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

Abstract

A method according to the present disclosure involves: acquiring image information including a main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message associated with the main picture layer; and acquiring, on the basis of the at least one SEI message, object mask information (OMI) associated with the main picture layer. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived on the basis of the object mask information, and object masks, which are designated by mask identification variables that have the same value and are derived on the basis of different SEI messages, correspond to the same object.

Description

Method for decoding image information, method for encoding 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 resolve the ambiguity of SEI messages.

[0005] The present disclosure seeks to suppress or prevent errors due to ambiguity in SEI messages.

[0006] The present disclosure seeks to improve coding efficiency by eliminating ambiguity in SEI messages.

[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 a main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message associated with the main picture layer, and obtaining object mask information (OMI) associated with the main picture layer based on the at least one SEI message. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value and derived based on different SEI messages correspond to the same object.

[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 the image information including a main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message associated with the main picture layer, and obtains object mask information (OMI) associated with the main picture layer based on the at least one SEI message. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value and derived based on different SEI messages correspond to the same object.

[0010] In the method or device for decoding the image information, the object mask information includes identification information of at least one object mask included in the at least one auxiliary picture layer, and the at least one mask identification variable can be derived based on the mask identification information of the at least one object mask.

[0011] In the method or device for decoding the image information, the different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, and based on the value of the mask identification variable of the first object mask derived based on the first SEI message being the same as the mask identification variable of the second object mask derived based on the second SEI message, the first object mask and the second object mask can correspond to the same object.

[0012] In the method or device for decoding the above image information, reuse of a mask identification variable having the same value may be restricted.

[0013] In the method or device for decoding the image information, the different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, and there is no SEI message that cancels the persistence of the SEI message between the first SEI message and the second SEI message, and the value of the mask identification variable of the first object mask derived based on the first SEI message is the same as the mask identification variable of the second object mask derived based on the second SEI message, so that the first object mask and the second object mask can correspond to the same object.

[0014] According to one aspect of the present disclosure, a method for encoding image information includes generating object mask information associated with a main picture layer, and encoding the image information including the main picture layer, the at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message generated based on the object mask information. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value and derived based on different SEI messages correspond to the same object.

[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 object mask information associated with a main picture layer, and encodes the image information including the main picture layer, the at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message generated based on the object mask information. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value and derived based on different SEI messages correspond to the same object.

[0016] In the method or device for encoding the image information, the object mask information includes identification information of at least one object mask included in the at least one auxiliary picture layer, and the at least one mask identification variable can be derived based on the mask identification information of the at least one object mask.

[0017] In the method or device for encoding the image information, the different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, and the first object mask and the second object mask can correspond to the same object based on the value of the mask identification variable of the first object mask derived based on the first SEI message being the same as the mask identification variable of the second object mask derived based on the second SEI message.

[0018] In the method or device for encoding the above image information, reuse of a mask identification variable having the same value may be restricted.

[0019] In the method or device for encoding the image information, the different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, and there is no SEI message that cancels the persistence of the SEI message between the first SEI message and the second SEI message, and the value of the mask identification variable of the first object mask derived based on the first SEI message is the same as the mask identification variable of the second object mask derived based on the second SEI message, so that the first object mask and the second object mask can correspond to the same object.

[0020] According to one aspect of the present disclosure, a method for a bitstream includes generating object mask information associated with a main picture layer, generating a bitstream based on image information including the main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message based on the object mask information, and transmitting the bitstream. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value and derived based on different SEI messages correspond to the same object.

[0021] According to one aspect of the present disclosure, a device for a bitstream includes a processor for generating object mask information associated with a main picture layer, and generating a bitstream based on image information including the main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message based on the object mask information, and a transmitting unit for transmitting the bitstream. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value and derived based on different SEI messages correspond to the same object.

[0022] According to one aspect of the present disclosure, object mask information associated with a main picture layer is generated, and a bitstream generated based on image information including the main picture layer, an auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message based on the object mask information is stored in a computer-readable storage medium. At least one mask identification variable for identifying at least one object mask of the at least one auxiliary picture layer is derived based on the object mask information, and object masks designated by mask identification variables having the same value derived based on different SEI messages correspond to the same object.

[0023] 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.

[0024] According to the present disclosure, ambiguity in SEI messages is resolved.

[0025] According to the present disclosure, errors due to ambiguity in SEI messages are suppressed or prevented.

[0026] According to the present disclosure, coding efficiency is improved by eliminating ambiguity in SEI messages.

[0027] 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.

[0028] FIG. 1 is a diagram schematically illustrating a video coding system to which an embodiment according to the present disclosure can be applied.

[0029] FIG. 2 is a schematic diagram of an encoding device to which an embodiment according to the present disclosure can be applied.

[0030] FIG. 3 is a schematic diagram showing a decoding device to which an embodiment according to the present disclosure can be applied.

[0031] Figure 4 illustrates an example of a hierarchical structure for coded video / images.

[0032] FIG. 5 is a diagram illustrating a method for decoding image information according to one embodiment of the present disclosure.

[0033] FIG. 6 is a diagram illustrating a method for encoding image information according to one embodiment of the present disclosure.

[0034] FIG. 7 is a diagram exemplifying a content streaming system to which an embodiment according to the present disclosure can be applied.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] The present disclosure presents various embodiments of video / image coding, and unless otherwise stated, the embodiments may be performed in combination with each other.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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."

[0048] 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."

[0049] 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."

[0050] 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."

[0051] FIG. 1 is a schematic diagram illustrating a video / image coding system to which an embodiment according to the present disclosure can be applied.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The renderer can render decoded video / images. The rendered video / images can be displayed through the display unit.

[0059] FIG. 2 is a schematic diagram illustrating an encoding device to which an embodiment according to the present disclosure can be applied.

[0060] 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 reconstruction unit or a reconstructed 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) according to an 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.

[0061] 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.

[0062] 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).

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 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.

[0073] Meanwhile, LMCS (luma mapping with chroma scaling) may be applied during the picture encoding and / or restoration process.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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).

[0078] FIG. 3 is a schematic diagram illustrating a decoding device to which an embodiment according to the present disclosure can be applied.

[0079] 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.

[0080] 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).

[0081] 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).

[0082] 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.

[0083] In the inverse transform unit (322), the transform coefficients can be inversely transformed to obtain a residual signal (residual block, residual sample array).

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] Meanwhile, LMCS (luma mapping with chroma scaling) may be applied during the picture decoding process.

[0089] 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.

[0090] 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).

[0091] 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.

[0092] Figure 4 illustrates an example of a hierarchical structure for coded video / images.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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).

[0097] 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.

[0098] 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.

[0099] 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.

[0100] Below are examples of NAL unit types, specified by the type of parameter set included in the Non-VCL NAL unit type.

[0101] - APS (Adaptation Parameter Set) NAL unit: Type for NAL units containing APS

[0102] - DPS (Decoding Parameter Set) NAL unit: Type for NAL unit containing DPS

[0103] - VPS (Video Parameter Set) NAL unit: Type for NAL units containing VPS

[0104] - SPS (Sequence Parameter Set) NAL unit: Type for NAL units containing SPS

[0105] - PPS (Picture Parameter Set) NAL unit: Type for NAL units containing PPS

[0106] 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.

[0107] 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.

[0108] 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.

[0109] Below, the SEI message related to the present invention will be described.

[0110] Table 1 shows an example of the syntax of an extensibility dimension information SEI message according to one embodiment.

[0111] [Table 1]

[0112]

[0113] The Scalability Dimension Information (SDI) SEI message provides the SDI for each layer in the current CVS (the CVS containing the SDI SEI message). For example, it includes 1) the view ID for each layer if multiple views are present; and 2) the additional ID for each layer if one or more layers contain additional information (e.g., depth or alpha).

