, a 2NxN partition mode, or a Nx2N partition mode.
  • a method for encoding multiview video data comprising:
  • a video encoding device comprising:
  • a memory storing a coded video bitstream that includes multiview video data
  • 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 current depth PU is coded with merge mode;
  • PU current depth prediction unit
  • a video encoding device for encoding multiview video data comprising:
  • a computer-readable storage medium having instructions stored thereon that, when executed by one or more processors of a video encoding device for encoding multiview video data, cause the one or more processors to:
  • Inter SDC Segment- wise DC coding for Inter prediction mode
  • the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over, as one or more instructions or code, a computer-readable medium and executed by a hardware-based processing unit.
  • Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol.
  • computer- readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave.
  • Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure.
  • a computer program product may include a computer-readable medium.
  • Such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium.
  • coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.
  • DSL digital subscriber line
  • computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but are instead directed to non-transient, tangible storage media.
  • Disk and disc includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
  • processors such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry.
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • FPGAs field programmable logic arrays
  • processors may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein.
  • the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.
  • the techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set).
  • IC integrated circuit
  • a set of ICs e.g., a chip set.
  • Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and/or firmware.

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Abstract

La présente invention concerne des techniques permettant de simplifier un codage en mode inter de profondeur dans un processus de codage vidéo tridimensionnel (3D), tel que 3D-HEVC. Les techniques peuvent consister à générer une liste de paramètres de mouvement candidats pour une unité de prédiction (PU) de profondeur courante dans une composante de profondeur d'une vue courante des données vidéo multivues. Les techniques peuvent consister à calculer un ou plusieurs candidats pour la liste de paramètres de mouvement candidats au moins en partie sur la base d'un accès à un bloc de texture de référence. Les techniques peuvent consister à calculer un candidat de codage de profondeur issue de la disparité (DDD) pour la liste de paramètres de mouvement candidats en se basant seulement sur le bloc de texture de référence qui a déjà fait l'objet d'un accès pour calculer le ou les candidats pour la liste de paramètres de mouvement candidats. Les techniques décrites consistent à décoder ou coder des informations de mouvement pour la PU de profondeur courante sur la base de la liste de paramètres de mouvement candidats pour la PU de profondeur courante.
PCT/CN2014/073358 2014-03-13 2014-03-13 Codage de profondeur issue de la disparité simplifié en codage vidéo tridimensionnel (3d) WO2015135174A1 (fr)

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CN102017627A (zh) * 2008-04-25 2011-04-13 汤姆森许可贸易公司 使用基于深度信息的视差估计的多视点视频编码
CN103493483A (zh) * 2011-03-10 2014-01-01 高通股份有限公司 译码多视图视频加深度内容
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