EP4029261A2 - Procédé et appareil de réglage adaptatif de précision de paramètre de prédiction de pondération pour harmoniser un mode de fusion non rectangulaire et une prédiction pondérée - Google Patents

Procédé et appareil de réglage adaptatif de précision de paramètre de prédiction de pondération pour harmoniser un mode de fusion non rectangulaire et une prédiction pondérée

Info

Publication number
EP4029261A2
EP4029261A2 EP20823097.9A EP20823097A EP4029261A2 EP 4029261 A2 EP4029261 A2 EP 4029261A2 EP 20823097 A EP20823097 A EP 20823097A EP 4029261 A2 EP4029261 A2 EP 4029261A2
Authority
EP
European Patent Office
Prior art keywords
value
weights
prediction
video
equal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20823097.9A
Other languages
German (de)
English (en)
Other versions
EP4029261A4 (fr
Inventor
Vasily Alexeevich RUFITSKIY
Alexey Konstantinovich FILIPPOV
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huawei Technologies Co Ltd
Original Assignee
Huawei Technologies Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co Ltd filed Critical Huawei Technologies Co Ltd
Publication of EP4029261A2 publication Critical patent/EP4029261A2/fr
Publication of EP4029261A4 publication Critical patent/EP4029261A4/fr
Pending legal-status Critical Current

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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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/115—Selection of the code volume for a coding unit prior to 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/103—Selection of coding mode or of prediction mode
    • H04N19/109—Selection of coding mode or of prediction mode among a plurality of temporal predictive coding modes
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • 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
    • H04N19/46—Embedding additional information in the video signal during the compression process
    • H04N19/463—Embedding additional information in the video signal during the compression process by compressing encoding parameters before transmission
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/103—Selection of coding mode or of prediction mode
    • H04N19/107—Selection of coding mode or of prediction mode between spatial and temporal predictive coding, e.g. picture refresh
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/119—Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
    • 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
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding

Definitions

  • Embodiments of the present application generally relate to the field of moving picture processing and more particularly to non-rectangular partitioning modes when they are used in a combination with weighted prediction for coding fades.
  • Video coding (video encoding and decoding) is used in a wide range of digital video applications, for example broadcast digital TV, video transmission over internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems, and camcorders of security applications.
  • digital video applications for example broadcast digital TV, video transmission over internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems, and camcorders of security applications.
  • Video compression devices often use software and/or hardware at the source to code the video data prior to transmission or storage, thereby decreasing the quantity of data needed to represent digital video images.
  • the compressed data is then received at the destination by a video decompression device that decodes the video data.
  • Some embodiments provide methods for encoding and decoding a video sequence with weighted prediction parameters that are combined from fade weighting parameters and blending weighting parameters.
  • the values of fade weighting parameters may be
  • blending weighting parameters may be determined by a position of a predicted sample in a predicted block.
  • Some embodiments provide for an efficient encoding and/or decoding using signal-related information in slice headers only for slices which allow or enable bidirectional inter-prediction, e.g. in bidirectional (B) prediction slices, also called B-slices.
  • B bidirectional
  • a method for a weighting inter prediction process comprising:
  • bit budget value indicating a number of bits available for the weighting parameter obtained from the at least two weights
  • the dynamic range of the at least two weights is to be understood as a value specifying how long, in terms of bits, the largest weight of the at least two weights is. If, for example, among the at least two weights there is a weight having a length of 7bits whereas all other weights of the at least two weights are smaller in terms of bits, then the dynamic range may be set to 7bits. This is of course not limited to a maximum length of 7bits but applies to any lengths of weights in terms of bits.
  • the adjusting by the right shifting allows for reducing the size of the weighting parameter in terms of its bit length without thereby reducing the accuracy adversely. Likewise, in some embodiments, this prevents overflows that could occur if values exceed the amount of bits that was originally intended for them.
  • the weighting parameter is provided in a look-up table, LUT.
  • LUT look-up table
  • the value of the dynamic range depends on at least the maximum bit depth of the at least two weights.
  • the value of the dynamic range is the maximum bit depth of the at least two weights.
  • a right shifting is not applied if the maximum bit depth is equal to or smaller than the bit budget value. In that case, compliance with the bit budget is already ensured, making the right shifting by 0 a redundant operation that can, in that case, be completely omitted.
  • the value shift_norm of the right shifting is obtained by
  • log2(w max ) is the maximum bit depth of the
  • Tb is the bit budget value.
  • the precision is adjusted on a slice-level of the inter prediction process. This allows for adjustment once per slice, reducing the computational complexity in the prediction further.
  • the at least two weights are position independent weights. This allows for implementing the method for example in TPM (triangular partitioning mode), where one of the weights used to obtain the weighting parameter is position independent.
  • the precision is adjusted on a block-level of the inter prediction process. Thereby, only the blocks of a slice that need adjustment of the precision are adjusted. This can lead to improved prediction results for all blocks.
  • one of the at least two weights is a position independent weight and the other of the at least two weights is a position dependent weight.
  • a coding system for performing a method for a weighting inter prediction process comprising a processing unit configured for performing a method for a weighting inter prediction process according to any of the above embodiments.
  • the coding system is or comprises a video coding device.
  • the above method is applied to video coding, which can reduce the computational complexity of predictions and/or the size of encoded datastreams, like encoded video sequences.
  • the coding system is or comprises a decoder or an encoder.
  • an encoder for encoding a video sequence using a weighting inter prediction process comprising:
  • the receiving unit is adapted to receive at least two weights that are to be used for obtaining a weighting parameter that is to be used in the weighting inter prediction process and to obtain a bit budget value, the bit budget value indicating a number of bits available for a weighting parameter obtained from the at least two weights;
  • the prediction unit is adapted to obtain a value of a dynamic range of the at least two weights and to obtain at least one predicted weighting parameter and to adjust a precision of the at least one weighting parameter, by right-shifting the value of the weighting parameter by a value that is equal to a difference between the value of the dynamic range and the bit budget value;
  • the encoding unit is adapted to encode the video sequence using the at least one predicted weighting parameter.
  • the prediction unit is adapted to include the predicted weighting parameter is in a look-up table, LUT. This allows for efficient provision of the predicted weighting parameter.
  • the encoder is adapted to provide the LUT in a header of the encoded video sequence.
  • the LUT can be obtained already when parsing the header of, for example, a slice of the encoded video sequence.
  • the value of the dynamic range depends on at least the maximum bit depth of the at least two weights.
  • the value of the dynamic range is the maximum bit depth of the at least two weights.
  • the prediction unit is adapted to obtain the maximum bit depth wherein wi and W2 are the at least two weights.
  • the prediction unit is adapted to not apply a right shifting if the maximum bit depth is equal to or smaller than the bit budget value. This reduces the computational complexity of preparing the encoded video sequence.
  • the prediction unit is adapted to obtain the value shift_norm of the right shifting by wherein log2(w max ) is the
  • maximum bit depth of the first and second weights and Tb is the bit budget value. This allows for computationally efficient obtaining of the shift_norm value.
  • the prediction unit is adapted to adjust the precision on a slice-level of the inter prediction process.
  • the at least two weights are position independent weights. Thereby, for example TPM becomes applicable.
  • the prediction unit is adapted to adjust the precision on a block-level of the inter prediction process. This can increase the encoding efficiency.
  • one of the at least two weights is a position independent weight and the other of the at least two weights is a position dependent weight.
  • a decoder for decoding a datastream representing an encoded video sequence comprising:
  • a receiving unit A decoding unit;
  • the receiving unit is adapted to receive the datastream, the datastream comprising at least two weights that are to be used for obtaining a weighting parameter to be used in the weighting inter prediction process and a bit budget value, the bit budget value indicating a number of bits available for a weighting parameter obtained from the at least two weights;
  • the decoding unit is adapted obtain a value of a dynamic range of the at least two weights and to obtain at least one predicted weighting parameter and to adjust a precision of the at least one weighting parameter, by right-shifting the value of the at least one weighting parameter by a value that is equal to a difference between the value of the dynamic range and the bit budget value;
  • the decoding unit is adapted to decode the encoded video sequence using the at least one predicted weighting parameter.
  • the decoding unit is adapted to obtain the at least two weights and/or the at least one predicted weighting parameter from a look-up table, LUT. Obtaining values from an LUT is computationally efficient.
  • the receiving unit is adapted to obtain the LUT from a header of the encoded video sequence.
  • the value of the dynamic range depends on at least the maximum bit depth of the at least two weights.
  • the value of the dynamic range can be the maximum bit depth of the at least two weights.
  • the decoding unit is adapted to obtain the maximum bit depth wherein w 1 and W 2 are the at least two weights.
  • the decoding unit is adapted to not apply a right shifting if the maximum bit depth is equal to or smaller than the bit budget value. This reduces the computational complexity in the decoding process.
  • the decoding unit is adapted to obtain the value shift_norm of the right shifting by wherein log2(w max ) is the
  • the decoding unit is adapted to adjust the precision on a slice-level of the inter prediction process. This provides the adjustment on a slice-level which can increase the computational efficiency.
  • the at least two weights are position independent weights. This does not necessarily mean that all weights of the at least two weights are position independent weights. In any case, this implementation can allows for implementing specific inter prediction processes like TPM.
  • the decoding unit is adapted to adjust the precision on a block-level of the inter prediction process. While this requires block-level specific information, this can improve the decoding quality.
  • one of the at least two weights is a position independent weight and the other of the at least two weights is a position dependent weight.
  • TPM can be applied for inter prediction.
  • a storage medium comprising instructions stored thereon that, when executing by a processing unit, cause the processing unit to perform a method for a weighting inter prediction process according to any of the above embodiments.
  • a method for a weighting inter prediction process comprising:
  • the weight value is selected from a look-up table, LUT.
  • LUT look-up table
  • an encoder comprising processing circuitry for carrying out the method according to any one of the above embodiments.
  • a decoder comprising processing circuitry for carrying out the method according to any one of the above embodiments.
  • a computer program product comprising program code for performing the method according to any one of the preceding embodiments when executed on a computer or a processor is provided.
  • a decoder comprising:
  • non-transitory storage medium coupled to the processors and storing programming for execution by the processors, wherein the programming, when executed by the processors, configures the decoder to carry out the method according to any one of the preceding embodiments.
  • an encoder comprising:
  • non-transitory storage medium coupled to the processors and storing programming for execution by the processors, wherein the programming, when executed by the processors, configures the encoder to carry out the method according to any one of the preceding embodiments.
  • an encoder for encoding a video sequence using a weighting inter prediction process comprising:
  • a receiving unit
  • the receiving unit is adapted to receive at least two weights that are to be used for obtaining a weighting parameter that is to be used in the weighting inter prediction process and to obtain a bit budget value, the bit budget value indicating a number of bits available for a weighting parameter obtained from the at least two weights; wherein the prediction unit is adapted to obtain a value of a dynamic range of the at least two weights and to obtain at least one predicted weighting parameter and to adjust a precision of the at least one weighting parameter, by right-shifting the value of the weighting parameter by a value that is equal to a difference between the value of the dynamic range and the bit budget value; wherein the encoding unit is adapted to encode the video sequence using the at least one predicted weighting parameter.
  • the prediction unit is adapted to include the predicted weighting parameter is in a look-up table, LUT.
  • the encoder is adapted to provide the LUT in a header of the encoded video sequence.
  • the value of the dynamic range depends on at least the maximum bit depth of the at least two weights.
  • the value of the dynamic range is the maximum bit depth of the at least two weights.
  • the prediction unit is adapted to not apply a right shifting if the maximum bit depth is equal to or smaller than the bit budget value.
  • the prediction unit is adapted to obtain the value shift_norm of the right shifting by s wherein log2(W max ) is the maximum bit depth of the first and second weights and Tb is the bit budget value.
  • the prediction unit is adapted to adjust the precision on a slice-level of the inter prediction process.
  • the at least two weights are position independent weights.
  • the prediction unit is adapted to adjust the precision on a block-level of the inter prediction process.
  • one of the at least two weights is a position independent weight and the other of the at least two weights is a position dependent weight.
  • a non-transitory medium carrying a program code which, when executed by a device, causes the device to perform the method of any one of the preceding embodiments is provided.
