Method for encoding image information, method for decoding image information, computer-readable storage medium, and method for transmitting image information

Abstract

A method according to the present disclosure may involve: acquiring image information including one or more basic picture layers and one or more object mask information (OMI)-related messages respectively associated with the one or more basic picture layers; and processing the OMI-related messages, wherein one OMI-related message among the one or more OMI-related messages may be associated with only the current basic picture layer among the one or more basic picture layers.

Description

Method for encoding image information, method for decoding image information, computer-readable storage medium and method for transmitting image information

[0001] The present disclosure relates to a method for decoding / encoding image information, a computer-readable storage medium for storing image information, and a method for transmitting image information.

[0002] Recently, demand for high-resolution, high-quality images, such as HD (High Definition) and UHD (Ultra High Definition) images, has been increasing across various fields. As image data becomes higher resolution and higher quality, the amount of information transmitted, or bits, increases relative to conventional image data. This increase in information or bits transmitted leads to increased transmission and storage costs.

[0003] Accordingly, a highly efficient image compression technology is required to effectively transmit, store, and play high-resolution, high-quality image information.

[0004] The present disclosure seeks to provide an encoding / decoding method and / or device with improved coding efficiency.

[0005] The present disclosure seeks to provide an encoding / decoding method and / or device having data transmission efficiency.

[0006] The present disclosure seeks to provide an encoding / decoding method and / or device capable of reducing power consumption of a decoding device and improving the accuracy of image analysis.

[0007] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0008] According to one aspect of the present disclosure, a method for decoding image information includes obtaining image information including at least one base picture layer and at least one object mask information (OMI)-related message associated with each of the at least one base picture layer, and processing the OMI-related message, wherein one of the at least one OMI-related message may be associated only with a current base picture layer among the at least one base picture layer.

[0009] According to one aspect of the present disclosure, a device for decoding image information includes a memory and a processor connected to the memory, wherein the processor obtains image information including at least one base picture layer and at least one object mask information (OMI)-related message associated with each of the at least one base picture layer, processes the OMI-related message, and wherein one of the at least one OMI-related message may be associated only with a current base picture layer among the at least one base picture layer.

[0010] In the method or device for decoding the above image information, the one OMI related message may exist in the current basic picture layer.

[0011] In the method or device for decoding the image information, the image information may further include at least one auxiliary layer associated with the current basic picture layer, and the one OMI-related message may include information about the at least one auxiliary layer.

[0012] In the method or device for decoding the above image information, the information about the at least one auxiliary layer may include information about an object mask of the at least one auxiliary layer.

[0013] In the method or device for decoding the image information, the OMI-related message may further include OMI persistence flag information indicating persistence of object mask information of the OMI-related message, and based on a value of the OMI persistence flag information being 0, the object mask information of the OMI-related message may be applied only to the current picture, and based on a value of the OMI persistence flag information being 1, the object mask information of the OMI-related message may be applied to the current picture and consecutive pictures of the current base picture layer.

[0014] According to one aspect of the present disclosure, a method of encoding image information includes generating at least one object mask information (OMI) related message, each message being associated with at least one base picture layer, and encoding image information including the at least one OMI related message, wherein one of the at least one OMI related message can be associated with only one base picture layer among the at least one base picture layer.

[0015] According to one aspect of the present disclosure, a device for encoding image information includes a memory and a processor connected to the memory, wherein the processor generates at least one object mask information (OMI) related message, each message being associated with at least one basic picture layer, and encodes image information including the at least one OMI related message, wherein one of the at least one OMI related message can be associated with only one basic picture layer among the at least one basic picture layer.

[0016] In the method or device for encoding the above image information, the OMI related message may exist in the current basic picture layer.

[0017] In the method or device for encoding the image information, the image information may further include at least one auxiliary layer associated with the current basic picture layer, and the OMI-related message may include information regarding the at least one auxiliary layer.

[0018] In the method or device for encoding the above image information, the information about the at least one auxiliary layer may include information about an object mask of the at least one auxiliary layer.

[0019] In the method or device for encoding the image information, the OMI-related message may further include OMI persistence flag information indicating persistence of object mask information of the OMI-related message, and a value of the OMI persistence flag information of 0 may indicate that the object mask information of the OMI-related message is applied only to the current picture, and a value of the OMI persistence flag information of 1 may indicate that the object mask information of the OMI-related message is applied to the current picture and consecutive pictures of the current base picture layer.

[0020] A computer-readable storage medium storing a bitstream generated by an encoding method, the encoding method comprising: generating at least one object mask information (OMI)-related message, each message being associated with at least one basic picture layer; and encoding image information including the at least one OMI-related message, wherein one of the at least one OMI-related message can be associated with only one basic picture layer among the at least one basic picture layer.

[0021] The features briefly summarized above regarding the present disclosure are merely exemplary aspects of the detailed description of the present disclosure that follows and do not limit the scope of the present disclosure.

[0022] According to the present disclosure, an encoding / decoding method and / or device with improved coding efficiency can be provided.

[0023] According to the present disclosure, an encoding / decoding method and / or device having data transmission efficiency can be provided.

[0024] According to the present disclosure, an encoding / decoding method and / or device can be provided that can reduce power consumption of a decoding device and improve the accuracy of image analysis.

[0025] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0026] FIG. 1 is a diagram schematically illustrating a video coding system to which an embodiment according to the present disclosure can be applied.

[0027] FIG. 2 is a schematic diagram of an encoding device to which an embodiment according to the present disclosure can be applied.

[0028] FIG. 3 is a schematic diagram showing a decoding device to which an embodiment according to the present disclosure can be applied.

[0029] Figure 4 illustrates an example of a hierarchical structure for coded video / images.

[0030] FIG. 5 is a diagram illustrating a method for decoding image information according to one embodiment of the present disclosure.

[0031] FIG. 6 is a diagram illustrating a method for encoding image information according to one embodiment of the present disclosure.

[0032] FIG. 7 is a diagram exemplifying a content streaming system to which an embodiment according to the present disclosure can be applied.

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0034] In describing embodiments of the present disclosure, detailed descriptions of known configurations or functions will be omitted if they are deemed to obscure the gist of the present disclosure. Furthermore, portions unrelated to the description of the present disclosure in the drawings have been omitted, and similar portions have been designated with similar reference numerals.

[0035] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection, but also an indirect connection in which another component exists in between. Furthermore, when a component is said to "include" or "have" another component, unless otherwise specifically stated, this does not exclude the other component, but rather implies that the other component may be included.

[0036] In this disclosure, terms such as first, second, etc. are used solely to distinguish one component from another, and do not limit the order or importance of components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0037] In this disclosure, distinct components are used to clearly illustrate their respective characteristics, and do not necessarily imply that the components are separated. That is, multiple components may be integrated into a single hardware or software unit, or a single component may be distributed into multiple hardware or software units. Therefore, even if not specifically mentioned, such integrated or distributed embodiments are also included within the scope of this disclosure.

[0038] In the present disclosure, the components described in various embodiments are not necessarily essential components, and some may be optional components. Therefore, embodiments comprising a subset of the components described in one embodiment are also within the scope of the present disclosure. Furthermore, embodiments including other components in addition to the components described in various embodiments are also within the scope of the present disclosure.

[0039] The present disclosure relates to encoding and decoding of video. For example, the methods and embodiments disclosed in this document can be applied to methods disclosed in the versatile video coding (VVC) standard, the essential video coding (EVC) standard, the AOMedia Video 1 (AV1) standard, the second generation of audio video coding standard (AVS2), or the next generation of video / image coding standards (e.g., H.267 or H.268).

[0040] The present disclosure presents various embodiments of video / image coding, and unless otherwise stated, the embodiments may be performed in combination with each other.

[0041] Terms used in this disclosure may have their usual meanings commonly used in the technical field to which this disclosure belongs, unless newly defined in this disclosure.

[0042] In this disclosure, "video" may mean a set of images over time. In this disclosure, "picture" generally means a unit representing one image at a specific time point, and a slice / tile is a unit that constitutes a part of a picture in coding. A slice / tile may include one or more CTUs (coding tree units). A picture may be composed of one or more slices / tiles. A picture may be composed of one or more tile groups. A tile group may include one or more tiles. A brick may represent a rectangular area of ​​CTU rows within a tile in a picture. In this document, tile group and slice may be used interchangeably. For example, in this document, a tile group / tile group header may be referred to as a slice / slice header.

[0043] In the present disclosure, "pixel" or "pel" may refer to the smallest unit that constitutes a picture (or image). Additionally, "sample" may be used as a term corresponding to a pixel. A sample may generally represent a pixel or a pixel value, and may represent only a pixel / pixel value of a luma component or only a pixel / pixel value of a chroma component.

[0044] In the present disclosure, a "unit" may represent a basic unit of image processing. A unit may include at least one of a specific region of a picture and information related to the region. One unit may include one luma block and two chroma (e.g., cb, cr) blocks. In some cases, the term "unit" may be used interchangeably with terms such as "block" or "area." In general, an MxN block may include a set (or array) of samples (or sample array) or transform coefficients consisting of M columns and N rows.

[0045] In the present disclosure, the "current block" may mean one of the following: a "current coding block," a "current coding unit," a "block to be encoded," a "block to be decoded," or a "block to be processed." When prediction is performed, the "current block" may mean a "current prediction block" or a "block to be predicted." When transformation (inverse transformation) / quantization (inverse quantization) is performed, the "current block" may mean a "current transformation block" or a "block to be transformed." When filtering is performed, the "current block" may mean a "block to be filtered."

[0046] In the present disclosure, a "current block" may mean a block that includes both a luma component block and a chroma component block, or a "luma block of the current block," unless explicitly described as a chroma block. The luma component block of the current block may be explicitly expressed by including an explicit description of the luma component block, such as "luma block" or "current luma block." Additionally, the chroma component block of the current block may be explicitly expressed by including an explicit description of the chroma component block, such as "chroma block" or "current chroma block."

[0047] In this disclosure, " / " and "," can be interpreted as "and / or". For example, "A / B" and "A, B" can be interpreted as "A and / or B". Additionally, "A / B / C" and "A, B, C" can mean "at least one of A, B, and / or C."

[0048] In this disclosure, "or" may be interpreted as "and / or." For example, "A or B" may mean 1) "A" only, 2) "B" only, or 3) "A and B." Alternatively, "or" in this disclosure may mean "additionally or alternatively."

[0049] FIG. 1 is a schematic diagram illustrating a video / image coding system to which an embodiment according to the present disclosure can be applied.

[0050] Referring to FIG. 1, a video / image coding system may include a first device (source device) and a second device (receiving device). The source device may transmit encoded video / image or data to the receiving device via a digital storage medium or a network in the form of a file or streaming.