[0114] If an SDI SEI message exists in any AU of a CVS, then the SDI SEI message must exist in the first AU of that CVS. All SDI SEI messages within a CVS must have identical content.

[0115] sdi_max_layers_minus1 plus 1 represents the maximum number of layers of the current CVS.

[0116] If sdi_multiview_info_flag is 1, there may be multi-views in the current CVS, and the SDI SEI message will contain the sdi_view_id_val[ ] syntax element. If sdi_multiview_info_flag is 0, there are no multi-views in the current CVS, and the SDI SEI message will not contain the sdi_view_id_val[ ] syntax element.

[0117] If sdi_auxiliary_info_flag is 1, there may be one or more auxiliary layers in the current CVS, and these auxiliary layers contain auxiliary information, and the SDI SEI message contains the sdi_aux_id[ ] syntax element. If sdi_auxiliary_info_flag is 0, there are no auxiliary layers in the current CVS, and the SDI SEI message does not contain the sdi_aux_id[ ] syntax element.

[0118] The value of sdi_view_id_len_minus1 plus 1 specifies the length in bits of the sdi_view_id_val[ i ] syntax element.

[0119] sdi_layer_id[ i ] specifies the layer identifier of the ith layer that can currently exist in CVS.

[0120] sdi_view_id_val[ i ] specifies the view identifier of the ith layer of the current CVS. The length of the sdi_view_id_val[ i ] syntax element is sdi_view_id_len_minus1 + 1 bits.

[0121] The variable NumViews, which specifies the number of views currently existing in CVS, and the list ViewId, which specifies the view identifiers of the views currently existing in CVS, are derived as follows:

[0122] [Table 2]

[0123]

[0124] If sdi_aux_id[ i ] is 0, it means that the i-th layer of the current CVS does not contain an auxiliary picture. If sdi_aux_id[ i ] is greater than 0, the type of the auxiliary picture contained in the i-th layer of the current CVS is as specified in Table 3. If sdi_auxiliary_info_flag is 0, the value of sdi_aux_id[ i ] is assumed to be 0.

[0125] [Table 3]

[0126]

[0127] NOTE - The interpretation of auxiliary pictures with sdi_aux_id[ i ] values ​​from 128 to 159 (inclusive) is specified in a different way than the sdi_aux_id[ i ] value.

[0128] sdi_aux_id[ i ] must be in the range 0 to 2 (inclusive) or 128 to 159 (inclusive) for compatible bitstreams. The value of sdi_aux_id[ i ] must be in the range 0 to 2 (inclusive) or 128 to 159 (inclusive), but decoders must also allow values ​​of sdi_aux_id[ i ] to be in the range 0 to 255 (inclusive).

[0129] If sdi_aux_id[ i ] is 0, the ith layer is referred to as the primary layer. Otherwise, the ith layer is referred to as the auxiliary layer. If sdi_aux_id[ i ] is 1, the ith layer is also referred to as the alpha auxiliary layer. If sdi_aux_id[ i ] is equal to 2, the ith layer is also referred to as the depth auxiliary layer.

[0130] The value of sdi_num_associated_primary_layers_minus1[ i ] plus 1 specifies the number of primary layers associated with the i-th layer (the auxiliary layer). The value of sdi_num_associated_primary_layers_minus1[ i ] must be less than the total number of primary layers.

[0131] sdi_associated_primary_layer_idx[ i ][ j ] specifies the layer index of the jth associated primary layer of the ith auxiliary layer. The value of sdi_aux_id[ sdi_associated_primary_layer_idx[ i ][ j ] ] must be equal to 0.

[0132] Note - Auxiliary layers describe the properties of the associated primary layer and apply to that layer.

[0133] Table 4 shows an example of the object mask information SEI message syntax according to one embodiment.

[0134] [Table 4]

[0135]

[0136]

[0137] The Object Mask Information (OMI) SEI message provides object mask information for an object mask picture contained in an auxiliary picture layer associated with the current main picture layer. If this SEI message exists, it must be present in the main picture layer. A main picture layer can be associated with one or more auxiliary picture layers. For each associated auxiliary picture layer that contains an object mask picture whose nuh_layer_id is equal to sdi_layer_id[i], the value of sdi_aux_id[i] must be equal to AUX_OBJECT_MASK, where i is in the range of 0 to sdi_max_layers_minus1, inclusive.

[0138] To use this SEI message, you must define the following variables:

[0139] - Cropped picture width and height (in luma samples), displayed as CroppedWidth and CroppedHeight, respectively.

[0140] - Compliance crop window left offset, ConfWinLeftOffset

[0141] - Compliance crop window top offset, ConfWinTopOffset

[0142] - Chroma format indicator, denoted as ChromaFormatIdc in this document.

[0143] The variables SubWidthC and SubHeightC are derived from ChromaFormatIdc.

[0144] If omi_cancel_flag is 1, the SEI message cancels the persistence of the previous object mask information SEI message in the same layer. If omi_cancel_flag is 0, the object mask information continues.

[0145] omi_persistence_flag specifies the persistence of the object mask information provided in this SEI message. If omi_persistence_flag is 0, the object mask information applies only to the current picture. If omi_persistence_flag is 1, the object mask information applies to all subsequent pictures in the output order of the same layer as the current picture until one or more of the following conditions are met:

[0146] - A new CLVS for the current layer starts.

[0147] - Bitstream ends.

[0148] - The picture containing the object mask information SEI message in the PU of the current layer is output after the current picture in the output order.

[0149] If the CVS does not contain an SDI SEI message whose sdi_aux_id[ i ] matches AUX_OBJECT_MASK for at least one value of i, the OMI SEI message is ignored.

[0150] If an AU contains both an SDI SEI message and an OMI SEI message whose sdi_aux_id[ i ] matches AUX_OBJECT_MASK, the SDI SEI message must be processed before the OMI SEI message in decoding order.

[0151] omi_num_aux_pic_layer represents the number of auxiliary picture layers associated with the current primary picture layer. According to bitstream compliance requirements, the value of omi_num_aux_pic_layer must be equal to numAuxLayer, and the variable numAuxLayer is derived as follows.

[0152] omiPrimaryLayerId is the nuh_layer_id value of the NAL unit containing the SEI message.

[0153] [Table 5]

[0154]

[0155] The value of omi_mask_id_length_minus1 plus 1 specifies the length in bits of the omi_mask_id[ i ][ j ] syntax element.

[0156] The value of omi_mask_sample_value_length_minus8 plus 8 specifies the length in bits of the omi_aux_sample_value[ i ][ j ] syntax element. The value of omi_mask_sample_value_length_minus8 must be in the range 0 to 8.

[0157] If omi_mask_confidence_info_present_flag is 1, it indicates that the omi_mask_confidence[ i ][ j ] syntax element exists. If omi_mask_confidence_info_present_flag is 0, it indicates that the omi_mask_confidence[ i ][ j ] syntax element does not exist.

[0158] The value of omi_mask_confidence_length_minus1 plus 1 specifies the length in bits of the omi_mask_confidence[ i ][ j ] syntax element.

[0159] If omi_mask_depth_info_present_flag is 1, it indicates that the omi_mask_depth[ i ][ j ] syntax element exists. If omi_mask_depth_info_present_flag is 0, it indicates that the omi_mask_depth[ i ][ j ] syntax element does not exist.

[0160] The value of omi_mask_depth_length_minus1 plus 1 specifies the length in bits of the omi_mask_depth[ i ][ j ] syntax element.