  • FIG. 1 A is a block diagram showing an example of a video coding system configured to implement embodiments of the invention
  • FIG. 1 B is a block diagram showing another example of a video coding system configured to implement embodiments of the invention
  • FIG. 2 is a block diagram showing an example of a video encoder configured to
  • FIG. 3 is a block diagram showing an example structure of a video decoder configured to implement embodiments of the invention
  • FIG. 4 is a block diagram illustrating an example of an encoding apparatus or a decoding apparatus
  • FIG. 5 is a block diagram illustrating another example of an encoding apparatus or a decoding apparatus
  • FIG. 6 is a flowchart for weighted prediction encoder-side decision making and parameter estimation
  • FIG. 7 is a diagram illustrating the proposed method applied to an inter-predicted block where triangular partitioning mode (TPM) is selected;
  • TPM triangular partitioning mode
  • FIG. 8 is a diagram illustrating of the proposed method applied to an inter-predicted block where geometric partitioning mode (GEO) is selected;
  • GEO geometric partitioning mode
  • FIG. 9 is a flowchart showing an embodiment of the proposed method where final
  • weights applied to prediction blocks are computed on the fly
  • FIG. 10 is a flowchart showing an embodiment of the proposed method where final
  • weights applied to prediction blocks are pre-calculated and stored into look-up tables
  • FIG. 11 is a block diagram showing an example structure of a content supply system 3100 which realizes a content delivery service
  • FIG. 12 is a block diagram showing a structure of an example of a terminal device
  • FIG. 13 is a block diagram showing an embodiment of the present invention.
  • FIG. 14 shows a block diagram of a method according to one embodiment
  • FIG. 15 shows a schematic depiction of an encoder according to one embodiment
  • FIG. 16 shows a schematic depiction of a decoder according to one embodiment.
  • a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa.
  • a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures.
  • a specific apparatus is described based on one or a plurality of units, e.g.
  • a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless specifically noted otherwise.
  • Video coding typically refers to the processing of a sequence of pictures, which form the video or video sequence. Instead of the term“picture” the term“frame” or“image” may be used as synonyms in the field of video coding.
  • Video coding (or coding in general) comprises two parts video encoding and video decoding. Video encoding is performed at the source side, typically comprising processing (e.g. by compression) the original video pictures to reduce the amount of data required for representing the video pictures (for more efficient storage and/or transmission). Video decoding is performed at the destination side and typically comprises the inverse processing compared to the encoder to reconstruct the video pictures.
  • Embodiments referring to“coding” of video pictures shall be understood to relate to“encoding” or“decoding” of video pictures or respective video sequences.
  • the combination of the encoding part and the decoding part is also referred to as CODEC (Coding and Decoding).
  • the original video pictures can be reconstructed, i.e. the reconstructed video pictures have the same quality as the original video pictures (assuming no transmission loss or other data loss during storage or transmission).
  • further compression e.g. by quantization, is performed, to reduce the amount of data representing the video pictures, which cannot be completely reconstructed at the decoder, i.e. the quality of the reconstructed video pictures is lower or worse compared to the quality of the original video pictures.
  • Video coding standards belong to the group of“lossy hybrid video codecs” (i.e. combine spatial and temporal prediction in the sample domain and 2D transform coding for applying quantization in the transform domain).
  • Each picture of a video sequence is typically partitioned into a set of non-overlapping blocks and the coding is typically performed on a block level.
  • the video is typically processed, i.e. encoded, on a block (video block) level, e.g.
  • the encoder duplicates the decoder processing loop such that both will generate identical predictions (e.g. intra- and inter predictions) and/or re-constructions for processing, i.e. coding, the subsequent blocks.
  • a video encoder 20 and a video decoder 30 are described based on Figs. 1 to 3.
  • Fig. 1A is a schematic block diagram illustrating an example coding system 10, e.g. a video coding system 10 (or short coding system 10) that may utilize techniques of this present application.
  • Video encoder 20 (or short encoder 20) and video decoder 30 (or short decoder 30) of video coding system 10 represent examples of devices that may be configured to perform techniques in accordance with various examples described in the present application.
  • the coding system 10 may comprise a source device 12 configured to provide encoded picture data 21 e.g. to a destination device 14 for decoding the encoded picture data 13.
  • the source device 12 may comprise an encoder 20, and may additionally, i.e. optionally, comprise a picture source 16, a pre-processor (or pre-processing unit) 18, e.g. a picture pre processor 18, and a communication interface or communication unit 22.
  • a pre-processor or pre-processing unit 18
  • a communication interface or communication unit 22 e.g. a communication interface or communication unit 22.
  • the picture source 16 may comprise or be any kind of picture capturing device, for example a camera for capturing a real-world picture, and/or any kind of a picture generating device, for example a computer-graphics processor for generating a computer animated picture, or any kind of other device for obtaining and/or providing a real-world picture, a computer generated picture (e.g. a screen content, a virtual reality (VR) picture) and/or any combination thereof (e.g. an augmented reality (AR) picture).
  • the picture source may be any kind of memory or storage storing any of the aforementioned pictures.
  • the picture or picture data 17 may also be referred to as raw picture or raw picture data 17.
  • Pre-processor 18 may be configured to receive the (raw) picture data 17 and to perform pre processing on the picture data 17 to obtain a pre-processed picture 19 or pre-processed picture data 19. Pre-processing performed by the pre-processor 18 may, e.g., comprise trimming, color format conversion (e.g. from RGB to YCbCr), color correction, or de-noising. It can be understood that the pre-processing unit 18 may be optional component.
  • the video encoder 20 may be configured to receive the pre-processed picture data 19 and provide encoded picture data 21 (further details will be described below, e.g., based on Fig. 2).
  • Communication interface 22 of the source device 12 may be configured to receive the encoded picture data 21 and to transmit the encoded picture data 21 (or any further processed version thereof) over communication channel 13 to another device, e.g. the destination device 14 or any other device, for storage or direct reconstruction.
  • the destination device 14 may comprise a decoder 30 (e.g. a video decoder 30), and may additionally, i.e. optionally, comprise a communication interface or communication unit 28, a post-processor 32 (or post-processing unit 32) and a display device 34.
  • the communication interface 28 of the destination device 14 may be configured receive the encoded picture data 21 (or any further processed version thereof), e.g. directly from the source device 12 or from any other source, e.g. a storage device, e.g. an encoded picture data storage device, and provide the encoded picture data 21 to the decoder 30.
  • a storage device e.g. an encoded picture data storage device
  • the communication interface 22 and the communication interface 28 may be configured to transmit or receive the encoded picture data 21 or encoded data 13 via a direct
  • the source device 12 and the destination device 14 e.g. a direct wired or wireless connection, or via any kind of network, e.g. a wired or wireless network or any combination thereof, or any kind of private and public network, or any kind of combination thereof.
  • the communication interface 22 may be, e.g., configured to package the encoded picture data 21 into an appropriate format, e.g. packets, and/or process the encoded picture data using any kind of transmission encoding or processing for transmission over a
  • the communication interface 28, forming the counterpart of the communication interface 22, may be, e.g., configured to receive the transmitted data and process the transmission data using any kind of corresponding transmission decoding or processing and/or de-packaging to obtain the encoded picture data 21.
  • Both, communication interface 22 and communication interface 28 may be configured as unidirectional communication interfaces as indicated by the arrow for the communication channel 13 in Fig. 1A pointing from the source device 12 to the destination device 14, or bi directional communication interfaces, and may be configured, e.g. to send and receive messages, e.g. to set up a connection, to acknowledge and exchange any other information related to the communication link and/or data transmission, e.g. encoded picture data transmission.
  • the decoder 30 may be configured to receive the encoded picture data 21 and provide decoded picture data 31 or a decoded picture 31 (further details will be described below, e.g., based on Fig. 3 or Fig. 5).
  • the post-processor 32 of destination device 14 may be configured to post-process the decoded picture data 31 (also called reconstructed picture data), e.g. the decoded picture 31 , to obtain post-processed picture data 33, e.g. a post-processed picture 33.
  • the post- processing performed by the post-processing unit 32 may comprise, e.g. color format conversion (e.g. from YCbCr to RGB), color correction, trimming, or re-sampling, or any other processing, e.g. for preparing the decoded picture data 31 for display, e.g. by display device 34.
  • the display device 34 of the destination device 14 may be configured to receive the post- processed picture data 33 for displaying the picture, e.g. to a user or viewer.
  • the display device 34 may be or comprise any kind of display for representing the reconstructed picture, e.g. an integrated or external display or monitor.
  • the displays may, e.g. comprise liquid crystal displays (LCD), organic light emitting diodes (OLED) displays, plasma displays, projectors , micro LED displays, liquid crystal on silicon (LCoS), digital light processor (DLP) or any kind of other display.
  • FIG. 1A depicts the source device 12 and the destination device 14 as separate devices
  • embodiments of devices may also comprise both or both functionalities, the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality.
  • 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 by separate hardware and/or software or any combination thereof.
  • the encoder 20 e.g. a video encoder 20
  • the decoder 30 e.g. a video decoder 30
  • both encoder 20 and decoder 30 may be implemented via processing circuitry as shown in Fig. 1 B, such as one or more microprocessors, digital signal processors (DSPs), application- specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware, video coding dedicated or any combinations thereof.
  • the encoder 20 may be implemented via processing circuitry 46 to embody the various modules as discussed with respect to encoder 20of FIG. 2 and/or any other encoder system or subsystem described herein.
  • the decoder 30 may be implemented via processing circuitry 46 to embody the various modules as discussed with respect to decoder 30 of FIG. 3 and/or any other decoder system or subsystem described herein.
  • the processing circuitry may be configured to perform the various operations as discussed later.
  • a device may store instructions for the software in a suitable, non-transitory computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the techniques of this disclosure.
  • Either of video encoder 20 and video decoder 30 may be integrated as part of a combined encoder/decoder (CODEC) in a single device, for example, as shown in Fig. 1 B.
  • CDEC combined encoder/decoder
  • Source device 12 and destination device 14 may comprise any of a wide range of devices, including any kind of handheld or stationary devices, e.g. notebook or laptop computers, mobile phones, smart phones, tablets or tablet computers, cameras, desktop computers, set-top boxes, televisions, display devices, digital media players, video gaming consoles, video streaming devices(such as content services servers or content delivery servers), broadcast receiver device, broadcast transmitter device, or the like and may use no or any kind of operating system.
  • the source device 12 and the destination device 14 may be equipped for wireless communication.
  • the source device 12 and the destination device 14 may be wireless communication devices.
  • video coding system 10 illustrated in Fig. 1A is merely an example and the techniques of the present application may apply to video coding settings (e.g., video encoding or video decoding) that do not necessarily include any data communication between the encoding and decoding devices.
  • data is retrieved from a local memory, streamed over a network, or the like.
  • a video encoding device may encode and store data to memory, and/or a video decoding device may retrieve and decode data from memory.
  • the encoding and decoding is performed by devices that do not communicate with one another, but simply encode data to memory and/or retrieve and decode data from memory.
  • the decoder and the encoder referred to above and referred to below may be implemented as any combination of software and/or hardware.
  • the decoder (or the encoder) can be realized by a plurality of software modules that realize, when interacting with hardware like a general purpose computer with associated processing circuitry and/or memory, the functionality of the decoder (or the encoder).
  • the decoder (or the encoder) may be implemented by software only that is adapted to realize the respective functionality by interaction with any general-purpose computer.
  • the decoder (or the encoder) may be realized by one or more specifically designed hardware components that realize the functionality of the decoder, for example when running software on these components.
  • the invention is in that sense not limited to a specific implementation of the encoder or the decoder.
  • HEVC High-Efficiency Video Coding
  • VVC Versatile Video coding
  • JCT-VC Joint Collaboration Team on Video Coding
  • VCEG ITU-T Video Coding Experts Group
  • MPEG ISO/IEC Motion Picture Experts Group
  • Fig. 2 shows a schematic block diagram of an example video encoder 20 that is configured to implement the techniques of the present application.
  • the video encoder 20 comprises an input 201 (or input interface 201), a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, and inverse transform processing unit 212, a reconstruction unit 214, a loop filter unit 220, a decoded picture buffer (DPB) 230, a mode selection unit 260, an entropy encoding unit 270 and an output 272 (or output interface 272).
  • the mode selection unit 260 may include an inter prediction unit 244, an intra prediction unit 254 and a partitioning unit 262.
  • Inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown).
  • a video encoder 20 as shown in Fig. 2 may also be referred to as hybrid video encoder or a video encoder according to a hybrid video codec.