[0051] The source device may include a video source, an encoding device, and a transmitter. The receiving device may include a receiver, a decoding device, and a renderer. The encoding device may be referred to as a video / video encoding device, and the decoding device may be referred to as a video / video decoding device. The transmitter may be included in the encoding device. The receiver may be included in the decoding device. The renderer may include a display unit, and the display unit may be configured as a separate device or an external component.

[0052] A video source may obtain video / images through a process of capturing, synthesizing, or generating video / images. The video source may include a video / image capture device and / or a video / image generation device. A video / image capture device may include, for example, one or more cameras, a video / image archive containing previously captured video / images, etc. A video / image generation device may include, for example, a computer, a tablet, a smartphone, etc., and may (electronically) generate video / images. For example, a virtual video / image may be generated through a computer, etc., in which case the video / image capture process may be replaced by a process of generating related data.

[0053] An encoding device can encode input video / images. The encoding device can perform a series of procedures, such as prediction, transformation, and quantization, to improve compression and coding efficiency. The encoded data (encoded video / image information) can be output in the form of a bitstream.

[0054] The transmission unit can transmit encoded video / image information or data output in the form of a bitstream to the receiving unit of a receiving device via a digital storage medium or network in the form of a file or streaming. The digital storage medium can include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, etc. The transmission unit can include an element for generating a media file via a predetermined file format and an element for transmission via a broadcasting / communication network. The receiving unit can receive / extract the bitstream and transmit it to a decoding device.

[0055] The decoding device can decode the video / image by performing a series of procedures such as inverse quantization, inverse transformation, and prediction corresponding to the operation of the encoding device.

[0056] The renderer can render decoded video / images. The rendered video / images can be displayed through the display unit.

[0057] FIG. 2 is a schematic diagram illustrating an encoding device to which an embodiment according to the present disclosure can be applied.

[0058] Referring to FIG. 2, the encoding device (200) may be configured to include an image partitioner (210), a prediction unit (predictor) 220, a residual processor (residual processor) 230, an entropy encoder (entropy encoder) 240, an adder (adder) 250, a filter (filter) 260, and a memory (memory) 270. The prediction unit (220) may include an inter prediction unit (221) and an intra prediction unit (222). The residual processor (230) may include a transformer (transformer) 232, a quantizer (quantizer) 233, a dequantizer (dequantizer) 234, and an inverse transformer (inverse transformer) 235. The residual processing unit (230) may further include a subtractor (231). The addition unit (250) may be called a reconstructor or a recontructed block generator. The image segmentation unit (210), the prediction unit (220), the residual processing unit (230), the entropy encoding unit (240), the addition unit (250), and the filtering unit (260) described above may be configured by one or more hardware components (e.g., an encoder chipset or a processor) depending on the embodiment. In addition, the memory (270) may include a DPB (Decoded Picture Buffer) and may be configured by a digital storage medium. The hardware component may further include the memory (270) as an internal / external component.

[0059] The image segmentation unit (210) can segment an input image (or picture, frame) input to the encoding device (200) into one or more processing units. For example, the processing units may be referred to as coding units (CUs). A coding unit may be recursively segmented into a coding tree unit (CTU) or a largest coding unit (LCU) according to a QTBTTT (Quad-tree binary-tree ternary-tree) structure. For example, one coding unit may be segmented into a plurality of coding units of deeper depth based on a quad-tree structure, a binary tree structure, and / or a ternary tree structure. For example, the quad-tree structure may be applied first, and the binary tree structure and / or the ternary tree structure may be applied later. Alternatively, the binary tree structure may be applied first. A coding procedure according to the present disclosure may be performed based on a final coding unit that is no longer segmented. In this case, based on coding efficiency according to image characteristics, etc., the maximum coding unit may be used as the final coding unit, or, if necessary, the maximum coding unit may be recursively divided into coding units of lower depths, and the coding unit of the optimal size may be used as the final coding unit. Here, the coding procedure may include procedures such as prediction, transformation, and restoration, which will be described later. As another example, the processing unit may further include a prediction unit (PU) or a transformation unit (TU). The prediction unit and the transformation unit may each be divided or partitioned from the final coding unit.The above prediction unit may be a unit of sample prediction, and the above transformation unit may be a unit for deriving a transformation coefficient and / or a unit for deriving a residual signal from a transformation coefficient.

[0060] The term "unit" may be used interchangeably with terms such as "block" or "area" depending on the case. In general, an MxN block can represent a set of samples or transform coefficients consisting of M columns and N rows. A sample can generally represent a pixel or a pixel value, and can represent only the pixel / pixel value of the luminance component, or only the pixel / pixel value of the chroma component. A sample can be used as a term corresponding to a pixel or pel in a picture (or image).

[0061] The encoding device (200) can generate a residual signal (residual block, residual sample array) by subtracting a prediction signal (predicted block, prediction sample array) output from an inter prediction unit (221) or an intra prediction unit (222) from an input video signal (original block, original sample array), and the generated residual signal is transmitted to a conversion unit (232). In this case, as illustrated, a unit that subtracts a prediction signal (prediction block, prediction sample array) from an input video signal (original block, original sample array) within the encoding device (200) may be called a subtraction unit (231). The prediction unit (220) can perform prediction on a block to be processed (hereinafter, current block) and generate a predicted block including prediction samples for the current block. The prediction unit (220) can determine whether intra prediction or inter prediction is applied on a current block or CU basis. The prediction unit (220) can generate various information regarding prediction, such as prediction mode information, as described later in the description of each prediction mode, and transmit the information to the entropy encoding unit (240). The information regarding prediction can be encoded in the entropy encoding unit (240) and output in the form of a bitstream.

[0062] The intra prediction unit (222) can predict the current block by referring to samples within the current picture. The referenced samples may be located in the neighborhood of the current block or may be located away from it depending on the prediction mode. In intra prediction, the prediction modes may include multiple non-directional modes and multiple directional modes. The non-directional modes may include, for example, a DC mode and a planar mode. The directional modes may include, for example, 33 directional prediction modes or 65 directional prediction modes depending on the degree of detail in the prediction direction. However, this is merely an example, and a greater or lesser number of directional prediction modes may be used depending on the settings. The intra prediction unit (222) may also determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring blocks.

[0063] The inter prediction unit (221) can derive a predicted block for the current block based on a reference block (reference sample array) specified by a motion vector on a reference picture. At this time, in order to reduce the amount of motion information transmitted in the inter prediction mode, the motion information can be predicted in units of blocks, subblocks, or samples based on the correlation of the motion information between the neighboring blocks and the current block. The motion information can include a motion vector and a reference picture index. The motion information can further include information on the inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.). In the case of inter prediction, the neighboring block can include a spatial neighboring block existing in the current picture and a temporal neighboring block existing in the reference picture. The reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different from each other. The temporal neighboring block may be called a collocated reference block, a collocated CU (colCU), etc. A reference picture including the above temporal neighboring blocks may be called a collocated picture (colPic). For example, the inter prediction unit (221) may construct a motion information candidate list based on neighboring blocks and generate information indicating which candidate is used to derive the motion vector and / or reference picture index of the current block. Inter prediction may be performed based on various prediction modes, and for example, in the case of skip mode and merge mode, the inter prediction unit (221) may use the motion information of neighboring blocks as the motion information of the current block. In the case of skip mode, unlike the merge mode, a residual signal may not be transmitted.In the motion vector prediction (MVP) mode, the motion vector of the surrounding blocks is used as a motion vector predictor, and the motion vector of the current block can be indicated by signaling the motion vector difference.

[0064] The prediction unit (220) can generate a prediction signal based on various prediction methods and / or prediction techniques described below. For example, the prediction unit (220) can apply intra prediction or inter prediction to predict the current block, and can also apply intra prediction and inter prediction simultaneously. A prediction method that simultaneously applies intra prediction and inter prediction to predict the current block may be called combined inter and intra prediction (CIIP). In addition, the prediction unit (220) may be based on an intra block copy (IBC) prediction mode or a palette mode for predicting a block. The IBC prediction mode or palette mode may be used for content image / video coding such as games, such as screen content coding (SCC). IBC basically performs prediction within the current picture, but can be performed similarly to inter prediction in that it derives a reference block within the current picture. That is, IBC may utilize at least one of the inter prediction techniques described in this document. Palette mode can be viewed as an example of intracoding or intraprediction. When applied, palette mode can signal sample values ​​within a picture based on information about the palette table and palette index.

[0065] The prediction signal generated through the prediction unit (220) can be used to generate a restoration signal or a residual signal. The subtraction unit (231) can generate a residual signal (residual block, residual sample array) by subtracting the prediction signal (predicted block, predicted sample array) output from the prediction unit (220) from the input image signal (original block, original sample array). The generated residual signal can be transmitted to the conversion unit (232).

[0066] The transform unit (232) can apply a transform technique to the residual signal to generate transform coefficients. For example, the transform technique can include at least one of a Discrete Cosine Transform (DCT), a Discrete Sine Transform (DST), a Karhunen-Loeve Transform (KLT), a Graph-Based Transform (GBT), or a Conditionally Non-linear Transform (CNT). Here, GBT refers to a transform obtained from a graph when the relationship information between pixels is expressed as a graph. CNT refers to a transform obtained based on generating a prediction signal using all previously reconstructed pixels. The transform process can be applied to a pixel block having a square equal size, or can be applied to a block of a non-square variable size.

[0067] The quantization unit (233) can quantize the transform coefficients and transmit them to the entropy encoding unit (240). The entropy encoding unit (240) can encode the quantized signal (information about the quantized transform coefficients) and output it as a bitstream. The information about the quantized transform coefficients can be called residual information. The quantization unit (233) can rearrange the quantized transform coefficients in a block form into a one-dimensional vector form based on the coefficient scan order, and can also generate information about the quantized transform coefficients based on the quantized transform coefficients in the one-dimensional vector form.

[0068] The entropy encoding unit (240) can perform various encoding methods such as, for example, exponential Golomb, context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), etc. The entropy encoding unit (190) can also encode, together or separately, information necessary for video / image restoration (e.g., values ​​of syntax elements, etc.) in addition to quantized transform coefficients. The encoded information (e.g., encoded video / image information) can be transmitted or stored in the form of a bitstream in the form of a network abstraction layer (NAL) unit. The video / image information may further include information on various parameter sets such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS). In addition, the video / image information may further include general constraint information. The signaled information, transmitted information, and / or syntax elements mentioned in the present disclosure may be included in video / image information. The video / image information may be encoded through the encoding procedure described above and included in the bitstream.

[0069] The above bitstream may be transmitted via a network or stored in a digital storage medium. Here, the network may include a broadcasting network and / or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, etc. A transmission unit (not shown) for transmitting the signal output from the entropy encoding unit (240) and / or a storage unit (not shown) for storing the signal may be provided as an internal / external element of the encoding device (200), or the transmission unit may be provided as a component of the entropy encoding unit (240).

