WO2019199024A1 - Procédé de traitement de données d'image à 360° en fonction d'une sous-image, et dispositif pour cela - Google Patents

Procédé de traitement de données d'image à 360° en fonction d'une sous-image, et dispositif pour cela Download PDF

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Publication number
WO2019199024A1
WO2019199024A1 PCT/KR2019/004212 KR2019004212W WO2019199024A1 WO 2019199024 A1 WO2019199024 A1 WO 2019199024A1 KR 2019004212 W KR2019004212 W KR 2019004212W WO 2019199024 A1 WO2019199024 A1 WO 2019199024A1
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WIPO (PCT)
Prior art keywords
track
information
video
metadata
subpicture
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PCT/KR2019/004212
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English (en)
Korean (ko)
Inventor
이장원
오세진
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엘지전자 주식회사
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Publication of WO2019199024A1 publication Critical patent/WO2019199024A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/10—Processing, recording or transmission of stereoscopic or multi-view image signals
    • H04N13/106—Processing image signals
    • H04N13/111—Transformation of image signals corresponding to virtual viewpoints, e.g. spatial image interpolation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/10—Processing, recording or transmission of stereoscopic or multi-view image signals
    • H04N13/106—Processing image signals
    • H04N13/161—Encoding, multiplexing or demultiplexing different image signal components
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/10—Processing, recording or transmission of stereoscopic or multi-view image signals
    • H04N13/106—Processing image signals
    • H04N13/172—Processing image signals image signals comprising non-image signal components, e.g. headers or format information
    • H04N13/178—Metadata, e.g. disparity information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
    • H04N13/10—Processing, recording or transmission of stereoscopic or multi-view image signals
    • H04N13/189—Recording image signals; Reproducing recorded image signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/434—Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/435—Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
    • H04N21/81—Monomedia components thereof

Definitions

  • the present invention relates to 360 images, and more particularly, to a subpicture based processing method and apparatus for 360 image data.
  • the VR (Vertial Reality) system gives the user the feeling of being in an electronically projected environment.
  • the system for providing VR can be further refined to provide higher quality images and spatial sound.
  • the VR system can enable a user to consume VR content interactively.
  • An object of the present invention is to provide a method and apparatus for processing 360 image data.
  • Another object of the present invention is to provide a method and apparatus for transmitting metadata for 360 image data.
  • Another object of the present invention is to provide a method and apparatus for subpicture-based processing of 360 image data.
  • Another object of the present invention is to provide a method and apparatus for transmitting metadata for subpicture-based processing of 360 image data.
  • a 360 video data processing method performed by a 360 video receiving apparatus includes receiving 360 video data, obtaining information and metadata about an encoded picture from the 360 video data, decoding at least a portion of a region of the picture based on the information about the encoded picture; Rendering at least a partial region of a decoded picture based on the metadata, and when the 360 video data includes a plurality of subpicture tracks, the picture includes a plurality of subpictures, and the metadata Is characterized by comprising track group information for the plurality of subpicture tracks.
  • a 360 video data processing method performed by the 360 video transmission device.
  • the method comprises the steps of obtaining 360 video, processing the 360 video to derive a picture, generating metadata about the 360 video, encoding at least a portion of the picture, and encoding the encoded picture.
  • Performing a process for storing or transmitting at least a partial region and the metadata and when the picture includes a plurality of subpictures, the plurality of subpictures are respectively stored or stored as a plurality of subpicture tracks.
  • Processing for transmission is performed, and the metadata includes track group information for the plurality of subpicture tracks.
  • a 360 video receiving apparatus receives 360 video data, and obtains information about the encoded picture and metadata from the 360 video data, and decodes at least a partial region of the picture based on the information about the encoded picture.
  • a data decoder and a renderer for rendering at least a partial region of a decoded picture based on the metadata, and when the 360 video data includes a plurality of subpicture tracks, the picture includes a plurality of subpictures.
  • the metadata may include track group information for the plurality of subpicture tracks.
  • a 360 video transmission device may include a data input unit for acquiring 360 video, a projection processor for processing the 360 video to derive a picture, a metadata processor for generating metadata regarding the 360 video, and encoding at least a partial region of the picture
  • a data encoder and a transmission processor configured to perform processing for storing or transmitting at least a portion of the encoded picture and the metadata, and when the picture includes a plurality of subpictures, the plurality of subpictures Processing for storing or transmitting each of the plurality of subpicture tracks is performed, and the metadata includes track group information for the plurality of subpicture tracks.
  • an efficient switching mechanism between tracks can be provided.
  • a method of signaling such that an area where a viewport is located can be of high quality can be proposed.
