CN112135137B

CN112135137B - Video encoder, video decoder and corresponding methods

Info

Publication number: CN112135137B
Application number: CN201910556291.5A
Authority: CN
Inventors: 陈焕浜; 杨海涛
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-06-25
Filing date: 2019-06-25
Publication date: 2024-04-09
Anticipated expiration: 2039-06-25
Also published as: CN112135137A

Abstract

The application discloses a video encoder, a video decoder and a corresponding method, in particular to a method for acquiring a time domain candidate motion vector, wherein an image block to be processed is positioned in a current coding tree unit, the current coding tree unit is positioned in a current image, and the method comprises the following steps: determining a first time domain position of the image block to be processed according to the position of the right lower corner of the image block to be processed, the boundary position of the current coding tree unit and the boundary position of the current image, wherein the first time domain position is positioned in a coding tree unit row where the current coding tree unit is positioned; determining a first neighborhood position corresponding to the first time domain position in a time domain corresponding image of the current image; and when a first motion vector corresponding to the first neighborhood position is available, determining a time domain candidate motion vector of the image block to be processed according to the first motion vector.

Description

Video encoder, video decoder and corresponding methods

Technical Field

The present invention relates to the field of video encoding and decoding, and in particular, to a method and apparatus for obtaining a time domain candidate motion vector in a video image inter-frame prediction process, and a corresponding encoder and decoder.

Background

Digital video capabilities can be incorporated into a wide variety of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal Digital Assistants (PDAs), laptop or desktop computers, tablet computers, electronic book readers, digital cameras, digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite radio telephones (so-called "smartphones"), 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 video coding standard H.265/High Efficiency Video Coding (HEVC) standard, and extensions of such standards. Video devices may more efficiently transmit, receive, encode, decode, and/or store digital video information by implementing such video compression techniques.

Video compression techniques perform spatial (intra-picture) prediction and/or temporal (inter-picture) prediction to reduce or eliminate redundancy inherent in video sequences. For block-based video coding, a video slice (i.e., a video frame or a portion of a video frame) may be partitioned into tiles, which may also be referred to as treeblocks, coding Units (CUs), and/or coding nodes. Image blocks in a slice to be intra-coded (I) of an image are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same image. Image blocks in a to-be-inter-coded (P or B) stripe of an image may use spatial prediction with respect to reference samples in neighboring blocks in the same image or temporal prediction with respect to reference samples in other reference images. An image may be referred to as a frame and a reference image may be referred to as a reference frame.

Disclosure of Invention

The embodiment of the application provides an inter-frame prediction method and device for video images and a corresponding encoder and decoder, and particularly provides a method for acquiring time domain candidate motion vectors, which reduces the computational complexity while guaranteeing the encoding and decoding performance and saves hardware resources and power consumption.

In a first aspect, an embodiment of the present application provides a method for obtaining a temporal candidate motion vector, where an image block to be processed is located in a current Coding Tree Unit (CTU), where the current coding tree unit is located in a current image, the method includes: determining a first time domain position of the image block to be processed according to the position of the right lower corner of the image block to be processed, the boundary position of the current coding tree unit and the boundary position of the current image, wherein the first time domain position is positioned in a coding tree unit row where the current coding tree unit is positioned; determining a first neighborhood position corresponding to the first time domain position in a time domain corresponding image (collocated picture) of the current image; and when a first motion vector corresponding to the first neighborhood position is available, determining a time domain candidate motion vector of the image block to be processed according to the first motion vector.

According to the embodiment of the application, the first time domain position is limited within the coding tree unit row where the current coding tree unit is located, so that the process of determining the second time domain position again when the first time domain position is unavailable is avoided, and the implementation complexity of the scheme is reduced.

In a possible implementation manner of the first aspect, the determining the first time domain position of the image block to be processed includes: taking the minimum value between the abscissa of the right lower corner position and the abscissa of the right boundary of the current image as the abscissa of the first time domain position; determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit; and taking the minimum value between the ordinate of the right lower corner point position and the ordinate of the lower boundary of the current coding tree unit as the ordinate of the first time domain position.

The embodiment of the application exemplarily provides a method for determining the first time domain position, by which the first time domain position can be limited to be within the coding tree unit row where the current coding tree unit is located, and the original coding and decoding performance can be maintained.

In a possible implementation manner of the first aspect, the determining a first neighborhood position corresponding to the first time domain position includes: rounding coordinates of the first time domain position; and taking the coordinates after the rounding operation as the coordinates of the first neighborhood position.

The embodiment of the application can complete rounding processing by adopting the operation of shifting the coordinates of the first time domain position by a plurality of digits to the right and shifting the coordinates by the same digits to the left, and can further reduce the complexity of realization.

In a possible implementation manner of the first aspect, the time domain corresponding image is a preset image or is determined by parsing the code stream information.

According to the embodiment of the application, different time domain corresponding images can be determined in different modes, and the flexibility of scheme implementation is improved.

In a possible implementation manner of the first aspect, before the determining the temporal candidate motion vector of the image block to be processed according to the first motion vector, the method further includes: determining a first prediction mode of an image block where the first neighborhood position is located; and determining availability of the first motion vector according to the first prediction mode, wherein the first motion vector is determined to be unavailable when the first prediction mode is intra-prediction or intra-block copy mode (block copy), and the first motion vector is determined to be available when the first prediction mode is inter-prediction.

According to the method and the device for determining the availability of the first motion vector, the availability of the first motion vector is determined according to the prediction mode, and complexity of scheme implementation is further reduced.

In a possible implementation manner of the first aspect, the determining a temporal candidate motion vector of the image block to be processed according to the first motion vector includes: and scaling the first motion vector according to the proportional relation between a first time domain distance and a second time domain distance to obtain the time domain candidate motion vector, wherein the first time domain distance is the distance between the current image and the reference frame of the current image, and the second time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the first motion vector.

In a possible implementation manner of the first aspect, the method further includes: when the first motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

In a possible implementation manner of the first aspect, the method further includes: when the first motion vector is unavailable, determining a second neighborhood position corresponding to a second time domain position of the image block to be processed in the time domain corresponding image; and when a second motion vector corresponding to the second neighborhood position is available, determining the time domain candidate motion vector according to the second motion vector.

One of the two implementations of the embodiments of the present application gives up using the time domain candidate motion vector after determining that the first motion vector is not available, and the other further examines the second time domain position after determining that the first motion vector is not available. The specific implementation scheme can be selected according to different bias to complexity and performance in practical use cases.

In a possible implementation manner of the first aspect, the second temporal location is a geometric center location of the image block to be processed.

According to the embodiment of the application, the proper position is selected as the second time domain position, so that the coding and decoding performance of the scheme is improved.

In a possible implementation manner of the first aspect, the determining a second neighborhood position corresponding to a second time domain position of the image block to be processed includes: rounding coordinates of the second time domain position; and taking the coordinates after the rounding operation as the coordinates of the second neighborhood position.

The embodiment of the application can complete rounding processing by adopting the operation of shifting the coordinates of the second time domain position by a plurality of digits to the right and shifting the coordinates by the same digits to the left, and can further reduce the complexity of realization.

In a possible implementation manner of the first aspect, before the determining the temporal candidate motion vector according to the second motion vector, the method further includes: determining a second prediction mode of the image block where the second neighborhood position is located; and determining availability of the second motion vector according to the second prediction mode, wherein the second motion vector is determined to be unavailable when the second prediction mode is intra-prediction or intra-block copy mode, and the second motion vector is determined to be available when the second prediction mode is inter-prediction.

According to the embodiment of the application, the availability of the second motion vector is determined according to the prediction mode, so that the complexity of scheme implementation is further reduced.

In a possible implementation manner of the first aspect, the determining the temporal candidate motion vector according to the second motion vector includes: and scaling the second motion vector according to the proportional relation between the first time domain distance and a third time domain distance to obtain the time domain candidate motion vector, wherein the third time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the second motion vector.

In a possible implementation manner of the first aspect, the method further includes: when the second motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

The embodiment of the application gives up to use the time domain candidate motion vector after determining that the second motion vector is not available.

In a possible implementation manner of the first aspect, the current image is a current image frame, and may also be a partial image area in the current image frame, such as a sub-image, a tile group (tile), a slice group (slice group), a slice (slice), and the like, and the corresponding image boundary is a boundary of the partial image area, for example, a sub-image boundary, a tile group boundary, a tile boundary, a slice group boundary, a slice boundary, and the like.

In a second aspect, an embodiment of the present application provides another method for obtaining a temporal candidate motion vector, where an image block to be processed is located in a current coding tree unit, where the current coding tree unit is located in a current image, and the method includes: determining a third neighborhood position corresponding to a third time domain position of the image block to be processed in the time domain corresponding image of the current image, wherein when the position of a right lower corner of the image block to be processed is positioned outside the lower boundary of the current coding tree unit or the position of the right lower corner is positioned outside the right boundary of the current image, the third time domain position is the geometric center position of the image block to be processed; and when a third motion vector corresponding to the third neighborhood position is available, determining a time domain candidate motion vector of the image block to be processed according to the third motion vector.

In a possible implementation manner of the second aspect, the method further includes: and when the position of the right lower corner of the image block to be processed is positioned in the lower boundary of the current coding tree unit, and the position of the right lower corner is positioned in the right boundary of the current image, the third time domain position is the position of the right lower corner of the image block to be processed.

According to the method and the device for determining the position of the right lower corner of the image block to be processed, the selection of the position of the third time domain is determined by judging the position of the right lower corner of the image block to be processed, the encoding and decoding performance is guaranteed, meanwhile, the calculation complexity is reduced, and meanwhile, hardware resources and power consumption are saved.

In a possible implementation manner of the second aspect, the determining a third neighborhood position corresponding to a third time domain position of the image block to be processed includes: rounding coordinates of the third time domain position; and taking the coordinates after the rounding operation as the coordinates of the third neighborhood position.

The embodiment of the application can complete rounding processing by adopting the operation of shifting the coordinates of the third time domain position by a plurality of digits to the right and shifting the coordinates by the same digits to the left, and can further reduce the complexity of realization.

In a possible implementation manner of the second aspect, the time domain corresponding image is a preset image or is determined by parsing the code stream information.

In a possible implementation manner of the second aspect, before the determining the temporal candidate motion vector of the image block to be processed according to the third motion vector, the method further includes: determining a third prediction mode of the image block where the third neighborhood position is located; and determining availability of the third motion vector according to the third prediction mode, wherein the third motion vector is determined to be unavailable when the third prediction mode is intra-prediction or intra-block copy mode, and the third motion vector is determined to be available when the third prediction mode is inter-prediction.

In a possible implementation manner of the second aspect, the determining a temporal candidate motion vector of the image block to be processed according to the third motion vector includes: and scaling the third motion vector according to a proportional relation between a fourth time domain distance and a fifth time domain distance to obtain the time domain candidate motion vector, wherein the fourth time domain distance is the distance between the current image and the reference frame of the current image, and the fifth time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the third motion vector.

In a possible implementation manner of the second aspect, the method further includes: when the third motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

The embodiment of the application gives up to use the time domain candidate motion vector after determining that the third motion vector is not available.

In a possible implementation manner of the second aspect, the method further includes: determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; and taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit.

It should be appreciated that since the longitudinal resolution of the image may not be a high integer multiple of the coding tree units, the coding tree units of the last line may exceed the lower boundary of the image. At this time, the lower boundary of the last line of the code tree unit is clamped to the lower boundary of the current image.

In a possible implementation manner of the second aspect, the current image is a current image frame, and may also be a partial image area in the current image frame, such as a sub-image, a slice group, or a slice, and the corresponding image boundary is a boundary of the partial image area, for example, a sub-image boundary, a slice group boundary, or a slice boundary.

In a third aspect, an embodiment of the present application provides an apparatus for acquiring a temporal candidate motion vector, where an image block to be processed is located in a current coding tree unit, where the current coding tree unit is located in a current image, and the apparatus includes: the computing module is used for determining a first time domain position of the image block to be processed according to the position of the right lower corner of the image block to be processed, the boundary position of the current coding tree unit and the boundary position of the current image, wherein the first time domain position is positioned in a coding tree unit row where the current coding tree unit is positioned; the mapping module is used for determining a first neighborhood position corresponding to the first time domain position in the time domain corresponding image of the current image; and the determining module is used for determining a time domain candidate motion vector of the image block to be processed according to the first motion vector when the first motion vector corresponding to the first neighborhood position is available.

In a possible implementation manner of the third aspect, the horizontal rectangular coordinate system corresponding to the current image is in a horizontal positive direction to the right and in a vertical positive direction to the bottom, and the calculating module is specifically configured to: taking the minimum value between the abscissa of the right lower corner position and the abscissa of the right boundary of the current image as the abscissa of the first time domain position; determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit; and taking the minimum value between the ordinate of the right lower corner point position and the ordinate of the lower boundary of the current coding tree unit as the ordinate of the first time domain position.

In a possible implementation manner of the third aspect, the mapping module is specifically configured to: rounding coordinates of the first time domain position; and taking the coordinates after the rounding operation as the coordinates of the first neighborhood position.