[0070] The quantized transform coefficients output from the quantization unit (233) can be used to generate a residual signal. For example, by applying inverse quantization and inverse transformation to the quantized transform coefficients through the inverse quantization unit (234) and inverse transformation unit (235), a residual signal (residual block or residual samples) can be restored.

[0071] Meanwhile, LMCS (luma mapping with chroma scaling) may be applied during the picture encoding and / or restoration process.

[0072] The addition unit (250) can generate a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array) by adding the reconstructed residual signal to the prediction signal output from the inter prediction unit (221) or the intra prediction unit (222). When there is no residual for the block to be processed, such as when skip mode is applied, the predicted block can be used as the reconstructed block. The addition unit (250) can be called a reconstructed unit or a reconstructed block generation unit. The generated reconstructed signal can be used for intra prediction of the next block to be processed within the current picture, and can also be used for inter prediction of the next picture after filtering as described below.

[0073] The filtering unit (260) can improve subjective / objective picture quality by applying filtering to the restoration signal. For example, the filtering unit (260) can apply various filtering methods to the restoration picture to generate a modified restoration picture, and store the modified restoration picture in the memory (270), specifically, the DPB of the memory (170). The various filtering methods may include, for example, deblocking filtering, sample adaptive offset, adaptive loop filter, bilateral filter, etc. The filtering unit (260) can generate various information regarding filtering and transmit it to the entropy encoding unit (240), as described later in the description of each filtering method. The information regarding filtering can be encoded by the entropy encoding unit (240) and output in the form of a bitstream.

[0074] The modified restored picture transmitted to the memory (270) can be used as a reference picture in the inter prediction unit (221). Through this, when inter prediction is applied, the encoding device (200) can avoid prediction mismatch between the encoding device (200) and the decoding device, and can also improve encoding efficiency.

[0075] The DPB in the memory (270) can store a modified reconstructed picture to be used as a reference picture in the inter prediction unit (221). The memory (270) can store motion information of a block from which motion information in the current picture is derived (or encoded) and / or motion information of blocks in a picture that has already been reconstructed. The stored motion information can be transferred to the inter prediction unit (221) to be used as motion information of a spatial neighboring block or motion information of a temporal neighboring block. The memory (270) can store reconstructed samples of reconstructed blocks in the current picture and transfer them to the intra prediction unit (222).

[0076] FIG. 3 is a schematic diagram illustrating a decoding device to which an embodiment according to the present disclosure can be applied.

[0077] As illustrated in FIG. 3, the decoding device (300) may be configured to include an entropy decoder (310), a residual processor (320), a predictor (330), an adder (340), a filter (350), and a memory (360). The predictor (330) may include an inter-prediction unit (332) and an intra-prediction unit (331). The residual processor (320) may include a dequantizer (321) and an inverse transformer (321). The entropy decoding unit (310), residual processing unit (320), prediction unit (330), addition unit (340), and filtering unit (350) described above may be configured by a single hardware component (e.g., decoder chipset or processor) depending on the embodiment. In addition, the memory (360) may include a decoded picture buffer (DPB) and may be configured by a digital storage medium. The hardware component may further include the memory (360) as an internal / external component.

[0078] When a bitstream including video / image information is input, the decoding device (300) can restore the image by performing a process corresponding to the process performed in the encoding device (200) of FIG. 2. For example, the decoding device (300) can perform decoding using a processing unit applied in the encoding device (200). Therefore, the processing unit for decoding may be, for example, a coding unit. The coding unit may be a coding tree unit or may be obtained by dividing the maximum coding unit according to a quad tree structure, a binary tree structure, and / or a ternary tree structure. In addition, the restored image signal decoded and output by the decoding device (300) can be reproduced through a reproduction device (not shown).

[0079] The decoding device (300) can receive a signal output from the encoding device (200) of FIG. 2 in the form of a bitstream. The received signal can be decoded through the entropy decoding unit (310). For example, the entropy decoding unit (310) can parse the bitstream to derive information (e.g., video / image information) necessary for image restoration (or picture restoration). The video / image information may further include information on various parameter sets, such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS). In addition, the video / image information may further include general constraint information. The decoding device (300) can decode a picture further based on the information on the parameter set and / or the general constraint information. The signaling / received information and / or syntax elements described below can be decoded through the decoding procedure and obtained from the bitstream. For example, the entropy decoding unit (310) can decode information in the bitstream based on a coding method such as exponential Golomb coding, CAVLC, or CABAC, and output the values ​​of syntax elements required for image restoration and the quantized values ​​of transform coefficients for residuals. More specifically, the CABAC entropy decoding method receives a bin corresponding to each syntax element in the bitstream, determines a context model using information of the syntax element to be decoded and decoding information of the surrounding and decoding target blocks or information of symbols / bins decoded in the previous step, and predicts the occurrence probability of the bin according to the determined context model to perform arithmetic decoding of the bin to generate a symbol corresponding to the value of each syntax element.At this time, the CABAC entropy decoding method can update the context model using the information of the decoded symbol / bin for the context model of the next symbol / bin after determining the context model. Information regarding prediction among the information decoded by the entropy decoding unit (310) is provided to the prediction unit (330), and residual values ​​on which entropy decoding is performed by the entropy decoding unit (310), i.e., quantized transform coefficients and related parameter information, can be input to the residual processing unit (320). The residual processing unit (320) can derive a residual signal (residual block, residual samples, residual sample array). In addition, information regarding filtering among the information decoded by the entropy decoding unit (310) can be provided to the filtering unit (350). Meanwhile, a receiving unit (not shown) that receives a signal output from an encoding device may be further configured as an internal / external element of the decoding device (300), or the receiving unit may be a component of an entropy decoding unit (310). Meanwhile, the decoding device according to the present document may be called a video / video / picture decoding device, and the decoding device may be divided into an information decoder (video / video / picture information decoder) and a sample decoder (video / video / picture sample decoder). The information decoder may include the entropy decoding unit (310), and the sample decoder may include at least one of the inverse quantization unit (321), the inverse transformation unit (322), the addition unit (340), the filtering unit (350), the memory (360), the inter prediction unit (332), and the intra prediction unit (331).

[0080] The inverse quantization unit (321) can inverse quantize the quantized transform coefficients and output the transform coefficients. The inverse quantization unit (321) can rearrange the quantized transform coefficients into a two-dimensional block form. In this case, the rearrangement can be performed based on the coefficient scanning order performed in the encoding device (200). The inverse quantization unit (321) can perform inverse quantization on the quantized transform coefficients using quantization parameters (e.g., quantization step size information) and obtain transform coefficients.

[0081] In the inverse transform unit (322), the transform coefficients can be inversely transformed to obtain a residual signal (residual block, residual sample array).

[0082] The prediction unit (330) can generate a prediction signal based on various prediction methods described below. For example, the prediction unit can apply intra prediction or inter prediction for prediction of a single block, and can also apply intra prediction and inter prediction simultaneously. This can be called combined inter and intra prediction (CIIP). In addition, the prediction unit can be based on an intra block copy (IBC) prediction mode or a palette mode for prediction of a block. The IBC prediction mode or palette mode can be used for content image / video coding such as games, such as screen content coding (SCC). IBC basically performs prediction within the current picture, but can be performed similarly to inter prediction in that it derives a reference block within the current picture. That is, IBC can utilize at least one of the inter prediction techniques described in this document. Palette mode can be viewed as an example of intra coding or intra prediction. When palette mode is applied, information about the palette table and palette index may be signaled and included in the video / image information.

[0083] The intra prediction unit (331) can predict the current block by referring to samples within the current picture. The description of the intra prediction unit (222) can be equally applied to the intra prediction unit (331). The referenced samples may be located in the neighborhood of the current block or may be located away from it, depending on the prediction mode. In intra prediction, the prediction modes may include multiple non-directional modes and multiple directional modes. The intra prediction unit (331) can also determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring blocks.

[0084] The inter prediction unit (332) can derive a predicted block for the current block based on a reference block (reference sample array) specified by a motion vector on a reference picture. At this time, in order to reduce the amount of motion information transmitted in the inter prediction mode, the motion information can be predicted in units of blocks, sub-blocks, or samples based on the correlation of the motion information between the neighboring blocks and the current block. The motion information can include a motion vector and a reference picture index. The motion information can further include information on the inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.). In the case of inter prediction, the neighboring blocks can include spatial neighboring blocks existing in the current picture and temporal neighboring blocks existing in the reference picture. For example, the inter prediction unit (332) can construct a motion information candidate list based on the neighboring blocks, and derive the motion vector and / or reference picture index of the current block based on the received candidate selection information. Inter prediction can be performed based on various prediction modes (techniques), and the information about the prediction can include information indicating the mode (technique) of inter prediction for the current block.

[0085] The addition unit (340) can generate a restoration signal (restored picture, restoration block, restoration sample array) by adding the acquired residual signal to the prediction signal (predicted block, prediction sample array) output from the prediction unit (330) (including the inter prediction unit (332) and / or the intra prediction unit (331)). When there is no residual for the block to be processed, such as when the skip mode is applied, the predicted block can be used as the restoration block. The description of the addition unit (250) can be equally applied to the addition unit (340). The addition unit (340) can be called a restoration unit or a restoration block generation unit. The generated restoration signal can be used for intra prediction of the next block to be processed within the current picture, and can also be used for inter prediction of the next picture after going through filtering as described below.

[0086] Meanwhile, LMCS (luma mapping with chroma scaling) may be applied during the picture decoding process.

[0087] The filtering unit (350) can improve subjective / objective image quality by applying filtering to the restored signal. For example, the filtering unit (350) can apply various filtering methods to the restored picture to generate a modified restored picture, and store the modified restored picture in the memory (360), specifically, in the DPB of the memory (360). The various filtering methods can include, for example, deblocking filtering, sample adaptive offset, adaptive loop filter, bilateral filter, etc.

[0088] The (modified) reconstructed picture stored in the DPB of the memory (360) can be used as a reference picture in the inter prediction unit (332). The memory (360) can store motion information of a block from which motion information is derived (or decoded) within the current picture and / or motion information of blocks within a picture that has already been reconstructed. The stored motion information can be transmitted to the inter prediction unit (332) to be used as motion information of a spatial neighboring block or motion information of a temporal neighboring block. The memory (360) can store reconstructed samples of reconstructed blocks within the current picture and transmit them to the intra prediction unit (331).

[0089] In this specification, the embodiments described in the filtering unit (260), the inter prediction unit (221), and the intra prediction unit (222) of the encoding device (200) can be applied to the filtering unit (350), the inter prediction unit (332), and the intra prediction unit (331) of the decoding device (300) in the same or corresponding manner, respectively.

