Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/90—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
  • H04N19/96—Tree coding, e.g. quad-tree coding
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
  • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
  • H04N19/51—Motion estimation or motion compensation
  • H04N19/513—Processing of motion vectors
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
  • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
  • H04N19/51—Motion estimation or motion compensation
  • H04N19/573—Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction

Definitions

• the present application generally relates to video coding and compression, and in particular but not limited to, methods and apparatus for motion compensated prediction using triangular prediction unit (i.e., a special case of geometric partition prediction unit) in video coding.
• triangular prediction unit i.e., a special case of geometric partition prediction unit
• an apparatus for video coding with geometric partition including:
• FIG. 5 is a schematic diagram illustrating multi-type tree splitting modes in accordance with some implementations of the present disclosure.
• FIG. 10 is a schematic diagram illustrating candidate positions for a temporal merge candidate in accordance with some implementations of the present disclosure.
• FIG. 11 A to FIG. 1 IB are schematic diagrams illustrating examples of uni -prediction motion vector (MV) selection for triangle prediction mode in accordance with some implementations of the present disclosure.
• MV motion vector
• FIG. 19 is a block diagram illustrating an exemplary apparatus for video coding in accordance with some implementations of the present disclosure.
• FIG. 20 is a flowchart illustrating an exemplary process of video coding for motion compensated prediction using geometric prediction unit in accordance with some implementations of the present disclosure.
• module may include memory (shared, dedicated, or group) that stores code or instructions that may be executed by one or more processors.
• a module may include one or more circuits with or without stored code or instructions.
• the module or circuit may include one or more components that are directly or indirectly connected. These components may or may not be physically attached to, or located adjacent to, one another.
• a unit or module may be implemented purely by software, purely by hardware, or by a combination of hardware and software. In a pure software implementation, for example, the unit or module may include functionally related code blocks or software components, that are directly or indirectly linked together, so as to perform a particular function.
• intra prediction is usually based on unfiltered reconstructed pixels, while inter prediction is based on filtered reconstructed pixels if these filter options are turned on by the encoder 100.
• FIG. 3 An example of block partitioning by using the QTBT scheme, and the corresponding tree representation are illustrated in FIG. 3.
• the solid lines indicate quadtree splitting and dotted lines indicate binary tree splitting.
• the coding tree unit (CTU) 300 is first partitioned by a quadtree structure, and three of the four quadtree leaf nodes 302, 304, 306, 308 are further partitioned by either a quadtree structure or a binary tree structure.
• the quadtree leaf node 306 is further partitioned by quadtree splitting;
• the quadtree leaf node 304 is further partitioned into two leaf nodes 304a, 304b by binary tree splitting; and the quadtree leaf node 302 is also further partitioned by binary tree splitting.
• the luma and chroma CTBs in one CTU share the same QTBT structure.
• the luma CTB is partitioned into CUs by a QTBT structure
• the chroma CTBs are partitioned into chroma CUs by another QTBT structure.
• a CU in an I slice consists of a coding block of the luma component or coding blocks of two chroma components
• a CU in a P or B slice consists of coding blocks of all three colour components.
• VVC Versatile Video Coding
• VTM1 VVC Test Model 1
• a CU Under the affine prediction mode, a CU may be split into multiple 4x4 PUs for prediction. Motion vectors may be derived for each 4x4 PU and motion compensation may be performed accordingly on the 4x4 PU.
• a CU Under the ATMVP mode, a CU may be split into one or multiple 8x8 PUs for prediction. Motion vectors are derived for each 8x8 PU and motion compensation may be performed accordingly on the 8x8 PU.
• Under the triangle prediction mode a CU may be split into two triangular shape prediction units. Motion vectors are derived for each PU and motion compensation is performed accordingly. The triangle prediction mode is supported for inter prediction. More details of the triangle prediction mode are illustrated below.
• FIG. 7 is a schematic diagram illustrating positions of the neighboring blocks in accordance with some implementations of the present disclosure.
• Both the left block and the top block have a triangle prediction flag of 0;
• the scaled motion vector for the temporal merge candidate is scaled from the motion vector of the co-located PU col PU using the POC distances, tb and td, where tb is defined to be the POC difference between the reference picture of the current picture curr ref and the current picture curr_pic and td is defined to be the POC difference between the reference picture of the co-located picture col ref and the co-located picture col_pic.
• the reference picture index of the temporal merge candidate is set equal to zero.
• a practical realization of the scaling process is described in the HEVC draft specification. For a B-slice, two motion vectors, one for reference picture List 0 and the other for reference picture List 1, are obtained and combined to make the bi-predictive merge candidate.
• a motion vector pruning process may be performed to make sure that the new motion vector to be added is different from those motion vectors already in the uni-directional prediction merge list.
• Such motion vector pruning process may also be performed in a partial manner for lower complexity, e.g., checking the new motion vector to be added only against some but not all motion vectors already in the uni-directional prediction merge list.
• no motion vector pruning i.e., motion vector comparison operation is performed in the process.