In a possible implementation manner of the third aspect, the time domain corresponding image is a preset image or is determined by parsing the code stream information.

In a possible implementation manner of the third aspect, before the determining, according to the first motion vector, a temporal candidate motion vector of the image block to be processed, the determining module is further configured to: determining a first prediction mode of an image block where the first neighborhood position is located; and determining availability of the first motion vector according to the first prediction mode, wherein the first motion vector is determined to be unavailable when the first prediction mode is intra-prediction or intra-block copy mode, and the first motion vector is determined to be available when the first prediction mode is inter-prediction.

In a possible implementation manner of the third aspect, the determining module is specifically configured to: and scaling the first motion vector according to the proportional relation between a first time domain distance and a second time domain distance to obtain the time domain candidate motion vector, wherein the first time domain distance is the distance between the current image and the reference frame of the current image, and the second time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the first motion vector.

In a possible implementation manner of the third aspect, the determining module is further configured to: when the first motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

In a possible implementation manner of the third aspect, the determining module is further configured to: when the first motion vector is unavailable, determining a second neighborhood position corresponding to a second time domain position of the image block to be processed in the time domain corresponding image; and when a second motion vector corresponding to the second neighborhood position is available, determining the time domain candidate motion vector according to the second motion vector.

In a possible implementation manner of the third aspect, the second time domain position is a geometric center position of the image block to be processed.

In a possible implementation manner of the third aspect, the mapping module is specifically configured to: rounding coordinates of the second time domain position; and taking the coordinates after the rounding operation as the coordinates of the second neighborhood position.

In a possible implementation manner of the third aspect, before the determining the temporal candidate motion vector according to the second motion vector, the determining module is further configured to: determining a second prediction mode of the image block where the second neighborhood position is located; and determining availability of the second motion vector according to the second prediction mode, wherein the second motion vector is determined to be unavailable when the second prediction mode is intra-prediction or intra-block copy mode, and the second motion vector is determined to be available when the second prediction mode is inter-prediction.

In a possible implementation manner of the third aspect, the determining module is specifically configured to: and scaling the second motion vector according to the proportional relation between the first time domain distance and a third time domain distance to obtain the time domain candidate motion vector, wherein the third time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the second motion vector.

In a possible implementation manner of the third aspect, the determining module is further configured to: when the second motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

In a possible implementation manner of the third aspect, the current image is a current image frame, and may also be a partial image area in the current image frame, such as a sub-image, a slice group, or a slice, and the corresponding image boundary is a boundary of the partial image area, for example, a sub-image boundary, a slice group boundary, or a slice boundary.

In a fourth aspect, an embodiment of the present application provides an apparatus for obtaining a temporal candidate motion vector, where an image block to be processed is located in a current coding tree unit, where the current coding tree unit is located in a current image, and the apparatus includes: the mapping module is configured to determine, in a time-domain corresponding image of the current image, a third neighborhood position corresponding to a third time-domain position of the image block to be processed, where when a lower right corner position of the image block to be processed is located outside a lower boundary of the current coding tree unit, or the lower right corner position is located outside a right boundary of the current image, the third time-domain position is a geometric center position of the image block to be processed; and the determining module is used for determining a time domain candidate motion vector of the image block to be processed according to the third motion vector when the third motion vector corresponding to the third neighborhood position is available.

In a possible implementation manner of the fourth aspect, the mapping module is specifically configured to: rounding coordinates of the third time domain position; and taking the coordinates after the rounding operation as the coordinates of the third neighborhood position.

In a possible implementation manner of the fourth aspect, the time domain corresponding image is a preset image or is determined by analyzing code stream information.

In a possible implementation manner of the fourth aspect, before the determining the temporal candidate motion vector of the image block to be processed according to the third motion vector, the determining module is further configured to: determining a third prediction mode of the image block where the third neighborhood position is located; and determining availability of the third motion vector according to the third prediction mode, wherein the third motion vector is determined to be unavailable when the third prediction mode is intra-prediction or intra-block copy mode, and the third motion vector is determined to be available when the third prediction mode is inter-prediction.

In a possible implementation manner of the fourth aspect, the determining module is specifically configured to: and scaling the third motion vector according to a proportional relation between a fourth time domain distance and a fifth time domain distance to obtain the time domain candidate motion vector, wherein the fourth time domain distance is the distance between the current image and the reference frame of the current image, and the fifth time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the third motion vector.

In a possible implementation manner of the fourth aspect, the determining module is further configured to: when the third motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

In a possible implementation manner of the fourth aspect, the method further includes: and when the position of the right lower corner of the image block to be processed is positioned in the lower boundary of the current coding tree unit, and the position of the right lower corner is positioned in the right boundary of the current image, the third time domain position is the position of the right lower corner of the image block to be processed.

In a possible implementation manner of the fourth aspect, the mapping module is further configured to: determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; and taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit.

In a possible implementation manner of the fourth aspect, the current image is a current image frame, and may also be a partial image area in the current image frame, such as a sub-image, a slice group, or a slice, and the corresponding image boundary is a boundary of the partial image area, for example, a sub-image boundary, a slice group boundary, or a slice boundary.

In a fifth aspect, embodiments of the present application provide a video encoder for encoding an image block, including: an inter-prediction apparatus as claimed in any one of the third or fourth aspects, wherein the inter-prediction apparatus is operable to predict motion information of a current encoded image block based on target candidate motion information, and to determine a predicted pixel value of the current encoded image block based on the motion information of the current encoded image block; an entropy encoding module for encoding an index identification of the target candidate motion information into a bitstream, the index identification indicating the target candidate motion information for the current encoded image block; a reconstruction module for reconstructing the current encoded image block based on the predicted pixel values.

In a sixth aspect, embodiments of the present application provide a video decoder for decoding an image block from a code stream, including: the entropy decoding module is used for decoding an index identifier from the code stream, wherein the index identifier is used for indicating target candidate motion information of the current decoded image block; an inter-frame prediction apparatus as claimed in any one of the third or fourth aspects, the inter-frame prediction apparatus being operable to predict motion information of a current decoded image block based on target candidate motion information indicated by the index identification, and to determine a predicted pixel value of the current decoded image block based on the motion information of the current decoded image block; a reconstruction module for reconstructing the current decoded image block based on the predicted pixel values.

In a seventh aspect, embodiments of the present application provide a video codec device, including: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform a method as described in any of the first or second aspects.

In an eighth aspect, embodiments of the present application provide an encoding apparatus, including: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform part or all of the steps of any of the methods of the first or second aspects.

In a ninth aspect, embodiments of the present application provide a decoding apparatus, including: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform part or all of the steps of any of the methods of the first or second aspects.

In a tenth aspect, embodiments of the present application provide a computer readable storage medium storing program code, wherein the program code comprises instructions for performing part or all of the steps of any one of the methods of the first or second aspects.

In an eleventh aspect, embodiments of the present application provide a computer program product which, when run on a computer, causes the computer to perform part or all of the steps of any one of the methods of the first or second aspects.

It should be understood that, in the device embodiment and the method embodiment provided in the present application, the technical solutions are consistent, and the obtained beneficial effects are similar and are not repeated.

Drawings

In order to more clearly describe the embodiments of the present invention or the technical solutions in the background art, the following description will describe the drawings that are required to be used in the embodiments of the present invention or the background art.

FIG. 1A is a block diagram of an example of a video encoding and decoding system 10 for implementing an embodiment of the invention;

FIG. 1B is a block diagram of an example of a video coding system 40 for implementing an embodiment of the invention;

FIG. 2 is a block diagram of an example structure of an encoder 20 for implementing an embodiment of the present invention;

FIG. 3 is a block diagram of an example architecture of a decoder 30 for implementing an embodiment of the present invention;

fig. 4 is a block diagram of an example of a video coding apparatus 400 for implementing an embodiment of the invention;

FIG. 5 is a block diagram of another example encoding or decoding device for implementing an embodiment of the present invention;

FIG. 6 is a schematic diagram of spatial or temporal motion information candidate locations used in AMVP or Merge modes for implementing embodiments of the present invention;

FIG. 7 is a schematic diagram of MV scaling operations for implementing a time domain allocated block according to an embodiment of the present invention;

FIG. 8 is a flow chart of a method for obtaining temporal candidate motion vectors for implementing an embodiment of the present invention;

FIG. 9 is a flow chart of another method for obtaining temporal candidate motion vectors for implementing an embodiment of the present invention;

FIG. 10 is a flow chart of yet another method for obtaining temporal candidate motion vectors for implementing an embodiment of the present invention;

fig. 11 is a block diagram of a time domain candidate motion vector obtaining apparatus for implementing an embodiment of the present invention;

fig. 12 is a block diagram of a structure of another time domain candidate motion vector obtaining apparatus for implementing an embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention. In the following description, reference is made to the accompanying drawings which form a part hereof and which show by way of illustration specific aspects in which embodiments of the invention may be practiced. It is to be understood that embodiments of the invention may be used in other aspects and may include structural or logical changes not depicted in the drawings. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. For example, it should be understood that the disclosure in connection with the described methods may be equally applicable to a corresponding apparatus or system for performing the methods, and vice versa. For example, if one or more specific method steps are described, the corresponding apparatus may comprise one or more units, such as functional units, to perform the one or more described method steps (e.g., one unit performing one or more steps, or multiple units each performing one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, if a specific apparatus is described based on one or more units such as a functional unit, for example, the corresponding method may include one step to perform the functionality of the one or more units (e.g., one step to perform the functionality of the one or more units, or multiple steps each to perform the functionality of one or more units, even if such one or more steps are not explicitly described or illustrated in the figures). Further, it is to be understood that features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless explicitly stated otherwise.

The technical scheme related to the embodiment of the invention can be applied to the existing video coding standards (such as H.264, HEVC and the like) and future video coding standards (such as H.266). The terminology used in the description of the embodiments of the invention herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting of the invention. Some concepts that may be related to embodiments of the present invention are briefly described below.

Video coding generally refers to processing a sequence of pictures that form a video or video sequence. In the field of video coding, the terms "picture", "frame" or "image" may be used as synonyms. Video encoding as used herein refers to video encoding or video decoding. Video encoding is performed on the source side, typically including processing (e.g., by compression) the original video picture to reduce the amount of data required to represent the video picture, thereby more efficiently storing and/or transmitting. Video decoding is performed on the destination side, typically involving inverse processing with respect to the encoder to reconstruct the video pictures. The embodiment relates to video picture "encoding" is understood to relate to "encoding" or "decoding" of a video sequence. The combination of the encoding portion and the decoding portion is also called codec (encoding and decoding).

A video sequence comprises a series of pictures (pictures) which are further divided into slices (slices) which are further divided into blocks (blocks). Video coding performs coding processing in units of blocks, and in some new video coding standards, the concept of blocks is further extended. For example, in the h.264 standard, there are Macro Blocks (MBs), which can be further divided into a plurality of prediction blocks (partition) that can be used for predictive coding. In the high performance video coding (high efficiency video coding, HEVC) standard, basic concepts such as a Coding Unit (CU), a Prediction Unit (PU), and a Transform Unit (TU) are adopted, and various block units are functionally divided and described by using a brand new tree-based structure. For example, a CU may be divided into smaller CUs according to a quadtree, and the smaller CUs may continue to be divided, thereby forming a quadtree structure, where a CU is a basic unit for dividing and encoding an encoded image. Similar tree structures exist for PUs and TUs, which may correspond to prediction blocks, being the basic unit of predictive coding. The CU is further divided into a plurality of PUs according to a division pattern. The TU may correspond to a transform block, which is a basic unit for transforming a prediction residual. However, whether CU, PU or TU, essentially belongs to the concept of blocks (or picture blocks).

In HEVC, for example, CTUs are split into multiple CUs by using a quadtree structure denoted as coding tree. A decision is made at the CU level whether to encode a picture region using inter-picture (temporal) or intra-picture (spatial) prediction. Each CU may be further split into one, two, or four PUs depending on the PU split type. The same prediction process is applied within one PU and the relevant information is transmitted to the decoder on a PU basis. After the residual block is obtained by applying the prediction process based on the PU split type, the CU may be partitioned into Transform Units (TUs) according to other quadtree structures similar to the coding tree for the CU. In a recent development of video compression technology, a Quad tree and a binary tree (qd-tree and binary tree, QTBT) partition frames are used to partition the encoded blocks. In QTBT block structures, a CU may be square or rectangular in shape.

Herein, for convenience of description and understanding, an image block to be encoded in a current encoded image may be referred to as a current block, for example, in encoding, a block currently being encoded; in decoding, a block currently being decoded is referred to. A decoded image block in a reference image used for predicting a current block is referred to as a reference block, i.e. a reference block is a block providing a reference signal for the current block, wherein the reference signal represents pixel values within the image block. A block in the reference picture that provides a prediction signal for the current block may be referred to as a prediction block, where the prediction signal represents pixel values or sample signals within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found, which will provide prediction for the current block, which is referred to as the prediction block.

In the case of lossless video coding, the original video picture may be reconstructed, i.e., the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, the amount of data needed to represent a video picture is reduced by performing further compression, e.g. quantization, whereas the decoder side cannot reconstruct the video picture completely, i.e. the quality of the reconstructed video picture is lower or worse than the quality of the original video picture.