[0161] According to bitstream compliance requirements, omi_num_aux_pic_layer, omi_mask_id_length_minus1, omi_mask_sample_value_length_minus8, omi_mask_confidence_info_present_flag, omi_mask_confidence_length_minus1, omi_mask_depth_info_present_flag if present, and omi_mask_depth_length_minus1, if present, must be identical across all object_mask_info( ) syntax structures in a CLVS.

[0162] If omi_mask_label_info_present_flag is 1, it indicates that omi_mask_label_language_present_flag and omi_mask_label[ i ][ j ] syntax elements are present. If omi_mask_label_info_present_flag is 0, it indicates that omi_mask_label_language_present_flag and omi_mask_label[ i ][ j ] syntax elements are not present.

[0163] If omi_mask_label_language_present_flag is 1, it indicates that the omi_mask_label_language syntax element is present. If omi_mask_label_language_present_flag is 0, it indicates that the omi_mask_label_language syntax element is not present.

[0164] omi_bit_equal_to_zero must be equal to 0.

[0165] omi_mask_label_language contains a language tag followed by a null-terminating 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-terminating byte. If it is not present, the label's language is not specified.

[0166] When omi_mask_pic_update_flag[ i ] is 1, the object mask information of the object mask picture of the i-th auxiliary picture layer associated with the current main picture layer can be updated. When omi_mask_pic_update_flag[ i ] is 0, there is no change in the mask information of the object mask picture of the i-th auxiliary picture layer associated with the current main picture layer. When omi_mask_pic_update_flag[ i ] is 0, a persistence mechanism is used, that is, the mask information of the object mask picture of the i-th auxiliary picture layer associated with the current main picture layer is inherited from the last OMI SEI message existing in the same layer in decoding order.

[0167] omi_num_mask_in_pic_update[i] specifies the number of object masks contained in the object mask picture in the i-th auxiliary picture layer associated with the current main picture layer. omi_num_mask_in_pic_update[i] must be in the range from 0 to (1<<(omi_mask_id_length_minus1 + 1)) - 1 (inclusive).

[0168] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask contained in the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0169] The variable maskId[ i ][ j ], which specifies the identifier of the jth object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0170] [Table 6]

[0171]

[0172] omi_aux_sample_value[ i ][ j ] specifies a sample value within the jth object mask region of the jth object mask picture within the ith auxiliary picture layer associated with the current main picture layer.

[0173] If omi_mask_cancel[ i ][ j ] is 1, the duration of the jth object mask of the jth object mask picture in the ith auxiliary picture layer associated with the current main picture is canceled. If omi_mask_cancel[ i ][ j ] is 0, the jth object mask information of the jth object mask picture in the ith auxiliary picture layer associated with the current main picture layer is transmitted as a signal.

[0174] According to the bitstream compliance requirements, the value of omi_mask_cancel[ i ][ j ] must be 0 when an omi_mask_id[ i ][ j ] with a specific value in the current CLVS is first parsed.

[0175] When omi_mask_bounding_box_present_flag[ i ][ j ] is 1, it indicates 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. When omi_mask_bounding_box_present_flag[ i ][ j ] is 0, it indicates 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.

[0176] omi_mask_top[ i ][ j ], omi_mask_left[ i ][ j ], omi_mask_width[ i ][ j ], and omi_mask_height [ i ][ j ] specify the coordinates of the upper left corner and the width and height, respectively, of the bounding box of the j-th picture mask in the cropped interpreted picture mask picture in the ith auxiliary picture layer associated with the current main picture layer relative to the compliant crop window specified by the active SPS.

[0177] The value of omi_mask_left[ i ][ j ] must be in the range of 0 to (CroppedWidth / SubWidthC - 1) (inclusive), where CroppedWidth and SubWidthC are associated with the object mask picture of the ith auxiliary picture layer associated with the current main picture layer. If not present, the value of omi_mask_left[i][j] is assumed to be 0.

[0178] The values ​​of omi_mask_top[ i ][ j ] must be in the range of 0 to (CroppedHeight / SubHeightC - 1) (inclusive), where CroppedHeight and SubHeightC are associated with the object mask picture of the ith auxiliary picture layer associated with the current main picture layer. If the layer does not exist, the value of omi_mask_top[i][j] is assumed to be 0.

[0179] The value of omi_mask_width[i][j] must be in the range of 0 to (CroppedWidth / SubWidthC - omi_mask_left[i][j]) (inclusive). If the value does not exist, the value of omi_mask_width[i][j] is assumed to be (CroppedWidth / SubWidthC - omi_mask_left[i][j]).

[0180] The value of omi_mask_height[ i ][ j ] must be in the range of 0 to (CroppedHeight / SubHeightC - omi_mask_top[ i ][ j ]) (inclusive). If the value does not exist, the value of omi_mask_height[i][j] is assumed to be (CroppedHeight / SubWidthC - omi_mask_top[i][j]).

[0181] The identified object mask is a bounding box containing luma samples with horizontal coordinates from SubWidthC * ( ConfWinLeftOffset + omi_mask_left[ i ][ j ] ) to SubWidthC * ( ConfWinLeftOffset + omi_mask_left[ i ][ j ] + omi_mask_width [ i ][ j ] ) - 1 (inclusive) and vertical coordinates from SubHeightC * ( ConfWinTopOffset + omi_mask_top[ i ][ j ] ) to SubHeightC * ( ConfWinTopOffset + omi_mask_top[ i ][ j ] + omi_mask_height[ i ][ j ] ) - 1 (inclusive).

[0182] The variable pI[ i ] [ x ][ y ] is the decoded value of the sample corresponding to the relative sample position (x, y) in the cropped object mask picture of the i-th auxiliary picture layer associated with the current main picture layer. The following process determines the mask area in the auxiliary picture:

[0183] [Table 7]

[0184]

[0185] omi_mask_confidence[ i ][ j ] specifies the confidence level associated with the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, in units of 2 - ( omi_mask_confidence_length_minus1 + 1 ). That is, a higher value of omi_mask_confidence[ i ][ j ] means a higher confidence level. The length of the omi_mask_confidence[ i ][ j ] syntax element is omi_mask_confidence_length_minus1 + 1 bits.

[0186] omi_mask_depth[ i ][ j ] specifies the object depth associated with the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. A smaller value of omi_mask_depth means a shorter distance to the object. The length of the omi_mask_depth[ i ][ j ] syntax element is omi_mask_depth_length_minus1 + 1 bits.

[0187] omi_mask_label[ i ][ j ] specifies the label contents of the object mask picture associated with the jth object mask in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_label[ i ][ j ] syntax element must be less than or equal to 255 bytes, excluding the terminating null byte.

[0188] In the design of the Object Mask Information (OMI) SEI message, the SEI message includes a cancellation and retention mechanism for the object masks within the SEI message. A specific mask ID may be defined and used in an object mask auxiliary layer associated with the current main picture layer, and that mask ID may be later canceled. A specific mask ID may be reused in other OMI SEI messages that exist since the last OMI SEI message that canceled that mask ID. In such a case, there is no information as to whether the object with the mask ID contained in the current OMI SEI message is the same or different from the object in the previously canceled OMI SEI message.

[0189] Currently, the object mask auxiliary layer within CLVS can ensure that the mask IDs in OMI SEI messages represent the same object.

[0190] One embodiment provides a solution to the problem described above. Each item may be applied individually or in combination.

[0191] 1. Explain the meaning of the mask ID in the object mask information SEI message by adding one of the following:

[0192] - A specific maskId[i][j] in the jth object mask in the object mask picture of the ith auxiliary picture layer associated with the current main picture layer represents the same object mask in the current CLVS.