  • the region information and the grouping information of the subpicture may be signaled to perform adaptive processing on a subpicture or subpicture group basis.
  • VR content (360 content) can be efficiently transmitted in an environment supporting next generation hybrid broadcasting using a terrestrial broadcasting network and an internet network.
  • a method for providing an interactive experience in consuming 360 content of a user may be proposed.
  • signaling information for 360 image data can be efficiently stored and transmitted through an International Organization for Standardization (ISO) based media file format such as ISO base media file format (ISOBMFF).
  • ISO International Organization for Standardization
  • ISO base media file format ISO base media file format
  • signaling information for 360 image data can be transmitted through HyperText Transfer Protocol (HTTP) -based adaptive streaming such as Dynamic Adaptive Streaming over HTTP (DASH).
  • HTTP HyperText Transfer Protocol
  • DASH Dynamic Adaptive Streaming over HTTP
  • signaling information for 360 video data may be stored and transmitted through a supplemental enhancement information (SEI) message or a video usability information (VUI), thereby improving overall transmission efficiency.
  • SEI Supplemental Enhancement Information
  • VUI video usability information
  • FIG. 1 is a diagram showing the overall architecture for providing 360 video according to the present invention.
  • FIGS. 2 and 3 illustrate the structure of a media file according to an embodiment of the present invention.
  • FIG 4 shows an example of the overall operation of the DASH-based adaptive streaming model.
  • FIG. 5 is a diagram schematically illustrating a configuration of a 360 video transmission apparatus to which the present invention may be applied.
  • FIG. 6 is a diagram schematically illustrating a configuration of a 360 video receiving apparatus to which the present invention can be applied.
  • FIG. 7 is a diagram illustrating the concept of an airplane main axis (Aircraft Principal Axes) for explaining the 3D space of the present invention.
  • FIG. 8 exemplarily illustrates a 2D image to which a region-specific packing process according to a 360-degree processing process and a projection format is applied.
  • 10A and 10B illustrate a tile according to an embodiment of the present invention.
  • FIG 11 illustrates an example of 360 degree video related metadata according to an embodiment of the present invention.
  • FIG. 12 schematically illustrates the concept of a viewpoint, a viewing position, a viewing orientation.
  • FIG. 13 is a diagram schematically illustrating an example of an architecture for providing 3DoF + video according to the present invention.
  • 14A and 14B are examples of 3DoF + end-to-end system architectures.
  • FIG. 15 schematically illustrates an example of a Framework for Live Uplink Streaming (FLUS) architecture.
  • FLUS Live Uplink Streaming
  • 16 schematically shows the configuration at the 3DoF + transmitter.
  • 19A and 19B illustrate an example in which the same subpicture track is included in two track groups.
  • FIG. 21 schematically illustrates a subpicture based processing method of 360 image data by a 360 image receiving apparatus according to the present invention.
  • each configuration in the drawings described in the present invention are shown independently for the convenience of description of the different characteristic functions, it does not mean that each configuration is implemented by separate hardware or separate software.
  • two or more of each configuration may be combined to form one configuration, or one configuration may be divided into a plurality of configurations.
  • Embodiments in which each configuration is integrated and / or separated are also included in the scope of the present invention without departing from the spirit of the present invention.
  • FIG. 1 is a diagram showing the overall architecture for providing 360 video according to the present invention.
  • the present invention proposes a method of providing 360 content in order to provide a user with virtual reality (VR).
  • VR may refer to a technique or environment for replicating a real or virtual environment.
  • VR artificially provides the user with a sensational experience, which allows the user to experience the same as being in an electronically projected environment.
  • 360 content refers to the overall content for implementing and providing VR, and may include 360 video and / or 360 audio.
  • 360 video may refer to video or image content that is required to provide VR, and simultaneously captured or played back in all directions (360 degrees).
  • 360 video may refer to 360 degree video.
  • 360 video may refer to video or an image displayed on various types of 3D space according to a 3D model, for example, 360 video may be represented on a spherical surface.
  • 360 audio is also audio content for providing VR, and may mean spatial audio content, in which a sound source can be recognized as being located in a specific space in three dimensions.
  • 360 content may be generated, processed, and transmitted to users, and users may consume the VR experience using 360 content.
  • 360 video may be called omnidirectional video and 360 image may be called omnidirectional image.
  • the present invention particularly proposes a method for effectively providing 360 video.
  • first 360 video may be captured through one or more cameras.
  • the captured 360 video is transmitted through a series of processes, and the receiving side can process and render the received data back into the original 360 video. Through this, 360 video may be provided to the user.