  • the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the mode selection unit 260 may be referred to as forming a forward signal path of the encoder 20, whereas 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 (DPB) 230, the inter prediction unit 244 and the intra-prediction unit 254 may be referred to as forming a backward signal path of the video encoder 20, wherein the backward signal path of the video encoder 20 corresponds to the signal path of the decoder (see video decoder 30 in Fig. 3).
  • the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244 and the intra-prediction unit 254 are also referred to forming the“built-in decoder” of video encoder 20.
  • the encoder 20 may be configured to receive, e.g. via input 201 , a picture 17 (or picture data 17), e.g. picture of a sequence of pictures forming a video or video sequence.
  • the received picture or picture data may also be a pre-processed picture 19 (or pre-processed picture data 19).
  • the picture 17 may also be referred to as current picture or picture to be coded (in particular in video coding to distinguish the current picture from other pictures, e.g. previously encoded and/or decoded pictures of the same video sequence, i.e. the video sequence which also comprises the current picture).
  • a (digital) picture is or can be regarded as a two-dimensional array or matrix of samples with intensity values.
  • a sample in the array may also be referred to as pixel (short form of picture element) or a pel.
  • the number of samples in horizontal and vertical direction (or axis) of the array or picture define the size and/or resolution of the picture.
  • typically three color components are employed, i.e. the picture may be represented or include three sample arrays.
  • a picture comprises a
  • each pixel is typically represented in a luminance and chrominance format or color space, e.g. YCbCr, which comprises a luminance component indicated by Y (sometimes also L is used instead) and two chrominance components indicated by Cb and Cr.
  • the luminance (or short luma) component Y represents the brightness or grey level intensity (e.g. like in a grey-scale picture), while the two chrominance (or short chroma) components Cb and Cr represent the chromaticity or color information components.
  • a picture in YCbCr format comprises a luminance sample array of luminance sample values (Y), and two chrominance sample arrays of chrominance values (Cb and Cr).
  • Pictures in RGB format may be converted or transformed into YCbCr format and vice versa, the process is also known as color transformation or conversion.
  • a picture is monochrome, the picture may comprise only a luminance sample array.
  • a picture may be, for example, an array of luma samples in monochrome format or an array of luma samples and two corresponding arrays of chroma samples in 4:2:0, 4:2:2, and 4:4:4 colour format.
  • Embodiments of the video encoder 20 may comprise a picture partitioning unit (not depicted in Fig. 2) configured to partition the picture 17 into a plurality of (typically non-overlapping) picture blocks 203. These blocks may also be referred to as root blocks, macro blocks (H.264/A VC) or coding tree blocks (CTB) or coding tree units (CTU) (H.265/HEVC and VVC).
  • the picture partitioning unit may be configured to use the same block size for all pictures of a video sequence and the corresponding grid defining the block size, or to change the block size between pictures or subsets or groups of pictures, and partition each picture into the corresponding blocks.
  • the video encoder may be configured to receive directly a block 203 of the picture 17, e.g. one, several or all blocks forming the picture 17.
  • the picture block 203 may also be referred to as current picture block or picture block to be coded.
  • the picture block 203 again is or can be regarded as a two-dimensional array or matrix of samples with intensity values (sample values), although of smaller dimension than the picture 17.
  • the block 203 may comprise, e.g., one sample array (e.g. a luma array in case of a monochrome picture 17, or a luma or chroma array in case of a color picture) or three sample arrays (e.g. a luma and two chroma arrays in case of a color picture 17) or any other number and/or kind of arrays depending on the color format applied.
  • the number of samples in horizontal and vertical direction (or axis) of the block 203 define the size of block 203.
  • a block may, for example, an MxN (M-column by N-row) array of samples, or an MxN array of transform coefficients.
  • N M e N.
  • This two-dimensional array may have arbitrary size.
  • N may be equal to M, resulting in a square matrix.
  • M 1 N so that a general rectangle is obtained for the two- dimensional array.
  • M and N may take any values.
  • Embodiments of the video encoder 20 as shown in Fig. 2 may be configured to encode the picture 17 block by block, e.g. the encoding and prediction is performed per block 203.
  • Embodiments of the video encoder 20 as shown in Fig. 2 may be further configured to partition and/or encode the picture by using slices (also referred to as video slices), wherein a picture may be partitioned into or encoded using one or more slices (typically non overlapping), and each slice may comprise one or more blocks (e.g. CTUs).
  • slices also referred to as video slices
  • each slice may comprise one or more blocks (e.g. CTUs).
  • Embodiments of the video encoder 20 as shown in Fig. 2 may be further configured to partition and/or encode the picture by using tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles), wherein a picture may be partitioned into or encoded using one or more tile groups (typically non-overlapping), and each tile group may comprise, e.g. one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile, e.g. may be of rectangular shape and may comprise one or more blocks (e.g. CTUs), e.g.
  • tile groups also referred to as video tile groups
  • tiles also referred to as video tiles
  • each tile group may comprise, e.g. one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile, e.g. may be of rectangular shape and may comprise one or more blocks (e.g. CTUs), e.g.
  • the residual calculation unit 204 may be configured to calculate a residual block 205 (also referred to as residual 205) based on the picture block 203 and a prediction block 265 (further details about the prediction block 265 are provided later), e.g. by subtracting sample values of the prediction block 265 from sample values of the picture block 203, sample by sample (pixel by pixel) to obtain the residual block 205 in the sample domain.
  • a residual block 205 also referred to as residual 205
  • a prediction block 265 further details about the prediction block 265 are provided later
  • the transform processing unit 206 may be configured to apply a transform, e.g. a discrete cosine transform (DCT) or discrete sine transform (DST), on the sample values of the residual block 205 to obtain transform coefficients 207 in a transform domain.
  • a transform e.g. a discrete cosine transform (DCT) or discrete sine transform (DST)
  • DCT discrete cosine transform
  • DST discrete sine transform
  • the transform processing unit 206 may be configured to apply integer approximations of DCT/DST, such as the transforms specified for H.265/HEVC. Compared to an orthogonal DCT transform, such integer approximations are typically scaled by a certain factor. In order to preserve the norm of the residual block which is processed by forward and inverse transforms, additional scaling factors are applied as part of the transform process.
  • the scaling factors are typically chosen based on certain constraints like scaling factors being a power of two for shift operations, bit depth of the transform coefficients, tradeoff between accuracy and implementation costs, etc. Specific scaling factors are, for example, specified for the inverse transform, e.g. by inverse transform processing unit 212 (and the
  • corresponding inverse transform e.g. by inverse transform processing unit 312 at video decoder 30
  • corresponding scaling factors for the forward transform e.g. by transform processing unit 206, at an encoder 20 may be specified accordingly.
  • Embodiments of the video encoder 20 may be configured to output transform parameters, e.g. a type of transform or transforms, e.g.
  • the video decoder 30 may receive and use the transform parameters for decoding.
  • the quantization unit 208 may be configured to quantize the transform coefficients 207 to obtain quantized coefficients 209, e.g. by applying scalar quantization or vector quantization.
  • the quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.
  • the quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, an n-bit transform coefficient may be rounded down to an m-bit Transform coefficient during quantization, where n is greater than m.
  • the degree of quantization may be modified by adjusting a quantization parameter (QP). For example for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, whereas larger quantization step sizes correspond to coarser quantization.
  • the applicable quantization step size may be indicated by a quantization parameter (QP).
  • the quantization parameter may for example be an index to a predefined set of applicable quantization step sizes. For example, small quantization parameters may correspond to fine quantization (small quantization step sizes) and large quantization parameters may correspond to coarse quantization (large
  • the quantization may include division by a
  • quantization step size and a corresponding and/or the inverse dequantization may include multiplication by the quantization step size.
  • Embodiments according to some standards may be configured to use a quantization parameter to determine the quantization step size.
  • the quantization step size may be calculated based on a quantization parameter using a fixed point approximation of an equation including division. Additional scaling factors may be introduced for quantization and dequantization to restore the norm of the residual block, which might get modified because of the scaling used in the fixed point approximation of the equation for quantization step size and quantization parameter.
  • the scaling of the inverse transform and dequantization might be combined.
  • customized quantization tables may be used and signaled from an encoder to a decoder, e.g. in a bitstream.
  • the quantization is a lossy operation, wherein the loss increases with increasing quantization step sizes.
  • the inverse quantization unit 210 is configured to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain dequantized coefficients 211 , e.g. by applying the inverse 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 and correspond - although typically not identical to the transform coefficients due to the loss by quantization - to the transform coefficients 207.
  • the inverse transform processing unit 212 is configured to apply the inverse transform of the transform applied by the transform processing unit 206, e.g. an inverse discrete cosine transform (DCT) or inverse discrete sine transform (DST) or other inverse transforms, to obtain a reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample domain.
  • the reconstructed residual block 213 may also be referred to as transform block 213.
  • the reconstruction unit 214 (e.g. adder or summer 214) is configured to add the transform block 213 (i.e. reconstructed residual block 213) to the prediction block 265 to obtain a reconstructed block 215 in the sample domain, e.g. by adding - sample by sample - the sample values of the reconstructed residual block 213 and the sample values of the prediction block 265.
  • the loop filter unit 220 (or short“loop filter” 220), is configured to filter the reconstructed block 215 to obtain a filtered block 221 , or in general, to filter reconstructed samples to obtain filtered samples.
  • the loop filter unit is, e.g., configured to smooth pixel transitions, or otherwise improve the video quality.
  • the loop filter unit 220 may comprise one or more loop filters such as a de-blocking filter, a sample-adaptive offset (SAO) filter or one or more other filters, e.g. a bilateral filter, an adaptive loop filter (ALF), a sharpening, a smoothing filters or a collaborative filters, or any combination thereof.
  • the loop filter unit 220 is shown in FIG. 2 as being an in loop filter, in other configurations, the loop filter unit 220 may be implemented as a post loop filter.
  • the filtered block 221 may also be referred to as filtered reconstructed block 221.
  • Embodiments of the video encoder 20 may be configured to output loop filter parameters (such as sample adaptive offset information), e.g. directly or encoded via the entropy encoding unit 270, so that, e.g., a decoder 30 may receive and apply the same loop filter parameters or respective loop filters for decoding.
  • loop filter parameters such as sample adaptive offset information
  • the decoded picture buffer (DPB) 230 may be a memory that stores reference pictures, or in general reference picture data, for encoding video data by video encoder 20.
  • the DPB 230 may be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices.
  • DRAM dynamic random access memory
  • SDRAM synchronous DRAM
  • MRAM magnetoresistive RAM
  • RRAM resistive RAM
  • the decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221.
  • the decoded picture buffer 230 may be further configured to store other previously filtered blocks, e.g. previously reconstructed and filtered blocks 221 , of the same current picture or of different pictures, e.g.
  • the decoded picture buffer (DPB) 230 may be also configured to store one or more unfiltered reconstructed blocks 215, or in general unfiltered
  • reconstructed samples e.g. if the reconstructed block 215 is not filtered by loop filter unit 220, or any other further processed version of the reconstructed blocks or samples.
  • the mode selection unit 260 comprises partitioning unit 262, inter-prediction unit 244 and intra-prediction unit 254, and is configured to receive or obtain original picture data, e.g. an original block 203 (current block 203 of the current picture 17), and reconstructed picture data, e.g. filtered and/or unfiltered reconstructed samples or blocks of the same (current) picture and/or from one or a plurality of previously decoded pictures, e.g. from decoded picture buffer 230 or other buffers (e.g. line buffer, not shown).
  • the reconstructed picture data is used as reference picture data for prediction, e.g. inter-prediction or intra-prediction, to obtain a prediction block 265 or predictor 265.
  • Mode selection unit 260 may be configured to determine or select a partitioning for a current block prediction mode (including no partitioning) and a prediction mode (e.g. an intra or inter prediction mode) and generate a corresponding prediction block 265, which is used for the calculation of the residual block 205 and for the reconstruction of the reconstructed block 215.
  • Embodiments of the mode selection unit 260 may be configured to select the partitioning and the prediction mode (e.g. from those supported by or available for mode selection unit 260), which provide the best match or in other words the minimum residual (minimum residual means better compression for transmission or storage), or a minimum signaling overhead (minimum signaling overhead means better compression for transmission or storage), or which considers or balances both.
  • the mode selection unit 260 may be configured to determine the partitioning and prediction mode based on rate distortion optimization (RDO), i.e. select the prediction mode which provides a minimum rate distortion.