[0090] Figure 4 illustrates an example of a hierarchical structure for coded video / images.

[0091] Referring to FIG. 4, the coded image is divided into a VCL (Video Coding Layer) that handles the decoding processing of the image and the image itself, a subsystem that transmits and stores the coded information, and a NAL (Network Abstraction Layer) that exists between the VCL and the subsystem and is responsible for network adaptation functions.

[0092] In VCL, VCL data containing compressed image data (slice data) can be generated, or a parameter set containing information such as a picture parameter set (PPS), a sequence parameter set (SPS), a video parameter set (VPS), etc., or an SEI (Supplemental Enhancement Information) message additionally required for the image decoding process can be generated.

[0093] In NAL, a NAL unit can be created by adding header information (NAL unit header) to an RBSP (Raw Byte Sequence Payload) generated from a VCL. At this time, RBSP refers to slice data, parameter sets, SEI messages, etc. generated from a VCL. The NAL unit header can include NAL unit type information that is specific to the RBSP data included in the NAL unit.

[0094] As illustrated in Fig. 4, NAL units can be divided into VCL NAL units and non-VCL NAL units according to the RBSP generated from VCL. A VCL NAL unit can refer to a NAL unit that contains information about a video (slice data), and a non-VCL NAL unit can refer to a NAL unit that contains information necessary for decoding a video (parameter set or SEI message).

[0095] The above-described VCL NAL units and non-VCL NAL units can be transmitted over a network by attaching header information according to the data specifications of the lower system. For example, NAL units can be transformed into data formats of a certain standard, such as the H.266 / VVC file format, RTP (Real-time Transport Protocol), TS (Transport Stream), etc., and transmitted over various networks.

[0096] As described above, a NAL unit can be specified as a NAL unit type according to the RBSP data structure included in the NAL unit, and information about the NAL unit type can be stored and signaled in the NAL unit header.

[0097] For example, depending on whether a NAL unit contains information about a picture (slice data), it can be broadly classified into VCL NAL unit types and Non-VCL NAL unit types. The VCL NAL unit type can be classified according to the nature and type of the picture contained in the VCL NAL unit, and the Non-VCL NAL unit type can be classified according to the type of parameter set, etc.

[0098] Below are examples of NAL unit types, specified by the type of parameter set included in the Non-VCL NAL unit type.

[0099] - APS (Adaptation Parameter Set) NAL unit: Type for NAL units containing APS

[0100] - DPS (Decoding Parameter Set) NAL unit: Type for NAL unit containing DPS

[0101] - VPS (Video Parameter Set) NAL unit: Type for NAL units containing VPS

[0102] - SPS (Sequence Parameter Set) NAL unit: Type for NAL units containing SPS

[0103] - PPS (Picture Parameter Set) NAL unit: Type for NAL units containing PPS

[0104] The above-described NAL unit types have syntax information for the NAL unit type, and the syntax information can be stored and signaled in the NAL unit header. For example, the syntax information can be nal_unit_type, and NAL unit types can be specified by the nal_unit_type value.

[0105] The slice header (slice header syntax, slice header information) may include information / parameters that are commonly applicable to the slices. The APS (APS syntax) or PPS (PPS syntax) may include information / parameters that are commonly applicable to one or more slices or pictures. The SPS (SPS syntax) may include information / parameters that are commonly applicable to one or more sequences. The VPS (VPS syntax) may include information / parameters that are commonly applicable to multiple layers. The DPS (DPS syntax) may include information / parameters that are commonly applicable to the entire video. The DPS may include information / parameters related to the concatenation of CVS (coded video sequence). In the present disclosure, the High Level Syntax (HLS) may include at least one of the APS syntax, PPS syntax, SPS syntax, VPS syntax, DPS syntax, or slice header syntax.

[0106] In the present disclosure, image / video information encoded in an encoding device and signaled in the form of a bitstream may include information related to partitioning within a picture, intra / inter prediction information, residual information, in-loop filtering information, etc., and may also include information included in the slice header, information included in the APS, information included in the PPS, information included in the SPS, information included in the VPS, and / or information included in the DPS.

[0107] Below, the SEI message related to the present invention will be described.

[0108] Table 1 shows an example of the object mask information SEI message syntax according to one embodiment.

[0109] [Table 1]

[0110]

[0111]

[0112] The Object Mask Information (OMI) SEI message provides information about object mask images coded as auxiliary pictures.

[0113] Using this SEI message requires defining the following variables:

[0114] - The width and height of the cropped picture in luminance sample units, denoted as CroppedWidth and CroppedHeight, respectively.

[0115] - Conformance cropping window left offset, ConfWinLeftOffset.

[0116] - Conformance cropping window top offset, ConfWinTopOffset.

[0117] - Chroma format indicator, denoted as ChromaFormatIdc.

[0118] The variables SubWidthC and SubHeightC are derived from ChromaFormatIdc.

[0119] If an access unit contains an auxiliary image picA contained in one layer with nuh_layer_id nuhLayerIdA, which is designated as an object mask auxiliary layer by an OMI SEI message, and a primary image picB contained in one layer with nuh_layer_id nuhLayerIdB, which is designated as a primary layer by an OMI SEI message, the OMI SEI message continues in the output order until one or more of the following conditions are met:

[0120] - CLVS containing auxiliary picture picA is terminated.

[0121] - CLVS containing the primary image picB is terminated.

[0122] - CVS is shutting down.

[0123] - The bitstream ends.

[0124] If the omi_cancel_flag value is 1, this SEI message indicates that the persistence of all previous Object Mask Information SEI messages in the output order is canceled.

[0125] If the omi_cancel_flag value is 0, it indicates that the object mask information will continue to be maintained.

[0126] omi_aux_id_minus128 plus 128 represents the sdi_aux_id value of the object mask auxiliary picture layer. The omi_aux_id_minus128 value must be in the range of 0 to 31.

[0127] If a CVS does not contain an SDI SEI message where sdi_aux_id[i] for at least one value of i is equal to omi_aux_id_minus128 + 128, then no picture in that CVS can be associated with an OMI SEI message.

[0128] If an access unit (AU) contains both an SDI SEI message and an OMI SEI message where sdi_aux_id[i] for at least one value of i is equal to omi_aux_id_minus128 + 128, then the SDI SEI message shall precede the OMI SEI message in decoding order.

[0129] omi_num_primary_pic_layer_minus1 plus 1 indicates the number of primary picture layers associated with the object mask auxiliary picture layer to which this SEI message applies. The value of omi_num_primary_pic_layer_minus1 must be in the range of 0 to sdi_max_layers_minus1, inclusive.

[0130] omi_primary_pic_layer_id[i] specifies the nuh_layer_id value of the ith primary picture layer associated with the object mask auxiliary picture layer to which this OMI SEI message applies. If sdi_layer_id[j] is equal to omi_primary_pic_layer_id[i], the value of sdi_aux_id[j] must be 0 for all values ​​of j in the range from 0 to sid_max_layers_minus1, inclusive.

[0131] omi_num_aux_pic[i] represents the number of auxiliary picture layers associated with the ith primary picture layer associated with the object mask auxiliary picture layer. According to the bitstream conformance requirement, the value of omi_num_aux_pic[i] must be equal to numAuxLayer[omi_primary_pic_layer_id[i]] for the value of i from 0 to omi_num_primary_pic_layer_minus1. Here, the variable numAuxLayer[primaryLayerId] represents the number of object mask auxiliary picture layers associated with the primary picture layer whose nuh_layer_id is equal to primaryLayerId, and is derived as shown in Table 2 below.

[0132] [Table 2]

[0133]

[0134] omi_mask_id_length_minus1 plus 1 specifies the length in bits of the omi_mask_id[i][j][k] syntax elements.

[0135] omi_mask_sample_value_length_minus8 plus 8 specifies the length in bits of the omi_aux_sample_value[i][j][k] syntax elements. The value of omi_mask_sample_value_length_minus8 must be in the range 0 to 8.

[0136] If the omi_mask_confidence_info_present_flag value is 1, it indicates that the omi_mask_confidence[i][j][k] syntax elements are present. If the omi_mask_confidence_info_present_flag value is 0, it indicates that the omi_mask_confidence[i][j][k] syntax elements are not present.

[0137] omi_mask_confidence_length_minus1 plus 1 specifies the length in bits of the omi_mask_confidence[i][j][k] syntax elements.

[0138] If the omi_mask_depth_info_present_flag value is 1, it indicates that the omi_mask_depth[i][j][k] syntax elements are present. If the omi_mask_depth_info_present_flag value is 0, it indicates that the omi_mask_depth[i][j][k] syntax elements are not present.

[0139] omi_mask_depth_length_minus1 plus 1 specifies the length in bits of the omi_mask_depth[i][j][k] syntax elements.

[0140] According to bitstream conformance requirements, omi_aux_id_minus128, omi_num_primary_pic_layer_minus1, omi_primary_pic_layer_id[ i ], omi_num_aux_pic[ i ], omi_mask_id_length_minus1 and omi_mask_sample_value_length_minus8, omi_mask_confidence_info_present_flag, omi_mask_confidence_length_minus1, omi_mask_depth_info_present_flag and omi_mask_depth_length_minus1 must be identical in all object_mask_info( ) syntax structures within a CVS.

[0141] If the omi_mask_label_info_present_flag value is 1, it indicates that the omi_mask_label_language_present_flag and omi_mask_label[i][j][k] syntax elements are present. If the omi_mask_label_info_present_flag value is 0, it indicates that the omi_mask_label_language_present_flag and omi_mask_label[i][j][k] syntax elements are not present.

[0142] If the omi_mask_label_language_present_flag value is 1, it indicates that the omi_mask_label_language syntax elements are present. If the omi_mask_label_language_present_flag value is 0, it indicates that the omi_mask_label_language syntax elements are not present.

[0143] The omi_bit_equal_to_zero value must be 0.

[0144] omi_mask_label_language contains a language tag as specified in IETF RFC 5646 followed by a null termination byte equal to 0x00. The length of the omi_mask_label_language syntax element must be less than or equal to 255 bytes, excluding the null termination byte. If the omi_mask_label_language syntax element is not present, the language of the label is unspecified.

[0145] If the value of omi_mask_pic_update_flag[i][j] is 1, it indicates that the mask information of the j-th object mask auxiliary picture associated with the i-th primary picture is signaled. If the value of omi_mask_pic_update_flag[i][j] is 0, it indicates that the mask information of the j-th object mask auxiliary picture associated with the i-th primary picture is not signaled. If the mask information of the j-th object mask auxiliary picture associated with the i-th primary picture does not exist, the persistence mechanism is used, i.e., the mask information is inherited from the last OMI SEI message that signaled the mask information of the j-th object mask auxiliary picture associated with the i-th primary picture.