  • the entire process for providing the 360 video may include a capture process, preparation process, transmission process, processing process, rendering process, and / or feedback process.
  • the capturing process may refer to capturing an image or video for each of a plurality of viewpoints through one or more cameras.
  • Image / video data such as 110 of FIG. 1 shown by the capture process may be generated.
  • Each plane of FIG. 1 110 shown may mean an image / video for each viewpoint.
  • the captured plurality of images / videos may be referred to as raw data.
  • metadata related to capture may be generated.
  • Special cameras for VR can be used for this capture.
  • capture through an actual camera may not be performed.
  • the corresponding capture process may be replaced by simply generating related data.
  • the preparation process may be a process of processing the captured image / video and metadata generated during the capture process.
  • the captured image / video may undergo a stitching process, a projection process, a region-wise packing process, and / or an encoding process in this preparation process.
  • each image / video can be stitched.
  • the stitching process may be a process of connecting each captured image / video to create a panoramic image / video or a spherical image / video.
  • the stitched image / video may be subjected to a projection process.
  • the stretched image / video can be projected onto a 2D image.
  • This 2D image may be called a 2D image frame depending on the context. It can also be expressed as mapping a projection to a 2D image to a 2D image.
  • the projected image / video data may be in the form of a 2D image as shown in FIG. 1 120.
  • the video data projected onto the 2D image may be subjected to region-wise packing to increase video coding efficiency and the like.
  • the region-specific packing may refer to a process of dividing the video data projected on the 2D image by region and applying the process.
  • the region may refer to a region in which 2D images projected with 360 video data are divided.
  • the regions may be divided evenly or arbitrarily divided into 2D images according to an embodiment. In some embodiments, regions may be divided according to a projection scheme.
  • the region-specific packing process is an optional process and may be omitted in the preparation process.
  • this processing may include rotating each region or rearranging on 2D images in order to increase video coding efficiency. For example, by rotating the regions so that certain sides of the regions are located close to each other, efficiency in coding can be increased.
  • the processing may include increasing or decreasing a resolution for a specific region in order to differentiate the resolution for each region of the 360 video. For example, regions that correspond to relatively more important areas on 360 video may have a higher resolution than other regions.
  • the video data projected onto the 2D image or the packed video data per region may be subjected to an encoding process through a video codec.
  • the preparation process may further include an editing process.
  • editing process editing of image / video data before and after projection may be further performed.
  • metadata about stitching / projection / encoding / editing may be generated.
  • metadata regarding an initial time point, a region of interest (ROI), or the like, of the video data projected on the 2D image may be generated.
  • the transmission process may be a process of processing and transmitting image / video data and metadata that have been prepared. Processing may be performed according to any transport protocol for the transmission. Data that has been processed for transmission may be delivered through a broadcast network and / or broadband. These data may be delivered to the receiving side in an on demand manner. The receiving side can receive the corresponding data through various paths.
  • the processing may refer to a process of decoding the received data and re-projecting the projected image / video data onto the 3D model.
  • image / video data projected on 2D images may be re-projected onto 3D space.
  • This process may be called mapping or projection depending on the context.
  • the mapped 3D space may have a different shape according to the 3D model.
  • the 3D model may have a sphere, a cube, a cylinder, or a pyramid.
  • the processing process may further include an editing process, an up scaling process, and the like.
  • editing process editing of image / video data before and after re-projection may be further performed.
  • the size of the sample may be increased by upscaling the samples during the upscaling process. If necessary, the operation of reducing the size through down scaling may be performed.
  • the rendering process may refer to a process of rendering and displaying re-projected image / video data in 3D space. Depending on the representation, it may be said to combine re-projection and rendering to render on a 3D model.
  • the image / video re-projected onto the 3D model (or rendered onto the 3D model) may have a shape such as 130 of FIG. 1 shown. 1, shown in FIG. 1, is a case in which a sphere is re-projected onto a 3D model of a sphere.
  • the user may view some areas of the rendered image / video through the VR display. In this case, the region seen by the user may be in the form as shown in 140 of FIG. 1.
  • the feedback process may mean a process of transmitting various feedback information that can be obtained in the display process to the transmitter. Through the feedback process, interactivity may be provided for 360 video consumption. According to an embodiment, in the feedback process, head orientation information, viewport information indicating an area currently viewed by the user, and the like may be transmitted to the transmitter. According to an embodiment, the user may interact with those implemented on the VR environment, in which case the information related to the interaction may be transmitted to the sender or service provider side in the feedback process. In some embodiments, the feedback process may not be performed.
  • the head orientation information may mean information about a head position, an angle, and a movement of the user. Based on this information, information about the area currently viewed by the user in the 360 video, that is, viewport information, may be calculated.