Several video coding standards of h.261 belong to the "lossy hybrid video codec" (i.e. spatial and temporal prediction in the sample domain is combined with 2D transform coding in the transform domain for applying quantization). Each picture of a video sequence is typically partitioned into non-overlapping sets of blocks, typically encoded at the block level. In other words, the encoder side typically processes, i.e. encodes, video at the block (video block) level, e.g. generates a prediction block by spatial (intra-picture) prediction and temporal (inter-picture) prediction, subtracts the prediction block from the current block (currently processed or to-be-processed block) to obtain a residual block, transforms the residual block in the transform domain and quantizes the residual block to reduce the amount of data to be transmitted (compressed), while the decoder side applies the inverse processing part of the relative encoder to the encoded or compressed block to reconstruct the current block for representation. In addition, the encoder replicates the decoder processing loop so that the encoder and decoder generate the same predictions (e.g., intra-prediction and inter-prediction) and/or reconstructions for processing, i.e., encoding, the subsequent blocks.

The system architecture to which the embodiments of the present invention are applied is described below. Referring to fig. 1A, fig. 1A schematically illustrates a block diagram of a video encoding and decoding system 10 to which embodiments of the present invention are applied. As shown in fig. 1A, video encoding and decoding system 10 may include a source device 12 and a destination device 14, source device 12 generating encoded video data, and thus source device 12 may be referred to as a video encoding apparatus. Destination device 14 may decode encoded video data generated by source device 12, and thus destination device 14 may be referred to as a video decoding apparatus. Various implementations of source apparatus 12, destination apparatus 14, or both may include one or more processors and memory coupled to the one or more processors. The memory may include, but is not limited to RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store the desired program code in the form of instructions or data structures that can be accessed by a computer, as described herein. The source device 12 and the destination device 14 may include a variety 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 game consoles, vehicle mount computers, wireless communication devices, or the like.

Although fig. 1A depicts source device 12 and destination device 14 as separate devices, device embodiments may also include the functionality of both source device 12 and destination device 14, or both, i.e., source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such embodiments, the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality may be implemented using the same hardware and/or software, or using separate hardware and/or software, or any combination thereof.

A communication connection may be made between source device 12 and destination device 14 via link 13, and destination device 14 may receive encoded video data from source device 12 via link 13. Link 13 may include one or more media or devices capable of moving encoded video data from source device 12 to destination device 14. In one example, link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real-time. In this example, source apparatus 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 apparatus 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. 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 apparatus 12 to destination apparatus 14.

Source device 12 includes an encoder 20 and, alternatively, source device 12 may also include a picture source 16, a picture preprocessor 18, and a communication interface 22. In a specific implementation, the encoder 20, the picture source 16, the picture preprocessor 18, and the communication interface 22 may be hardware components in the source device 12 or may be software programs in the source device 12. The descriptions are as follows:

the picture source 16 may include or be any type of picture capture device for capturing, for example, real world pictures, and/or any type of picture or comment (for screen content encoding, some text on the screen is also considered part of the picture or image to be encoded), for example, a computer graphics processor for generating computer animated pictures, or any type of device for capturing and/or providing real world pictures, computer animated pictures (e.g., screen content, virtual Reality (VR) pictures), and/or any combination thereof (e.g., live (augmented reality, AR) pictures). Picture source 16 may be a camera for capturing pictures or a memory for storing pictures, picture source 16 may also include any type of (internal or external) interface for storing previously captured or generated pictures and/or for capturing or receiving pictures. When picture source 16 is a camera, picture source 16 may be, for example, an integrated camera, either local or integrated in the source device; when picture source 16 is memory, picture source 16 may be local or integrated memory integrated in the source device, for example. When the picture source 16 comprises an interface, the interface may for example be an external interface receiving pictures from an external video source, for example an external picture capturing device, such as a camera, an external memory or an external picture generating device, for example an external computer graphics processor, a computer or a server. The interface may be any kind of interface according to any proprietary or standardized interface protocol, e.g. a wired or wireless interface, an optical interface.

Wherein a picture can be regarded as a two-dimensional array or matrix of pixel elements. The pixels in the array may also be referred to as sampling points. The number of sampling points of the array or picture in the horizontal and vertical directions (or axes) defines the size and/or resolution of the picture. To represent color, three color components are typically employed, i.e., a picture may be represented as or contain three sample arrays. For example, in RBG format or color space, the picture includes corresponding red, green, and blue sample arrays. However, in video coding, each pixel is typically represented in a luminance/chrominance format or color space, e.g., for a picture in YUV format, comprising a luminance component indicated by Y (which may sometimes also be indicated by L) and two chrominance components indicated by U and V. The luminance (luma) component Y represents the luminance or grayscale level intensity (e.g., the same in a grayscale picture), while the two chrominance (chroma) components U and V represent the chrominance or color information components. Accordingly, a picture in YUV format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (U and V). Pictures in RGB format may be converted or transformed into YUV format and vice versa, a process also known as color transformation or conversion. If the picture is black and white, the picture may include only an array of luma samples. In the embodiment of the present invention, the picture transmitted from the picture source 16 to the picture processor may also be referred to as the original picture data 17.

A picture preprocessor 18 for receiving the original picture data 17 and performing preprocessing on the original picture data 17 to obtain a preprocessed picture 19 or preprocessed picture data 19. For example, the preprocessing performed by the picture preprocessor 18 may include truing, color format conversion (e.g., from RGB format to YUV format), toning, or denoising.

Encoder 20 (or video encoder 20) receives pre-processed picture data 19, and processes pre-processed picture data 19 using an associated prediction mode (e.g., a prediction mode in various embodiments herein) to provide encoded picture data 21 (details of the structure of encoder 20 will be described further below based on fig. 2 or fig. 4 or fig. 5). In some embodiments, encoder 20 may be configured to perform various embodiments described below to implement the application of the chroma block prediction method described in the present invention on the encoding side.

Communication interface 22 may be used to receive encoded picture data 21 and may transmit encoded picture data 21 over link 13 to destination device 14 or any other device (e.g., memory) for storage or direct reconstruction, which may be any device for decoding or storage. Communication interface 22 may be used, for example, to encapsulate encoded picture data 21 into a suitable format, such as a data packet, for transmission over link 13.

Destination device 14 includes a decoder 30, and alternatively destination device 14 may also include a communication interface 28, a picture post-processor 32, and a display device 34. The descriptions are as follows:

communication interface 28 may be used to receive encoded picture data 21 from source device 12 or any other source, such as a storage device, such as an encoded picture data storage device. The communication interface 28 may be used to transmit or receive encoded picture data 21 via a link 13 between the source device 12 and the destination device 14, such as a direct wired or wireless connection, or via any type of network, such as a wired or wireless network or any combination thereof, or any type of private and public networks, or any combination thereof. Communication interface 28 may, for example, be used to decapsulate data packets transmitted by communication interface 22 to obtain encoded picture data 21.

Both communication interface 28 and communication interface 22 may be configured as unidirectional communication interfaces or bidirectional communication interfaces and may be used, for example, to send and receive messages to establish connections, to acknowledge and to exchange any other information related to the communication link and/or to the transmission of data, for example, encoded picture data transmissions.

Decoder 30 (or referred to as decoder 30) for receiving encoded picture data 21 and providing decoded picture data 31 or decoded picture 31 (details of the structure of decoder 30 will be described below further based on fig. 3 or fig. 4 or fig. 5). In some embodiments, decoder 30 may be configured to perform various embodiments described below to implement the application of the chroma block prediction method described in the present invention on the decoding side.

A picture post-processor 32 for performing post-processing on the decoded picture data 31 (also referred to as reconstructed slice data) to obtain post-processed picture data 33. The post-processing performed by the picture post-processor 32 may include: color format conversion (e.g., from YUV format to RGB format), toning, truing, or resampling, or any other process, may also be used to transmit post-processed picture data 33 to display device 34.

A display device 34 for receiving the post-processed picture data 33 for displaying pictures to, for example, a user or viewer. The display device 34 may be or include any type of display for presenting reconstructed pictures, for example, an integrated or external display or monitor. For example, the display may include a liquid crystal display (liquid crystal display, LCD), an organic light emitting diode (organic light emitting diode, OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (liquid crystal on silicon, LCoS), a digital light processor (digital light processor, DLP), or any other type of display.

It will be apparent to those skilled in the art from this description that the functionality of the different units or the existence and (exact) division of the functionality of the source device 12 and/or destination device 14 shown in fig. 1A may vary depending on the actual device and application. Source device 12 and destination device 14 may comprise any of a variety of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, mobile phone, smart phone, tablet or tablet computer, video camera, desktop computer, set-top box, television, camera, in-vehicle device, display device, digital media player, video game console, video streaming device (e.g., content service server or content distribution server), broadcast receiver device, broadcast transmitter device, etc., and may not use or use any type of operating system.

Encoder 20 and decoder 30 may each be implemented as any of a variety of suitable circuits, such as, for example, one or more microprocessors, digital signal processors (digital signal processor, DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware or any combinations thereof. If the techniques are implemented in part in software, an apparatus may store instructions of 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 one or more processors.

In some cases, the video encoding and decoding system 10 shown in fig. 1A is merely an example, and the techniques of this disclosure may be applicable to video encoding settings (e.g., video encoding or video decoding) that do not necessarily involve any data communication between encoding and decoding devices. In other examples, the data may be retrieved from local memory, streamed over a network, and the like. The video encoding device may encode and store data to the memory and/or the video decoding device may retrieve and decode data from the memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but instead only encode data to memory and/or retrieve data from memory and decode data.

Referring to fig. 1B, fig. 1B is an illustration of an example of a video coding system 40 including encoder 20 of fig. 2 and/or decoder 30 of fig. 3, according to an example embodiment. Video coding system 40 may implement a combination of the various techniques of embodiments of the present invention. In the illustrated embodiment, video coding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video codec implemented by logic circuitry 47 of a processing unit 46), an antenna 42, one or more processors 43, one or more memories 44, and/or a display device 45.

As shown in fig. 1B, the imaging device 41, the antenna 42, the processing unit 46, the logic circuit 47, the encoder 20, the decoder 30, the processor 43, the memory 44, and/or the display device 45 can communicate with each other. As discussed, although video coding system 40 is depicted with encoder 20 and decoder 30, in different examples, video coding system 40 may include only encoder 20 or only decoder 30.

In some examples, antenna 42 may be used to transmit or receive an encoded bitstream of video data. Additionally, in some examples, display device 45 may be used to present video data. In some examples, logic 47 may be implemented by processing unit 46. The processing unit 46 may comprise application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, or the like. The video coding system 40 may also include an optional processor 43, which optional processor 43 may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general purpose processor, or the like. In some examples, logic 47 may be implemented in hardware, such as video encoding dedicated hardware, processor 43 may be implemented in general purpose software, an operating system, or the like. In addition, the memory 44 may be any type of memory, such as volatile memory (e.g., static random access memory (Static Random Access Memory, SRAM), dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.) or non-volatile memory (e.g., flash memory, etc.), and the like. In a non-limiting example, the memory 44 may be implemented by an overspeed cache. In some examples, logic circuitry 47 may access memory 44 (e.g., for implementing an image buffer). In other examples, logic 47 and/or processing unit 46 may include memory (e.g., a cache, etc.) for implementing an image buffer, etc.

In some examples, encoder 20 implemented by logic circuitry may include an image buffer (e.g., implemented by processing unit 46 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include encoder 20 implemented by logic circuitry 47 to implement the various modules discussed with reference to fig. 2 and/or any other encoder system or subsystem described herein. Logic circuitry may be used to perform various operations discussed herein.

In some examples, decoder 30 may be implemented in a similar manner by logic circuit 47 to implement the various modules discussed with reference to decoder 30 of fig. 3 and/or any other decoder system or subsystem described herein. In some examples, decoder 30 implemented by logic circuitry may include an image buffer (implemented by processing unit 2820 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include decoder 30 implemented by logic circuit 47 to implement the various modules discussed with reference to fig. 3 and/or any other decoder system or subsystem described herein.

In some examples, antenna 42 may be used to receive an encoded bitstream of video data. As discussed, the encoded bitstream may include data related to the encoded video frame, indicators, index values, mode selection data, etc., discussed herein, such as data related to the encoded partitions (e.g., transform coefficients or quantized transform coefficients, optional indicators (as discussed), and/or data defining the encoded partitions). Video coding system 40 may also include a decoder 30 coupled to antenna 42 and used to decode the encoded bitstream. The display device 45 is used to present video frames.

It should be understood that decoder 30 may be used to perform the reverse process for the example described with reference to encoder 20 in embodiments of the present invention. Regarding signaling syntax elements, decoder 30 may be configured to receive and parse such syntax elements and decode the associated video data accordingly. In some examples, encoder 20 may entropy encode the syntax elements into an encoded video bitstream. In such examples, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.

It should be noted that, the method for obtaining the time domain candidate motion vector described in the embodiment of the present invention is mainly used in the inter-frame prediction process, where the process exists in both the encoder 20 and the decoder 30, and the encoder 20 and the decoder 30 in the embodiment of the present invention may be, for example, a video standard protocol such as h.263, h.264, HEVV, MPEG-2, MPEG-4, VP8, VP9, or a codec corresponding to a next-generation video standard protocol (such as h.266).