• prediction List 0 motion vectors of the candidates in the first merge list are checked and selected into the uni-directional prediction merge list first, followed by prediction List 1 motion vectors of those candidates; and if the uni-directional prediction merge list is still not full, uni prediction zero motion vectors may be added.
• prediction List 0 motion vectors of the candidates in the first merge list are used as the uni-directional prediction merge candidates, indexed according to the same index order as they are in the first merge list. That is, upon determining that the POC of the current picture is greater than each one of the POCs of the reference pictures, the reference indices are arranged according to a same order of List 0 motion vectors of the candidates in the first merge list.
• prediction List 0 motion vectors of the candidates in the first merge list are used as the uni-directional prediction merge candidates, indexed according to the same index order as they are in the first merge list. Otherwise, if the current picture uses backward prediction, List 0 and List 1 motion vectors of each candidate in the first merge list are used as the uni-directional prediction merge candidates, indexed based on an interleaving manner as described above, i.e., List 0 motion vector of the first candidate in the first merge list followed by List 1 motion vector of the first candidate, and then List 0 motion vector of the second candidate followed by list 1 motion vector of the second candidate, and so on.
• the motion vector plus certain motion offset is indexed as the uni-directional prediction merge candidate following the motion vector of the candidate.
• uni-prediction merge candidates may be selected for triangle prediction according to the following rules:
• a candidate’s List x (with x being 0 or 1) motion vector is preferred and selected first if it is available, and an example where x is equal to 0 is shown in FIG. 16B. Similar to other examples explained earlier, in the case where a uni-prediction motion vector is not available for a certain candidate in the first merge list, the corresponding uni-prediction motion vector of the same candidate from the other reference list is selected. As a result, for each candidate in the first merge list, a uni-prediction motion vector can be obtained and used for triangle and/or geometric prediction mode. The obtained uni-prediction motion vector shares the same index value as the merge candidate in the first merge list.
• up to 2N uni-prediction motion vectors may be used for each of the two triangular partitions.
• the two merge index values for the two partitions under triangle prediction mode do not have to be different from each other. In other words, they may take the same value.
• the index values are signaled directly without adjustment before signaling. More specifically, unlike what is defined in the current VVC, the second index value is signaled to the decoder directly without performing any adjustment to the value prior to signaling.
• 1 IB is used in determining from which prediction list a motion vector of a merge candidate is selected for triangle mode prediction. In other words, if indexl is an even value, List 0 motion vector of the candidate indicated by indexl is selected, and if indexl is an odd value, List 1 motion vector of the candidate indicated by indexl is selected. For index2, if it is an even value, List 1 motion vector is selected, and if it is an odd value, List 0 motion vector is selected. In the case where a motion vector corresponding to certain prediction list does not exist, certain default motion vector may be used instead, e.g. a zero motion vector, or the corresponding motion vector from the other prediction list, etc. It is also possible that the pattern shown in FIG. 1 IB is used for indexl and that shown in FIG.
• a list-0 zero vector and a list-1 zero vector may be separately added into the uni-directional prediction merge list until the list is full.
• motion vector pruning operations are performed to see if the motion vector is the same as any of the motion vectors already selected in that uni-directional prediction merge list. If the pruning operations conclude that the motion vector is different from those motion vectors it is compared against, this motion vector is added into the uni-directional prediction merge list. Otherwise, the motion vector is not selected or added into that list. If the total number of motion vector pruning operations performed reaches N, then no more pruning operations are performed in selecting remaining motion vectors into that list.
• motion vector pruning operations are performed only among the first K candidates from the first merge list, where K is a positive integer.
• K is a positive integer.
• motion vector pruning operations would be performed while checking the first K motion vectors in the order indicated by those arrows. Starting from the (K+l)th candidate, no motion vector pruning operations will be performed in selecting the remaining uni-prediction motion vectors into that uni-directional prediction merge list.
• the sensor component 1914 may further include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.
• the communication component 1916 is configured to facilitate wired or wireless communication between the apparatus 1900 and other devices.
• the apparatus 1900 may access a wireless network based on a communication standard, such as WiFi, 4G, or a combination thereof.
• the communication component 1916 receives a broadcast signal or broadcast related information from an external broadcast management system via a broadcast channel.
• the communication component 1916 may further include a Near Field Communication (NFC) module for promoting short-range communication.
• the NFC module may be implemented based on Radio Frequency Identification (RFID) technology, infrared data association (IrDA) technology, Ultra-Wide Band (UWB) technology, Bluetooth (BT) technology and other technology.
• RFID Radio Frequency Identification
• IrDA infrared data association
• UWB Ultra-Wide Band
• Bluetooth Bluetooth
• step 2008 the processor 1920 constructs a uni-directional prediction merge list based on the uni-prediction MVs.

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• 2020
  • 2020-12-31 CN CN202080089982.XA patent/CN114982230A/zh active Pending
  • 2020-12-31 WO PCT/US2020/067735 patent/WO2021138605A1/en active Application Filing

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