[0146] omi_num_mask_in_pic_update[i][j] represents the number of object masks signaled in the jth object mask auxiliary picture associated with the ith primary picture. The value of omi_num_mask_in_pic_update[i][j] must be in the range of 0 to (1 << (omi_mask_id_length_minus1 + 1)) - 1.

[0147] omi_mask_id[i][j][k] represents the identifier of the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture. The length of the omi_mask_id[i][j][k] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0148] The variable maskId[i][j][k], which specifies the global identifier of the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture within the SEI message, is derived as shown in Table 3 below.

[0149] [Table 3]

[0150]

[0151] If the omi_mask_bounding_box_present_flag[i][j][k] value is 1, it indicates that the syntax elements omi_mask_top[i][j][k], omi_mask_left[i][j][k], omi_mask_width[i][j][k], and omi_mask_height[i][j][k] are present. If the omi_mask_bounding_box_present_flag[i][j][k] value is 0, it indicates that the syntax elements omi_mask_top[i][j][k], omi_mask_left[i][j][k], omi_mask_width[i][j][k], and omi_mask_height[i][j][k] are not present.

[0152] omi_mask_top[i][j][k], omi_mask_left[i][j][k], omi_mask_width[i][j][k], and omi_mask_height[i][j][k] represent the top-left coordinate, width, and height of the bounding box of the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture in the cropped decoded picture, relative to the conformance cropping window specified by the activated SPS.

[0153] The omi_mask_left[i][j][k] values ​​must be in the range of 0 to (CroppedWidth / SubWidthC - 1), where CroppedWidth and SubWidthC are associated with the jth object mask auxiliary picture associated with the ith primary picture. If the omi_mask_left[i][j][k] value does not exist, the omi_mask_left[i][j][k] value is considered to be 0.

[0154] The omi_mask_top[i][j][k] values ​​must be in the range of 0 to (CroppedHeight / SubHeightC - 1), where CroppedHeight and SubHeightC are associated with the jth object mask auxiliary picture associated with the ith primary picture. If the omi_mask_top[i][j][k] value does not exist, the omi_mask_top[i][j][k] value is considered to be 0.

[0155] The omi_mask_width[i][j][k] value must be in the range of 0 to (CroppedWidth / SubWidthC - omi_mask_left[i][j][k]). If the omi_mask_width[i][j][k] value does not exist, the omi_mask_width[i][j][k] value is assumed to be (CroppedWidth / SubWidthC - omi_mask_left[i][j][k]).

[0156] The omi_mask_height[i][j][k] value must be in the range of 0 to (CroppedHeight / SubHeightC - omi_mask_top[i][j][k]). If the omi_mask_height[i][j][k] value does not exist, the omi_mask_height[i][j][k] value is considered to be (CroppedHeight / SubHeightC - omi_mask_top[i][j][k]).

[0157] The identified object mask is located within a bounding box containing luminance samples whose horizontal coordinates range from SubWidthC * (ConfWinLeftOffset + omi_mask_left[i][j][k]) to SubWidthC * (ConfWinLeftOffset + omi_mask_left[i][j][k] + omi_mask_width[i][j][k]) - 1, and whose vertical coordinates range from SubHeightC * (ConfWinTopOffset + omi_mask_top[i][j][k]) to SubHeightC * (ConfWinTopOffset + omi_mask_top[i][j][k] + omi_mask_height[i][j][k]) - 1.

[0158] The variable pI[i][j][x][y] represents the decoded sample value at the relative sample position (x, y) in the j-th object mask auxiliary picture that is cropped and associated with the i-th primary picture.

[0159] Table 4 below shows how to determine the mask area in the auxiliary picture.

[0160] [Table 4]

[0161]

[0162] If the value of omi_mask_cancel[i][j][k] is 1, it indicates that the persistence range of the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture is canceled. If the value of omi_mask_cancel[i][j][k] is 0, it indicates that the information of the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture is signaled.

[0163] As a bitstream conformance requirement, when a particular value of omi_mask_id[i][j][k] is parsed for the first time in the current CLVS, the corresponding omi_mask_cancel[i][j][k] value must be 0.

[0164] omi_mask_confidence[i][j][k] represents the degree of confidence of the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture, and its unit is 2-(omi_mask_confidence_length_minus1 + 1). A larger value of omi_mask_confidence[ i ][ j ][ k ] indicates a higher degree of confidence of the corresponding object mask. The length of the omi_mask_confidence[i][j][k] syntax element is omi_mask_confidence_length_minus1 + 1 bits.

[0165] omi_mask_depth[i][j][k] represents the object depth of the kth object mask signaled in the jth object mask auxiliary picture associated with the ith base picture. A smaller omi_mask_depth value indicates a shorter distance to the corresponding object. The length of the omi_mask_depth[i][j][k] syntax element is omi_mask_depth_length_minus1 + 1 bit.

[0166] omi_mask_label[i][j][k] specifies the contents of the label associated with the kth signaled object mask in the jth object mask auxiliary picture associated with the ith primary picture. The length of the syntax element of omi_mask_label[i][j][k] must be less than or equal to 255 bytes, excluding the null termination byte.

[0167] In the design of the Object Mask Information (OMI) SEI message, a single SEI message includes object mask information for all layers. This design has been pointed out to have at least the following problems.

[0168] 1. When there are multiple primary picture layers, it becomes difficult to perform bitstream thinning (i.e., remove some layers) because if one SEI message contains object mask information for all layers, it may be necessary to update the contents of the SEI message.

[0169] 2. Changing object mask information for one layer requires updating the SEI message containing information for all other layers. This is pointed out as inefficient.

[0170] 3. If persistence needs to be canceled, the current design requires object mask information for all base picture layers to be canceled simultaneously. This is undesirable because it requires synchronization between all base picture layers.

[0171] One embodiment provides a solution to the problem described above. Each embodiment may be performed individually or in combination with two or more embodiments.

[0172] A summary of one example is as follows.

[0173] 1. Modify the signaling method of Object Mask Information (OMI) in SEI messages so that one OMI SEI message only contains object mask information for pictures belonging to one primary picture layer.

[0174] 2. A single base picture layer can have object mask information through auxiliary pictures contained in one or more auxiliary picture layers. These auxiliary picture layers are called associated auxiliary picture layers.

[0175] 3. At any given time, there is only one active OMI SEI message in a primary picture layer.

[0176] 4. The OMI SEI message cancels the persistence of the previous OMI SEI message within the same base picture layer.

[0177] 5. If there is an OMI SEI message with a cancel flag value of 1, the persistence of the previous OMI SEI message within the same base picture layer is canceled.

[0178] The embodiments proposed by the present invention are described in detail as follows.

[0179] One embodiment provides a description of the summary described above.

[0180] Table 5 shows the syntax of an object mask information SEI message according to one embodiment.

[0181] [Table 5]

[0182]

[0183]

[0184] According to one embodiment, an Object Mask Information (OMI) SEI message provides object masking information for pictures in a layer associated with the corresponding SEI message. The object masking information is contained in auxiliary pictures that may be present in one or more associated auxiliary picture layers. Each associated auxiliary layer shall have nuh_layer_id equal to sdi_layer_id[i] whenever i is a value between 0 and sid_max_layers_minus1. The layer in which the pictures associated with the OMI SEI message are located is called a primary picture layer. Auxiliary layers that contain object mask data associated with pictures in the primary picture layer are called associated auxiliary picture layers.

[0185] Using SEI messages requires defining the following variables:

[0186] - The width and height of the cropped picture in luminance sample units. These are denoted as CroppedWidth and CroppedHeight, respectively.

[0187] - Left offset of the conformance cropping window, ConfWinLeftOffset

[0188] - Top offset of the conformance cropping window, ConfWinTopOffset

[0189] - Chroma format indicator, denoted as ChromaFormatIdc.

[0190] The SubWidthC and SubHeightC variables are derived from ChromaFormatIdc.

[0191] If the omi_cancel_flag value is 1, this SEI message indicates that the persistence of the previous object mask information SEI message existing in the base picture layer in the output order is canceled. If the omi_cancel_flag value is 0, this indicates that object mask information follows.

[0192] omi_persistence_flag specifies the persistence of the object mask information provided in this SEI message. If the omi_persistence_flag value is 0, it specifies that the object mask information applies only to the current picture. If the omi_persistence_flag value is 1, it specifies that the object mask information applies not only to the current picture but also to all pictures in the base picture layer that follow it in output order, until one or more of the following conditions are true:

[0193] - When a new CLVS of the base picture layer starts

[0194] - When the bitstream ends

[0195] - If the picture associated with the object mask information SEI message in the current layer is output after the current picture.

[0196] The omi_aux_id_minus128 plus 128 value represents the sdi_aux_id value of the object mask auxiliary picture layer. The value of omi_aux_id_minus128 must be in the range of 0 to 31.

[0197] If a CVS does not contain an SDI SEI message with sdi_aux_id[i] equal to omi_aux_id_minus128 plus 128, where i is in the range 0 to sid_max_layers_minus1, inclusive, then no picture in that CVS can be associated with an OMI SEI message.

[0198] If an AU (Access Unit) contains both an SDI SEI message and an OMI SEI message where sdi_aux_id[i] for at least one value of i is equal to omi_aux_id_minus128 plus 128, the SDI SEI message shall precede the OMI SEI message in decoding order.

[0199] omi_primary_pic_layer_id specifies the nuh_layer_id of the primary picture layer. For all values ​​of i in the range 0 to sid_max_layers_minus1, if sdi_layer_id[i] is equal to omi_primary_pic_layer_id, the corresponding sdi_aux_id[i] value must be 0.

[0200] omi_num_aux_pic represents the number of auxiliary layers associated with the primary layer. According to bitstream conformance requirements, the value of omi_num_aux_pic must be equal to numAuxLayer[omi_primary_pic_layer_id], where the variable numAuxLayer[omi_primary_pic_layer_id] represents the number of associated auxiliary layers, derived according to Table 6 below.

[0201] [Table 6]

[0202]

[0203] omi_mask_id_length_minus1 plus 1 specifies the length in bits of the omi_mask_id[i][j][k] syntax element.

[0204] omi_mask_sample_value_length_minus8 plus 8 specifies the length in bits of the omi_aux_sample_value[i][j][k] syntax element. The value of omi_mask_sample_value_length_minus8 must be in the range 0 to 8.

[0205] If the omi_mask_confidence_info_present_flag value is 1, it means that the omi_mask_confidence[i][j][k] syntax element exists. If the omi_mask_confidence_info_present_flag value is 0, it means that the omi_mask_confidence[i][j][k] syntax element does not exist.

[0206] omi_mask_confidence_length_minus1 plus 1 specifies the length in bits of the omi_mask_confidence[i][j][k] syntax element.