Referring to fig. 2, fig. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing an embodiment of the invention. In the example of fig. 2, encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter unit 220, a decoded picture buffer (decoded picture buffer, DPB) 230, a prediction processing unit 260, and an entropy encoding unit 270. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The encoder 20 shown in fig. 2 may also be referred to as a hybrid video encoder or a video encoder according to a hybrid video codec.

For example, the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260 and the entropy encoding unit 270 form a forward signal path of the encoder 20, whereas for example the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (decoded picture buffer, DPB) 230, the prediction processing unit 260 form a backward signal path of the encoder, wherein the backward signal path of the encoder corresponds to the signal path of the decoder (see decoder 30 in fig. 3).

Encoder 20 receives picture 201 or an image block 203 of picture 201, e.g., a picture in a sequence of pictures forming a video or video sequence, through, e.g., input 202. Image block 203 may also be referred to as a current picture block or a picture block to be encoded, and picture 201 may be referred to as a current picture or a picture to be encoded (especially when distinguishing the current picture from other pictures in video encoding, such as previously encoded and/or decoded pictures in the same video sequence, i.e., a video sequence that also includes the current picture).

An embodiment of encoder 20 may comprise a partitioning unit (not shown in fig. 2) for partitioning picture 201 into a plurality of blocks, e.g. image blocks 203, typically into a plurality of non-overlapping blocks. The segmentation unit may be used to use the same block size for all pictures in the video sequence and a corresponding grid defining the block size, or to alter the block size between pictures or subsets or groups of pictures and to segment each picture into corresponding blocks.

In one example, prediction processing unit 260 of encoder 20 may be used to perform any combination of the above-described partitioning techniques.

Like picture 201, image block 203 is also or may be considered as a two-dimensional array or matrix of sampling points having sampling values, albeit of smaller size than picture 201. In other words, the image block 203 may comprise, for example, one sampling array (e.g., a luminance array in the case of a black-and-white picture 201) or three sampling arrays (e.g., one luminance array and two chrominance arrays in the case of a color picture) or any other number and/or class of arrays depending on the color format applied. The number of sampling points in the horizontal and vertical directions (or axes) of the image block 203 defines the size of the image block 203.

The encoder 20 as shown in fig. 2 is used for encoding a picture 201 block by block, for example, performing encoding and prediction for each image block 203.

The residual calculation unit 204 is configured to calculate a residual block 205 based on the picture image block 203 and the prediction block 265 (further details of the prediction block 265 are provided below), for example, by subtracting sample values of the prediction block 265 from sample values of the picture image block 203 on a sample-by-sample (pixel-by-pixel) basis to obtain the residual block 205 in a sample domain.

The transform processing unit 206 is configured to apply a transform, such as a discrete cosine transform (discrete cosine transform, DCT) or a discrete sine transform (discrete sine transform, DST), on the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. The transform coefficients 207 may also be referred to as transform residual coefficients and represent the residual block 205 in the transform domain.

The transform processing unit 206 may be used to apply integer approximations of DCT/DST, such as the transforms specified for HEVC/H.265. Such integer approximations are typically scaled by some factor compared to the orthogonal DCT transform. To maintain the norms of the forward and inverse transformed processed residual blocks, an additional scaling factor is applied as part of the transformation process. The scaling factor is typically selected based on certain constraints, e.g., the scaling factor is a tradeoff between power of 2, bit depth of transform coefficients, accuracy, and implementation cost for shift operations, etc. For example, a specific scaling factor is specified for inverse transformation by, for example, the inverse transformation processing unit 212 on the decoder 30 side (and for corresponding inverse transformation by, for example, the inverse transformation processing unit 212 on the encoder 20 side), and accordingly, a corresponding scaling factor may be specified for positive transformation by the transformation processing unit 206 on the encoder 20 side.

The quantization unit 208 is for quantizing the transform coefficients 207, for example by applying scalar quantization or vector quantization, to obtain quantized transform coefficients 209. The quantized transform coefficients 209 may also be referred to as quantized residual coefficients 209. The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients may be rounded down to m-bit transform coefficients during quantization, where n is greater than m. The quantization level may be modified by adjusting quantization parameters (quantization parameter, QP). For example, for scalar quantization, different scales may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, while larger quantization step sizes correspond to coarser quantization. The appropriate quantization step size may be indicated by a quantization parameter (quantization parameter, QP). For example, the quantization parameter may be an index of a predefined set of suitable quantization steps. For example, smaller quantization parameters may correspond to fine quantization (smaller quantization step size) and larger quantization parameters may correspond to coarse quantization (larger quantization step size) and vice versa. Quantization may involve division by a quantization step size and corresponding quantization or inverse quantization, e.g., performed by inverse quantization 210, or may involve multiplication by a quantization step size. Embodiments according to some standards, such as HEVC, may use quantization parameters to determine quantization step sizes. In general, the quantization step size may be calculated based on quantization parameters using a fixed-point approximation of an equation that includes division. Additional scaling factors may be introduced for quantization and inverse quantization to recover norms of residual blocks that may be modified due to the scale used in the fixed point approximation of the equation for quantization step size and quantization parameters. In one example embodiment, the inverse transformed and inverse quantized scales may be combined. Alternatively, a custom quantization table may be used and signaled from the encoder to the decoder, e.g., in a bitstream. Quantization is a lossy operation, where the larger the quantization step size, the larger the loss.

The inverse quantization unit 210 is configured to apply inverse quantization of the quantization unit 208 on the quantized coefficients to obtain inverse quantized coefficients 211, e.g., apply an inverse quantization scheme of the quantization scheme applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208. The dequantized coefficients 211 may also be referred to as dequantized residual coefficients 211, correspond to the transform coefficients 207, although the losses due to quantization are typically different from the transform coefficients.

The inverse transform processing unit 212 is configured to apply an inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (discrete cosine transform, DCT) or an inverse discrete sine transform (discrete sine transform, DST), to obtain an inverse transform block 213 in the sample domain. The inverse transform block 213 may also be referred to as an inverse transformed inverse quantized block 213 or an inverse transformed residual block 213.

A reconstruction unit 214 (e.g., a summer 214) is used to add the inverse transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, e.g., to add sample values of the reconstructed residual block 213 to sample values of the prediction block 265.

Optionally, a buffer unit 216, e.g. a line buffer 216 (or simply "buffer" 216), is used to buffer or store the reconstructed block 215 and the corresponding sample values for e.g. intra prediction. In other embodiments, the encoder may be configured to use the unfiltered reconstructed block and/or the corresponding sample values stored in the buffer unit 216 for any kind of estimation and/or prediction, such as intra prediction.

For example, embodiments of encoder 20 may be configured such that buffer unit 216 is used not only to store reconstructed blocks 215 for intra prediction 254, but also for loop filter unit 220 (not shown in fig. 2), and/or such that buffer unit 216 and decoded picture buffer unit 230 form one buffer, for example. Other embodiments may be used to use the filtered block 221 and/or blocks or samples (neither shown in fig. 2) from the decoded picture buffer 230 as an input or basis for the intra prediction 254.

The loop filter unit 220 (or simply "loop filter" 220) is used to filter the reconstructed block 215 to obtain a filtered block 221, which facilitates pixel transitions or improves video quality. Loop filter unit 220 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, adaptive loop filters (adaptive loop filter, ALF), or sharpening or smoothing filters, or collaborative filters. Although loop filter unit 220 is shown in fig. 2 as an in-loop filter, in other configurations loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as a filtered reconstructed block 221. Decoded picture buffer 230 may store the reconstructed encoded block after loop filter unit 220 performs a filtering operation on the reconstructed encoded block.

Embodiments of encoder 20 (and correspondingly loop filter unit 220) may be configured to output loop filter parameters (e.g., sample adaptive offset information), e.g., directly or after entropy encoding by entropy encoding unit 270 or any other entropy encoding unit, e.g., such that decoder 30 may receive and apply the same loop filter parameters for decoding.

Decoded picture buffer (decoded picture buffer, DPB) 230 may be a reference picture memory that stores reference picture data for use by encoder 20 in encoding video data. DPB 230 may be formed of any of a variety of memory devices, such as dynamic random access memory (dynamic random access memory, DRAM) (including Synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM)), or other types of memory devices. DPB 230 and buffer 216 may be provided by the same memory device or separate memory devices. In a certain example, a decoded picture buffer (decoded picture buffer, DPB) 230 is used to store the filtered block 221. The decoded picture buffer 230 may further be used to store the same current picture or other previously filtered blocks, e.g., previously reconstructed and filtered blocks 221, of different pictures, e.g., previously reconstructed pictures, and may provide complete previously reconstructed, i.e., decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current pictures (and corresponding reference blocks and samples), e.g., for inter prediction. In a certain example, if the reconstructed block 215 is reconstructed without in-loop filtering, the decoded picture buffer (decoded picture buffer, DPB) 230 is used to store the reconstructed block 215.

The prediction processing unit 260, also referred to as block prediction processing unit 260, is adapted to receive or obtain image blocks 203 (current image blocks 203 of a current picture 201) and reconstructed slice data, e.g. reference samples of the same (current) picture from the buffer 216 and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and to process such data for prediction, i.e. to provide a prediction block 265, which may be an inter-predicted block 245 or an intra-predicted block 255.

The mode selection unit 262 may be used to select a prediction mode (e.g., intra or inter prediction mode) and/or a corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.

Embodiments of mode selection unit 262 may be used to select the prediction mode (e.g., from those supported by prediction processing unit 260) that provides the best match or minimum residual (minimum residual meaning better compression in transmission or storage), or that provides the minimum signaling overhead (minimum signaling overhead meaning better compression in transmission or storage), or both. The mode selection unit 262 may be adapted to determine a prediction mode based on a rate-distortion optimization (rate distortion optimization, RDO), i.e. to select the prediction mode that provides the least rate-distortion optimization, or to select a prediction mode for which the associated rate-distortion at least meets a prediction mode selection criterion.

The prediction processing performed by an instance of encoder 20 (e.g., by prediction processing unit 260) and the mode selection performed (e.g., by mode selection unit 262) will be explained in detail below.

As described above, the encoder 20 is configured to determine or select the best or optimal prediction mode from a (predetermined) set of prediction modes. The set of prediction modes may include, for example, intra prediction modes and/or inter prediction modes.

The set of intra prediction modes may include 35 different intra prediction modes, for example, a non-directional mode such as a DC (or mean) mode and a planar mode, or a directional mode as defined in h.265, or 67 different intra prediction modes, for example, a non-directional mode such as a DC (or mean) mode and a planar mode, or a directional mode as defined in h.266 under development.

In a possible implementation, the set of inter prediction modes depends on the available reference pictures (i.e. at least part of the decoded pictures stored in the DBP 230 as described above, for example) and other inter prediction parameters, e.g. on whether the entire reference picture is used or only a part of the reference picture is used, e.g. a search window area surrounding an area of the current block, to search for the best matching reference block, and/or on whether pixel interpolation like half-pixel and/or quarter-pixel interpolation is applied, e.g. the set of inter prediction modes may comprise advanced motion vector (Advanced Motion Vector Prediction, AMVP) mode and fusion (merge) mode, for example. In particular implementations, the set of inter prediction modes may include an improved control point-based AMVP mode, and an improved control point-based merge mode, according to embodiments of the present invention. In one example, intra-prediction unit 254 may be used to perform any combination of the inter-prediction techniques described below.

In addition to the above prediction modes, embodiments of the present invention may also apply skip modes and/or direct modes.

The prediction processing unit 260 may be further operative to partition the image block 203 into smaller block partitions or sub-blocks, for example, by iteratively using a quad-tree (QT) partition, a binary-tree (BT) partition, or a ternary-tree (TT) partition, or any combination thereof, and to perform prediction for each of the block partitions or sub-blocks, for example, wherein the mode selection includes selecting a tree structure of the partitioned image block 203 and selecting a prediction mode applied to each of the block partitions or sub-blocks.

The inter prediction unit 244 may include a motion estimation (motion estimation, ME) unit (not shown in fig. 2) and a motion compensation (motion compensation, MC) unit (not shown in fig. 2). The motion estimation unit is used to receive or obtain a picture image block 203 (current picture image block 203 of current picture 201) and a decoded picture 231, or at least one or more previously reconstructed blocks, e.g. reconstructed blocks of one or more other/different previously decoded pictures 231, for motion estimation. For example, the video sequence may include a current picture and a previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of, or form, a sequence of pictures that form the video sequence.

For example, encoder 20 may be configured to select a reference block from a plurality of reference blocks of the same or different pictures of a plurality of other pictures, and provide the reference picture and/or an offset (spatial offset) between a position (X, Y coordinates) of the reference block and a position of a current block to a motion estimation unit (not shown in fig. 2) as an inter prediction parameter. This offset is also called Motion Vector (MV).