  • the viewport information may be information about an area currently viewed by the user in the 360 video. Through this, a gaze analysis may be performed to determine how the user consumes 360 video, which areas of the 360 video are viewed and how much. Gayes analysis may be performed at the receiving end and delivered to the transmitting side via a feedback channel.
  • a device such as a VR display may extract a viewport area based on the position / direction of a user's head, vertical or horizontal field of view (FOV) information supported by the device, and the like.
  • FOV horizontal field of view
  • the above-described feedback information may be consumed at the receiving side as well as being transmitted to the transmitting side. That is, the decoding, re-projection, rendering process, etc. of the receiving side may be performed using the above-described feedback information. For example, only 360 video for the area currently viewed by the user may be preferentially decoded and rendered using head orientation information and / or viewport information.
  • the viewport to the viewport area may mean an area that the user is viewing in 360 video.
  • a viewpoint is a point that the user is viewing in the 360 video and may mean a center point of the viewport area. That is, the viewport is an area centered on the viewpoint, and the size shape occupied by the area may be determined by a field of view (FOV) to be described later.
  • FOV field of view
  • 360 video data image / video data that undergoes a series of processes of capture / projection / encoding / transmission / decoding / re-projection / rendering may be referred to as 360 video data.
  • 360 video data may also be used as a concept including metadata or signaling information associated with such image / video data.
  • the media file may have a file format based on ISO base media file format (ISO BMFF).
  • ISO BMFF ISO base media file format
  • FIGS. 2 and 3 illustrate the structure of a media file according to an embodiment of the present invention.
  • the media file according to the present invention may include at least one box.
  • the box may be a data block or an object including media data or metadata related to the media data.
  • the boxes may form a hierarchical structure with each other, such that the data may be classified so that the media file may be in a form suitable for storage and / or transmission of a large amount of media data.
  • the media file may have an easy structure for accessing the media information, such as a user moving to a specific point of the media content.
  • the media file according to the present invention may include an ftyp box, a moov box and / or an mdat box.
  • An ftyp box can provide file type or compatibility related information for a corresponding media file.
  • the ftyp box may include configuration version information about media data of a corresponding media file.
  • the decoder can identify the media file by referring to the ftyp box.
  • the moov box may be a box including metadata about media data of a corresponding media file.
  • the moov box can act as a container for all metadata.
  • the moov box may be a box of the highest layer among metadata related boxes. According to an embodiment, only one moov box may exist in a media file.
  • the mdat box may be a box containing actual media data of the media file.
  • Media data may include audio samples and / or video samples, where the mdat box may serve as a container for storing these media samples.
  • the above-described moov box may further include a mvhd box, a trak box and / or an mvex box as a lower box.
  • the mvhd box may include media presentation related information of media data included in the media file. That is, the mvhd box may include information such as media generation time, change time, time specification, duration, etc. of the media presentation.
  • the trak box can provide information related to the track of the media data.
  • the trak box may include information such as stream related information, presentation related information, and access related information for an audio track or a video track.
  • the trak box may further include a tkhd box (track header box) as a lower box.
  • the tkhd box may include information about the track indicated by the trak box.
  • the tkhd box may include information such as a creation time, a change time, and a track identifier of the corresponding track.
  • the mvex box (movie extend box) may indicate that the media file may have a moof box to be described later. To know all the media samples of a particular track, moof boxes may have to be scanned.
  • the media file according to the present invention may be divided into a plurality of fragments (200). Through this, the media file may be divided and stored or transmitted.
  • the media data (mdat box) of the media file may be divided into a plurality of fragments, and each fragment may include a mdat box and a moof box.
  • information of the ftyp box and / or the moov box may be needed to utilize the fragments.
  • the moof box may provide metadata about media data of the fragment.
  • the moof box may be a box of the highest layer among metadata-related boxes of the fragment.
  • the mdat box may contain the actual media data as described above.
  • This mdat box may include media samples of media data corresponding to each corresponding fragment.
  • the above-described moof box may further include a mfhd box and / or a traf box as a lower box.
  • the mfhd box may include information related to an association between a plurality of fragmented fragments.
  • the mfhd box may include a sequence number to indicate how many times the media data of the fragment is divided. In addition, it may be confirmed whether there is no missing data divided using the mfhd box.
  • the traf box may include information about a corresponding track fragment.
  • the traf box may provide metadata about the divided track fragments included in the fragment.
  • the traf box may provide metadata so that media samples in the track fragment can be decoded / played back. There may be a plurality of traf boxes according to the number of track fragments.