[0207] If the omi_mask_depth_info_present_flag value is 1, it means that the omi_mask_depth[i][j][k] syntax element exists. If the omi_mask_depth_info_present_flag value is 0, it means that the omi_mask_depth[i][j][k] syntax element does not exist.

[0208] omi_mask_depth_length_minus1 plus 1 specifies the length in bits of the omi_mask_depth[i][j][k] syntax element.

[0209] According to bitstream conformance requirements, in all object_mask_info() syntax structures within a CVS, the values ​​omi_aux_id_minus128, omi_num_primary_pic_layer_minus1, omi_primary_pic_layer_id[ i ], omi_num_aux_pic[ i ], omi_mask_id_length_minus1 and omi_mask_sample_value_length_minus8, omi_mask_confidence_info_present_flag, omi_mask_confidence_length_minus1, omi_mask_depth_info_present_flag and omi_mask_depth_length_minus1 must all be identical.

[0210] If the omi_mask_label_info_present_flag value is 1, it indicates that the omi_mask_label_language_present_flag and omi_mask_label[i][j][k] syntax elements are present.

[0211] If the omi_mask_label_info_present_flag value is 0, it indicates that the omi_mask_label_language_present_flag and omi_mask_label[i][j][k] syntax elements are not present.

[0212] If the omi_mask_label_language_present_flag value is 1, it indicates that the omi_mask_label_language syntax element exists, and if the omi_mask_label_language_present_flag value is 0, it indicates that the omi_mask_label_language syntax element does not exist.

[0213] The omi_bit_equal_to_zero value must be 0.

[0214] omi_mask_label_language contains a language tag specified according to IETF RFC 5646, followed by a null termination byte (value 0x00). The length of the omi_mask_label_language syntax element must be less than or equal to 255 bytes, excluding the null termination byte. If omi_mask_label_language does not exist, the label's language is considered unspecified.

[0215] If the value of omi_mask_pic_update_flag[i] is 1, it indicates that an update of the mask information from the i-th associated auxiliary picture layer is signaled. If the value of omi_mask_pic_update_flag[i] is 0, it indicates that there is no change in the mask information from the i-th associated auxiliary picture layer. If the value of omi_mask_pic_update_flag[i] is 0, the persistence mechanism is applied, i.e., the information inherits the mask information of the i-th associated auxiliary picture layer from the last OMI SEI message associated with the base picture layer.

[0216] omi_num_mask_in_pic_update[i] specifies the number of object masks signaled in the i-th associated auxiliary picture layer. The value of omi_num_mask_in_pic_update[i] must be in the range of 0 to (1 << (omi_mask_id_length_minus1 + 1)) - 1.

[0217] omi_mask_id[i][j] represents the identifier of the jth object mask in the ith associated auxiliary picture layer. The length of the omi_mask_id[i][j] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0218] The variable maskId[i][j], which is specified as a global identifier for the j-th object mask of the i-th associated auxiliary picture layer, is derived according to Table 7 below.

[0219] [Table 7]

[0220]

[0221] If the value of omi_mask_bounding_box_present_flag[i][j] is 1, it specifies that the syntax elements omi_mask_top[i][j], omi_mask_left[i][j], omi_mask_width[i][j], and omi_mask_height[i][j] are present, and if the value of omi_mask_bounding_box_present_flag[i][j] is 0, it specifies that the syntax elements omi_mask_top[i][j], omi_mask_left[i][j], omi_mask_width[i][j], and omi_mask_height[i][j] are not present.

[0222] omi_mask_top[i][j], omi_mask_left[i][j], omi_mask_width[i][j], and omi_mask_height[i][j] specify the upper left coordinate, width, and height, respectively, of the bounding box within the cropped decoded picture of the j-th signaled object mask in the i-th associated auxiliary picture layer, with respect to the conformance cropping window defined in the active SPS.

[0223] The value of omi_mask_left[i][j] must be in the range of 0 to (CroppedWidth / SubWidthC - 1), where CroppedWidth and SubWidthC are values ​​associated with the i-th associated auxiliary picture layer. If the corresponding syntax element does not exist, the value of omi_mask_left[i][j] is considered to be 0.

[0224] The value of omi_mask_top[i][j] must be in the range of 0 to (CroppedHeight / SubHeightC - 1), where CroppedHeight and SubHeightC are values ​​associated with the ith associated auxiliary picture layer. If the corresponding syntax element does not exist, the value of omi_mask_top[i][j] is assumed to be 0.

[0225] The value of omi_mask_width[i][j] must be in the range 0 to (CroppedWidth / SubWidthC - omi_mask_left[i][j]). If the corresponding syntax element is not present, the value of omi_mask_width[i][j] is assumed to be (CroppedWidth / SubWidthC - omi_mask_left[i][j]).

[0226] The value of omi_mask_height[i][j] must be in the range 0 to (CroppedHeight / SubHeightC - omi_mask_top[i][j]). If the corresponding syntax element is not present, the value of omi_mask_height[i][j] is assumed to be (CroppedHeight / SubHeightC - omi_mask_top[i][j]).

[0227] The identified object mask exists within a bounding box containing luminance samples whose horizontal coordinates range from SubWidthC × (ConfWinLeftOffset + omi_mask_left[i][j]) to SubWidthC × (ConfWinLeftOffset + omi_mask_left[i][j] + omi_mask_width[i][j]) - 1, and whose vertical coordinates range from SubHeightC × (ConfWinTopOffset + omi_mask_top[i][j]) to SubHeightC × (ConfWinTopOffset + omi_mask_top[i][j] + omi_mask_height[i][j]) - 1.

[0228] The variable pI[i][x][y] is the decoded sample value corresponding to the relative sample position (x, y) in the cropped i-th associated auxiliary layer. Table 8 below shows the process for determining the mask area within the auxiliary picture.

[0229] [Table 8]

[0230]

[0231] If the value of omi_mask_cancel[i][j] is 1, it indicates that the persistence range of the jth signaled object mask in the i-th associated auxiliary picture layer is canceled. If the value of omi_mask_cancel[i][j] is 0, it indicates that the information of the jth signaled object mask in the i-th associated auxiliary picture layer is valid.

[0232] As a bitstream conformance requirement, when an omi_mask_id[i][j] with a specific value in the current CLVS is parsed for the first time, the corresponding omi_mask_cancel[i][j] value must be 0.

[0233] omi_mask_confidence[i][j] represents the confidence level for the jth signaled object mask in the i-th associated auxiliary picture layer, and its unit is 2-(omi_mask_confidence_length_minus1 + 1). A larger value of omi_mask_confidence[i][j] indicates a higher confidence level. The length of the omi_mask_confidence[i][j] syntax element is omi_mask_confidence_length_minus1 + 1 bits.

[0234] omi_mask_depth[i][j] represents the depth of the object associated with the jth signaled object mask in the i-th associated auxiliary picture layer. A smaller omi_mask_depth value indicates a shorter distance to the object. The length of the omi_mask_depth[i][j] syntax element is omi_mask_depth_length_minus1 + 1 bit.

[0235] omi_mask_label[i][j] specifies the contents of the label associated with the jth signaled object mask in the i-th associated auxiliary picture layer. The length of the omi_mask_label[i][j] syntax element must be less than or equal to 255 bytes, excluding the null termination byte.

[0236] The terms or names described below (e.g., names of syntax elements or names of variables, etc.) are merely examples, and the technical features of the present disclosure are not limited to the terms described below. For example, the image information described below may include various information according to the embodiments described in the present disclosure, and may include information described in at least one of the tables described above.

[0237] The operations described below are not essential components of an embodiment, and at least some of the operations described below may be omitted. Furthermore, the operations described below are not sufficient components of an embodiment, and previously described operations may be added. Furthermore, the operations described below, unless they contradict the previously described operations, form an embodiment together with the previously described operations, and do not form a separate embodiment distinct from the previously described operations.

[0238] As described above, the image information encoded by the encoding device or received by the decoding device may include at least one basic layer including a picture, and at least one auxiliary layer associated with each of the at least one basic layer. The basic layer is not limited to its name and may be called by various names, such as a basic picture layer. In addition, the auxiliary layer is not limited to its name and may be called by various names, such as an auxiliary picture layer.

[0239] For example, at least one auxiliary layer can be used for object detection and tracking applications for the base layer. The encoding device can perform image analysis on the pictures of the base layer and generate an object region, i.e., an object mask, for object detection and tracking tasks. The object mask can be transmitted to the decoding device through the pictures of the at least one auxiliary layer. By transmitting the object mask generated by the encoding device to the decoding device, power consumption for object detection and tracking tasks in the decoding device can be reduced. In addition, since the computational power of the encoding device is generally superior to the associative power of the decoding device, more accurate object detection and tracking becomes possible.

[0240] At this time, the image information may further include an OMI-related message including information about an object mask of at least one auxiliary layer (hereinafter referred to as object mask information). In other words, the OMI-related message provides information about an object mask associated with a picture of the base layer, and the object mask may be included in a picture of the auxiliary layer associated with the base layer.

[0241] In this way, the image information may include at least one (or multiple) base layers containing pictures, at least one (or multiple) auxiliary layers containing object masks associated with each of the at least one (or multiple) base layers, and at least one (or multiple) OMI-related messages containing information about the object masks associated with each of the at least one (or multiple) base layers.

[0242] For example, image information may include an access unit including six layers (base layer and auxiliary layer) as shown in Table 9.

[0243] [Table 9]

[0244]

[0245] The image information may include a first base layer (layer 0) including base pictures and a second base layer (layer 1). The image information may include a first auxiliary layer (layer 2) including first object mask information for the first base layer (layer 0) and a second auxiliary layer (layer 3) including second object mask information for the first base layer (layer 0). Furthermore, the image information may include a third auxiliary layer (layer 4) including third object mask information for the second base layer (layer 1) and a fourth auxiliary layer (layer 5) including fourth object mask information for the second base layer (layer 1).

[0246] In one embodiment, the image information may include (Example 1) one OMI-related message associated with both the first and second base layers, or (Example 2) first and second OMI-related messages associated with each of the first and second base layers.

[0247] Each example is explained.

[0248] (Example 1) If one OMI-related message is provided that is associated with both the first and second base layers, the OMI-related message may include both the first and second object mask information for the first base layer (Layer 0) and the third and fourth object mask information for the second base layer (Layer 1). In other words, one OMI-related message may be provided for all layers.

[0249] For example, the image information may include a sequence of access units including a first base layer, a second base layer, and one OMI-related message, as illustrated in Table 10.

[0250] [Table 10]

[0251]

[0252] As illustrated in Table 10, OMI-related messages may be signaled (encoded or acquired) depending on whether there is movement of objects within pictures included in an access unit. Specifically, if there is movement of objects within pictures of the first base layer or if there is movement of objects within pictures of the second base layer, OMI-related messages may be signaled (encoded or acquired).