  • RDO rate distortion optimization
  • Terms like“best”, “minimum”,“optimum” etc. in this context do not necessarily refer to an overall“best”, “minimum”,“optimum”, etc. but may also refer to the fulfillment of a termination or selection criterion like a value exceeding or falling below a threshold or other constraints leading potentially to a“sub-optimum selection” but reducing complexity and processing time.
  • the partitioning unit 262 may be configured to partition the block 203 into smaller block partitions or sub-blocks (which form again blocks), e.g. iteratively using quad- tree-partitioning (QT), binary partitioning (BT) or triple-tree-partitioning (TT) or any combination thereof, and to perform, e.g., the prediction for each of the block partitions or sub-blocks, wherein the mode selection comprises the selection of the tree-structure of the partitioned block 203 and the prediction modes are applied to each of the block partitions or sub-blocks.
  • QT quad- tree-partitioning
  • BT binary partitioning
  • TT triple-tree-partitioning
  • partitioning e.g. by partitioning unit 260
  • prediction processing by inter-prediction unit 244 and intra-prediction unit 254
  • the partitioning unit 262 may partition (or split) a current block 203 into smaller partitions, e.g. smaller blocks of square or rectangular size. These smaller blocks (which may also be referred to as sub-blocks) may be further partitioned into even smaller partitions.
  • This is also referred to tree-partitioning or hierarchical tree-partitioning, wherein a root block, e.g. at root tree-level 0 (hierarchy-level 0, depth 0), may be recursively partitioned, e.g. partitioned into two or more blocks of a next lower tree-level, e.g.
  • nodes at tree-level 1 (hierarchy-level 1 , depth 1), wherein these blocks may be again partitioned into two or more blocks of a next lower level, e.g. tree-level 2 (hierarchy-level 2, depth 2), etc. until the partitioning is terminated, e.g. because a termination criterion is fulfilled, e.g. a maximum tree depth or minimum block size is reached.
  • Blocks which are not further partitioned are also referred to as leaf-blocks or leaf nodes of the tree.
  • a tree using partitioning into two partitions is referred to as binary-tree (BT)
  • BT binary-tree
  • TT ternary- tree
  • QT quad-tree
  • the term“block” as used herein may be a portion, in particular a square or rectangular portion, of a picture.
  • the block may be or correspond to a coding tree unit (CTU), a coding unit (CU), prediction unit (PU), and transform unit (TU) and/or to the corresponding blocks, e.g. a coding tree block (CTB), a coding block (CB), a transform block (TB) or prediction block (PB).
  • CTU coding tree unit
  • CU coding unit
  • PU prediction unit
  • TU transform unit
  • a coding tree block CB
  • CB coding block
  • TB transform block
  • PB prediction block
  • a coding tree unit may be or comprise a CTB of luma samples, two corresponding CTBs of chroma samples of a picture that has three sample arrays, or a CTB of samples of a monochrome picture or a picture that is coded using three separate colour planes and syntax structures used to code the samples.
  • a coding tree block may be an NxN block of samples for some value of N such that the division of a component into CTBs is a partitioning.
  • a coding unit may be or comprise a coding block of luma samples, two corresponding coding blocks of chroma samples of a picture that has three sample arrays, or a coding block of samples of a monochrome picture or a picture that is coded using three separate colour planes and syntax structures used to code the samples.
  • a coding block may be an MxN block of samples for some values of M and N such that the division of a CTB into coding blocks is a partitioning.
  • a coding tree unit may be split into CUs by using a quad-tree structure denoted as coding tree.
  • the decision whether to code a picture area using inter-picture (temporal) or intra-picture (spatial) prediction is made at the CU level.
  • Each CU can be further split into one, two or four PUs according to the PU splitting type. Inside one PU, the same prediction process is applied and the relevant information is transmitted to the decoder on a PU basis.
  • a CU can be partitioned into transform units (TUs) according to another quadtree structure similar to the coding tree for the CU.
  • a combined Quad-tree and binary tree (QTBT) partitioning is for example used to partition a coding block.
  • a CU can have either a square or rectangular shape.
  • a coding tree unit (CTU) is first partitioned by a quadtree structure.
  • the quadtree leaf nodes are further partitioned by a binary tree or ternary (or triple) tree structure.
  • the partitioning tree leaf nodes are called coding units (CUs), and that segmentation is used for prediction and transform processing without any further partitioning.
  • CUs coding units
  • multiple partition for example, triple tree partition may be used together with the QTBT block structure.
  • the mode selection unit 260 of video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.
  • the video encoder 20 is configured to determine or select the best or an optimum prediction mode from a set of (e.g. pre-determined) prediction modes.
  • the set of prediction modes may comprise, e.g., intra-prediction modes and/or inter-prediction modes.
  • the set of intra-prediction modes may comprise 35 different intra-prediction modes, e.g. non-directional modes like DC (or mean) mode and planar mode, or directional modes, e.g. as defined in HEVC, or may comprise 67 different intra-prediction modes, e.g. non- directional modes like DC (or mean) mode and planar mode, or directional modes, e.g. as defined for VVC.
  • intra-prediction modes e.g. non-directional modes like DC (or mean) mode and planar mode
  • directional modes e.g. as defined for VVC.
  • the intra-prediction unit 254 is configured to use reconstructed samples of neighboring blocks of the same current picture to generate an intra-prediction block 265 according to an intra-prediction mode of the set of intra-prediction modes.
  • the intra prediction unit 254 (or in general the mode selection unit 260) is further configured to output intra-prediction parameters (or in general information indicative of the selected intra prediction mode for the block) to the entropy encoding unit 270 in form of syntax
  • the video decoder 30 may receive and use the prediction parameters for decoding.
  • the set of (or possible) inter-prediction modes depends on the available reference pictures (i.e. previous at least partially decoded pictures, e.g. stored in DBP 230) and other inter prediction parameters, e.g. whether the whole reference picture or only a part, e.g. a search window area around the area of the current block, of the reference picture is used for searching for a best matching reference block, and/or e.g. whether pixel interpolation is applied, e.g. half/semi-pel and/or quarter-pel interpolation, or not.
  • inter prediction parameters e.g. whether the whole reference picture or only a part, e.g. a search window area around the area of the current block, of the reference picture is used for searching for a best matching reference block, and/or e.g. whether pixel interpolation is applied, e.g. half/semi-pel and/or quarter-pel interpolation, or not.
  • the inter prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (both not shown in Fig.2).
  • the motion estimation unit may be configured to receive or obtain the picture block 203 (current picture block 203 of the current picture 17) and a decoded picture 231 , or at least one or a plurality of previously
  • reconstructed blocks e.g. reconstructed blocks of one or a plurality of other/different previously decoded pictures 231 , for motion estimation.
  • a video sequence may comprise the current picture and the previously decoded pictures 231 , or in other words, the current picture and the previously decoded pictures 231 may be part of or form a sequence of pictures forming a video sequence.
  • the encoder 20 may, e.g., be configured to select a reference block from a plurality of reference blocks of the same or different pictures of the plurality of other pictures and provide a reference picture (or reference picture index) and/or an offset (spatial offset) between the position (x, y coordinates) of the reference block and the position of the current block as inter prediction parameters to the motion estimation unit.
  • This offset is also called motion vector (MV).
  • the motion compensation unit is configured to obtain, e.g. receive, an inter prediction parameter and to perform inter prediction based on or using the inter prediction parameter to obtain an inter prediction block 265.
  • Motion compensation performed by the motion compensation unit, may involve fetching or generating the prediction block based on the motion/block vector determined by motion estimation, possibly performing interpolations to sub-pixel precision. Interpolation filtering may generate additional pixel samples from known pixel samples, thus potentially increasing the number of candidate prediction blocks that may be used to code a picture block.
  • the motion compensation unit may locate the prediction block to which the motion vector points in one of the reference picture lists.
  • the motion compensation unit may also generate syntax elements associated with the blocks and video slices for use by video decoder 30 in decoding the picture blocks of the video slice.
  • syntax elements associated with the blocks and video slices for use by video decoder 30 in decoding the picture blocks of the video slice.
  • tile groups and/or tiles and respective syntax elements may be generated or used.
  • the entropy encoding unit 270 is configured to apply, for example, an entropy encoding algorithm or scheme (e.g. a variable length coding (VLC) scheme, an context adaptive VLC scheme (CAVLC), an arithmetic coding scheme, a binarization, a context adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding or another entropy encoding methodology or technique) or bypass (no compression) on the quantized coefficients 209, inter prediction parameters, intra prediction parameters, loop filter parameters and/or other syntax elements to obtain encoded picture data 21 which can be output via the output 272, e.g.
  • an entropy encoding algorithm or scheme e.g. a variable length coding (VLC) scheme, an context adaptive VLC scheme (CAVLC), an arithmetic coding scheme, a binarization, a context adaptive binary a
  • an encoded bitstream 21 in the form of an encoded bitstream 21 , so that, e.g., the video decoder 30 may receive and use the parameters for decoding, .
  • the encoded bitstream 21 may be transmitted to video decoder 30, or stored in a memory for later transmission or retrieval by video decoder 30.
  • a non-transform based encoder 20 can quantize the residual signal directly without the transform processing unit 206 for certain blocks or frames.
  • an encoder 20 can have the quantization unit 208 and the inverse quantization unit 210 combined into a single unit.
  • Fig. 3 shows an example of a video decoder 30 that is configured to implement the techniques of this present application.
  • the video decoder 30 is configured to receive encoded picture data 21 (e.g. encoded bitstream 21), e.g. encoded by encoder 20, to obtain a decoded picture 331.
  • the encoded picture data or bitstream comprises information for decoding the encoded picture data, e.g. data that represents picture blocks of an encoded video slice (and/or tile groups or tiles) and associated syntax elements.
  • the decoder 30 comprises an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g. a summer 314), a loop filter 320, a decoded picture buffer (DBP) 330, a mode application unit 360, an inter prediction unit 344 and an intra prediction unit 354.
  • Inter prediction unit 344 may be or include a motion compensation unit.
  • Video decoder 30 may, in some examples, perform a decoding pass generally reciprocal to the encoding pass described with respect to video encoder 100 from FIG. 2.
  • the inverse quantization unit 210 may be identical in function to the inverse quantization unit 110
  • the inverse transform processing unit 312 may be identical in function to the inverse transform processing unit 212
  • the reconstruction unit 314 may be identical in function to reconstruction unit 214
  • the loop filter 320 may be identical in function to the loop filter 220
  • the decoded picture buffer 330 may be identical in function to the decoded picture buffer 230. Therefore, the explanations provided for the respective units and functions of the video 20 encoder apply correspondingly to the respective units and functions of the video decoder 30.
  • the entropy decoding unit 304 is configured to parse the bitstream 21 (or in general encoded picture data 21) and perform, for example, entropy decoding to the encoded picture data 21 to obtain, e.g., quantized coefficients 309 and/or decoded coding parameters (not shown in Fig. 3), e.g. any or all of inter prediction parameters (e.g. reference picture index and motion vector), intra prediction parameter (e.g. intra prediction mode or index), transform parameters, quantization parameters, loop filter parameters, and/or other syntax elements.
  • Entropy decoding unit 304 maybe configured to apply the decoding algorithms or schemes corresponding to the encoding schemes as described with regard to the entropy encoding unit 270 of the encoder 20.
  • Entropy decoding unit 304 may be further configured to provide inter prediction parameters, intra prediction parameter and/or other syntax elements to the mode application unit 360 and other parameters to other units of the decoder 30.
  • Video decoder 30 may receive the syntax elements at the video slice level and/or the video block level.
  • tile groups and/or tiles and respective syntax elements may be received and/or used.
  • the inverse quantization unit 310 may be configured to receive quantization parameters (QP) (or in general information related to the inverse quantization) and quantized coefficients from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) and to apply based on the quantization parameters an inverse quantization on the decoded quantized coefficients 309 to obtain dequantized coefficients 311 , which may also be referred to as transform coefficients 311.
  • the inverse quantization process may include use of a quantization parameter determined by video encoder 20 for each video block in the video slice (or tile or tile group) to determine a degree of quantization and, likewise, a degree of inverse quantization that should be applied.
  • QP quantization parameters
  • quantized coefficients from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) and to apply based on the quantization parameters an inverse quantization
  • Inverse transform processing unit 312 may be configured to receive dequantized coefficients 311 , also referred to as transform coefficients 311 , and to apply a transform to the dequantized coefficients 311 in order to obtain reconstructed residual blocks 213 in the sample domain.