  • the above-described traf box may further include a tfhd box and / or a trun box as a lower box.
  • the tfhd box may include header information of the corresponding track fragment.
  • the tfhd box may provide information such as a basic sample size, a duration, an offset, an identifier, and the like for media samples of the track fragment indicated by the traf box described above.
  • the trun box may include corresponding track fragment related information.
  • the trun box may include information such as duration, size, and playback time of each media sample.
  • the aforementioned media file or fragments of the media file may be processed into segments and transmitted.
  • the segment may have an initialization segment and / or a media segment.
  • the file of the illustrated embodiment 210 may be a file including information related to initialization of the media decoder except media data. This file may correspond to the initialization segment described above, for example.
  • the initialization segment may include the ftyp box and / or moov box described above.
  • the file of the illustrated embodiment 220 may be a file including the above-described fragment. This file may correspond to the media segment described above, for example.
  • the media segment may include the moof box and / or mdat box described above.
  • the media segment may further include a styp box and / or a sidx box.
  • the styp box may provide information for identifying the media data of the fragmented fragment.
  • the styp box may play the same role as the above-described ftyp box for the divided fragment.
  • the styp box may have the same format as the ftyp box.
  • the sidx box may provide information indicating an index for the divided fragment. Through this, it is possible to indicate how many fragments are the corresponding fragments.
  • the ssix box may be further included.
  • the ssix box (subsegment index box) may provide information indicating an index of the subsegment when the segment is further divided into subsegments.
  • the boxes in the media file may include more extended information based on a box-to-full box form such as the illustrated embodiment 250.
  • the size field and the largesize field may indicate the length of the corresponding box in bytes.
  • the version field may indicate the version of the box format.
  • the Type field may indicate the type or identifier of the corresponding box.
  • the flags field may indicate a flag related to the box.
  • the DASH-based adaptive streaming model according to the illustrated embodiment 400 describes the operation between an HTTP server and a DASH client.
  • DASH Dynamic Adaptive Streaming over HTTP
  • DASH is a protocol for supporting HTTP-based adaptive streaming, and can dynamically support streaming according to network conditions. Accordingly, the AV content can be provided without interruption.
  • the DASH client can obtain the MPD.
  • the MPD may be delivered from a service provider such as an HTTP server.
  • the DASH client can request the segments from the server using the access information to the segment described in the MPD. In this case, the request may be performed by reflecting the network state.
  • the DASH client may process it in the media engine and display the segment on the screen.
  • the DASH client may request and acquire a required segment by adaptively reflecting a playing time and / or a network condition (Adaptive Streaming). This allows the content to be played back seamlessly.
  • Adaptive Streaming a network condition
  • MPD Media Presentation Description
  • the DASH client controller may generate a command for requesting the MPD and / or the segment reflecting the network situation.
  • the controller can control the obtained information to be used in an internal block of the media engine or the like.
  • the MPD Parser may parse the acquired MPD in real time. This allows the DASH client controller to generate a command to obtain the required segment.
  • the segment parser may parse the acquired segment in real time. Internal blocks such as the media engine may perform a specific operation according to the information included in the segment.
  • the HTTP client may request the HTTP server for necessary MPDs and / or segments.
  • the HTTP client may also pass MPD and / or segments obtained from the server to the MPD parser or segment parser.
  • the media engine may display content on the screen using media data included in the segment. At this time, the information of the MPD may be utilized.
  • the DASH data model may have a hierarchical structure 410.
  • Media presentation can be described by MPD.
  • the MPD may describe a temporal sequence of a plurality of periods that make up a media presentation.
  • the duration may represent one section of media content.
  • the data may be included in the adaptation sets.
  • the adaptation set may be a collection of a plurality of media content components that may be exchanged with each other.
  • the adaptation may comprise a set of representations.
  • the representation may correspond to a media content component.
  • content can be divided in time into a plurality of segments. This may be for proper accessibility and delivery.
  • the URL of each segment may be provided to access each segment.
  • the MPD may provide information related to the media presentation, and the pyorium element, the adaptation set element, and the presentation element may describe the corresponding pyoride, the adaptation set, and the presentation, respectively.
  • Representation may be divided into sub-representations, the sub-representation element may describe the sub-representation.
  • Common attributes / elements can be defined here, which can be applied (included) to adaptation sets, representations, subrepresentations, and the like.
  • common properties / elements there may be an essential property and / or a supplemental property.
  • the essential property may be information including elements that are considered essential in processing the media presentation related data.
  • the supplemental property may be information including elements that may be used in processing the media presentation related data. According to an embodiment, descriptors to be described below may be defined and delivered in essential properties and / or supplemental properties when delivered through the MPD.