[0253] Here, one OMI related message can be activated for one or more base layers.

[0254] For example, based on the existence of object motion in pictures 0, 3, and 7 of the first base layer and the existence of object motion in pictures 0, 2, 5, and 8 of the second base layer, access unit 0, access unit 2, access unit 3, access unit 5, access unit 7, and access unit 8 may include OMI-related messages.

[0255] Here, the application of the decoding device can only track objects of the first base layer. In other words, object mask information associated with the second base layer may not be required. In this way, even if an OMI-related message associated with the second base layer is not required, one OMI-related message is provided for all layers, so access units 0, 2, 3, 5, 7, and 8 include OMI-related messages. As a result, the coding efficiency of image information and the transmission efficiency of image information are reduced.

[0256] (Example 2) When a first OMI-related message and a second OMI-related message are provided, each associated with a first base layer and a second base layer, the first OMI-related message may include first and second object mark information for the first base layer (layer 0), and the second OMI-related message may include third and fourth object mask information for the second base layer (layer 1). In other words, one OMI-related message may be provided for each of all layers.

[0257] For example, the image information may include a sequence of access units including a first base layer, a first OMI-related message, a second base layer, and a second OMI-related message, as illustrated in Table 11.

[0258] [Table 11]

[0259]

[0260] As shown in Table 11, the first OMI-related message and the second OMI-related message may be signaled (encoded or acquired) depending on whether there is movement of objects in pictures included in the first base layer and pictures included in the second base layer, respectively. Specifically, if there is movement of objects in pictures of the first base layer, the first OMI-related message may be signaled (encoded or acquired), and if there is movement of objects in pictures of the second base layer, the second OMI-related message may be signaled (encoded or acquired).

[0261] Here, one OMI-related message can be activated for only one base layer.

[0262] For example, based on the presence of object motion in picture 0, picture 3, and picture 7 of the first base layer, access unit 0, access unit 3, and access unit 7 may include a first OMI-related message. Additionally, based on the presence of object motion in picture 0, picture 2, picture 5, and picture 8 of the second base layer, access unit 0, access unit 2, access unit 5, and access unit 8 may include a second OMI-related message.

[0263] Here, the application of the decoding device may only require object information of the first base layer. In other words, object mask information associated with the second base layer may not be required. In this way, if an OMI-related message associated with the second base layer is not required, a second OMI-related message associated with the second base layer may not be signaled (encoded or acquired). As a result, access unit 0, access unit 3, and access unit 7 may include the first OMI-related message, and access unit 2, access unit 5, and access unit 8 may not include the OMI-related message. As a result, the coding efficiency of image information may be improved, and further, the transmission efficiency of image information may be improved.

[0264] As described above, transmitting at least one (or multiple) OMI-related messages for each of at least one (or multiple) base layers can improve the coding efficiency of image information and the transmission efficiency of image information compared to transmitting one OMI-related message for all of at least one (or multiple) base layers.

[0265] FIG. 5 is a diagram illustrating a method for decoding image information according to one embodiment of the present disclosure.

[0266] Terms or names (e.g., names of syntax elements or names of variables, etc.) are merely examples, and the technical features of the present disclosure are not limited to the terms described in FIG. 5. For example, the image information described in FIG. 5 may include various information according to the embodiments described in the present disclosure, and may include information described in at least one of the tables described above.

[0267] The decoding method (S500) may include the operations described below. The operations described below are not essential components of the decoding method according to an embodiment, and at least some of the operations described below may be omitted. Furthermore, the operations described below are not sufficient components of the decoding method according to an embodiment, and the operations described above may be added. Furthermore, the operations described below form an embodiment together with the operations described above, unless they contradict the operations described above, and do not form a separate embodiment distinct from the operations described above.

[0268] The decoding method (S500) can be executed by a decoding device including a memory and a processor electrically connected to the memory, and can be executed by, for example, a processor.

[0269] The decoding device can obtain image information (S510).

[0270] For example, a processor of a decoding device may obtain image information. The image information may include at least one (or multiple) base layers among multiple layers. Each of the at least one (or multiple) base layers may include a picture to be decoded. Here, the base layer is not limited to its name and may be referred to in various ways, such as a base picture layer.

[0271] The image information may further include at least one auxiliary layer associated with one of the current basic layers among at least one (or multiple) basic layers. Here, the auxiliary layer is not limited to its name and may be referred to by various names, such as an auxiliary picture layer.

[0272] For example, at least one auxiliary layer may be utilized for object detection and tracking applications for the base layer. The encoding device may perform image analysis on the pictures of the base layer and provide information about object regions for object detection and tracking to the decoding device. This reduces power consumption of the decoding device and enables more accurate object detection and tracking. In this way, at least one auxiliary layer may include an object mask for object detection and tracking for the base layer.

[0273] The image information may include at least one (or multiple) base layers and at least one (or multiple) object mask information (OMI) related message, respectively. Specifically, the OMI related message may include at least one (or multiple) base layers and at least one (or multiple) object mask information related message, respectively.

[0274] In particular, at least one (or multiple) OMI-related messages may be associated with at least one (or multiple) base layers. In other words, one of the at least one (or multiple) OMI-related messages may be associated with only one current base layer among the at least one (or multiple) base layers. Furthermore, one OMI-related message may exist in one current base layer.

[0275] OMI related messages may have various names, such as OMI SEI (supplemental enhancement information) message, and the names are not limited.

[0276] An OMI-related message can take various forms. For example, an OMI-related message can be a syntax element or a syntax structure containing one or more syntax elements. Furthermore, an OMI-related message can be a raw byte sequence payload (RBSP) containing one or more syntax elements or one or more syntax structures. For example, an OMI-related message can be expressed as, but is not limited to, object_mask_info(payloadSize).

[0277] OMI related messages may include OMI cancel flag information, OMI persistence flag information, base layer identification information, auxiliary layer count information, and information about object masks.

[0278] The OMI cancel flag information can indicate whether the persistence of an OMI-related message preceding the current OMI-related message has been canceled. For example, a value of 1 for the OMI cancel flag information can indicate that the persistence of a previous OMI-related message currently existing in the base layer in terms of output order has been canceled. Additionally, a value of 0 for the OMI cancel flag information can indicate that object mask information follows.

[0279] OMI cancel flag information can take various forms and be expressed by various names. For example, OMI cancel flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, OMI cancel flag information as a syntax element can be expressed as omi_cancel_flag, but is not limited thereto.

[0280] The OMI persistence flag information can indicate the persistence of object mask information included in an OMI-related message. A value of 1 for the OMI persistence flag information can indicate that the object mask information included in the OMI-related message is applied not only to the current picture but also to pictures of all base layers that appear later in the output order. In addition, a value of 0 for the OMI persistence flag information can indicate that the object mask information included in the OMI-related message is applied to the current picture. However, the present invention is not limited thereto, and alternatively, what the value of the OMI persistence flag information specifies as 1 can be changed from what the value of the OMI persistence flag information specifies as 0.

[0281] OMI persistence flag information can take various forms and be expressed by various names. For example, OMI persistence flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, OMI persistence flag information as a syntax element can be a one-bit persistence flag or a two-bit persistence indicator. OMI persistence flag information as a syntax element can be expressed as, but is not limited to, omi_persistence_flag.

[0282] The base layer identification information can indicate the identification information of the base layer. The base layer identification information can take various forms and be expressed by various names. For example, the base layer identification information can be a syntax element or a syntax structure containing one or more syntax elements. For example, the syntax element base layer identification information can be expressed as, but is not limited to, "omi_primary_pic_layer_id."

[0283] The auxiliary layer count information can indicate the number of auxiliary layers associated with the base layer. The auxiliary layer count information can take various forms and be expressed by various names. For example, the auxiliary layer count information can be a syntax element or a syntax structure including one or more syntax elements. For example, the auxiliary layer count information as a syntax element can be expressed as omi_num_aux_pic or omi_num_aux_pic_layer_minus1, but is not limited thereto. When expressed as omi_num_aux_pic_layer_minus1, the auxiliary layer count information can have a value of 1 added to that value to indicate the number of auxiliary layers associated with the base layer.

[0284] Information about an object mask may include information representing an object mask included in at least one auxiliary layer. For example, information about an object mask may include information about a depth of the object mask, information about a label of the object mask, information about a position of the object mask (top coordinates and left coordinates), information about a size of the object mask (width and height), etc.

[0285] The decoding device can process OMI related messages (S520).

[0286] For example, a processor of a decoding device can process an OMI-related message. The decoding device can identify a current base layer and at least one associated auxiliary layer based on the OMI-related message. The decoding device can obtain information about at least one object mask for the current base layer based on the at least one associated auxiliary layer. Furthermore, the decoding device can detect at least one object included in a picture of the base layer and track the at least one object based on the information about the at least one object mask.

[0287] As described above, the image information may include at least one (or multiple) base layers, at least one auxiliary layer associated with the at least one (or multiple) base layer, and at least one (or multiple) OMI-related messages each associated with the at least one (or multiple) base layer. The at least one auxiliary layer may include at least one object mask for detecting and tracking an object included in a picture within the at least one base layer.

[0288] Additionally, at least one (or multiple) OMI-related messages may include information regarding an object mask associated with at least one (or multiple) base layer, wherein each of the at least one (or multiple) OMI-related messages is associated with each of the at least one (or multiple) base layer. In other words, one of the at least one (or multiple) OMI-related messages is associated with one of the at least one (or multiple) base layers.

[0289] At least one (or multiple) OMI-related messages are each associated with at least one (or multiple) base layer, such that OMI-related messages containing information regarding an object mask required by an application of the decoding device can be selectively obtained. This improves the coding efficiency of the OMI-related messages, and further improves transmission efficiency.

[0290] FIG. 6 is a diagram illustrating a method for encoding image information according to one embodiment of the present disclosure.

[0291] The terms or names described in FIG. 6 (e.g., names of syntax elements or names of variables, etc.) are merely examples, and the technical features of the present disclosure are not limited to the terms described in FIG. 6. For example, the image information described in FIG. 6 may include various information according to the embodiments described in the present disclosure, and may include information described in at least one of the tables described above.

[0292] The encoding method (S600) may include the operations described below. The operations described below do not constitute essential components of the decoding method according to an embodiment, and at least some of the operations described below may be omitted. In addition, the operations described below do not constitute sufficient components of the encoding method according to an embodiment, and the operations described above may be added. Furthermore, the operations described below form an embodiment together with the operations described above, unless they contradict the operations described above, and do not form a separate embodiment distinct from the operations described above.

[0293] The encoding device can generate a message related to object mask information (OMI) (S610).