  • the reconstructed residual blocks 213 may also be referred to as transform blocks 313.
  • the transform may be an inverse transform, e.g., an inverse DCT, an inverse DST, an inverse integer transform, or a conceptually similar inverse transform process.
  • the inverse transform processing unit 312 may be further configured to receive transform parameters or corresponding information from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) to determine the transform to be applied to the dequantized coefficients 311.
  • the reconstruction unit 314 (e.g. adder or summer 314) may be configured to add the reconstructed residual block 313, to the prediction block 365 to obtain a reconstructed block 315 in the sample domain, e.g. by adding the sample values of the reconstructed residual block 313 and the sample values of the prediction block 365.
  • the loop filter unit 320 (either in the coding loop or after the coding loop) is configured to filter the reconstructed block 315 to obtain a filtered block 321 , e.g. to smooth pixel transitions, or otherwise improve the video quality.
  • the loop filter unit 320 may comprise one or more loop filters such as a de-blocking filter, a sample-adaptive offset (SAO) filter or one or more other filters, e.g. a bilateral filter, an adaptive loop filter (ALF), a sharpening, a smoothing filters or a collaborative filters, or any combination thereof.
  • the loop filter unit 320 is shown in FIG. 3 as being an in loop filter, in other configurations, the loop filter unit 320 may be implemented as a post loop filter.
  • decoded video blocks 321 of a picture are then stored in decoded picture buffer 330, which stores the decoded pictures 331 as reference pictures for subsequent motion compensation for other pictures and/or for output respectively display.
  • the decoder 30 is configured to output the decoded picture 311 , e.g. via output 312, for presentation or viewing to a user. Prediction
  • the inter prediction unit 344 may be identical to the inter prediction unit 244 (in particular to the motion compensation unit) and the intra prediction unit 354 may be identical to the inter prediction unit 254 in function, and performs split or partitioning decisions and prediction based on the partitioning and/or prediction parameters or respective information received from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304).
  • Mode application unit 360 may be configured to perform the prediction (intra or inter prediction) per block based on reconstructed pictures, blocks or respective samples (filtered or unfiltered) to obtain the prediction block 365.
  • intra prediction unit 354 of mode application unit 360 is configured to generate prediction block 365 for a picture block of the current video slice based on a signaled intra prediction mode and data from previously decoded blocks of the current picture.
  • inter prediction unit 344 e.g. motion compensation unit
  • the prediction blocks may be produced from one of the reference pictures within one of the reference picture lists.
  • Video decoder 30 may construct the reference frame lists, List 0 and List 1 , using default construction techniques based on reference pictures stored in DPB 330. The same or similar may be applied for or by embodiments using tile groups (e.g. video tile groups) and/or tiles (e.g. video tiles) in addition or alternatively to slices (e.g. video slices), e.g. a video may be coded using I, P or B tile groups and /or tiles.
  • tile groups e.g. video tile groups
  • tiles e.g. video tiles
  • slices e.g. video slices
  • Mode application unit 360 is configured to determine the prediction information for a video block of the current video slice by parsing the motion vectors or related information and other syntax elements, and uses the prediction information to produce the prediction blocks for the current video block being decoded. For example, the mode application unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction) used to code the video blocks of the video slice, an inter prediction slice type (e.g., B slice, P slice, or GPB slice), construction information for one or more of the reference picture lists for the slice, motion vectors for each inter encoded video block of the slice, inter prediction status for each inter coded video block of the slice, and other information to decode the video blocks in the current video slice.
  • a prediction mode e.g., intra or inter prediction
  • an inter prediction slice type e.g., B slice, P slice, or GPB slice
  • construction information for one or more of the reference picture lists for the slice motion vectors for each inter encoded video block of the slice, inter prediction status for each
  • tile groups e.g. video tile groups
  • tiles e.g. video tiles
  • slices e.g. video slices
  • Embodiments of the video decoder 30 as shown in Fig. 3 may be configured to partition and/or decode the picture by using slices (also referred to as video slices), wherein a picture may be partitioned into or decoded using one or more slices (typically non-overlapping), and each slice may comprise one or more blocks (e.g. CTUs).
  • slices also referred to as video slices
  • each slice may comprise one or more blocks (e.g. CTUs).
  • Embodiments of the video decoder 30 as shown in Fig. 3 may be configured to partition and/or decode the picture by using tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles), wherein a picture may be partitioned into or decoded using one or more tile groups (typically non-overlapping), and each tile group may comprise, e.g. one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile, e.g. may be of rectangular shape and may comprise one or more blocks (e.g. CTUs), e.g. complete or fractional blocks.
  • tile groups also referred to as video tile groups
  • tiles also referred to as video tiles
  • each tile group may comprise, e.g. one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile, e.g. may be of rectangular shape and may comprise one or more blocks (e.g. CTUs), e.g. complete or fractional blocks.
  • the video decoder 30 can be used to decode the encoded picture data 21.
  • the decoder 30 can produce the output video stream without the loop filtering unit 320.
  • a non-transform based decoder 30 can inverse-quantize the residual signal directly without the inverse-transform processing unit 312 for certain blocks or frames.
  • the video decoder 30 can have the inverse-quantization unit 310 and the inverse-transform processing unit 312 combined into a single unit.
  • a processing result of a current step may be further processed and then output to the next step.
  • a further operation such as Clip or shift, may be performed on the processing result of the interpolation filtering, motion vector derivation or loop filtering.
  • the value of motion vector is constrained to a predefined range according to its representing bit. If the representing bit of motion vector is bitDepth, then the range is - 2 A (bitDepth-1) ⁇ 2 A (bitDepth-1)-1 , where“ A ” means exponentiation. For example, if bitDepth is set equal to 16, the range is -32768 ⁇ 32767; if bitDepth is set equal to 18, the range is - 131072-131071.
  • the value of the derived motion vector (e.g. the MVs of four 4x4 sub-blocks within one 8x8 block) is constrained such that the max difference between integer parts of the four 4x4 sub-block MVs is no more than N pixels, such as no more than 1 pixel.
  • N pixels such as no more than 1 pixel.
  • mvx is a horizontal component of a motion vector of an image block or a sub-block
  • mvy is a vertical component of a motion vector of an image block or a sub-block
  • ux and uy indicates an intermediate value
  • decimal numbers are stored as two’s complement.
  • the two’s complement of -32769 is 1,0111,1111,1111,1111 (17 bits), then the MSB is discarded, so the resulting two’s complement is 0111,1111,1111,1111 (decimal number is 32767), which is same as the output by applying formula (1) and (2).
  • the operations may be applied during the sum of mvp and mvd, as shown in formula (5) to (8).
  • vx is a horizontal component of a motion vector of an image block or a sub-block
  • vy is a vertical component of a motion vector of an image block or a sub-block
  • x, y and z respectively correspond to three input value of the MV clipping process, and the definition of function Clip3 is as follow:
  • FIG. 4 is a schematic diagram of a video coding device 400 according to an embodiment of the disclosure.
  • the video coding device 400 is suitable for implementing the disclosed embodiments as described herein.
  • the video coding device 400 may be a decoder such as video decoder 30 of FIG. 1 A or an encoder such as video encoder 20 of FIG. 1A.
  • the video coding device 400 comprises ingress ports 410 (or input ports 410) and receiver units (Rx) 420 for receiving data; a processor, logic unit, or central processing unit (CPU) 430 to process the data; transmitter units (Tx) 440 and egress ports 450 (or output ports 450) for transmitting the data; and a memory 460 for storing the data.
  • the video coding device 400 may also comprise optical-to-electrical (OE) components and electrical-to-optical (EO) components coupled to the ingress ports 410, the receiver units 420, the transmitter units 440, and the egress ports 450 for egress or ingress of optical or electrical signals.
  • OE optical-to-electrical
  • EO electrical-to-optical
  • the processor 430 is implemented by hardware and software.
  • the processor 430 may be implemented as one or more CPU chips, cores (e.g., as a multi-core processor), FPGAs, ASICs, and DSPs.
  • the processor 430 is in communication with the ingress ports 410, receiver units 420, transmitter units 440, egress ports 450, and memory 460.
  • the processor 430 comprises a coding module 470.
  • the coding module 470 implements the disclosed embodiments described above. For instance, the coding module 470 implements, processes, prepares, or provides the various coding operations. The inclusion of the coding module 470 therefore provides a substantial improvement to the functionality of the video coding device 400 and effects a transformation of the video coding device 400 to a different state.
  • the coding module 470 is implemented as instructions stored in the memory 460 and executed by the processor 430.
  • the memory 460 may comprise one or more disks, tape drives, and solid-state drives and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution.
  • the memory 460 may be, for example, volatile and/or non-volatile and may be a read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and/or static random-access memory (SRAM).
  • 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 from Fig. 1 according to an exemplary embodiment.
  • a processor 502 in the apparatus 500 can be a central processing unit.
  • the processor 502 can be any other type of device, or multiple devices, capable of manipulating or processing information now-existing or hereafter developed.
  • the disclosed implementations can be practiced with a single processor as shown, e.g., the processor 502, advantages in speed and efficiency can be achieved using more than one processor.
  • a memory 504 in the apparatus 500 can be a read only memory (ROM) device or a random access memory (RAM) device in an implementation. Any other suitable type of storage device can be used as the memory 504.
  • the memory 504 can include code and data 506 that is accessed by the processor 502 using a bus 512.
  • the memory 504 can further include an operating system 508 and application programs 510, the application programs 510 including at least one program that permits the processor 502 to perform the methods described here.
  • the application programs 510 can include applications 1 through N, which further include a video coding application that performs the methods described here.
  • the apparatus 500 can also include one or more output devices, such as a display 518.
  • the display 518 may be, in one example, a touch sensitive display that combines a display with a touch sensitive element that is operable to sense touch inputs.
  • the display 518 can be coupled to the processor 502 via the bus 512.
  • the bus 512 of the apparatus 500 can be composed of multiple buses.
  • the secondary storage 514 can be directly coupled to the other components of the apparatus 500 or can be accessed via a network and can comprise a single integrated unit such as a memory card or multiple units such as multiple memory cards.
  • the apparatus 500 can thus be implemented in a wide variety of configurations.
  • Weighted Prediction is a tool, which is particularly useful for coding fades.
  • the weighted prediction (WP) tool has been adopted in the H.264 video coding standard’s Main and Extended profiles to improve coding efficiency by applying a multiplicative weighting factor and an additive offset to the motion compensated prediction to form a weighted prediction.
  • a weighting factor and offset may be coded in the slice header for each allowable reference picture index.
  • the weighting factors are not coded but are derived based on the relative picture order count (POC) distances of the two reference pictures.
  • POC picture order count
  • WP When applied to a single prediction, as in P pictures, WP is similar to leaky prediction, which has been previously proposed for error resiliency.
  • Leaky prediction becomes a special case of WP, with the scaling factor limited to the range 0 £ a £ 1.
  • H.264 WP allows negative scaling factors, and scaling factors greater than one.
  • a weighting-factor is applied pixel-by-pixel using a coded label field, for efficient compression of covered and uncovered regions.
  • a key difference of H.264’s WP tool from previous proposals involving weighted prediction for compression efficiency is the association of the reference picture index with the weighting factor parameters, which allows for efficient signaling of these parameters in a multiple reference picture environment.
  • the WP When encoding a picture, if there is a FADE state in either the current picture or one of its reference pictures, the WP will be used for this current-reference pair, and statistics of current picture and the corresponding reference picture are processed at step 650 to estimate the WP parameters. These parameters are then passed on to the encoding engine 660. Otherwise, the normal encoding is done.
  • a macroblock in H.264 is divided into macroblock partitions.
  • a reference is selected from each one of the available reference lists (frequently denoted in specifications as RefPicList), list 0 for P or B-coded slices or reference list 1 for B-coded slices.
  • the references used may be different for each partition.
  • a prediction block is generated for each list, i.e. P for single list prediction and Po and Pi for bi- prediction, using motion information with, optionally, subpixel precision.
  • the prediction blocks may be further processed depending on the availability of weighted prediction for the current slice.
  • the WP parameters are transmitted at the slice header.
  • B slices there are two options. In the explicit WP, the parameters are transmitted in the slice header, and in the implicit WP the parameters are derived based on the Picture Order Count (POC) number that is signaled in the slice header.