The motion compensation unit is used to acquire inter prediction parameters and perform inter prediction based on or using the inter prediction parameters to acquire the inter prediction block 245. The motion compensation performed by the motion compensation unit (not shown in fig. 2) may involve fetching or generating a prediction block based on motion/block vectors determined by motion estimation (possibly performing interpolation of sub-pixel accuracy). Interpolation filtering may generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks available for encoding a picture block. Upon receiving the motion vector for the PU of the current picture block, motion compensation unit 246 may locate the prediction block to which the motion vector points in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with the blocks and video slices for use by decoder 30 in decoding the picture blocks of the video slices.

Specifically, the inter prediction unit 244 may transmit a syntax element including inter prediction parameters (e.g., indication information of an inter prediction mode selected for current block prediction after traversing a plurality of inter prediction modes) to the entropy encoding unit 270. In a possible application scenario, if the inter prediction mode is only one, the inter prediction parameter may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding. It is appreciated that the inter prediction unit 244 may be used to perform any combination of inter prediction techniques.

The intra prediction unit 254 is used to obtain, for example, a picture block 203 (current picture block) that receives the same picture and one or more previously reconstructed blocks, for example, reconstructed neighboring blocks, for intra estimation. For example, encoder 20 may be configured to select an intra-prediction mode from a plurality of (predetermined) intra-prediction modes.

Embodiments of encoder 20 may be used to select an intra-prediction mode based on optimization criteria, such as based on a minimum residual (e.g., the intra-prediction mode that provides a prediction block 255 most similar to current picture block 203) or minimum rate distortion.

The intra prediction unit 254 is further adapted to determine an intra prediction block 255 based on intra prediction parameters like the selected intra prediction mode. In any case, after the intra-prediction mode for the block is selected, the intra-prediction unit 254 is also configured to provide the intra-prediction parameters, i.e., information indicating the selected intra-prediction mode for the block, to the entropy encoding unit 270. In one example, intra-prediction unit 254 may be used to perform any combination of intra-prediction techniques.

Specifically, the intra-prediction unit 254 may transmit a syntax element including an intra-prediction parameter (such as indication information of an intra-prediction mode selected for the current block prediction after traversing a plurality of intra-prediction modes) to the entropy encoding unit 270. In a possible application scenario, if there is only one intra prediction mode, the intra prediction parameter may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding.

The entropy encoding unit 270 is configured to apply an entropy encoding algorithm or scheme (e.g., a variable length coding (variable length coding, VLC) scheme, a Context Adaptive VLC (CAVLC) scheme, an arithmetic coding scheme, a context adaptive binary arithmetic coding (context adaptive binary arithmetic coding, CABAC), a syntax-based context-based binary arithmetic coding (SBAC), a probability interval partitioning entropy (probability interval partitioning entropy, PIPE) coding, or other entropy encoding methods or techniques) to one or all of the quantized residual coefficients 209, inter-prediction parameters, intra-prediction parameters, and/or loop filter parameters (or not) to obtain encoded picture data 21 that may be output by the output 272 in the form of, for example, an encoded bitstream 21. The encoded bitstream may be transmitted to video decoder 30 or archived for later transmission or retrieval by video decoder 30. Entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.

Other structural variations of video encoder 20 may be used to encode the video stream. For example, the non-transform based encoder 20 may directly quantize the residual signal without a transform processing unit 206 for certain blocks or frames. In another embodiment, encoder 20 may have quantization unit 208 and inverse quantization unit 210 combined into a single unit.

Specifically, in the embodiment of the present invention, the encoder 20 may be used to implement the method for acquiring the time domain candidate motion vector described in the later embodiment.

It should be appreciated that other structural variations of video encoder 20 may be used to encode the video stream. For example, for some image blocks or image frames, video encoder 20 may directly quantize the residual signal without processing by transform processing unit 206, and accordingly without processing by inverse transform processing unit 212; alternatively, for some image blocks or image frames, video encoder 20 does not generate residual data and accordingly does not need to be processed by transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212; alternatively, video encoder 20 may store the reconstructed image block directly as a reference block without processing via filter 220; alternatively, quantization unit 208 and inverse quantization unit 210 in video encoder 20 may be combined together. The loop filter 220 is optional, and in the case of lossless compression encoding, the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212 are optional. It should be appreciated that inter-prediction unit 244 and intra-prediction unit 254 may be selectively enabled depending on the different application scenarios.

Referring to fig. 3, fig. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing an embodiment of the invention. Video decoder 30 is operative to receive encoded picture data (e.g., encoded bitstream) 21, e.g., encoded by encoder 20, to obtain decoded picture 231. During the decoding process, video decoder 30 receives video data, such as an encoded video bitstream representing picture blocks of an encoded video slice and associated syntax elements, from video encoder 20.

In the example of fig. 3, decoder 30 includes entropy decoding unit 304, inverse quantization unit 310, inverse transform processing unit 312, reconstruction unit 314 (e.g., summer 314), buffer 316, loop filter 320, decoded picture buffer 330, and prediction processing unit 360. The prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362. In some examples, video decoder 30 may perform a decoding pass that is substantially reciprocal to the encoding pass described with reference to video encoder 20 of fig. 2.

Entropy decoding unit 304 is used to perform entropy decoding on encoded picture data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in fig. 3), e.g., any or all of inter-prediction, intra-prediction parameters, loop filter parameters, and/or other syntax elements (decoded). Entropy decoding unit 304 is further configured to forward inter-prediction parameters, intra-prediction parameters, and/or other syntax elements to prediction processing unit 360. Video decoder 30 may receive syntax elements at the video stripe level and/or the video block level.

Inverse quantization unit 310 may be functionally identical to inverse quantization unit 110, inverse transform processing unit 312 may be functionally identical to inverse transform processing unit 212, reconstruction unit 314 may be functionally identical to reconstruction unit 214, buffer 316 may be functionally identical to buffer 216, loop filter 320 may be functionally identical to loop filter 220, and decoded picture buffer 330 may be functionally identical to decoded picture buffer 230.

The prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354, where the inter prediction unit 344 may be similar in function to the inter prediction unit 244 and the intra prediction unit 354 may be similar in function to the intra prediction unit 254. The prediction processing unit 360 is typically used to perform block prediction and/or to obtain a prediction block 365 from the encoded data 21, as well as to receive or obtain prediction related parameters and/or information about the selected prediction mode (explicitly or implicitly) from, for example, the entropy decoding unit 304.

When a video slice is encoded as an intra-coded (I) slice, the intra-prediction unit 354 of the prediction processing unit 360 is used to generate a prediction block 365 for a picture block of the current video slice based on the signaled intra-prediction mode and data from a previously decoded block of the current frame or picture. When a video frame is encoded as an inter-coded (i.e., B or P) slice, an inter-prediction unit 344 (e.g., a motion compensation unit) of prediction processing unit 360 is used to generate a prediction block 365 for a video block of the current video slice based on the motion vector and other syntax elements received from entropy decoding unit 304. For inter prediction, a prediction block may be generated from one reference picture within one reference picture list. Video decoder 30 may construct a reference frame list based on the reference pictures stored in DPB330 using default construction techniques: list 0 and list 1.

The prediction processing unit 360 is configured to determine prediction information for a video block of a current video slice by parsing the motion vector and other syntax elements, and generate a prediction block for the current video block being decoded using the prediction information. In an example of this disclosure, prediction processing unit 360 uses some syntax elements received to determine a prediction mode (e.g., intra or inter prediction) for encoding video blocks of a video slice, an inter prediction slice type (e.g., B slice, P slice, or GPB slice), construction information for one or more of a reference picture list of the slice, motion vectors for each inter-encoded video block of the slice, inter prediction state for each inter-encoded video block of the slice, and other information to decode video blocks of a current video slice. In another example of the present disclosure, the syntax elements received by video decoder 30 from the bitstream include syntax elements received in one or more of an adaptive parameter set (adaptive parameter set, APS), a sequence parameter set (sequence parameter set, SPS), a picture parameter set (picture parameter set, PPS), or a slice header.

Inverse quantization unit 310 may be used to inverse quantize (i.e., inverse quantize) the quantized transform coefficients provided in the bitstream and decoded by entropy decoding unit 304. The inverse quantization process may include using quantization parameters calculated by video encoder 20 for each video block in a video stripe to determine the degree of quantization that should be applied and likewise the degree of inverse quantization that should be applied.

The inverse transform processing unit 312 is configured to apply an inverse transform (e.g., an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients in order to generate a residual block in the pixel domain.

A reconstruction unit 314 (e.g., a summer 314) is used to add the inverse transform block 313 (i.e., the reconstructed residual block 313) to the prediction block 365 to obtain a reconstructed block 315 in the sample domain, e.g., by adding sample values of the reconstructed residual block 313 to sample values of the prediction block 365.

Loop filter unit 320 is used (during or after the encoding cycle) to filter reconstructed block 315 to obtain filtered block 321, to smooth pixel transitions or improve video quality. In one example, loop filter unit 320 may be used to perform any combination of the filtering techniques described below. Loop filter unit 320 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bilateral filter, an adaptive loop filter (adaptive loop filter, ALF), or a sharpening or smoothing filter, or a collaborative filter. Although loop filter unit 320 is shown in fig. 3 as an in-loop filter, in other configurations loop filter unit 320 may be implemented as a post-loop filter.

The decoded video blocks 321 in a given frame or picture are then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.

Decoder 30 is for outputting decoded picture 31, e.g., via output 332, for presentation to a user or for viewing by a user.

Other variations of video decoder 30 may be used to decode the compressed bitstream. For example, decoder 30 may generate the output video stream without loop filter unit 320. For example, the non-transform based decoder 30 may directly inverse quantize the residual signal without an inverse transform processing unit 312 for certain blocks or frames. In another embodiment, the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.

Specifically, in the embodiment of the present invention, the decoder 30 is configured to implement the method for acquiring the time domain candidate motion vector described in the later embodiment.

It should be appreciated that other structural variations of video decoder 30 may be used to decode the encoded video bitstream. For example, video decoder 30 may generate an output video stream without processing by filter 320; alternatively, for some image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not decode quantized coefficients, and accordingly does not need to be processed by the inverse quantization unit 310 and the inverse transform processing unit 312. Loop filter 320 is optional; and for the case of lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional. It should be appreciated that the inter prediction unit and the intra prediction unit may be selectively enabled according to different application scenarios.

It should be understood that, in the encoder 20 and the decoder 30 of the present application, the processing result for a certain link may be further processed and then output to a next link, for example, after the links such as interpolation filtering, motion vector derivation or loop filtering, the processing result for the corresponding link is further processed by performing operations such as Clip or shift.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a video decoding apparatus 400 (e.g., a video encoding apparatus 400 or a video decoding apparatus 400) according to an embodiment of the present invention. The video coding apparatus 400 is adapted to implement the embodiments described herein. In one embodiment, video coding device 400 may be a video decoder (e.g., decoder 30 of fig. 1A) or a video encoder (e.g., encoder 20 of fig. 1A). In another embodiment, video coding apparatus 400 may be one or more of the components described above in decoder 30 of fig. 1A or encoder 20 of fig. 1A.

The video coding apparatus 400 includes: an ingress port 410 and a receiving unit (Rx) 420 for receiving data, a processor, logic unit or Central Processing Unit (CPU) 430 for processing data, a transmitter unit (Tx) 440 and an egress port 450 for transmitting data, and a memory 460 for storing data. The video decoding apparatus 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of optical or electrical signals.

The processor 430 is implemented in hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (e.g., multi-core processors), FPGAs, ASICs, and DSPs. Processor 430 is in communication with inlet port 410, receiver unit 420, transmitter unit 440, outlet port 450, and memory 460. The processor 430 includes a coding module 470 (e.g., an encoding module 470 or a decoding module 470). The encoding/decoding module 470 implements embodiments disclosed herein to implement the chroma block prediction methods provided by embodiments of the present invention. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations. Thus, substantial improvements are provided to the functionality of the video coding device 400 by the encoding/decoding module 470 and affect the transition of the video coding device 400 to different states. Alternatively, the encoding/decoding module 470 is implemented in instructions stored in the memory 460 and executed by the processor 430.

Memory 460 includes one or more disks, tape drives, and solid state drives, and may be used as an overflow data storage device for storing programs when selectively executing such programs, as well as storing instructions and data read during program execution. Memory 460 may be volatile and/or nonvolatile and may be Read Only Memory (ROM), random Access Memory (RAM), random access memory (TCAM) and/or Static Random Access Memory (SRAM).

Referring to fig. 5, fig. 5 is a simplified block diagram of an apparatus 500 that may be used as either or both of the source device 12 and the destination device 14 in fig. 1A, according to an example embodiment. The apparatus 500 may implement the techniques of this application. In other words, fig. 5 is a schematic block diagram of one implementation of an encoding device or decoding device (simply referred to as decoding device 500) of an embodiment of the present application. The decoding device 500 may include, among other things, a processor 510, a memory 530, and a bus system 550. The processor is connected with the memory through the bus system, the memory is used for storing instructions, and the processor is used for executing the instructions stored by the memory. The memory of the decoding device stores program code, and the processor may invoke the program code stored in the memory to perform the various video encoding or decoding methods described herein. To avoid repetition, a detailed description is not provided herein.