[0193] - A particular maskId[i][j] in the jth object mask in the object mask factor of the ith auxiliary picture layer associated with the current main picture layer must contain the same object mask in the current CLVS.

[0194] 2. When all of the following conditions are met, the maskId[ i0 ][ j0 ] value of an OMI SEI message seiA is equal to the maskId[ i1 ][ j1 ] value of another OMI SEI message seiB, and they specify a constraint that they point to the same object mask of the ith object mask auxiliary layer associated with the main picture layer:

[0195] - When i0 is equal to i1 and j0 is equal to j1

[0196] - When seiA and seiB are associated with the same main picture layer.

[0197] 3. If the maskId[ i0 ][ j0 ] value of an OMI SEI message seiA is the same as the maskId[ i1 ][ j1 ] value of another OMI SEI message seiB, and seiA and seiB are associated with the same main picture layer, it is specified that they point to the same object mask.

[0198] 4. Specify a constraint to prevent the identifier of object mask objectMaskA from being reused as an object mask for another object within the same CLVS. This constraint is applied before objectMaskA is canceled.

[0199] 5. Specifies the constraint that if the maskId[ i0 ][ j0 ] values ​​of an OMI SEI message omiA are the same as the maskId[ i1 ][ j1 ] values ​​of another OMI SEI message omiB, omiA and omiB are associated with the same main picture layer, and if omiA or omiB is not canceled, they point to the same object within the current CLVS.

[0200] 6. Specifies a constraint that there is no OMI SEI message with omi_cancel_flag equal to 1 that comes after omiA and before omiB in output order within the same CLVS.

[0201] One embodiment relates to item 1 described above.

[0202] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0203] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0204] [Table 8]

[0205]

[0206] A particular maskId[i][j] in the jth object mask in the object mask picture of the ith auxiliary picture layer associated with the current main picture layer indicates the same object mask in the current CLVS.

[0207] One embodiment relates to item 1 described above.

[0208] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0209] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0210] [Table 9]

[0211]

[0212] A particular maskId[ i ][ j ] in the jth object mask in the object mask image of the ith auxiliary picture layer associated with the current main picture layer must contain the same object mask in the current CLVS.

[0213] One embodiment relates to item 2 described above.

[0214] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0215] If all of the following conditions are met, the omi_mask_id[ i0 ][ j0 ] values ​​of an OMI SEI message seiA and the omi_mask_id[ i1 ][ j1 ] values ​​of another OMI SEI message seiB must be equal and point to the same object mask:

[0216] - i0 is equal to i1 and j0 is equal to j1.

[0217] - seiA and seiB are associated with the same main picture layer.

[0218] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0219] [Table 10]

[0220]

[0221] One embodiment relates to item 3 described above.

[0222] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0223] If maskId[ i0 ][ j0 ] of an OMI SEI message seiA within the same CLVS and maskId[ i1 ][ j1 ] of another OMI SEI message seiB have the same value, they point to the same object mask.

[0224] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0225] [Table 11]

[0226]

[0227] One embodiment relates to item 4 described above.

[0228] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0229] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0230] [Table 12]

[0231]

[0232] omiA is defined as an OMI SEI message containing a mask object objectMaskA with maskId[ i0 ][ j0 ], and omiB is the first OMI SEI message in the output order following omiA within the same CLVS, containing a mask object objectMaskB with maskId[ i1 ][ j1 ], and if the value of maskId[ i0 ][ j0 ] is equal to maskId[ i1 ][ j1 ], and the value of omi_mask_cancel[ i0 ][ j0 ] of omiA is equal to 0, then objectMaskA and objectMaskB are mask objects of the same object.

[0233] One embodiment relates to item 5 described above.

[0234] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0235] If within the same CLVS, an OMI SEI message omiA has the same maskId[ i0 ][ j0 ] as another OMI SEI message omiB and omiA or omiB is not canceled by omi_mask_cancel[ i0 ][ j0 ] or omi_mask_cancel[ i1 ][ j1 ], then they point to the same object.

[0236] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0237] [Table 13]

[0238]

[0239] One embodiment relates to items 4 and 6 described above.

[0240] omi_mask_id[ i ][ j ] represents the identifier of the jth object mask of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer. The length of the omi_mask_id[ i ][ j ] syntax element is omi_mask_id_length_minus1 + 1 bits.

[0241] The variable maskId[ i ][ j ], which specifies the jth object mask identifier of the object mask picture in the ith auxiliary picture layer associated with the current main picture layer, is derived as follows:

[0242] [Table 14]

[0243]

[0244] When omiA is an OMI SEI message containing a mask object objectMaskA with maskId[ i0 ][ j0 ], and omiB is the first OMI SEI message in output order following omiA within the same CLVS and contains a mask object objectMaskB with maskId[ i1 ][ j1 ], and maskId[ i0 ][ j0 ] is equal to maskId[ i1 ][ j1 ], then objectMaskA and objectMaskB are mask objects of the same object if both of the following conditions are met:

[0245] 1) The value of omi_mask_cancel[ i0 ][ j0 ] of omiA is equal to 0.

[0246] 2) There is no OMI SEI message with omi_cancel_flag equal to 1 within the same CLVS in the output sequence between omiA and omiB.

[0247] 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.

[0248] 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.

[0249] FIG. 5 is a diagram illustrating a method for decoding image information according to one embodiment of the present disclosure.

[0250] 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.

[0251] 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.

[0252] 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.

[0253] The decoding device can obtain image information (S510).

[0254] For example, a processor of a decoding device may obtain image information. The image information may include at least one (or multiple) primary layers among multiple layers. Each of the at least one (or multiple) primary layers may include a picture to be decoded. Here, the primary layer is not limited to its name and may be referred to in various ways, such as a "primary picture layer."

[0255] The image information may further include at least one auxiliary layer associated with the current primary layer among at least one (or multiple) primary 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.

[0256] For example, at least one auxiliary layer may provide multi-views or additional information (e.g., depth or alpha) of the primary layer.

[0257] Additionally, for example, at least one auxiliary layer may be utilized for object detection and tracking applications for the primary layer. The encoding device may perform image analysis on the pictures of the primary 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 primary layer.

[0258] The video information may include a supplemental enhancement information (SEI) message. The SEI message may convey a specific type of information that assists in processes related to decoding, displaying, or other purposes of the video information. Here, the SEI message may not be necessary for the decoding process to determine the sample values ​​of the decoded picture.

[0259] For example, an SEI message may include an SDI SEI message that provides scalability dimension information (SDI) for each layer. Specifically, an SDI SEI message may provide information about multi-views and auxiliary information about layers.

[0260] An SDI SEI message can take various forms. For example, an SDI SEI message can be a syntax element or a syntax structure containing one or more syntax elements. Additionally, an SDI SEI message can be a raw byte sequence payload (RBSP) containing one or more syntax elements or containing one or more syntax structures. For example, an SDI SEI message can be expressed as, but is not limited to, scalability_dimension_info(payloadSize).

[0261] SDI SEI messages may have various names, such as SDI message, SEI message, SDI related message, SDI related information, etc., and the names are not limited.

[0262] Additionally, the SEI message may include an OMI SEI message that provides at least one (or multiple) object mask information (OMI) associated with at least one (or multiple) primary layers, respectively. Specifically, the OMI SEI message may include at least one (or multiple) primary layer and ...

[0263] In particular, at least one (or multiple) OMI SEI messages may be associated with at least one (or multiple) primary layers. In other words, one of the at least one (or multiple) OMI SEI messages may be associated with a current primary layer among the at least one (or multiple) primary layers. Furthermore, one OMI SEI message may be present in the current primary layer.