  • POC Picture Order Count
  • Terms w x and o x are the WP gain and offset parameters for reference list x.
  • Term logWD is transmitted in the bit stream and controls the mathematical precision of the weighted prediction process. For logWD 3 1 , the expression above rounds away from zero.
  • two prediction blocks, one for each reference list, are considered. Let po and pi denote samples in each of the two prediction blocks Po and Pi . If weighted prediction is not used, prediction is performed as:
  • prediction is performed as:
  • weighted prediction can compensate for illumination changes, such as a fade-in, fade-out, or a cross-fade.
  • SPS On high level in VVC, weighted prediction is signaled in SPS, PPS and slice header.
  • SPS the following syntax elements are used for that:
  • sps_weighted_pred_flag 1 specifies that weighted prediction may be applied to P slices referring to the SPS.
  • sps_weighted_pred_flag 0 specifies that weighted prediction is not applied to P slices referring to the SPS;
  • - sps_weighted_bipred_flag 1 specifies that explicit weighted prediction may be applied to B slices referring to the SPS.
  • sps_weighted_bipred_flag 0 specifies that explicit weighted prediction is not applied to B slices referring to the SPS.
  • pps_weighted_pred_flag 0 specifies that weighted prediction is not applied to P slices referring to the PPS.
  • pps_weighted_pred_flag 1 specifies that weighted prediction is applied to P slices referring to the PPS.
  • pps_weighted_bipred_flag 0 specifies that explicit weighted prediction is not applied to B slices referring to the PPS.
  • pps_weighted_bipred_flag 1 specifies that explicit weighted prediction is applied to B slices referring to the PPS.
  • weighted prediction parameters are signaled as pred_weight_table( ) structured as in Table 1 and containing the following elements: luma_log2_weight_denom is the base 2 logarithm of the denominator for all luma weighting factors. The value of luma_log2_weight_denom shall be in the range of 0 to 7, inclusive. delta_chroma_log2_weight_denom is the difference of the base 2 logarithm of the denominator for all chroma weighting factors. When delta_chroma_log2_weight_denom is not present, it is inferred to be equal to 0.
  • the variable Chromal_og2WeightDenom is derived to be equal to luma_log2_weight_denom + delta_chroma_log2_weight_denom and the value shall be in the range of 0 to 7, inclusive.
  • luma_weight_I0_flag[ i ] 1 specifies that weighting factors for the luma component of list 0 prediction using RefPicList[ 0 ][ i ] are present.
  • luma_weight_I0_flag[ i ] equal to 0 specifies that these weighting factors are not present.
  • chroma_weight_I0_flag[ i ] 1 specifies that weighting factors for the chroma prediction values of list 0 prediction using RefPicList[ 0 ][ i ] are present.
  • chroma_weight_I0_flag[ i ] 0 specifies that these weighting factors are not present.
  • delta_luma_weight_I0[ i ] is the difference of the weighting factor applied to the luma prediction value for list 0 prediction using RefPicList[ 0 ][ i ].
  • LumaWeightl_0[ i ] is derived to be equal to ( 1 « luma_log2_weight_denom ) + delta_luma_weight_I0[ i ].
  • luma_weight_I0_flag[ i ] is equal to 1
  • the value of delta_luma_weight_I0[ i ] shall be in the range of -128 to 127, inclusive.
  • LumaWeightl_0[ i ] is inferred to be equal to 2 luma - l092 - we ' 9ht - denom .
  • luma_offset_I0[ i ] is the additive offset applied to the luma prediction value for list 0 prediction using RefPicList[ 0 ][ i ].
  • the value of luma_offset_I0[ i ] shall be in the range of -128 to 127, inclusive.
  • luma_weight_I0_flag[ i ] is equal to 0
  • luma_offset_I0[ i ] is inferred to be equal to 0.
  • delta_chroma_weight_I0[ i ][ j ] is the difference of the weighting factor applied to the chroma prediction values for list 0 prediction using RefPicList[ 0 ][ i ] with j equal to 0 for Cb and j equal to 1 for Cr.
  • ChromaWeightl_0[ i ][ j ] is derived to be equal to ( 1 « Chromal_og2WeightDenom ) + delta_chroma_weight_I0[ i ][ j ].
  • chroma_weight_I0_flag[ i ] is equal to 1
  • the value of delta_chroma_weight_I0[ i ][ j ] shall be in the range of -128 to 127, inclusive.
  • ChromaWeightl_0[ i ][ j ] is inferred to be equal to 2 ChromaLo92Wei9htDenom .
  • delta_chroma_offset_I0[ i ][ j ] is the difference of the additive offset applied to the chroma prediction values for list 0 prediction using RefPicList[ 0 ][ i ] with j equal to 0 for Cb and j equal to 1 for Cr.
  • ChromaOffsetLO[ i ][ j ] is derived as follows:
  • ChromaOffsetL0[ i ][ j ] Clip3( -128, 127,
  • delta_chroma_offset_I0[ i ][ j ] shall be in the range of -4 * 128 to 4 * 127, inclusive.
  • ChromaOffsetLO[ i ][ j ] is inferred to be equal to 0.
  • Iuma_weight_l1_flag[ i ], chroma_weight_l1_flag[ i ], delta_luma_weight_l1 [ i ], luma_offset_l1 [ i ], delta_chroma_weightJ1 [ i ][ j ] and delta_chroma_offset_l1 [ i ][ j ] have the same semantics as luma_weight_I0_flag[ i ], chroma_weight_I0_flag[ i ], delta_luma_weight_I0[ i ], luma_offset_I0[ i ], delta_chroma_weight_I0[ i ][ j ] and delta_chroma_offset_I0[ i ][ j ], respectively, with 10, LO, list 0 and ListO replaced by 11 , L1 , list 1 and Listl , respectively.
  • the ref_pic_list_struct( listldx, rplsldx ) syntax structure may be present in an SPS or in a slice header. Depending on whether the syntax structure is included in a slice header or an SPS, the following applies:
  • the ref_pic_list_struct( listldx, rplsldx ) syntax structure specifies reference picture list listldx of the current picture (the picture containing the slice).
  • the ref_pic_list_struct( listldx, rplsldx ) syntax structure specifies a candidate for reference picture list listldx, and the term "the current picture” in the semantics specified in the remainder of this clause refers to each picture that: (1) has one or more slices containing ref_pic_list_idx[ listldx ] equal to an index into the list of the ref_pic_list_struct( listldx, rplsldx ) syntax structures included in the SPS, and (2) is in a CVS that refers to the SPS.
  • num_ref_entries[ listldx ][ rplsldx ] specifies the number of entries in the ref_pic_list_struct( listldx, rplsldx ) syntax structure.
  • the value of num_ref_entries[ listldx ][ rplsldx ] shall be in the range of 0 to sps_max_dec_pic_buffering_minus1 + 14, inclusive.
  • Itrp_in_slice_header_flag[ listldx ][ rplsldx ] equal to 0 specifies that the POC LSBs of the LTRP entries in the ref_pic_list_struct( listldx, rplsldx ) syntax structure are present in the ref_pic_list_struct( listldx, rplsldx ) syntax structure.
  • Itrp_in_slice_header_flag[ listldx ][ rplsldx ] 1 specifies that the POC LSBs of the LTRP entries in the ref_pic_list_struct( listldx, rplsldx ) syntax structure are not present in the ref_pic_list_struct( listldx, rplsldx ) syntax structure.
  • inter_layer_ref_pic_flag[ listldx ][ rplsldx ][ i ] 1 specifies that the i-th entry in the ref_pic_list_struct( listldx, rplsldx ) syntax structure is an ILRP entry.
  • inter_layer_ref_pic_flag[ listldx ][ rplsldx ][ i ] 0 specifies that the i-th entry in the ref_pic_list_struct( listldx, rplsldx ) syntax structure is not an ILRP entry.
  • the value of inter_layer_ref_pic_flag[ listldx ][ rplsldx ][ i ] is inferred to be equal to 0.
  • st_ref_pic_flag[ listldx ][ rplsldx ][ i ] 1 specifies that the i-th entry in the ref_pic_list_struct( listldx, rplsldx ) syntax structure is an STRP entry.
  • st_ref_pic_flag[ listldx ][ rplsldx ][ i ] 0 specifies that the i-th entry in the ref_pic_list_struct( listldx, rplsldx ) syntax structure is an LTRP entry.
  • Numl_trpEntries[ listldx ][ rplsldx ]++ abs_delta_poc_st[ listldx ][ rplsldx ][ i ] specifies the value of the variable AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] as follows: if( sps_weighted_pred_flag
  • AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] abs_delta_poc_st[ listldx ][ rplsldx ][ i ] else
  • AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] abs_delta_poc_st[ listldx ][ rplsldx ][ i ] + 1
  • abs_delta_poc_st[ listldx ][ rplsldx ][ i ] shall be in the range of 0 to 215 - 1 , inclusive.
  • strp_entry_sign_flag[ listldx ][ rplsldx ][ i ] equal to 1 specifies that i-th entry in the syntax structure ref_pic_list_struct( listldx, rplsldx ) has a value greater than or equal to 0.
  • strp_entry_sign_flag[ listldx ][ rplsldx ][ i ] 0 specifies that the i-th entry in the syntax structure ref_pic_list_struct( listldx, rplsldx ) has a value less than 0.
  • the value of strp_entry_sign_flag[ listldx ][ rplsldx ][ i ] is inferred to be equal to 1.
  • DeltaPocValSt[ listldx ][ rplsldx ][ i ] ( strp_entry_sign_flag[ listldx ][ rplsldx ][ i ]
  • AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] : 0 - AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] rpls_poc_lsb_lt[ listldx ][ rplsldx ][ i ] specifies the value of the picture order count modulo MaxPicOrderCntLsb of the picture referred to by the i-th entry in the ref_pic_list_struct( listldx, rplsldx ) syntax structure.
  • the length of the rpls_poc_lsb_lt[ listldx ][ rplsldx ][ i ] syntax element is log2_max_pic_order_cnt_lsb_minus4 + 4 bits.
  • ilrp_idc[ listldx ][ rplsldx ][ i ] specifies the index, to the list of directly dependent layers, of the ILRP of i-th entry in ref_pic_list_struct( listldx, rplsldx ) syntax structure to the list of directly dependent layers.
  • ilrp_idc[ listldx ][ rplsldx ][ i ] shall be in the range of 0 to the GeneralLayerldx[ nuhjayerjd ] - 1 , inclusive.
  • weighted prediction parameters are signaled after reference picture list signaling.
  • these syntax elements are reordered to restrict binarization of delta POC syntax element based on the values of the weighted prediction flags.
  • delta POC the variable AbsDeltaPocSt
  • abs_delta_poc_st[ listldx ][ rplsldx ][ i ] specifies the value of the variable AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] as follows:
  • AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] abs_delta_poc_st[ listldx ][ rplsldx ][ i ] else
  • AbsDeltaPocSt[ listldx ][ rplsldx ][ i ] abs_delta_poc_st[ listldx ][ rplsldx ][ i ] + 1
  • Triangular partitioning mode and geometric motion partitioning (GEO) are partitioning techniques that enable non-horizontal and non-vertical boundaries between prediction partitions, as exemplarily shown in Fig. 6, where prediction unit PU1 601 and prediction unit PU 1 602 are combined in region 603 using a weighted averaging procedure of subsets of their samples related to different color components.
  • TPM enables boundaries between prediction partitions only along a rectangular block diagonals, whereas boundaries according to GEO may be located at arbitrary positions as Fig. 9 illustrates.
  • integer numbers within squares denote weights W/ PU1 applied to luma component of prediction unit PU1.
  • weights W PU2 applied to luma component of prediction unit PU2 are calculated as follows: W PU2 — 8— W/ PU1 .
  • Weights applied to chroma components of corresponding prediction units may differ from weights applied to luma components of corresponding prediction units.
  • MergeTriangleFlag is a flag that identifies whether TPM is selected or not (“0” means that TPM is not selected; otherwise, TPM is chosen); merge_triangle_split_dir is a split direction flag for TPM (“0” means the split direction from top-left corner to the below-right corner; otherwise, the split direction is from top-right corner to the below-left corner); merge_triangle_idxO and merge_triangle_idx1 are indices of merge candidates 0 and 1 used for TPM. Table 1. Merge data syntax including syntax for TPM
  • TPM is described in the following proposal: R-L. Liao and C.S. Lim
  • Prediction errors are localized only in near-boundary region that covers the boundary between partitions that to use a more compact representation. Transform and quantization are performed only for this near-boundary region.