In the present embodiment, the processor 510 may be a central processing unit (Central Processing Unit, abbreviated as "CPU"), and the processor 510 may also be other general purpose processors, digital Signal Processors (DSPs), application Specific Integrated Circuits (ASICs), off-the-shelf programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 530 may include a Read Only Memory (ROM) device or a Random Access Memory (RAM) device. Any other suitable type of storage device may also be used as memory 530. Memory 530 may include code and data 531 accessed by processor 510 using bus 550. The memory 530 may further include an operating system 533 and an application 535, the application 535 including at least one program that allows the processor 510 to perform the video encoding or decoding methods described herein (particularly the temporal candidate motion vector acquisition methods described herein). For example, applications 535 may include applications 1 through N, which further include video encoding or decoding applications (simply video coding applications) that perform the video encoding or decoding methods described herein.

The bus system 550 may include a power bus, a control bus, a status signal bus, and the like in addition to a data bus. For clarity of illustration, the various buses are labeled in the figure as bus system 550.

Optionally, the decoding device 500 may also include one or more output devices, such as a display 570. In one example, the display 570 may be a touch sensitive display that incorporates a display with a touch sensitive unit operable to sense touch input. A display 570 may be connected to processor 510 via bus 550.

First, an application scenario of the embodiment of the present application will be described. Generally, the acquisition of temporal candidate motion vectors is applied in the process of inter prediction, and more specifically, exemplary, temporal candidate motion vectors can be used in Merge and AMVP prediction modes.

In one possible implementation, for AMVP mode, a candidate motion vector list is first constructed according to motion information of coded units adjacent to a current coding unit in the spatial domain or the temporal domain, and then an optimal motion vector is determined from the constructed candidate motion vector list as a motion vector predictor (Motion vector predictor, MVP) of the current coding unit, where the determination of the optimal motion vector can be accomplished by comparing rate-distortion cost values corresponding to different candidate motion vectors. The rate-distortion Cost is calculated as shown in formula (1), wherein J is a rate-distortion Cost value RD Cost, SAD is a sum of absolute errors (Sum of Absolute Differences, SAD) between a predicted pixel value obtained by performing motion estimation using a candidate motion vector predicted value, R is a code rate, and λ is a lagrangian multiplier. The encoding end transmits the selected motion vector, that is, MVP, the index value in the candidate motion vector list and the reference frame index value of the reference frame of the current encoding unit to the decoding end. Further, a motion search is performed in a neighborhood centered on the location at which the MVP points to obtain a motion vector for encoding of the current encoding unit, and the encoding end passes the difference (Motion vector difference) between the MVP and the motion vector for encoding to the decoding end.

J＝SAD+λR (1)

In a possible embodiment, for the Merge mode, a candidate motion information list is first constructed according to motion information of coded units adjacent to a current coding unit in the spatial domain or the temporal domain, wherein the motion information comprises a motion vector and/or a reference frame index value, and then optimal motion information is determined from the constructed candidate motion information list according to the rate-distortion cost as the motion information of the current coding unit. The encoding end transmits the index value of the optimal motion information in the candidate motion information list to the decoding end. Fig. 6 is an exemplary schematic diagram of spatial and temporal candidate motion information sources for a current coding unit. The spatial candidate motion information is from 5 blocks (A0, A1, B0, B1 and B2) spatially adjacent to the current coding unit, and if the adjacent blocks are not available or are in intra coding mode, the candidate motion information list is not added. The time-domain candidate motion information of the current coding unit is obtained by scaling the motion vector of the corresponding position block (co-located) in the reference frame based on the sequence counts (Picture order count, POC) of the reference frame and the current frame, as shown in fig. 7, wherein in a possible embodiment, as shown in fig. 6, it is first determined whether the block at the corresponding position of T in the reference frame is available, and if not, the block at the corresponding position of C is selected as the corresponding position block.

The following describes the application of temporal candidate motion vectors in inter prediction for video image coding in detail using AMVP mode as an example.

In one possible implementation, as shown in fig. 6, the motion vector candidate positions of AMVP mode include 2 spatial candidate sets { A0, A1} and { B0, B1, B2} and 1 temporal motion candidate set { C, T }. In some embodiments, the maximum length of the candidate prediction motion vector list of AMVP may be a preset number, and may be set to 2.

Step 1: the spatial candidates are selected from the two spatial candidate sets, respectively.

Step 1.1: the left spatial candidate is obtained, i.e. the first available block in the order is taken as left spatial candidate, i.e. the search is performed in the order from A0 to A1.

Specifically, if the A0 position is available, acquiring motion information of the A0 position; otherwise, if the A0 position is not available, confirming whether the A1 position is available, if the A1 position is available, acquiring the motion information of the A1 position, otherwise, acquiring the left airspace candidate, namely, the left airspace candidate is unavailable.

If the reference picture pointed by the MV at the A position (for example, A0 and A1) is the same as the reference picture of the current block, the MV at the A position is used as a candidate, and the candidate prediction motion vector list of the AMVP mode is added, otherwise, when the reference picture pointed by the MV at the A position is different from the reference picture of the current block, the MV at the A position needs to be scaled according to the POCs of the reference picture and the current picture, the scaled MVs are used as candidates, and the candidate prediction motion vector list of the AMVP mode is added. The scaling method is shown in formula (2):

Wherein CurPoc represents the POC number of the current frame, desPoc represents the POC number of the reference frame of the current block, spaPoc represents the POC number of the reference frame of the spatial neighboring block, MV _s Representing the scaled result of the MV.

Step 1.2: the upper spatial candidate is obtained, i.e. the first available block in this order is the upper spatial candidate, as per the lookup from B0, B1 to B2.

If the B position (one of B0, B1 and B2) is available, when the MV of the B position points to the reference image which is the same as the reference image of the current block, using the MV of the B position as a candidate, adding the candidate prediction motion vector list of AMVP mode, otherwise, when the MV of the B position points to the reference image which is different from the reference image of the current block, if the left spatial candidate is not available, scaling the MV of the B position according to the method of formula (2), adding the scaled MV to the candidate prediction motion vector list, if the left spatial candidate is available, failing to acquire the upper spatial candidate, i.e., the upper spatial candidate is not available.

Illustratively, an X position (X may be A0, A1, A2, B0, B1, B2, B3, or T) is available, a block representing the X position has been encoded and an inter prediction mode is employed; otherwise, i.e. the neighboring block does not exist, or the neighboring block is not coded, or the prediction mode adopted by the neighboring block is not inter prediction mode, the X position is not available.

When two spatial candidates have the same motion vector, then one of them is deleted, i.e. the redundant spatial candidate is deleted. Step 2 is performed when the above spatial candidates are less than 2 (i.e., the maximum length of the candidate predicted motion vector list) and the use of time domain candidates is allowed; it should be understood that when the spatial candidates in the candidate prediction motion vector list are 2, there is no need to use the time domain candidates, and the following steps are not required to be performed.

Step 2: when the length of the candidate predicted motion vector list is less than 2 and the use of the time domain candidate is allowed, the motion vector of the time domain position corresponding block is acquired.

Specifically, a motion vector of a block corresponding to a T position in an adjacent encoded frame is obtained, and if the motion vector of the block corresponding to the T position does not exist, a motion vector of a block corresponding to a C position is obtained.

Scaling the obtained motion vector and adding the motion vector into a candidate predicted motion vector list;

illustratively, the scaling process is as shown in FIG. 7:

cur_pic, col_pic, col_ref, cur_ref represent the current picture, the co-located reference picture, respectively. tb, td denote the distances of cur_pic and cur_ref, and col_pic and col_ref, respectively. Cur_blk, col_blk represents the current block and the corresponding position block. Then the MV curMV of the current block can be obtained by scaling the MV colMV of the corresponding position block by formula (3):

Step 3: if the length of the candidate predicted motion vector list is still less than 2, the zero motion vector is filled in until the length of the candidate predicted motion vector list is equal to 2.

Step 4: and acquiring a motion vector of the current block.

Specifically, motion vectors in the candidate prediction motion vector list are traversed, motion compensation is carried out, a reconstruction value is further obtained, and then the candidate motion vector with the minimum RD cost is determined to be used as the motion vector prediction value of the current block according to a rate distortion optimization method.

The coding end transmits the index value of the selected motion vector predicted value in the candidate predicted motion vector list and the reference frame index value of the reference frame of the current block to the decoding end. Further, a motion search is performed in a neighborhood centered on the position pointed by the MVP to obtain a motion vector for encoding of the current block, and the encoding end passes a difference value (MVD) between the MVP and the motion vector for encoding to the decoding end. At the decoding end, the index number is analyzed, the MVP is determined in the candidate predicted motion vector list according to the index number, the MVD is analyzed, and the MVD and the MVP are added to obtain the motion vector of the current block.

In one possible implementation, the time domain candidates may be obtained by:

The block to be processed is not limited to be a current Coding Unit (CU), a two-dimensional rectangular coordinate system is established by taking the upper left corner of the current image where the current CU is located as an original point, the horizontal right is the positive direction of the horizontal axis, and the vertical downward is the positive direction of the vertical axis. The coordinates of the top left corner pixel of the current CU are (xCb, yCb), i.e. the horizontal coordinates of the top left corner pixel are xCb and the vertical coordinates are yCb, and the coordinates herein are all represented in this way, and are not described in detail later. cbWidth is the width of the current CU and cbHeight is the height of the current CU.

S1001, acquiring coordinate positions (xColBr, yColBr) of a right lower corner of the current CU, as shown in a formula (4):

xColBr＝xCb+cbWidth (4)

yColBr＝yCb+cbHeight

it should be appreciated that the vertical resolution of the image may not be a high integer multiple of the CU, at which point the actual height of the last row of CUs may be less than cbHeight. Thus, the lower right corner of the CU resulting from equation (4) may lie outside the image range, and the ordinate of the lower right corner of the current CU in this context refers to the ordinate position obtained according to equation (4). Correspondingly, the abscissa of the lower right corner of the current CU refers to the abscissa position obtained according to formula (4).

S1002, when the coordinate position of the lower right corner of the current CU does not exceed the image boundary of the current image, and does not exceed the CTU row where the current CU is located, S1003 is performed, otherwise (the coordinate position of the lower right corner of the current CU exceeds the image boundary of the current image, or exceeds the CTU row where the current CU is located), S1005 is performed.

Specifically, it can be determined by:

s1003 is performed when yCb > CtbLog2SizeY is equal to ycibr > CtbLog2SizeY, and xColBr is less than pic_width_in_luma_samples, and yColBr is less than pic_height_in_luma_samples, otherwise S1006 is performed. Where CtbLog2SizeY represents a log2 value of the height of the coding tree unit (CTU or CTB) where the current CU is located, pic_width_in_luma_samples represents the width of the luminance pixel matrix of the current picture, and pic_height_in_luma_samples represents the height of the luminance pixel matrix of the current picture.

S1003, determining the corresponding position (xCbCol, yCbCol) of the right lower corner in the corresponding image of the current image, as shown in a formula (5):

(xCbCol,yCbCol)＝((xColBr>>3)<<3,(yColBr>>3)<<3) (5)

the corresponding image of the current image may be determined by analyzing an index of the image, or by analyzing identification information, or by preset determination, for example, the corresponding image may be preset as an image closest to the current image in a reference frame list of the current image.

It should be understood that the rounding operation is performed on (xColBr, yColBr) by the shift process in the formula (5), and other manners, such as rounding, may be used, but are not limited thereto.

S1004, according to the coordinates of the corresponding positions, obtaining the prediction modes of the corresponding image blocks where the corresponding positions are located.

If the prediction mode of the corresponding image block is inter prediction, determining that the motion vector of the corresponding image block is available, and performing scaling processing on the motion vector as shown in formula (3) to obtain a motion vector of the position of the lower right corner as a temporal candidate, and ending the flow.

If the prediction mode of the corresponding image block is intra prediction or intra block copy mode, it is determined that the motion vector of the corresponding image block is not available, and S1005 is performed.

S1005, acquiring a coordinate position (xColCtr, yColCtr) of a central point of the current CU, wherein the coordinate position is shown in a formula (6):

xColBr＝xCb+(cbWidth>>1) (6)

yColBr＝yCb+(cbHeight>>1)

s1006, determining the corresponding position (xCbCol, yCbCol) of the center point in the corresponding image of the current image, as shown in a formula (7):

(xCbCol,yCbCol)＝((xColCtr>>3)<<3,(yColCtr>>3)<<3) (7)

it should be appreciated that the rounding operation performed on (xColCtr, yColCtr) by the shift process is performed by equation (7), and that the rounding operation may be performed in other manners, such as rounding, without limitation.

S1007, according to the coordinates of the corresponding position, obtaining the prediction mode of the corresponding image block where the corresponding position is located.

If the prediction mode of the corresponding image block is inter prediction, it is determined that the motion vector of the corresponding image block is available, and the motion vector is scaled as shown in formula (3) to obtain a motion vector of the center point position as a temporal candidate, and the process ends.

If the prediction mode of the corresponding image block is intra prediction or intra block copy mode, the motion vector of the corresponding image block is judged to be unavailable, then the time domain candidate cannot be obtained is judged, and the process is ended.