[0264] OMI SEI messages may have various names, such as OMI message, SEI message, OMI related message, OMI related information, etc., and the names are not limited.

[0265] An OMI SEI message can take various forms. For example, an OMI SEI message can be a syntax element or a syntax structure containing one or more syntax elements. Additionally, an OMI SEI 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 SEI message can be expressed as, but is not limited to, object_mask_info(payloadSize).

[0266] The decoding device can obtain object mask information based on the SEI message (S520).

[0267] For example, a processor of a decoding device can process SDI SEI messages and OMI SEI messages. The decoding device can obtain scalability dimension information and object mask information, respectively, based on processing the SDI SEI messages and OMI SEI messages.

[0268] The extensibility dimension information provided by the SDI SEI message may include multiview flag information, auxiliary information flag information, layer identification information, auxiliary identification information, etc.

[0269] The multiview flag information may indicate whether the current image information includes multiviews. For example, a value of the multiview flag information of 1 may indicate that the current image information includes multiviews. Additionally, a value of the multiview flag information of 0 may indicate that the current image information does not include multiviews. However, the present invention is not limited thereto, and alternatively, what the multiview flag information of 1 indicates may be interchangeable with what the multiview flag information of 0 indicates.

[0270] Multiview flag information can take various forms and be expressed by various names. For example, multiview flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, multiview flag information as a syntax element can be expressed as a syntax element such as sdi_multiview_info_flag, but is not limited thereto.

[0271] The auxiliary information flag information may indicate whether the current image information includes an auxiliary layer containing auxiliary information. For example, a value of the auxiliary information flag information of 1 may indicate that the current image information includes an auxiliary layer containing auxiliary information. In addition, a value of the auxiliary information flag information of 0 may indicate that the current image information does not include an auxiliary layer containing auxiliary information. However, the present invention is not limited thereto, and alternatively, what the auxiliary information flag information of 1 indicates may be interchangeable with what the auxiliary information flag information of 0 indicates.

[0272] Auxiliary information flag information can take various forms and be expressed by various names. For example, auxiliary information flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, auxiliary information flag information as a syntax element can be expressed as a syntax element such as sdi_auxiliary_info_flag, but is not limited thereto.

[0273] Layer identification information may indicate an identifier for identifying a layer included in image information. Layer identification information may take various forms and may be expressed by various names. For example, layer identification information may be a syntax element or a syntax structure including one or more syntax elements. For example, layer identification information as a syntax element may be expressed as a syntax element sdi_layer_id[ i ], but is not limited thereto.

[0274] Additionally, layer identification information can be expressed as an array or a vector, depending on the number of layers. For example, if the number of layers is 2 or greater, layer identification information can be expressed as an array that depends on the index i indicating the layer. Index i indicates the ith layer, and each value constituting the array can indicate identification information for the ith layer.

[0275] Auxiliary identification information may indicate identifiers for identifying the primary layer and auxiliary layer and for identifying the type of auxiliary information included in the auxiliary layer. The type of auxiliary information may be identified by the auxiliary identification information. For example, the type of auxiliary information may include depth information, alpha information, and object mask information, and the type of auxiliary information included in the auxiliary layer may be identified based on the auxiliary identification information.

[0276] Auxiliary identification information can take various forms and be expressed by various names. For example, auxiliary identification information can be a syntax element or a syntax structure containing one or more syntax elements. For example, auxiliary identification information as a syntax element can be expressed as, but is not limited to, the syntax element sdi_aux_id[ i ].

[0277] Object mask information provided by the OMI SEI message may include OMI cancellation flag information, OMI persistence flag information, auxiliary layer count information, object mask count information, mask identification information, etc.

[0278] The OMI cancel flag information may indicate whether the persistence of an OMI SEI message preceding the current OMI SEI message is canceled. For example, a value of 1 for the OMI cancel flag information may indicate that the persistence of a previous OMI SEI message existing in the current main layer in terms of output order is canceled. In addition, a value of 0 for the OMI cancel flag information may indicate that object mask information follows. However, the present invention is not limited thereto, and alternatively, what the value of 1 for the OMI cancel flag information specifies may be changed from what the value of 0 for the OMI cancel flag information specifies.

[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 a syntax element such as omi_cancel_flag, but is not limited thereto.

[0280] The OMI persistence flag information can indicate the persistence of the object mask information included in the OMI SEI message. A value of 1 for the OMI persistence flag information can indicate that the object mask information included in the OMI SEI message is applied not only to the current picture but also to pictures of all subsequent primary layers 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 SEI 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, a syntax element such as omi_persistence_flag.

[0282] The auxiliary layer count information can indicate the number of auxiliary layers associated with the primary 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 a syntax element such 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 primary layer.

[0283] The object mask count information can indicate the number of object masks in an auxiliary layer associated with a primary layer. The object mask count information can have various forms and can be expressed by various names. For example, the object mask 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 a syntax element omi_num_mask_in_pic_update[ i ] or omi_num_mask_in_pic_update_minus1[ i ], but is not limited thereto. When expressed as omi_num_mask_in_pic_update_minus1[ i ], the object mask count information can have a value that adds 1 to that value to indicate the number of object masks in the auxiliary layer.

[0284] Additionally, the object mask count information can be expressed as an array or a vector depending on the number of auxiliary layers. For example, if the number of auxiliary layers is 2 or more, the object mask count information can be expressed as an array depending on the index i indicating the auxiliary layer. The index i indicates the ith auxiliary layer, and each value constituting the array can indicate the number of object masks in the ith auxiliary layer.

[0285] The mask identification information may represent an identifier for identifying an object mask within an auxiliary layer associated with a primary layer. The mask identification information may take various forms and may be expressed by various names. For example, the mask identification information may be a syntax element or a syntax structure including one or more syntax elements. For example, the mask identification information as a syntax element may be expressed as, but is not limited to, syntax elements omi_mask_id[ i ][ j ].

[0286] The mask identification information can be expressed as a two-dimensional array or matrix depending on the number of auxiliary layers and the number of object masks. For example, if the number of auxiliary layers and the number of object masks are both 2 or more, the mask identification information can be expressed as a two-dimensional array depending on an index i indicating an auxiliary layer and an index j indicating an object mask. The index i indicates the ith auxiliary layer, and the index j indicates the jth object mask within the ith auxiliary layer, and each value constituting the two-dimensional array can indicate the mask identification information of the jth object mask within the ith auxiliary layer.

[0287] Here, the mask identification information can be used to identify one or more object masks within one auxiliary layer. The mask identification information of object masks within different auxiliary layers can overlap with each other.

[0288] To identify object masks in all auxiliary layers, a mask identification variable can be derived. The mask identification variable can be derived based on an index i indicating the i-th mask identification information and the mask identification information of the j-th object mask.

[0289] For example, the mask identification variable can be derived as follows.

[0290] [Table 15]

[0291]

[0292] The mask identification variable can be used to identify a specific object mask across all auxiliary layers.

[0293] Here, one mask identification variable may correspond to one object mask. More specifically, one mask identification variable may correspond to an object represented by one object mask.

[0294] For example, a picture within a main picture layer may contain an object tracked by an object mask. Depending on the display order, the object may disappear or reappear in the picture within the main picture layer due to reasons such as screen transitions.

[0295] When an object disappears from a picture within a primary picture layer, the object mask tracking the object in the secondary picture layer associated with the primary picture layer may be removed, and mask identification information for identifying the object may also be removed from the object mask information of the OMI SEI message. In addition, the mask identification variable may be updated.