  • FIG. 5 is a diagram schematically illustrating a configuration of a 360 video transmission apparatus to which the present invention may be applied.
  • the 360 video transmission apparatus may perform operations related to the above-described preparation process or transmission process.
  • the 360 video transmission device includes a data input unit, a stitcher, a projection processor, a region-specific packing processor (not shown), a metadata processor, a (transmitter) feedback processor, a data encoder, an encapsulation processor, a transmission processor, and /
  • the transmission unit may be included as an internal / external element.
  • the data input unit may receive the captured images / videos for each viewpoint. These point-in-time images / videos may be images / videos captured by one or more cameras. In addition, the data input unit may receive metadata generated during the capture process. The data input unit may transfer the input image / video for each view to the stitcher, and may transmit metadata of the capture process to the signaling processor.
  • the stitcher may perform stitching on the captured view-point images / videos.
  • the stitcher may transfer the stitched 360 video data to the projection processor. If necessary, the stitcher may receive the necessary metadata from the metadata processor and use the stitching work.
  • the stitcher may transmit metadata generated during the stitching process to the metadata processing unit.
  • the metadata of the stitching process may include information such as whether stitching is performed or a stitching type.
  • the projection processor may project the stitched 360 video data onto the 2D image.
  • the projection processor may perform projection according to various schemes, which will be described later.
  • the projection processor may perform mapping in consideration of a corresponding depth of 360 video data for each viewpoint. If necessary, the projection processing unit may receive metadata required for projection from the metadata processing unit and use the same for the projection work.
  • the projection processor may transmit the metadata generated in the projection process to the metadata processor. Metadata of the projection processing unit may include a type of projection scheme.
  • the region-specific packing processor may perform the region-specific packing process described above. That is, the region-specific packing processor may divide the projected 360 video data into regions, and perform processing such as rotating and rearranging regions or changing resolution of each region. As described above, the region-specific packing process is an optional process. If the region-specific packing is not performed, the region-packing processing unit may be omitted.
  • the region-specific packing processor may receive metadata necessary for region-packing from the metadata processor and use the region-specific packing operation if necessary.
  • the region-specific packing processor may transmit metadata generated in the region-specific packing process to the metadata processor.
  • the metadata of each region packing processing unit may include a rotation degree and a size of each region.
  • the stitcher, the projection processing unit, and / or the regional packing processing unit may be performed in one hardware component according to an embodiment.
  • the metadata processor may process metadata that may occur in a capture process, a stitching process, a projection process, a region-specific packing process, an encoding process, an encapsulation process, and / or a processing for transmission.
  • the metadata processor may generate 360 video related metadata using these metadata.
  • the metadata processor may generate 360 video related metadata in the form of a signaling table.
  • 360 video related metadata may be referred to as metadata or 360 video related signaling information.
  • the metadata processor may transfer the acquired or generated metadata to internal elements of the 360 video transmission apparatus as needed.
  • the metadata processor may transmit the 360 video related metadata to the data encoder, the encapsulation processor, and / or the transmission processor so that the 360 video related metadata may be transmitted to the receiver.
  • the data encoder may encode 360 video data projected onto the 2D image and / or region-packed 360 video data.
  • 360 video data may be encoded in various formats.
  • the encapsulation processing unit may encapsulate the encoded 360 video data and / or 360 video related metadata in the form of a file.
  • the 360 video related metadata may be received from the above-described metadata processing unit.
  • the encapsulation processing unit may encapsulate the data in a file format such as ISOBMFF, CFF, or other DASH segments.
  • the encapsulation processing unit may include 360 video-related metadata on a file format.
  • the 360 video related metadata may be contained, for example, in boxes at various levels in the ISOBMFF file format or as data in separate tracks within the file.
  • the encapsulation processing unit may encapsulate the 360 video-related metadata itself into a file.
  • the transmission processor may apply processing for transmission to the encapsulated 360 video data according to the file format.
  • the transmission processor may process the 360 video data according to any transmission protocol. Processing for transmission may include processing for delivery through a broadcast network and processing for delivery through a broadband. According to an exemplary embodiment, the transmission processor may receive not only 360 video data but also metadata related to 360 video from the metadata processor and apply processing for transmission thereto.
  • the transmitter may transmit the processed 360 video data and / or 360 video related metadata through a broadcast network and / or broadband.
  • the transmitter may include an element for transmission through a broadcasting network and / or an element for transmission through a broadband.
  • the 360 video transmission device may further include a data storage unit (not shown) as an internal / external element.
  • the data store may store the encoded 360 video data and / or 360 video related metadata before transmitting to the transfer processor.