  • each inter-predictor Po 710 and P 1 720 are weighted for block 750 in accordance with the WP parameters (WP parameters 730 ⁇ wo, Oo ⁇ and WP parameters 740 ⁇ w 1 , O 1 ⁇ for Po and P 1 , respectively) defined for each picture in the reference picture list.
  • WP parameters 730 ⁇ wo, Oo ⁇ and WP parameters 740 ⁇ w 1 , O 1 ⁇ for Po and P 1 , respectively defined for each picture in the reference picture list.
  • a rectangular block predicted using bi-prediction mechanism for example either TPM or GEO
  • the following process may be performed as described below.
  • Inputs to this process may, in some embodiments, be:
  • nCbW and nCbH specifying the width and the height of the current coding block (also referred to as current block or to-be-predicted block),
  • refldxLO and refldxLI which preferably refer to the respective picture lists of reference blocks used for the prediction of the current block the variable cldx specifying the colour component index
  • bitDepth the sample bit depth
  • Output of this process may be the (nCbW)x(nCbH) array pbSamples of prediction sample values for the current coding block.
  • variable shiftl may be set equal to Max( 2, 14 - bitDepth ).
  • log2Wd, oO, o1 , wO and w1 may be derived as follows:
  • predFlagLO is equal to 1 and predFlagLI is equal to 0
  • pbSamples[ x ][ y ] Clip3( 0, ( 1 « bitDepth ) - 1 , ( ( predSamplesl_0[ x ][ y ] * wO + 2'° 92Wd 1 ) » log2Wd ) + oO ) else
  • predFlagLO is equal to 0 and predFlagLI is equal to 1
  • Parameters of the slice-level weighted prediction could be represented as a set of variables, assigned for each element of a reference picture list. Index of the element is denoted further as Y. These parameters may comprise:
  • luma_offset_I0[ / ] is the additive offset applied to the luma prediction value for list 0 prediction using RefPicList[ 0 ][ i ].
  • the value of luma_offset_I0[ i ] shall be in the range of -128 to 127, inclusive.
  • LumaWeightL0[ i ] is derived to be equal to ( 1 « luma_log2_weight_denom ) + delta_luma_weight_I0[ i ].
  • luma_weight_I0_flag[ i ] is equal to 1
  • the value of delta_luma_weight_I0[ i ] shall be in the range of -128 to 127, inclusive.
  • LumaWeightL0[ i ] is inferred to be equal to be equal to
  • Inputs to this process may be:
  • nCbW and nCbH specifying the width and the height of the current coding block
  • Output of this process may be the (nCbW)x(nCbH) array pbSamples of prediction sample values.
  • nCbR ( nCbW > nCbH ) ? ( nCbW / nCbH ) : ( nCbH / nCbW )
  • variable bitDepth is derived as follows:
  • bitDepth is set equal to BitDepthy.
  • bitDepth is set equal to BitDepthc.
  • Variables shiftl and offsetl may be derived as follows:
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • variable wldx is derived as follows:
  • wldx ( nCbW > nCbH ) ? ( Clip3( 0, 8, ( nCbH - 1 - x / nCbR - y ) + 4 ) )
  • One embodiment referred to herein refers to a method of a weighted sample prediction process that combines two weighting processes (see Fig. 9 and Fig.10). Both weighting processes obtain predicted samples using a linear combination of samples belonging to two uni-predicted reference blocks, wherein a predicted sample (940, 1005) in a predicted block having a position defined as (x,y) relative to the top-left corner of the predicted block is derived using a linear combination of two samples, each of these samples have a position (x,y) correspondingly relative to the top-left corners of their reference blocks.
  • weights applied to the two samples being of the reference blocks do not depend on the position (x,y) of a predicted sample within a predicted block.
  • BCW CU-level Weights
  • slice-level weighted prediction For example, Bi-prediction with CU-level Weights (BCW) or slice-level weighted prediction.
  • BCW CU-level Weights
  • weights of the linear combination are assigned per-block.
  • slice-level weighted prediction each element of the reference picture list that is signalled on the slice level has a pair of weight and offset assigned for the referenced picture.
  • a block determines weights and offsets for the linear combination with respect to the pair of reference indices that indicate a pair of reference picture list elements, and hence, a set of parameters for linear combination (including weights and offsets).
  • predicted sample f is determined as follows:
  • parameter WD is the bit depth of weights w ⁇ , that is required for the normalization of the result of weighting process. In a particular implementation, WD could be set equal to 6 or 7.
  • weights vi ⁇ applied to the two samples being of the reference blocks depend on the position (x,y) of a predicted sample within a predicted block.
  • predicted sample p is determined as follows: wherein the sum of weights (902, 912) is constant, i.e. and the
  • weights’ values are normalized to the weight bitdepth s.
  • s 3 .
  • weighting operation may comprise rounding step:
  • This rounding comprises a right-shift by the value s. Both weighting processes could be combined in a single one, thus obtaining a predicted sample as follows:
  • a process of restoration of a triangle merge mode with the slice-level weighted prediction parameters is provided:
  • Inputs to this process are: - two variables nCbW and nCbH specifying the width and the height of the current coding block,
  • nCbR ( nCbW > nCbH ) ? ( nCbW / nCbH ) : ( nCbH / nCbW )
  • variable bitDepth is derived as follows:
  • bitDepth is set equal to BitDepthy. - Otherwise, bitDepth is set equal to BitDepthc.
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • variable wldx is derived as follows:
  • wO may be defined as follows
  • combined linear combination parameters may be obtained, as was already referred to above.
  • these parameters may be: wBiO, wBi1 , offsetBi and (3+ log2Wd + 1). It is understood, that the value“3” is in fact a weight bitdepth parameter of the set of parameters that do not depend on the position of the predicted samples.
  • combined linear combination parameters may be precalculated per each of the allowed values of position-dependent linear combination parameters.
  • ⁇ wBiO[wValue], wBi1 [wValue], offsetBi[wValue] ⁇ could be precalculated and stored per each element of the reference picture list.
  • Inputs to this process may be:
  • nCbW and nCbH specifying the width and the height of the current coding block
  • nCbR ( nCbW > nCbH ) ? ( nCbW / nCbH ) : ( nCbH / nCbW )
  • bitDepth is derived as follows:
  • bitDepth is set equal to BitDepthy.
  • bitDepth is set equal to BitDepthc.
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • variable wldx is derived as follows:
  • VVC specification draft a corresponding part of the VVC specification draft may be defined as follows:
  • Inputs to this process may be:
  • nCbW and nCbH specifying the width and the height of the current coding block
  • a variable triangleDir specifying the partition direction
  • a variable cldx specifying colour component index
  • nCbR ( nCbW > nCbH ) ? ( nCbW / nCbH ) : ( nCbH / nCbW )
  • variable bitDepth is derived as follows:
  • bitDepth is set equal to BitDepthy.
  • bitDepth is set equal to BitDepthc.
  • Variables shiftl and offsetl are derived as follows:
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • the variable wldx is derived as follows:
  • the values of multiplied weights ⁇ w 0 x w 0 , w 1 x w 1 ⁇ are right-shifted, preferably before their further use. This can be done in order to maintain the dynamic range that is used for weighting in bi-prediction.
  • the dynamic range is considered the number of bits corresponding to the maximum length (in terms of bits) of one of the values of the weights.
  • predicted sample value may be derived as follows:
  • the values w Ni are the normalized weighting parameters that are obtained by applying the right-shift to the respective weights (specifically, to the product of the weights). This does not necessarily mean that the“normalized” weighting parameters have a value between 0 and 1 after the“normalizing”.
  • the normalizing in this context is only intended to mean that a right shift is applied to the respective products of the weights, i.e. to w m . This, of course, does not exclude that some weighting parameters will have a value between 0 and 1.
  • the steps to obtain the value of predicted sample from corresponding two samples of the two reference blocks are as follows.
  • non-normalized values of weights are obtained from position-dependent weights by multiplying slice-level weight by corresponding position-dependent weight
  • this right-shift operation may comprise rounding offset:
  • a predicted sample value may be obtained as a linear combination of two samples, and parameters of linear combination comprising the normalized weights ⁇ w Ni ⁇ and an optional offset value ( j
  • the offset value may be added after a linear combination. Specifically:
  • This post-weighting offset O bi is defined as This 0ffset value may be obtained using a right-shift operation, e.g. as follows: or as follows:
  • the value of s for bitdepth for a position-dependent weight could be equal, e.g. to 3.
  • offset value may be obtained, e.g. as follows: or as follows:
  • the value of s for bitdepth for position-dependent weight could be equal, e.g. to 4.
  • offset value may be obtained, e.g. as follows: or as follows:
  • bitdepth for position-dependent weight could be equal, e.g. to 2.
  • offset value may be obtained, e.g. as follows: or as follows:
  • the value of s could be signaled in the bitstream at picture level (e.g., picture header or AUD), slice level (e.g. slice header) or in PPS or SPS, or it may have a hierarchical syntax wherein signaling on different levels is combined.
  • picture level e.g., picture header or AUD
  • slice level e.g. slice header
  • PPS or SPS PPS or SPS
  • Inputs to this process may be:
  • nCbW and nCbH specifying the width and the height of the current coding block
  • Output of this process may be the (nCbW)x(nCbH) array pbSamples of prediction sample values.
  • nCbR ( nCbW > nCbH ) ? ( nCbW / nCbH ) : ( nCbH / nCbW )
  • variable bitDepth may be derived as follows:
  • bitDepth is set equal to BitDepthy.
  • bitDepth is set equal to BitDepthc.
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • variable wldx may be derived as follows:
  • wO may be defined as follows
  • the deriving of the offset value, the deriving of the weight wBiO referred to previously and the calculation of the prediction sample values could be defined in the same way as in“Explicit weighted sample prediction process” section of the VVC specification draft:
  • the defined range of the values (like weighting parameters or weights from which the weighting parameters are obtained by linear combination) being processed should not exceed the constraint. Otherwise, overflow may occur, thus leading to significant performance degradation or even hardware malfunctioning.
  • Embodiment described herein discuss a method (specifically, a method as the one referred to in the summary of the invention above) of adaptive adjustment of weighting parameter precision (also referred to as weighting prediction parameter precision).
  • the weighting parameter is the actual parameter that is used for predicting the sample value(s) in the bi-prediction process, like TPM.
  • the weighting parameter may be obtained as explained above, by linearly combining position dependent and position-independent weights.
  • a value of the dynamic range of weights is determined.
  • the dynamic range is considered the number of bits corresponding to the maximum length (in terms of bits) of one of the values of the weights.
  • this value may be the maximum value of a most significant bit position between the two weights that are provided for a pair of samples to be weighted, i.e. the value of the most significant bit of the one weight or of the other weight, depending on which value is larger.
  • This decision can be made by, for example, calculating, for two weights w1 and w2, max(log2
  • a bit budget value is calculated, by the values of weights being used in weighting of a predicted sample. For example, for all weighting parameters together, there might only be a bit budget available that is 24bit. Or, for each weighting parameter, there might be a number of bits (i.e. a bit budget) reserved.
  • a precision adjustment is performed.
  • This precision adjustment may comprise right-shifting the value of the obtained weighting parameter (see above) or of each of the weights by a value that is equal to a difference between the maximum bitdepth of the weights and the bit budget value.
  • Precision adjustment of the weights values could be performed for a block, or at the slice level.
  • prediction adjustment may be performed for the two weighting parameters of the slice-level weighted prediction.
  • the resulting“shift_norm” shift value may be further used to fetch two pre-multiplied weights from LUTO and LUT1 , correspondingly.
  • Each LUT may represent a fetch operation and, hence weights may be selected from a LUT in accordance with the values of refldx.
  • the weights fetched may be input weight values ⁇ w, ⁇ and input weight w l values of position-dependent weighting method (e.g. TPM) or it may be the (normalized) weighting parameters.
  • TPM position-dependent weighting method
  • it can be provided that the LUT is filled in such a way, that the value fetched from the LUT already has a precision defined by the value of the shift_norm, i.e. which meets the bit budget, preferably.
  • Inputs to this process may be:
  • nCbW and nCbH specifying the width and the height of the current coding block
  • Output of this process may be the (nCbW)x(nCbH) array pbSamples of prediction sample values.
  • variable bitDepth is derived as follows:
  • bitDepth is set equal to BitDepthy.