In the embodiment of the application, the motion vector of the time domain corresponding image block at the right lower corner of the current CU or the time domain corresponding image block at the central position of the current CU is obtained and used for obtaining the time domain motion vector candidate of the current CU, so that the selection of the prediction motion vector of the current CU is enriched, and the coding efficiency of inter-frame prediction is improved. Meanwhile, it should also be understood that, due to the fact that the right lower corner of the current CU is not suitable, complex logic judgment is required to determine suitable time domain candidates, and the complexity is high.

In one possible implementation, the time domain candidates may be obtained by, in particular, as shown in fig. 8:

it is not necessary that the image block to be processed (current CU) is located in a current coding tree unit, which is located in the current image.

S1101, determining a first time domain position of the image block to be processed according to the position of the right lower corner of the image block to be processed, the boundary position of the current coding tree unit and the boundary position of the current image.

Specifically, the first time domain position is located within a coding tree unit row where the current coding tree unit is located. It should be understood that each coding tree unit in the current image is arranged in sequence in a preset order. One line of coding tree units in the current image is one coding tree unit line.

The method may further include that the horizontal rectangular coordinate system corresponding to the current image is in a horizontal positive direction to the right and in a vertical positive direction to the downward, and determining the first time domain position of the image block to be processed includes:

1. determining the abscissa of the first time domain position: and taking the minimum value between the abscissa of the right lower corner position and the abscissa of the right boundary of the current image as the abscissa of the first time domain position.

2. Determining an ordinate of the first time domain position: determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit; and taking the minimum value between the ordinate of the right lower corner point position and the ordinate of the lower boundary of the current coding tree unit as the ordinate of the first time domain position.

It should be appreciated that, similar to the current CU, the longitudinal resolution of the image may not be a high integer multiple of the coding tree units, where the actual height of the last line of coding tree units may be less than the height of the non-last line of coding tree units, and thus, for clarity of description, the sum of the ordinate at which the upper boundary of the current coding tree unit is located and the high of the current coding tree unit is referred to herein as the virtual lower boundary of the coding tree unit. In various embodiments, the ordinate at which the virtual lower boundary of the coding tree unit is located may be replaced by the sum of the ordinate at which the upper boundary of the current coding tree unit is located and the height of the current coding tree unit.

Specific:

s11011, acquiring the coordinate position (xColBr, yColBr) of the right lower corner of the current CU according to the method described in S1001;

s11012, determining the position of the ordinate where the virtual lower boundary of the current coding tree unit is located, as shown in a formula (8):

yCtbBr＝yCb|((1<<CtbLog2SizeY)–1) (8)

wherein yCtbBr is the ordinate where the virtual lower boundary of the current coding tree unit is located, and "|" is the or operation in binary computation.

In some possible embodiments, yCtbBr may also be calculated by other means, exemplary:

yCtbBr＝(yCb>>CtbLog2SizeY<<CtbLog2SizeY)+CtbSizeY–1

Where CtbSizeY represents the height of the coding tree unit (CTU or CTB) where the current CU is located.

S11013, determining a first time domain position (xColBr, yColBr), as shown in formula (9):

xColBr＝Min(xColBr,pic_width_in_luma_samples–1) (9)

yColBr＝Min(yColBr,Min(pic_height_in_luma_samples-1,yCtbBr))

where "Min" is the operation that takes the minimum value between the two.

It should be appreciated that taking the minimum value of pic_height_in_luma_samples-1 and yCtbBr is the smallest ordinate value of the lower boundary of the taken image and the virtual lower boundary of the current coding tree unit, i.e. determining the ordinate at which the lower boundary of the current coding tree unit is located. When the virtual lower boundary of the current coding tree unit is located outside the lower boundary of the image, the lower boundary of the current coding tree unit is restricted to the image lower boundary.

In some possible embodiments, step S1101 may also be described as: when the lower right corner position coordinate (first time domain position) of the current CU exceeds the image boundary or the current CTU line, the position (first time domain position) CLIP is added to the image boundary and the current Coding Tree Unit (CTU) line.

S1102, in a time domain corresponding image (collocated picture) of the current image, determining a first neighborhood position corresponding to the first time domain position.

Specifically, the method comprises the following steps: rounding coordinates of the first time domain position; and taking the coordinates after the rounding operation as the coordinates of the first neighborhood position.

The method of formula (10) may be adopted, the coordinates of the first time domain position are shifted to complete the rounding operation, and then the coordinates of the first neighborhood position are:

(xCbCol,yCbCol)＝((xColBr>>3)<<3,(yColBr>>3)<<3) (10)

the time domain corresponding image is a preset image or is determined by analyzing code stream information.

Specifically, reference may be made to the specific description of the foregoing embodiments, for example, step S1003, which is not repeated.

S1103, determining a first prediction mode of the image block where the first neighborhood position is located, and determining the availability of the first motion vector according to the first prediction mode.

Wherein the first motion vector is determined to be unavailable when the first prediction mode is intra prediction or intra block copy mode (block copy), and the first motion vector is determined to be available when the first prediction mode is inter prediction.

In some possible implementations, when the current image block is predicted according to the first prediction mode, a motion vector is generated, and if not (no motion vector is generated), the first motion vector is determined to be available. It should be appreciated that the first prediction mode is not limited to the specifically enumerated prediction modes described above.

S1104, when a first motion vector corresponding to the first neighborhood position is available, determining a time domain candidate motion vector of the image block to be processed according to the first motion vector.

Specifically, scaling the first motion vector according to a proportional relation between a first time domain distance and a second time domain distance to obtain the time domain candidate motion vector, wherein the first time domain distance is a distance between the current image and a reference frame of the current image, and the second time domain distance is a distance between the time domain corresponding image and the reference frame pointed by the first motion vector.

Reference may be made to the embodiment shown in fig. 7, cur_pic, col_pic, col_ref, cur_ref respectively representing the current picture, the reference frame of the temporal corresponding picture. tb, td denote the distances of cur_pic and cur_ref, and col_pic and col_ref, respectively, i.e. the first time domain distance and the second time domain distance. Cur_blk, col_blk, represents a block of positions of the image block to be processed and a corresponding block of positions of the image block to be processed (the positions of which in the time-domain corresponding image are the same as the positions of the image block to be processed in the current image). The MV curMV of the image block to be processed can be obtained by scaling the MV colMV (first motion vector) of the corresponding position block through formula (3), and the process is ended.

S1105, when the first motion vector is unavailable, determining that the time domain candidate motion vector of the image block to be processed is unavailable, and ending the flow.

Compared with the previous embodiment of the present application, in the embodiment of the present application, the first time domain position is defined, so that the opportunity of availability of the first motion vector is improved, the process of obtaining and judging the motion vector at the center point of the corresponding position block of the current CU is omitted, the complexity is reduced, and the coding efficiency is improved.

In order to achieve the balance between coding complexity and performance, in another possible implementation, as shown in fig. 9, step S1105 may alternatively be:

s1105, when the first motion vector is unavailable, determining a second neighborhood position corresponding to a second time domain position of the image block to be processed in the time domain corresponding image.

Illustratively, the second temporal location is a geometric center location of the image block to be processed.

Specifically, the method comprises the following steps: rounding coordinates of the second time domain position; and taking the coordinates after the rounding operation as the coordinates of the second neighborhood position.

For the specific embodiment, the determination method of the first neighborhood position in step S1102 is not described in detail.

S1106, determining a second prediction mode of the image block where the second neighborhood position is located, and determining availability of the second motion vector according to the second prediction mode.

Wherein the second motion vector is determined to be unavailable when the second prediction mode is intra prediction or intra block copy mode, and the second motion vector is determined to be available when the second prediction mode is inter prediction.

S1107, when a second motion vector corresponding to the second neighborhood position is available, determining the time domain candidate motion vector according to the second motion vector.

Specifically, scaling the second motion vector according to the proportional relation between the first temporal distance and a third temporal distance to obtain the temporal candidate motion vector, where the third temporal distance is the distance between the temporal corresponding image and the reference frame pointed by the second motion vector.

For the specific embodiment, refer to the processing manner of the first motion vector in step S1104, which is not described herein, and the flow is ended.

S1108, when the second motion vector is unavailable, determining that the time domain candidate motion vector of the image block to be processed is unavailable, and ending the flow.

Compared with the previous embodiments of the present application, in the embodiments of the present application, the first time domain position is defined, so that the opportunity of using the first motion vector is improved, but at the same time, the utilization of the motion vector at the center point of the corresponding position block of the current CU is reserved, and the balance between complexity and coding efficiency is achieved.

In another possible embodiment, the time domain candidates may also be obtained by, in particular, as shown in fig. 10:

Consistent with the foregoing embodiment, the ordinate of the virtual lower boundary of the current coding tree unit may be determined according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; and taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit.

S1201, determining a third time domain position.

When the position of the right lower corner of the image block to be processed is located outside the lower boundary of the current coding tree unit, or the position of the right lower corner is located outside the right boundary of the current image, the third time domain position is the geometric center position of the image block to be processed; otherwise (the lower right corner position of the image block to be processed is located within the lower boundary of the current coding tree unit, and the lower right corner position is located within the right boundary of the current image), the third time domain position is the lower right corner position of the image block to be processed.

It should be understood that, when the virtual lower boundary of the current coding tree unit is used as the lower boundary of the current coding tree unit, the determining process of step S1201 also needs to consider the factors of the lower boundary of the image, namely:

when the right lower corner position of the image block to be processed is located outside the lower boundary of the current coding tree unit, or the right lower corner position is located outside the right boundary and/or the lower boundary of the current image, the third time domain position is the geometric center position of the image block to be processed; otherwise (the lower right corner position of the image block to be processed is located within the lower boundary of the current coding tree unit, and the lower right corner position is located within the right boundary and the lower boundary of the current image), the third time domain position is the lower right corner position of the image block to be processed.

Specifically, the position of the lower right corner of the image block to be processed is located outside the lower boundary of the current coding tree unit, including: the ordinate of the lower right corner of the image block to be processed is larger than the ordinate of the lower boundary of the current coding tree unit.

And when the position of the right lower corner point is positioned outside the right boundary of the current image, the method comprises the following steps: and the abscissa of the right lower corner point is larger than the abscissa of the right boundary of the current image.

S1202, determining a third neighborhood position corresponding to a third time domain position of the image block to be processed in the time domain corresponding image of the current image.

Specifically, the method comprises the following steps: rounding coordinates of the third time domain position; and taking the coordinates after the rounding operation as the coordinates of the third neighborhood position.

S1203 determines a third prediction mode of the image block where the third neighborhood position is located, and determines availability of the third motion vector according to the third prediction mode.

Wherein the third motion vector is determined to be unavailable when the third prediction mode is intra prediction or intra block copy mode, and the third motion vector is determined to be available when the third prediction mode is inter prediction.

And S1204, when a third motion vector corresponding to the third neighborhood position is available, determining a time domain candidate motion vector of the image block to be processed according to the third motion vector.

Specifically, scaling the third motion vector according to a proportional relation between a fourth time domain distance and a fifth time domain distance to obtain the time domain candidate motion vector, wherein the fourth time domain distance is a distance between the current image and a reference frame of the current image, and the fifth time domain distance is a distance between the time domain corresponding image and the reference frame pointed by the third motion vector.

And S1205, when the third motion vector is unavailable, determining that the time domain candidate motion vector of the image block to be processed is unavailable, and ending the flow.

Compared with the previous embodiment of the present application, in the embodiment of the present application, according to the position of the lower right corner of the current CU, the motion vector of the lower right corner position and the center position of the corresponding position block of the current CU is alternatively utilized, so as to achieve the balance between complexity and coding efficiency.

It should be understood that in the foregoing embodiments, the current image is a current image frame, i.e., an entire image frame, and in other possible embodiments, the current image may also be a partial image area in the current image frame, such as a sub-image, a slice group, a slice band, and the like, and the image boundary is a boundary of the partial image area, for example, a sub-image boundary, a slice group boundary, a slice boundary, and the like. In a specific embodiment, if the current image is a slice, the current image is replaced by the slice where the image block to be processed is located, and the slice boundary is replaced by the image boundary in the steps of the above embodiments, which will not be described again.

As shown in fig. 11, an embodiment of the present application provides a device 1300 for obtaining a temporal candidate motion vector, where an image block to be processed is located in a current coding tree unit, and the current coding tree unit is located in a current image, and the device includes: a calculating module 1301, configured to determine a first time domain position of the image block to be processed according to a position of a lower right corner of the image block to be processed, a boundary position of the current coding tree unit, and a boundary position of the current image, where the first time domain position is located within a coding tree unit row where the current coding tree unit is located; a mapping module 1302, configured to determine a first neighborhood position corresponding to the first time domain position in a time domain corresponding image of the current image; a determining module 1303, configured to determine, when a first motion vector corresponding to the first neighboring location is available, a temporal candidate motion vector of the image block to be processed according to the first motion vector.

In a possible implementation manner, the horizontal rectangular coordinate system corresponding to the current image takes a horizontal right direction as a horizontal positive direction and takes a vertical downward direction as a vertical positive direction, and the calculating module 1301 is specifically configured to: taking the minimum value between the abscissa of the right lower corner position and the abscissa of the right boundary of the current image as the abscissa of the first time domain position; determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit; and taking the minimum value between the ordinate of the right lower corner point position and the ordinate of the lower boundary of the current coding tree unit as the ordinate of the first time domain position.