  • the data is stored in the form of a file such as ISOBMFF.
  • the data storage unit may not be required.However, when transmitting through on demand, non real time (NRT), broadband, etc., the encapsulated 360 data is stored in the data storage unit for a certain period of time. May be sent.
  • the 360 video transmitting apparatus may further include a (transmitting side) feedback processing unit and / or a network interface (not shown) as internal / external elements.
  • the network interface may receive the feedback information from the 360 video receiving apparatus according to the present invention, and transmit the feedback information to the transmitter feedback processor.
  • the transmitter feedback processor may transmit the feedback information to the stitcher, the projection processor, the region-specific packing processor, the data encoder, the encapsulation processor, the metadata processor, and / or the transmission processor.
  • the feedback information may be delivered to each of the internal elements after being transmitted to the metadata processor.
  • the internal elements receiving the feedback information may reflect the feedback information in the subsequent processing of the 360 video data.
  • the region-specific packing processing unit may rotate each region to map on the 2D image.
  • the regions may be rotated at different angles and at different angles and mapped on the 2D image.
  • the rotation of the region can be performed taking into account the portion where the 360 video data was adjacent before projection on the spherical face, the stitched portion, and the like.
  • Information about the rotation of the region i.e., rotation direction, angle, etc., may be signaled by 360 video related metadata.
  • the data encoder may encode differently for each region. The data encoder may encode at a high quality in one region and at a low quality in another region.
  • the transmitter feedback processor may transmit the feedback information received from the 360 video receiving apparatus to the data encoder so that the data encoder uses a region-differential encoding method.
  • the transmitter feedback processor may transmit the viewport information received from the receiver to the data encoder.
  • the data encoder may perform encoding with higher quality (UHD, etc.) than other regions for regions including the region indicated by the viewport information.
  • the transmission processing unit may perform processing for transmission differently for each region.
  • the transmission processing unit may apply different transmission parameters (modulation order, code rate, etc.) for each region to vary the robustness of the data transmitted for each region.
  • the transmitting-side feedback processor may transmit the feedback information received from the 360 video receiving apparatus to the transmission processing unit so that the transmission processing unit may perform regional differential transmission processing.
  • the transmitter feedback processor may transmit the viewport information received from the receiver to the transmitter.
  • the transmission processor may perform transmission processing on regions that include an area indicated by corresponding viewport information so as to have higher robustness than other regions.
  • Inner and outer elements of the 360 video transmission apparatus may be hardware elements implemented in hardware.
  • the inner and outer elements may be changed, omitted, or replaced with other elements.
  • additional elements may be added to the 360 video transmission device.
  • FIG. 6 is a diagram schematically illustrating a configuration of a 360 video receiving apparatus to which the present invention can be applied.
  • the 360 video receiving apparatus may perform operations related to the above-described processing and / or rendering.
  • the 360 video receiving apparatus may include a receiver, a receiver processor, a decapsulation processor, a data decoder, a metadata parser, a (receiver side) feedback processor, a re-projection processor, and / or a renderer as internal / external elements.
  • the signaling parser may be called a metadata parser.
  • the receiver may receive 360 video data transmitted by the 360 video transmission device according to the present invention. According to the transmitted channel, the receiver may receive 360 video data through a broadcasting network or may receive 360 video data through a broadband.
  • the reception processor may perform processing according to a transmission protocol on the received 360 video data.
  • the reception processing unit may perform a reverse process of the above-described transmission processing unit so as to correspond to that the processing for transmission is performed at the transmission side.
  • the reception processor may transmit the obtained 360 video data to the decapsulation processing unit, and the obtained 360 video data may be transferred to the metadata parser.
  • the 360 video related metadata acquired by the reception processor may be in the form of a signaling table.
  • the decapsulation processor may decapsulate the 360 video data in the form of a file received from the reception processor.
  • the decapsulation processing unit may decapsulate files according to ISOBMFF or the like to obtain 360 video data to 360 video related metadata.
  • the obtained 360 video data may be transmitted to the data decoder, and the obtained 360 video related metadata may be transmitted to the metadata parser.
  • the 360 video-related metadata obtained by the decapsulation processing unit may be in the form of a box or track in the file format.
  • the decapsulation processing unit may receive metadata necessary for decapsulation from the metadata parser if necessary.
  • the data decoder may perform decoding on 360 video data.
  • the data decoder may receive metadata required for decoding from the metadata parser.
  • the 360 video-related metadata obtained in the data decoding process may be delivered to the metadata parser.
  • the metadata parser may parse / decode 360 video related metadata.