  • bitDepth is set equal to BitDepthc.
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • variable wldx is derived as follows:
  • shift_norm max(0, max(log2[w1], log2[w1] - (Tb-3) )
  • Tb is the total bit depth for multiplications and this may be predefined. It could be set equal to 8, or to 7 or it could be assigned any integer value in the range of [0, 32]
  • the value of shift_norm could be signaled within a bitstream.
  • Inputs to this process may be:
  • nCbW and nCbH specifying the width and the height of the current coding block
  • nCbR ( nCbW > nCbH ) ? ( nCbW / nCbH ) : ( nCbH / nCbW )
  • variable bitDepth is derived as follows:
  • bitDepth is set equal to BitDepthy.
  • bitDepth is set equal to BitDepthc.
  • variable shiftl is set equal to Max( 5, 17 - bitDepth).
  • variable offsetl is set equal to 1 « ( shiftl - 1 ).
  • variable wldx is derived as follows:
  • variable wValue specifying the weight of the prediction sample is derived using wldx and cldx as follows:
  • the value shift_norm may be calculated as follows
  • shift_norm max(0, max(abs(w0), abs(w1)) - (Tb-3) )
  • log2Wd luma_log2_weight_denom + shift1-shift_norm
  • log2Wd ChromaLog2WeightDenom + shiftl - shift_norm -
  • the offset value may be derived as follows:
  • the prediction sample values may be derived as follows:
  • Tb may be predefined. It could be set equal to 8, or to 7 or it could be assigned any integer value in the range of [0, 32]
  • the value of shift_norm could be signaled within a bitstream.
  • FIG. 11 is a block diagram showing a content supply system 3100 for realizing content distribution service.
  • This content supply system 3100 includes capture device 3102, terminal device 3106, and optionally includes display 3126.
  • the capture device 3102 communicates with the terminal device 3106 over communication link 3104.
  • the communication link may include the communication channel 13 described above.
  • the communication link 3104 includes but not limited to WIFI, Ethernet, Cable, wireless (3G/4G/5G), USB, or any kind of combination thereof, or the like.
  • the capture device 3102 generates data, and may encode the data by the encoding method as shown in the above embodiments. Alternatively, the capture device 3102 may distribute the data to a streaming server (not shown in the Figures), and the server encodes the data and transmits the encoded data to the terminal device 3106.
  • the capture device 3102 includes but not limited to camera, smart phone or Pad, computer or laptop, video conference system, PDA, vehicle mounted device, or a combination of any of them, or the like.
  • the capture device 3102 may include the source device 12 as described above.
  • the video encoder 20 included in the capture device 3102 may actually perform video encoding processing.
  • an audio encoder included in the capture device 3102 may actually perform audio encoding processing.
  • the capture device 3102 distributes the encoded video and audio data by multiplexing them together.
  • the encoded audio data and the encoded video data are not multiplexed.
  • Capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.
  • the terminal device 310 receives and reproduces the encoded data.
  • the terminal device 3106 could be a device with data receiving and recovering capability, such as smart phone or Pad 3108, computer or laptop 3110, network video recorder (NVR)/ digital video recorder (DVR) 3112, TV 3114, set top box (STB) 3116, video conference system 3118, video surveillance system 3120, personal digital assistant (PDA) 3122, vehicle mounted device 3124, or a combination of any of them, or the like capable of decoding the above-mentioned encoded data.
  • the terminal device 3106 may include the destination device 14 as described above.
  • the encoded data includes video
  • the video decoder 30 included in the terminal device is prioritized to perform video decoding.
  • an audio decoder included in the terminal device is prioritized to perform audio decoding processing.
  • the terminal device can feed the decoded data to its display.
  • NVR network video recorder
  • DVR digital video recorder
  • TV 3114 TV 3114
  • PDA personal digital assistant
  • vehicle mounted device 3124 the terminal device can feed the decoded data to its display.
  • NVR network video recorder
  • DVR digital video recorder
  • TV 3114 TV 3114
  • PDA personal digital assistant
  • vehicle mounted device 3124 the terminal device can feed the decoded data to its display.
  • a terminal device equipped with no display for example, STB 3116, video conference system 3118, or video surveillance system 3120, an external display 3126 is contacted therein to receive and show the decoded data.
  • the picture encoding device or the picture decoding device can be used.
  • FIG. 12 is a diagram showing a structure of an example of the terminal device 3106.
  • the protocol proceeding unit 3202 analyzes the transmission protocol of the stream.
  • the protocol includes but not limited to Real Time Streaming Protocol (RTSP), Hyper Text Transfer Protocol (HTTP), HTTP Live streaming protocol (HLS), MPEG-DASH, Real-time Transport protocol (RTP), Real Time Messaging Protocol (RTMP), or any kind of combination thereof, or the like.
  • stream file is generated.
  • the file is outputted to a demultiplexing unit 3204.
  • the demultiplexing unit 3204 can separate the multiplexed data into the encoded audio data and the encoded video data. As described above, for some practical scenarios, for example in the video conference system, the encoded audio data and the encoded video data are not multiplexed. In this situation, the encoded data is transmitted to video decoder 3206 and audio decoder 3208 without through the demultiplexing unit 3204.
  • video elementary stream (ES), audio ES, and optionally subtitle are generated.
  • the video decoder 3206 which includes the video decoder 30 as explained in the above mentioned embodiments, decodes the video ES by the decoding method as shown in the above-mentioned embodiments to generate video frame, and feeds this data to the synchronous unit 3212.
  • the audio decoder 3208 decodes the audio ES to generate audio frame, and feeds this data to the synchronous unit 3212.
  • the video frame may store in a buffer (not shown in FIG. 12) before feeding it to the synchronous unit 3212.
  • the audio frame may store in a buffer (not shown in FIG. 12) before feeding it to the synchronous unit 3212.
  • the synchronous unit 3212 synchronizes the video frame and the audio frame, and supplies the video/audio to a video/audio display 3214.
  • the synchronous unit 3212 synchronizes the presentation of the video and audio information.
  • Information may code in the syntax using time stamps concerning the presentation of coded audio and visual data and time stamps concerning the delivery of the data stream itself.
  • the subtitle decoder 3210 decodes the subtitle, and synchronizes it with the video frame and the audio frame, and supplies the
  • the present invention is not limited to the above-mentioned system, and either the picture encoding device or the picture decoding device in the above-mentioned embodiments can be incorporated into other system, for example, a car system.
  • Fig. 14 shows a block diagram of a method 1400 according to an embodiment of the invention.
  • This method may preferably be a method 1400 for a weighting inter prediction process.
  • the method comprises, in this embodiment, the following steps.
  • Determining 1401 a value of a dynamic range of at least two weights that are to be used for obtaining a weighting parameter to be used in the weighting inter prediction process.
  • bit budget value indicating a number of bits available for the weighting parameter obtained from the at least two weights.
  • Adjusting 1403 a precision of the weighting parameter by right-shifting the value of the weighting parameter by a value that is equal to a difference between the value of the dynamic range and the bit budget value.
  • Fig. 15 further shows a schematic depiction of an encoder according to one embodiment.
  • the encoder 1500 is an encoder 1500 for encoding a video sequence using a weighting inter prediction process and the encoder 1500 comprises a receiving unit 1501 , a prediction unit 1502 and an encoding unit 1503.
  • the receiving unit 1501 is adapted to receive at least two weights that are to be used for obtaining a weighting parameter that is to be used in the weighting inter prediction process and to obtain a bit budget value, the bit budget value indicating a number of bits available for a weighting parameter obtained from the at least two weights.
  • the prediction unit 1502 is adapted to obtain a value of a dynamic range of the at least two weights and to obtain at least one predicted weighting parameter and to adjust a precision of the at least one weighting parameter, by right-shifting the value of the weighting parameter by a value that is equal to a difference between the value of the dynamic range and the bit budget value.
  • the encoding unit 1503 is adapted to encode the video sequence using the at least one predicted weighting parameter.
  • a decoder is provided as shown in fig. 16.
  • the decoder 1600 is a decoder for decoding a datastream representing an encoded video sequence.
  • the decoder 1600 comprises a receiving unit 1601 and a decoding unit 1602.
  • the receiving unit 1601 is adapted to receive the datastream, the datastream comprising at least two weights that are to be used for obtaining a weighting parameter to be used in the weighting inter prediction process and a bit budget value, the bit budget value indicating a number of bits available for a weighting parameter obtained from the at least two weights.
  • the decoding unit 1602 is adapted obtain a value of a dynamic range of the at least two weights and to obtain at least one predicted weighting parameter and to adjust a precision of the at least one weighting parameter, by right-shifting the value of the at least one weighting parameter by a value that is equal to a difference between the value of the dynamic range and the bit budget value.
  • the decoding unit 1602 is adapted to decode the encoded video sequence using the at least one predicted weighting parameter.
  • C-language or C program code may, in some embodiments, be rather considered as pseudo-code, reflecting what, according to embodiments of the invention, happens, but not restricting the invention to the application of a specific
  • the first is equivalent to the 0-th
  • the second is equivalent to the 1-th
  • na When a relational operator is applied to a syntax element or variable that has been assigned the value "na” (not applicable), the value "na” is treated as a distinct value for the syntax element or variable. The value “na” is considered not to be equal to any other value.
  • L Bit-wise "exclusive or" When operating on integer arguments, operates on a two's complement representation of the integer value. When operating on a binary argument that contains fewer bits than another argument, the shorter argument is extended by adding more significant bits equal to 0.
  • Asin( x ) the trigonometric inverse sine function, operating on an argument x that is in the range of -1.0 to 1.0, inclusive, with an output value in the range of -p ⁇ 2 to p ⁇ 2, inclusive, in units of
  • Atan( x ) the trigonometric inverse tangent function, operating on an argument x, with an output value in the range of -p ⁇ 2 to p ⁇ 2, inclusive, in units of radians
  • Ceil( x ) the smallest integer greater than or equal to x.
  • Clip1 Y ( X ) Clip3( 0, ( 1 « BitDepthy ) - 1 , x
  • Clip1c( x ) Clip3( 0, ( 1 « BitDepthc ) - 1 , X
  • Cos( x ) the trigonometric cosine function operating on an argument x in units of radians.
  • Floor( x ) the largest integer less than or equal to
  • Round( x ) Sign( x ) * Floor( Abs( x ) + 0.5
  • the table below specifies the precedence of operations from highest to lowest; a higher position in the table indicates a higher precedence.
  • n may be described in the following manner:
  • n may be described in the following manner:
  • statement 1 If one or more of the following conditions are true, statement 1 :
  • statement 1 may be described in the following manner:
  • Embodiments, e.g. of the encoder 20 and the decoder 30, and functions described herein, e.g. with reference to the encoder 20 and the decoder 30, may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted over communication media as one or more instructions or code and executed by a hardware-based processing unit.
  • Computer-readable media may include computer-readable storage media, which
  • computer-readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave.
  • Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure.
  • a computer program product may include a computer-readable medium.
  • such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.
  • any connection is properly termed a computer-readable medium.
  • a computer-readable medium For example, if 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.
  • DSL digital subscriber line
  • Disk and disc includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.
  • processors such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry.
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • FPGAs field programmable logic arrays
  • 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.
  • the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.
  • the techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set).
  • IC integrated circuit
  • a set of ICs e.g., a chip set.
  • Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and/or firmware.

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Abstract

L'invention concerne un procédé mis en oeuvre par ordinateur pour un processus de prédiction inter, le procédé consistant à: déterminer une valeur d'une plage dynamique d'au moins deux poids qui doivent être utilisés pour obtenir un paramètre de pondération à utiliser dans le processus de prédiction inter de pondération; l'obtention d'une valeur de budget de bits, la valeur de budget de bits indiquant un nombre de bits disponibles pour le paramètre de pondération obtenu à partir des au moins deux poids; et l'ajustement d'une précision du paramètre de pondération, par décalage à droite de la valeur du paramètre de pondération par une valeur qui est égale à une différence entre la valeur de la plage dynamique et la valeur de budget binaire. La présente invention présente au moins partiellement également un codeur et un décodeur mettant en oeuvre le procédé.
EP20823097.9A 2019-10-07 2020-10-05 Procédé et appareil de réglage adaptatif de précision de paramètre de prédiction de pondération pour harmoniser un mode de fusion non rectangulaire et une prédiction pondérée Pending EP4029261A4 (fr)

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