In one possible implementation, the mapping module 1302 is specifically configured to: rounding coordinates of the first time domain position; and taking the coordinates after the rounding operation as the coordinates of the first neighborhood position.

In a possible implementation manner, the time domain corresponding image is a preset image or is determined by analyzing code stream information.

In a possible implementation, before the determining the temporal candidate motion vector of the image block to be processed according to the first motion vector, the determining module 1303 is further configured to: determining a first prediction mode of an image block where the first neighborhood position is located; and determining availability of the first motion vector according to the first prediction mode, wherein the first motion vector is determined to be unavailable when the first prediction mode is intra-prediction or intra-block copy mode, and the first motion vector is determined to be available when the first prediction mode is inter-prediction.

In a possible implementation manner, the determining module 1303 is specifically configured to: and scaling the first motion vector according to the proportional relation between a first time domain distance and a second time domain distance to obtain the time domain candidate motion vector, wherein the first time domain distance is the distance between the current image and the reference frame of the current image, and the second time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the first motion vector.

In a possible implementation, the determining module 1303 is further configured to: when the first motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

In a possible implementation, the determining module 1303 is further configured to: when the first motion vector is unavailable, determining a second neighborhood position corresponding to a second time domain position of the image block to be processed in the time domain corresponding image; and when a second motion vector corresponding to the second neighborhood position is available, determining the time domain candidate motion vector according to the second motion vector.

In a possible embodiment, the second temporal location is a geometric center location of the image block to be processed.

In one possible implementation, the mapping module 1302 is specifically configured to: rounding coordinates of the second time domain position; and taking the coordinates after the rounding operation as the coordinates of the second neighborhood position.

In a possible implementation, before said determining said temporal candidate motion vector from said second motion vector, said determining module 1303 is further configured to: determining a second prediction mode of the image block where the second neighborhood position is located; and determining availability of the second motion vector according to the second prediction mode, wherein the second motion vector is determined to be unavailable when the second prediction mode is intra-prediction or intra-block copy mode, and the second motion vector is determined to be available when the second prediction mode is inter-prediction.

In a possible implementation manner, the determining module 1303 is specifically configured to: and scaling the second motion vector according to the proportional relation between the first time domain distance and a third time domain distance to obtain the time domain candidate motion vector, wherein the third time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the second motion vector.

In a possible implementation, the determining module 1303 is further configured to: when the second motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

As shown in fig. 12, another apparatus 1400 for obtaining a temporal candidate motion vector is provided in an embodiment of the present application, where an image block to be processed is located in a current coding tree unit, and the current coding tree unit is located in a current image, and the apparatus includes: a mapping module 1401, configured to determine, in a time-domain corresponding image of the current image, a third neighborhood position corresponding to a third time-domain position of the image block to be processed, where when a lower right corner position of the image block to be processed is located outside a lower boundary of the current coding tree unit, or the lower right corner position is located outside a right boundary of the current image, the third time-domain position is a geometric center position of the image block to be processed; a determining module 1402, configured to determine, when a third motion vector corresponding to the third neighboring location is available, a temporal candidate motion vector of the image block to be processed according to the third motion vector.

In one possible implementation, the mapping module 1401 is specifically configured to: rounding coordinates of the third time domain position; and taking the coordinates after the rounding operation as the coordinates of the third neighborhood position.

In a possible implementation, before the determining the temporal candidate motion vector of the image block to be processed according to the third motion vector, the determining module 1402 is further configured to: determining a third prediction mode of the image block where the third neighborhood position is located; and determining availability of the third motion vector according to the third prediction mode, wherein the third motion vector is determined to be unavailable when the third prediction mode is intra-prediction or intra-block copy mode, and the third motion vector is determined to be available when the third prediction mode is inter-prediction.

In a possible implementation, the determining module 1402 is specifically configured to: and scaling the third motion vector according to a proportional relation between a fourth time domain distance and a fifth time domain distance to obtain the time domain candidate motion vector, wherein the fourth time domain distance is the distance between the current image and the reference frame of the current image, and the fifth time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the third motion vector.

In a possible implementation, the determining module 1402 is further configured to: when the third motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

In a possible embodiment, the method further includes: and when the position of the right lower corner of the image block to be processed is positioned in the lower boundary of the current coding tree unit, and the position of the right lower corner is positioned in the right boundary of the current image, the third time domain position is the position of the right lower corner of the image block to be processed.

In one possible implementation, the mapping module 1401 is further configured to: determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit; and taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit.

Those of skill in the art will appreciate that the functions described in connection with the various illustrative logical blocks, modules, and algorithm steps described in connection with the disclosure herein may be implemented as hardware, software, firmware, or any combination thereof. If implemented in software, the functions described by the various illustrative logical blocks, modules, and steps may be stored on a computer readable medium or transmitted as one or more instructions or code and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media corresponding to tangible media, 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). In this manner, a computer-readable medium may generally correspond to (1) a non-transitory tangible computer-readable storage medium, 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 implementing the techniques described herein. The computer program product may include a computer-readable medium.

By way of example, and not limitation, 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. For example, if the instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that the computer-readable storage medium and data storage medium do not include connections, carrier waves, signals, or other transitory media, but are actually directed to non-transitory tangible storage media. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, digital Versatile Disc (DVD), 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.

The instructions may be executed by one or more 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. Thus, the term "processor" as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Additionally, in some aspects, the functions described by the various illustrative logical blocks, modules, and steps described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combination codec. Moreover, the techniques may 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 chipset). The various components, modules, or units are described in this application to emphasize functional aspects of the devices for performing the disclosed techniques but do not necessarily require realization by different hardware units. Indeed, as described above, the various units may be combined in a codec hardware unit in combination with suitable software and/or firmware, or provided by an interoperable hardware unit (including one or more processors as described above).

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

The foregoing is merely illustrative of specific embodiments of the present application, and the scope of the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of obtaining a temporal candidate motion vector, wherein a block of an image to be processed is located in a current Coding Tree Unit (CTU), the current coding tree unit being located in a current image, the method comprising:

determining a first time domain position of the image block to be processed according to the position of the right lower corner of the image block to be processed, the boundary position of the current coding tree unit and the boundary position of the current image, wherein the first time domain position is positioned in a coding tree unit row where the current coding tree unit is positioned;

determining a first neighborhood position corresponding to the first time domain position in a time domain corresponding image (collocated picture) of the current image;

When a first motion vector corresponding to the first neighborhood position is available, determining a time domain candidate motion vector of the image block to be processed according to the first motion vector;

the determining the first time domain position of the image block to be processed includes:

taking the minimum value between the abscissa of the right lower corner position and the abscissa of the right boundary of the current image as the abscissa of the first time domain position;

determining the ordinate of the virtual lower boundary of the current coding tree unit according to the ordinate of the upper boundary of the current coding tree unit and the height of the current coding tree unit;

taking the minimum value of the ordinate of the lower boundary of the current image and the ordinate of the virtual lower boundary as the ordinate of the lower boundary of the current coding tree unit;

and taking the minimum value between the ordinate of the right lower corner point position and the ordinate of the lower boundary of the current coding tree unit as the ordinate of the first time domain position.

2. The method of claim 1, wherein the determining the first neighborhood location corresponding to the first time domain location comprises:

Rounding coordinates of the first time domain position;

and taking the coordinates after the rounding operation as the coordinates of the first neighborhood position.

3. The method according to claim 1 or 2, wherein the time domain corresponding image is a preset image or is determined by parsing a code stream information.

4. The method according to claim 1 or 2, further comprising, prior to said determining a temporal candidate motion vector for said image block to be processed from said first motion vector:

determining a first prediction mode of an image block where the first neighborhood position is located;

determining availability of the first motion vector according to the first prediction mode, wherein,

when the first prediction mode is intra prediction or intra block copy mode (block copy), determining that the first motion vector is not available,

when the first prediction mode is inter prediction, it is determined that the first motion vector is available.

5. The method of claim 1, wherein said determining a temporal candidate motion vector for the image block to be processed from the first motion vector comprises:

and scaling the first motion vector according to the proportional relation between a first time domain distance and a second time domain distance to obtain the time domain candidate motion vector, wherein the first time domain distance is the distance between the current image and the reference frame of the current image, and the second time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the first motion vector.

6. The method as recited in claim 5, further comprising:

when the first motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

7. The method as recited in claim 5, further comprising:

when the first motion vector is unavailable, determining a second neighborhood position corresponding to a second time domain position of the image block to be processed in the time domain corresponding image;

and when a second motion vector corresponding to the second neighborhood position is available, determining the time domain candidate motion vector according to the second motion vector.

8. The method of claim 7, wherein the second temporal location is a geometric center location of the image block to be processed.

9. The method of claim 8, wherein determining a second neighborhood position corresponding to a second temporal position of the image block to be processed comprises:

rounding coordinates of the second time domain position;

and taking the coordinates after the rounding operation as the coordinates of the second neighborhood position.

10. The method of claim 7, further comprising, prior to said determining said temporal candidate motion vector from said second motion vector:

Determining a second prediction mode of the image block where the second neighborhood position is located;

determining availability of the second motion vector according to the second prediction mode, wherein,

when the second prediction mode is an intra prediction or intra block copy mode, determining that the second motion vector is not available,

when the second prediction mode is inter prediction, determining that the second motion vector is available.

11. The method of claim 7, wherein said determining the temporal candidate motion vector from the second motion vector comprises:

and scaling the second motion vector according to the proportional relation between the first time domain distance and a third time domain distance to obtain the time domain candidate motion vector, wherein the third time domain distance is the distance between the time domain corresponding image and the reference frame pointed by the second motion vector.

12. The method as recited in claim 7, further comprising:

when the second motion vector is not available, determining that a temporal candidate motion vector of the image block to be processed is not available.

13. An apparatus for obtaining a temporal candidate motion vector, wherein an image block to be processed is located in a current coding tree unit, and the current coding tree unit is located in a current image, the apparatus comprising:

The computing module is used for determining a first time domain position of the image block to be processed according to the position of the right lower corner of the image block to be processed, the boundary position of the current coding tree unit and the boundary position of the current image, wherein the first time domain position is positioned in a coding tree unit row where the current coding tree unit is positioned;

the mapping module is used for determining a first neighborhood position corresponding to the first time domain position in the time domain corresponding image of the current image;

a determining module, configured to determine, when a first motion vector corresponding to the first neighborhood position is available, a time-domain candidate motion vector of the image block to be processed according to the first motion vector;

the horizontal rectangular coordinate system corresponding to the current image takes the horizontal right direction as the horizontal positive direction and takes the vertical downward direction as the vertical positive direction, and the calculation module is specifically used for:

14. The apparatus of claim 13, wherein the mapping module is specifically configured to:

rounding coordinates of the first time domain position;

15. The apparatus according to claim 13 or 14, wherein the time domain corresponding image is a preset image or is determined by parsing a code stream information.

16. The apparatus according to claim 13 or 14, wherein before said determining a temporal candidate motion vector for said image block to be processed from said first motion vector, said determining means is further for:

When the first prediction mode is an intra prediction or intra block copy mode, determining that the first motion vector is not available,

17. The apparatus according to claim 13 or 14, wherein the determining module is specifically configured to:

18. The apparatus of claim 13 or 14, wherein the determining module is further configured to:

19. The apparatus of claim 13 or 14, wherein the determining module is further configured to:

20. The apparatus of claim 19, wherein the second temporal location is a geometric center location of the image block to be processed.

21. The apparatus of claim 20, wherein the mapping module is specifically configured to:

rounding coordinates of the second time domain position;

22. The apparatus according to claim 20 or 21, wherein the determining module is further configured to, prior to the determining the temporal candidate motion vector from the second motion vector:

23. The apparatus of claim 22, wherein the determining module is specifically configured to:

24. The apparatus of claim 22, wherein the means for determining is further configured to:

25. A video encoder for encoding image blocks, comprising:

inter prediction means for performing the method of any of claims 1 to 12, wherein the inter prediction means is adapted to predict motion information of a current encoded image block based on target candidate motion information, and to determine predicted pixel values of the current encoded image block based on the motion information of the current encoded image block;

an entropy encoding module for encoding an index identification of the target candidate motion information into a bitstream, the index identification indicating the target candidate motion information for the current encoded image block;

A reconstruction module for reconstructing the current encoded image block based on the predicted pixel values.

26. A video decoder for decoding image blocks from a bitstream, comprising:

the entropy decoding module is used for decoding an index identifier from the code stream, wherein the index identifier is used for indicating target candidate motion information of the current decoded image block;

inter-frame prediction means for performing the method of any of claims 1 to 12, the inter-frame prediction means being adapted to predict motion information of a current decoded image block based on target candidate motion information indicated by the index identification, and to determine predicted pixel values of the current decoded image block based on the motion information of the current decoded image block;

a reconstruction module for reconstructing the current decoded image block based on the predicted pixel values.

27. A video codec device, comprising: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform the method as described in any of claims 1-12.