[0296] At this time, if the object reappears in the current picture within the primary picture layer, an object mask that tracks the object in the secondary picture layer associated with the primary picture layer may be added, and mask identification information for identifying the object may also be added to the object mask information of the OMI SEI message. In addition, the mask identification variable may also be updated.

[0297] At this time, if the value of the mask identification information (or the mask identification variable derived from the mask identification information) of the object mask corresponding to the object appearing in the current picture is the same as the value of the mask identification information (or the mask identification variable derived from the mask identification information) of the object mask corresponding to the object that disappeared in the previous picture, it may not be clear whether the object appearing in the current picture is the same as the object that disappeared in the previous picture.

[0298] To address this, it can be defined that identical mask identification information (or mask identification variables derived from mask identification information) correspond to identical objects contained in pictures within the main picture layer.

[0299] For example, a specific mask identification variable derived from the mask identification information of an object mask of an auxiliary picture layer associated with the current main picture layer indicates the same object mask in the current image information and corresponds to the same object.

[0300] For example, a specific mask identification variable derived from the mask identification information of an object mask of an auxiliary picture layer associated with the current main picture layer includes the same object mask in the current image information and corresponds to the same object.

[0301] For example, if (i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is the same as the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, (ii) the first auxiliary layer corresponding to the first mask identification variable and the second auxiliary layer corresponding to the second mask identification variable have the same index, (iii) the first object mask corresponding to the first mask identification variable and the second object mask corresponding to the second mask identification variable have the same index, and (iv) the first auxiliary layer and the second auxiliary layer are associated with the same main layer, then the first mask identification variable and the second mask identification variable indicate the same object mask.

[0302] For example, if the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, the first mask identification variable and the second mask identification variable indicate the same object mask.

[0303] For example, if (i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, and (ii) the persistence of the first OMI SEI message is not canceled, then the first object mask corresponding to the first mask identification variable and the second object mask corresponding to the second mask identification variable are equal. In other words, the first object mask and the second object mask correspond to the same object.

[0304] For example, if i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, and (ii) neither the first object mask corresponding to the first mask identification variable nor the second object mask corresponding to the second mask identification variable is canceled, then the first object mask and the second object mask are equal. In other words, the first object mask and the second object mask correspond to the same object.

[0305] For example, if (i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, (ii) the first auxiliary layer corresponding to the first mask identification variable and the second auxiliary layer corresponding to the second mask identification variable have the same index, (iii) the first object mask corresponding to the first mask identification variable and the second object mask corresponding to the second mask identification variable have the same index, and (iv) there is no OMI SEI message that cancels persistence between the first OMI SEI message and the second OMI SEI message, then the first object mask and the second object mask are equal. In other words, the first object mask and the second object mask correspond to the same object.

[0306] In this way, if the mask identification variables derived from the mask identification information of different SEI messages associated with the same main picture layer have the same value, the object masks indicated by the mask identification variables are the same, and the object masks indicated by the mask identification variables correspond to the same object.

[0307] Additionally, if the first mask identification variable derived from the first mask identification information of the first SEI message is identical to the second mask identification variable derived from the second mask identification information of the second SEI message, the first object mask corresponding to the first mask identification variable is identical to the second object mask corresponding to the second mask identification variable, and the first object mask and the second object mask correspond to the same object.

[0308] In addition, if the first mask identification variable derived from the first mask identification information of the first SEI message is identical to the second mask identification variable derived from the second mask identification information of the second SEI message, and there is no SEI message that cancels the persistence of object mask information between the first SEI message and the second SEI message, the first object mask corresponding to the first mask identification variable is identical to the second object mask corresponding to the second mask identification variable, and the first object mask and the second object mask may correspond to the same object.

[0309] By this, by defining that object masks corresponding to mask identification variables having the same value correspond to the same object, ambiguity regarding whether object masks corresponding to mask identification variables having the same value correspond to the same object can be resolved, and further, potential errors that may occur due to object masks corresponding to mask identification variables having the same value corresponding to different objects can be suppressed or prevented.

[0310] FIG. 6 is a diagram illustrating a method for encoding image information according to one embodiment of the present disclosure.

[0311] 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.

[0312] 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.

[0313] The encoding device can generate object mask information (S610).

[0314] For example, a processor of an encoding device may generate object mask information based on a primary layer and an auxiliary layer associated with the primary layer. Here, the primary layer may include a picture to be decoded. The primary layer is not limited to its name and may be called variously, such as a primary picture layer. In addition, the auxiliary layer may provide multi-views or include additional information (e.g., depth or alpha) of the primary layer. The auxiliary layer is not limited to its name and may be called variously, such as a secondary picture layer.

[0315] The encoding device can perform image analysis on the pictures of the main layer and generate information about the 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 the pictures of the main layer. In this way, by performing image analysis on the pictures of the main layer by the encoding device, the power consumption of the decoding device is reduced, and more accurate object detection and tracking is enabled. Here, the main layer is not limited to its name, and can be referred to by various names, such as a main picture layer.

[0316] The encoding device can generate an auxiliary layer associated with the primary layer based on an object mask. The auxiliary layer can include an object mask for object detection and tracking operations in the primary layer. The auxiliary layer is not limited to its name and may be referred to by various names, such as an auxiliary picture layer.

[0317] The encoding device can generate object mask information based on an auxiliary layer including an object mask.

[0318] Object mask information may include OMI cancellation flag information, OMI persistence flag information, auxiliary layer count information, object mask count information, mask identification information, etc.

[0319] The OMI cancel flag information may indicate whether the persistence of an OMI SEI message preceding the current OMI SEI message is canceled. For example, a value of 1 for the OMI cancel flag information may indicate that the persistence of a previous OMI SEI message existing in the current main layer in terms of output order is canceled. In addition, a value of 0 for the OMI cancel flag information may indicate that object mask information follows. However, the present invention is not limited thereto, and alternatively, what the value of 1 for the OMI cancel flag information specifies may be changed from what the value of 0 for the OMI cancel flag information specifies.

[0320] 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 a syntax element such as omi_cancel_flag, but is not limited thereto.

[0321] The OMI persistence flag information can indicate the persistence of the object mask information included in the OMI SEI message. A value of 1 for the OMI persistence flag information can indicate that the object mask information included in the OMI SEI message is applied not only to the current picture but also to pictures of all subsequent primary layers 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 SEI 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.

[0322] 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, a syntax element such as omi_persistence_flag.

[0323] The auxiliary layer count information can indicate the number of auxiliary layers associated with the primary 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 a syntax element such 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 primary layer.

[0324] The object mask count information can indicate the number of object masks in an auxiliary layer associated with a primary layer. The object mask count information can have various forms and can be expressed by various names. For example, the object mask 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 a syntax element omi_num_mask_in_pic_update[ i ] or omi_num_mask_in_pic_update_minus1[ i ], but is not limited thereto. When expressed as omi_num_mask_in_pic_update_minus1[ i ], the object mask count information can have a value that adds 1 to that value to indicate the number of object masks in the auxiliary layer.

[0325] Additionally, the object mask count information can be expressed as an array or a vector depending on the number of auxiliary layers. For example, if the number of auxiliary layers is 2 or more, the object mask count information can be expressed as an array depending on the index i indicating the auxiliary layer. The index i indicates the ith auxiliary layer, and each value constituting the array can indicate the number of object masks in the ith auxiliary layer.

[0326] The mask identification information may represent an identifier for identifying an object mask within an auxiliary layer associated with a primary layer. The mask identification information may take various forms and may be expressed by various names. For example, the mask identification information may be a syntax element or a syntax structure including one or more syntax elements. For example, the mask identification information as a syntax element may be expressed as, but is not limited to, syntax elements omi_mask_id[ i ][ j ].