[0294] For example, a processor of an encoding device can generate OMI-related messages based on the base layer.

[0295] An encoding device can perform image analysis on pictures of a base layer and generate information about an object region for object detection and tracking. In other words, the encoding device can generate an object mask for object detection and tracking based on pictures of the base layer. In this way, by performing image analysis on pictures of the base layer by the encoding device, power consumption of the decoding device is reduced, and more accurate object detection and tracking is enabled. Here, the base layer is not limited to its name, and can be called by various names, such as a base picture layer.

[0296] The encoding device can generate an auxiliary layer associated with the base layer based on an object mask. The auxiliary layer can include an object mask for object detection and tracking operations of the base layer. The auxiliary layer is not limited to its name and can be called various names, such as an auxiliary picture layer.

[0297] An encoding device can generate a supplemental enhancement information (SEI) message, i.e., an object mask information (OMI) message, based on information about an object mask. The OMI message can include information about an object mask of an auxiliary layer associated with a base layer (hereinafter referred to as object mask information).

[0298] In particular, the encoding device can generate at least one (or multiple) OMI-related messages associated with each of at least one (or multiple) base layers. For example, the encoding device can generate at least one (or multiple) object masks associated with each of at least one (or multiple) base layers. The encoding device can generate at least one (or multiple) OMI-related messages that include information regarding the at least one (or multiple) object masks.

[0299] Here, one of the at least one (or multiple) OMI-related messages may be associated with only one current base layer among the at least one (or multiple) base layers. Furthermore, one OMI-related message may exist in one current base layer.

[0300] OMI related messages may have various names, such as OMI SEI (supplemental enhancement information) message, and the names are not limited.

[0301] An OMI-related message can take various forms. For example, an OMI-related message can be a syntax element or a syntax structure containing one or more syntax elements. Furthermore, an OMI-related message can be a raw byte sequence payload (RBSP) containing one or more syntax elements or one or more syntax structures. For example, an OMI-related message can be expressed as, but is not limited to, object_mask_info(payloadSize).

[0302] OMI related messages may include OMI cancel flag information, OMI persistence flag information, base layer identification information, auxiliary layer count information, and information about object masks.

[0303] The OMI cancel flag information can indicate whether the persistence of an OMI-related message preceding the current OMI-related message has been canceled. For example, a value of 1 for the OMI cancel flag information can indicate that the persistence of a previous OMI-related message currently existing in the base layer in terms of output order has been canceled. Additionally, a value of 0 for the OMI cancel flag information can indicate that object mask information follows.

[0304] OMI cancel flag information can take various forms and be expressed by various names. For example, OMI cancel flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, OMI cancel flag information as a syntax element can be expressed as omi_cancel_flag, but is not limited thereto.

[0305] The OMI persistence flag information can indicate the persistence of object mask information included in an OMI-related message. A value of 1 for the OMI persistence flag information can indicate that the object mask information included in the OMI-related message is applied not only to the current picture but also to pictures of all base layers that appear later in the output order. In addition, a value of 0 for the OMI persistence flag information can indicate that the object mask information included in the OMI-related message is applied to the current picture. However, the present invention is not limited thereto, and alternatively, what the value of the OMI persistence flag information specifies as 1 can be changed from what the value of the OMI persistence flag information specifies as 0.

[0306] OMI persistence flag information can take various forms and be expressed by various names. For example, OMI persistence flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, OMI persistence flag information as a syntax element can be a one-bit persistence flag or a two-bit persistence indicator. OMI persistence flag information as a syntax element can be expressed as, but is not limited to, omi_persistence_flag.

[0307] The base layer identification information can indicate the identification information of the base layer. The base layer identification information can take various forms and be expressed by various names. For example, the base layer identification information can be a syntax element or a syntax structure containing one or more syntax elements. For example, the syntax element base layer identification information can be expressed as, but is not limited to, "omi_primary_pic_layer_id."

[0308] The auxiliary layer count information can indicate the number of auxiliary layers associated with the base layer. The auxiliary layer count information can take various forms and be expressed by various names. For example, the auxiliary layer count information can be a syntax element or a syntax structure including one or more syntax elements. For example, the auxiliary layer count information as a syntax element can be expressed as omi_num_aux_pic or omi_num_aux_pic_layer_minus1, but is not limited thereto. When expressed as omi_num_aux_pic_layer_minus1, the auxiliary layer count information can have a value of 1 added to that value to indicate the number of auxiliary layers associated with the base layer.

[0309] Information about an object mask may include information representing an object mask included in at least one auxiliary layer. For example, information about an object mask may include information about a depth of the object mask, information about a label of the object mask, information about a position of the object mask (top coordinates and left coordinates), information about a size of the object mask (width and height), etc.

[0310] The encoding device can encode image information (S620).

[0311] For example, a processor of an encoding device can encode image information including at least one (or multiple) base layers including a picture, at least one (or multiple) auxiliary layers including an object mask for the picture, and at least one (or multiple) OMI-related messages including information about the object mask.

[0312] As described above, the image information may include at least one (or multiple) base layers, at least one auxiliary layer associated with the at least one (or multiple) base layer, and at least one (or multiple) OMI-related messages each associated with the at least one (or multiple) base layer. The at least one auxiliary layer may include at least one object mask for detecting and tracking an object included in a picture within the at least one base layer.

[0313] Additionally, at least one (or multiple) OMI-related messages may include information regarding an object mask associated with at least one (or multiple) base layer, wherein each of the at least one (or multiple) OMI-related messages is associated with each of the at least one (or multiple) base layer. In other words, one of the at least one (or multiple) OMI-related messages is associated with one of the at least one (or multiple) base layers.

[0314] At least one (or multiple) OMI-related messages are each associated with at least one (or multiple) base layer, such that OMI-related messages containing information regarding an object mask required by an application of the decoding device can be selectively encoded. This improves the coding efficiency of OMI-related messages, and further improves transmission efficiency.

[0315] A bitstream is generated based on image information encoded according to the encoding method (S600) described above, and the bitstream can be stored in a computer-readable storage medium.

[0316] Additionally, a bitstream is generated based on the image information encoded according to the encoding method (S600) described above, and the bitstream can be transmitted through a transmission unit and / or a transmission medium.

[0317] FIG. 7 is a diagram exemplifying a content streaming system to which an embodiment according to the present disclosure can be applied.

[0318] As illustrated in FIG. 7, a content streaming system to which an embodiment of the present disclosure is applied may largely include an encoding server, a streaming server, a web server, a media storage, a user device, and a multimedia input device.

[0319] The encoding server compresses content input from multimedia input devices such as smartphones, cameras, and camcorders into digital data, generates a bitstream, and transmits it to the streaming server. Alternatively, if multimedia input devices such as smartphones, cameras, and camcorders directly generate bitstreams, the encoding server may be omitted.

[0320] The above bitstream can be generated by a video encoding method and / or encoding device to which an embodiment of the present disclosure is applied, and the streaming server can temporarily store the bitstream during the process of transmitting or receiving the bitstream.

[0321] The streaming server transmits multimedia data to a user device based on a user request via a web server, and the web server can act as an intermediary to inform the user of available services. When a user requests a desired service from the web server, the web server transmits the request to the streaming server, and the streaming server can transmit multimedia data to the user. At this time, the content streaming system may include a separate control server, and in this case, the control server may control commands / responses between each device within the content streaming system.

[0322] The streaming server can receive content from a media repository and / or encoding server. For example, when receiving content from the encoding server, the content can be received in real time. In this case, to provide a smooth streaming service, the streaming server can store the bitstream for a certain period of time.

[0323] Examples of the user devices may include mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation devices, slate PCs, tablet PCs, ultrabooks, wearable devices (e.g., smartwatches, smart glasses, HMDs), digital TVs, desktop computers, digital signage, etc.

[0324] Each server within the above content streaming system can be operated as a distributed server, in which case data received from each server can be processed in a distributed manner.

[0325] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer.

[0326] Embodiments according to the present disclosure can be used to encode / decode images.

Claims

1. Obtain image information including at least one basic picture layer among a plurality of layers and at least one object mask information (OMI) related message associated with each of the at least one basic picture layer; Including processing the above OMI related messages, A method wherein one of the at least one OMI-related message is associated only with the current base picture layer among the at least one base picture layer.

2. In paragraph 1, The above one OMI related message exists in the current base picture layer, method.

3. In paragraph 1, The above image information further includes at least one auxiliary layer associated with the current basic picture layer, A method wherein said one OMI related message includes information about said at least one auxiliary layer.

4. In paragraph 3, A method wherein the information about the at least one auxiliary layer includes information about an object mask of the at least one auxiliary layer.

5. In paragraph 1, The above OMI related message further includes OMI persistence flag information indicating the persistence of object mask information of the above OMI related message, Based on the value of the OMI persistence flag information being 0, the object mask information of the OMI-related message is applied only to the current picture, A method in which the object mask information of the OMI-related message is applied to the current picture and the consecutive pictures of the current base picture layer based on the value of the OMI persistence flag information being 1.

6. In a method for encoding image information, Generate at least one object mask information (OMI) related message associated with at least one base picture layer among a plurality of layers; Encoding image information including at least one OMI-related message, A method wherein one of the at least one OMI-related message is associated with only one base picture layer among the at least one base picture layer.

7. In paragraph 6, The above OMI related message exists in the current basic picture layer, method.

8. In paragraph 6 The above image information further includes at least one auxiliary layer associated with the current basic picture layer, A method wherein the OMI related message includes information about the at least one auxiliary layer.

9. In paragraph 8, A method wherein the information about the at least one auxiliary layer includes information about an object mask of the at least one auxiliary layer.

10. In paragraph 6, The above OMI related message further includes OMI persistence flag information indicating the persistence of object mask information of the above OMI related message, The value of the above OMI persistence flag information being 0 indicates that the object mask information of the above OMI-related message is applied only to the current picture. A method in which the value of the OMI persistence flag information is 1, which indicates that the object mask information of the OMI-related message is applied to the current picture and the consecutive pictures of the current base picture layer.

11. In a computer-readable storage medium storing a bitstream generated by an encoding method, The above encoding method is, Generate at least one object mask information (OMI) related message associated with at least one base picture layer among a plurality of layers; Encoding image information including at least one OMI-related message, A storage medium, wherein one of the at least one OMI-related message is associated with only one basic picture layer among the at least one basic picture layer.

12. Generate at least one object mask information (OMI) related message associated with at least one base picture layer among a plurality of layers; Generating a bitstream regarding image information including at least one OMI-related message; Including transmitting the above bitstream, The above image information further includes at least one auxiliary layer associated with the current basic picture layer, A method wherein one of the at least one OMI-related message is associated with only one base picture layer among the at least one base picture layer.

Images