[0327] The mask identification information can be expressed as a two-dimensional array or matrix depending on the number of auxiliary layers and the number of object masks. For example, if the number of auxiliary layers and the number of object masks are both 2 or more, the mask identification information can be expressed as a two-dimensional array depending on an index i indicating an auxiliary layer and an index j indicating an object mask. The index i indicates the ith auxiliary layer, and the index j indicates the jth object mask within the ith auxiliary layer, and each value constituting the two-dimensional array can indicate the mask identification information of the jth object mask within the ith auxiliary layer.

[0328] Here, the mask identification information can be used to identify one or more object masks within one auxiliary layer. The mask identification information of object masks within different auxiliary layers can overlap with each other.

[0329] To identify object masks in all auxiliary layers, a mask identification variable can be derived. The mask identification variable can be derived based on an index i indicating the i-th mask identification information and the mask identification information of the j-th object mask.

[0330] For example, the mask identification variable can be derived as follows.

[0331] [Table 16]

[0332]

[0333] The mask identification variable can be used to identify a specific object mask across all auxiliary layers.

[0334] Here, one mask identification variable may correspond to one object mask. More specifically, one mask identification variable may correspond to an object represented by one object mask.

[0335] For example, a picture within a main picture layer may contain an object tracked by an object mask. Depending on the display order, the object may disappear or reappear in the picture within the main picture layer due to reasons such as screen transitions.

[0336] When an object disappears from a picture within a primary picture layer, the object mask tracking the object in the secondary picture layer associated with the primary picture layer may be removed, and mask identification information for identifying the object may also be removed from the object mask information of the OMI SEI message. In addition, the mask identification variable may be updated.

[0337] At this time, if the object reappears in the current picture within the primary picture layer, an object mask that tracks the object in the secondary picture layer associated with the primary picture layer may be added, and mask identification information for identifying the object may also be added to the object mask information of the OMI SEI message. In addition, the mask identification variable may also be updated.

[0338] At this time, if the value of the mask identification information (or the mask identification variable derived from the mask identification information) of the object mask corresponding to the object appearing in the current picture is the same as the value of the mask identification information (or the mask identification variable derived from the mask identification information) of the object mask corresponding to the object that disappeared in the previous picture, it may not be clear whether the object appearing in the current picture is the same as the object that disappeared in the previous picture.

[0339] To address this, it can be defined that identical mask identification information (or mask identification variables derived from mask identification information) correspond to identical objects contained in pictures within the main picture layer.

[0340] For example, a specific mask identification variable derived from the mask identification information of an object mask of an auxiliary picture layer associated with the current main picture layer indicates the same object mask in the current image information and corresponds to the same object.

[0341] For example, a specific mask identification variable derived from the mask identification information of an object mask of an auxiliary picture layer associated with the current main picture layer includes the same object mask in the current image information and corresponds to the same object.

[0342] For example, if (i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is the same as the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, (ii) the first auxiliary layer corresponding to the first mask identification variable and the second auxiliary layer corresponding to the second mask identification variable have the same index, (iii) the first object mask corresponding to the first mask identification variable and the second object mask corresponding to the second mask identification variable have the same index, and (iv) the first auxiliary layer and the second auxiliary layer are associated with the same main layer, then the first mask identification variable and the second mask identification variable indicate the same object mask.

[0343] For example, if the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, the first mask identification variable and the second mask identification variable indicate the same object mask.

[0344] For example, if (i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, and (ii) the persistence of the first OMI SEI message is not canceled, then the first object mask corresponding to the first mask identification variable and the second object mask corresponding to the second mask identification variable are equal. In other words, the first object mask and the second object mask correspond to the same object.

[0345] For example, if i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, and (ii) neither the first object mask corresponding to the first mask identification variable nor the second object mask corresponding to the second mask identification variable is canceled, then the first object mask and the second object mask are equal. In other words, the first object mask and the second object mask correspond to the same object.

[0346] For example, if (i) the value of the first mask identification variable derived from the first mask identification information of the first OMI SEI message associated with the current main picture layer is equal to the value of the second mask identification variable derived from the second mask identification information of the second OMI SEI message, (ii) the first auxiliary layer corresponding to the first mask identification variable and the second auxiliary layer corresponding to the second mask identification variable have the same index, (iii) the first object mask corresponding to the first mask identification variable and the second object mask corresponding to the second mask identification variable have the same index, and (iv) there is no OMI SEI message that cancels persistence between the first OMI SEI message and the second OMI SEI message, then the first object mask and the second object mask are equal. In other words, the first object mask and the second object mask correspond to the same object.

[0347] Additionally, the processor of the encoding device can generate scalability dimension information based on the primary layer and the auxiliary layer associated with the primary layer.

[0348] Scalability dimension information may include information about multi-views and auxiliary information about layers.

[0349] For example, the scalability dimension information may include multiview flag information, auxiliary information flag information, layer identification information, auxiliary identification information, etc.

[0350] The multiview flag information may indicate whether the current image information includes multiviews. For example, a value of the multiview flag information of 1 may indicate that the current image information includes multiviews. Additionally, a value of the multiview flag information of 0 may indicate that the current image information does not include multiviews. However, the present invention is not limited thereto, and alternatively, what the multiview flag information of 1 indicates may be interchangeable with what the multiview flag information of 0 indicates.

[0351] Multiview flag information can take various forms and be expressed by various names. For example, multiview flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, multiview flag information as a syntax element can be expressed as a syntax element such as sdi_multiview_info_flag, but is not limited thereto.

[0352] The auxiliary information flag information may indicate whether the current image information includes an auxiliary layer containing auxiliary information. For example, a value of the auxiliary information flag information of 1 may indicate that the current image information includes an auxiliary layer containing auxiliary information. In addition, a value of the auxiliary information flag information of 0 may indicate that the current image information does not include an auxiliary layer containing auxiliary information. However, the present invention is not limited thereto, and alternatively, what the auxiliary information flag information of 1 indicates may be interchangeable with what the auxiliary information flag information of 0 indicates.

[0353] Auxiliary information flag information can take various forms and be expressed by various names. For example, auxiliary information flag information can be a syntax element or a syntax structure containing one or more syntax elements. For example, auxiliary information flag information as a syntax element can be expressed as a syntax element such as sdi_auxiliary_info_flag, but is not limited thereto.

[0354] Layer identification information may indicate an identifier for identifying a layer included in image information. Layer identification information may take various forms and may be expressed by various names. For example, layer identification information may be a syntax element or a syntax structure including one or more syntax elements. For example, layer identification information as a syntax element may be expressed as a syntax element sdi_layer_id[ i ], but is not limited thereto.

[0355] Additionally, layer identification information can be expressed as an array or a vector, depending on the number of layers. For example, if the number of layers is 2 or greater, layer identification information can be expressed as an array that depends on the index i indicating the layer. Index i indicates the ith layer, and each value constituting the array can indicate identification information for the ith layer.

[0356] Auxiliary identification information may indicate an identifier for identifying the type of auxiliary information included in the auxiliary layer. The type of auxiliary information may be identified by the auxiliary identification information. For example, the type of auxiliary information may include depth information, alpha information, and object mask information, and the type of auxiliary information included in the auxiliary layer may be identified based on the auxiliary identification information.

[0357] Auxiliary identification information can take various forms and be expressed by various names. For example, auxiliary identification information can be a syntax element or a syntax structure containing one or more syntax elements. For example, auxiliary identification information as a syntax element can be expressed as, but is not limited to, the syntax element sdi_aux_id[ i ].

[0358] The encoding device can encode image information (S620).

[0359] For example, a processor of an encoding device may encode image information including a primary layer, an auxiliary layer associated with the primary layer, and an SEI message.

[0360] The image information may further include at least one auxiliary layer associated with the current primary layer among at least one (or multiple) primary 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.

[0361] For example, at least one auxiliary layer may provide multi-views or additional information (e.g., depth or alpha) of the primary layer.

[0362] Additionally, for example, at least one auxiliary layer may be utilized for object detection and tracking applications for the primary layer. The encoding device may perform image analysis on the pictures of the primary 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 primary layer.

[0363] The video information may include a supplemental enhancement information (SEI) message. The SEI message may convey a specific type of information that assists in processes related to decoding, displaying, or other purposes of the video information. Here, the SEI message may not be necessary for the decoding process to determine the sample values ​​of the decoded picture.

[0364] For example, an SEI message may include an SDI SEI message that includes scalability dimension information (SDI) for each layer. Specifically, the SDI SEI message may include information about multi-views and auxiliary information about layers.

[0365] An SDI SEI message can take various forms. For example, an SDI SEI message can be a syntax element or a syntax structure containing one or more syntax elements. Additionally, an SDI SEI message can be a raw byte sequence payload (RBSP) containing one or more syntax elements or containing one or more syntax structures. For example, an SDI SEI message can be expressed as, but is not limited to, scalability_dimension_info(payloadSize).

[0366] SDI SEI messages may have various names, such as SDI message, SEI message, SDI related message, SDI related information, etc., and the names are not limited.

[0367] Additionally, the SEI message may include an OMI SEI message that provides at least one (or multiple) object mask information (OMI) associated with at least one (or multiple) primary layers, respectively. Specifically, the OMI SEI message may include at least one (or multiple) primary layer and ...

[0368] In particular, at least one (or multiple) OMI SEI messages may be associated with at least one (or multiple) primary layers. In other words, one of the at least one (or multiple) OMI SEI messages may be associated with a current primary layer among the at least one (or multiple) primary layers. Furthermore, one OMI SEI message may be present in the current primary layer.

[0369] OMI SEI messages may have various names, such as OMI message, SEI message, OMI related message, OMI related information, etc., and the names are not limited.

[0370] An OMI SEI message can take various forms. For example, an OMI SEI message can be a syntax element or a syntax structure containing one or more syntax elements. Additionally, an OMI SEI 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 SEI message can be expressed as, but is not limited to, object_mask_info(payloadSize).

[0371] In this way, the processor of the encoding device may include an SDI SEI message including a primary layer, an auxiliary layer associated with the primary layer, and extensibility dimension information, and an OMI SEI message including object mask information.

[0372] As explained above, if the mask identification variables derived from the mask identification information of different SEI messages associated with the same main picture layer have the same value, the object masks indicated by the mask identification variables are the same and the object masks indicated by the mask identification variables correspond to the same object.

[0373] Additionally, if the first mask identification variable derived from the first mask identification information of the first SEI message is identical to the second mask identification variable derived from the second mask identification information of the second SEI message, the first object mask corresponding to the first mask identification variable is identical to the second object mask corresponding to the second mask identification variable, and the first object mask and the second object mask correspond to the same object.

[0374] In addition, if the first mask identification variable derived from the first mask identification information of the first SEI message is identical to the second mask identification variable derived from the second mask identification information of the second SEI message, and there is no SEI message that cancels the persistence of object mask information between the first SEI message and the second SEI message, the first object mask corresponding to the first mask identification variable is identical to the second object mask corresponding to the second mask identification variable, and the first object mask and the second object mask may correspond to the same object.

[0375] By this, by defining that object masks corresponding to mask identification variables having the same value correspond to the same object, ambiguity regarding whether object masks corresponding to mask identification variables having the same value correspond to the same object can be resolved, and further, potential errors that may occur due to object masks corresponding to mask identification variables having the same value corresponding to different objects can be suppressed or prevented.

[0376] 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.

[0377] 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.

[0378] FIG. 7 is a diagram exemplifying a content streaming system to which an embodiment according to the present disclosure can be applied.

[0379] 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.

[0380] 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.

[0381] 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.

[0382] 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.

[0383] 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.

[0384] 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.

[0385] 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.

[0386] 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.

[0387] Embodiments according to the present disclosure can be used to encode / decode images.

Claims

1. In a method for decoding video information, Obtaining image information including a main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message associated with the main picture layer; Including obtaining object mask information (OMI) associated with the main picture layer based on at least one SEI message, At least one mask identification variable is derived for identifying at least one object mask of at least one auxiliary picture layer based on the object mask information, A method in which object masks designated by mask identification variables having the same value, derived based on different SEI messages, correspond to the same object.

2. In paragraph 1, The above object mask information includes identification information of at least one object mask included in the at least one auxiliary picture layer, A method wherein said at least one mask identification variable is derived based on mask identification information of said at least one object mask.

3. In paragraph 1, The above different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, A method in which the first object mask and the second object mask correspond to the same object based on the value of the mask identification variable of the first object mask derived based on the first SEI message being the same as the mask identification variable of the second object mask derived based on the second SEI message.

4. In paragraph 1, A method of restricting the reuse of mask identification variables having the same values ​​as above.

5. In paragraph 1, The above different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, A method in which the first object mask and the second object mask correspond to the same object based on the fact that there is no SEI message that cancels the persistence of the SEI message between the first SEI message and the second SEI message and the value of the mask identification variable of the first object mask derived based on the first SEI message is the same as the mask identification variable of the second object mask derived based on the second SEI message.

6. In a method for encoding image information, Generate object mask information associated with the main picture layer; Encoding the image information including the main picture layer, the at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message generated based on the object mask information, At least one mask identification variable is derived for identifying at least one object mask of at least one auxiliary picture layer based on the object mask information, A method in which object masks designated by mask identification variables having the same value, derived based on different SEI messages, correspond to the same object.

7. In paragraph 6, The above object mask information includes identification information of at least one object mask included in the at least one auxiliary picture layer, A method wherein said at least one mask identification variable is derived based on mask identification information of said at least one object mask.

8. In paragraph 6 The above different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, A method in which the first object mask and the second object mask correspond to the same object based on the value of the mask identification variable of the first object mask derived based on the first SEI message being the same as the mask identification variable of the second object mask derived based on the second SEI message.

9. In paragraph 6, A method of restricting the reuse of mask identification variables having the same values ​​as above.

10. In paragraph 6, The above different SEI messages include a first SEI message and a second SEI message associated with the main picture layer, A method in which the first object mask and the second object mask correspond to the same object based on the fact that there is no SEI message that cancels the persistence of the SEI message between the first SEI message and the second SEI message and the value of the mask identification variable of the first object mask derived based on the first SEI message is the same as the mask identification variable of the second object mask derived based on the second SEI message.

11. In a method regarding bitstream, Generate object mask information associated with the main picture layer; Generating a bitstream based on image information including the main picture layer, at least one auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message based on the object mask information; Including transmitting the above bitstream, At least one mask identification variable is derived for identifying at least one object mask of at least one auxiliary picture layer based on the object mask information, A method in which object masks designated by mask identification variables having the same value, derived based on different SEI messages, correspond to the same object.

12. In a computer-readable storage medium storing a bitstream, Object mask information associated with the main picture layer is generated, A bitstream generated based on image information including the main picture layer, an auxiliary picture layer associated with the main picture layer, and at least one supplemental enhancement information (SEI) message based on the object mask information is stored in a computer-readable storage medium, At least one mask identification variable is derived for identifying at least one object mask of at least one auxiliary picture layer based on the object mask information, Object masks, which are identified by mask identification variables having the same value based on different SEI messages, are storage media corresponding to the same object.

Images