  • the metadata parser may transfer the obtained metadata to the data decapsulation processor, the data decoder, the re-projection processor, and / or the renderer.
  • the re-projection processor may perform re-projection on the decoded 360 video data.
  • the re-projection processor may re-project the 360 video data into the 3D space.
  • the 3D space may have a different shape depending on the 3D model used.
  • the re-projection processor may receive metadata required for re-projection from the metadata parser.
  • the re-projection processor may receive information about the type of the 3D model used and the details thereof from the metadata parser.
  • the re-projection processor may re-project only 360 video data corresponding to a specific area in the 3D space into the 3D space by using metadata required for the re-projection.
  • the renderer may render the re-projected 360 video data.
  • the 360 video data may be rendered in 3D space. If the two processes occur at once, the re-projection unit and the renderer may be integrated so that all processes may be performed in the renderer. According to an exemplary embodiment, the renderer may render only the portion that the user is viewing based on the viewpoint information of the user.
  • the user may view a portion of the 360 video rendered through the VR display.
  • the VR display is a device for playing 360 video, which may be included in the 360 video receiving device (tethered) or may be un-tethered as a separate device to the 360 video receiving device.
  • the 360 video receiving apparatus may further include a (receiving side) feedback processing unit and / or a network interface (not shown) as internal / external elements.
  • the receiving feedback processor may obtain and process feedback information from a renderer, a re-projection processor, a data decoder, a decapsulation processor, and / or a VR display.
  • the feedback information may include viewport information, head orientation information, gaze information, and the like.
  • the network interface may receive the feedback information from the receiver feedback processor and transmit the feedback information to the 360 video transmission apparatus.
  • the receiving side feedback processor may transmit the obtained feedback information to the internal elements of the 360 video receiving apparatus to be reflected in a rendering process.
  • the receiving feedback processor may transmit the feedback information to the renderer, the re-projection processor, the data decoder, and / or the decapsulation processor.
  • the renderer may preferentially render the area that the user is viewing by using the feedback information.
  • the decapsulation processing unit, the data decoder, and the like may preferentially decapsulate and decode the region viewed by the user or the region to be viewed.
  • Inner and outer elements of the 360 video receiving apparatus may be hardware elements implemented in hardware. In some embodiments, the inner and outer elements may be changed, omitted, or replaced with other elements. According to an embodiment, additional elements may be added to the 360 video receiving apparatus.
  • Another aspect of the invention may relate to a method of transmitting 360 video and a method of receiving 360 video.
  • the method of transmitting / receiving 360 video according to the present invention may be performed by the above-described 360 video transmitting / receiving device or embodiments of the device, respectively.
  • the above-described embodiments of the 360 video transmission / reception apparatus, the transmission / reception method, and the respective internal / external elements may be combined with each other.
  • the embodiments of the projection processing unit and the embodiments of the data encoder may be combined with each other to produce as many embodiments of the 360 video transmission device as that case. Embodiments thus combined are also included in the scope of the present invention.
  • FIG. 7 is a diagram illustrating the concept of an airplane main axis (Aircraft Principal Axes) for explaining the 3D space of the present invention.
  • the plane principal axis concept may be used to represent a specific point, position, direction, spacing, area, etc. in 3D space. That is, in the present invention, the plane axis concept may be used to describe the 3D space before the projection or after the re-projection and to perform signaling on the 3D space.
  • a method using an X, Y, Z axis concept or a spherical coordinate system may be used.
  • the plane can rotate freely in three dimensions.
  • the three-dimensional axes are called pitch axes, yaw axes, and roll axes, respectively. In the present specification, these may be reduced to express pitch, yaw, roll to pitch direction, yaw direction, and roll direction.
  • the pitch axis may mean an axis that is a reference for the direction in which the nose of the airplane rotates up and down.
  • the pitch axis may mean an axis extending from the wing of the plane to the wing.
  • the Yaw axis may mean an axis that is a reference of the direction in which the front nose of the plane rotates left and right.
  • the yaw axis can mean an axis running from top to bottom of the plane.
  • the roll axis is an axis extending from the front nose to the tail of the plane in the illustrated plane axis concept, and the rotation in the roll direction may mean a rotation about the roll axis.
  • the 3D space in the present invention can be described through the concept of pitch, yaw, and roll.
  • region-wise packing may be performed on video data projected on a 2D image to increase video coding efficiency and the like.
  • the region-specific packing process may mean a process of dividing and processing the video data projected on the 2D image for each region.
  • the region may represent a region in which the 2D image on which the 360 video data is projected is divided, and the regions in which the 2D image is divided may be divided according to a projection scheme.
  • the 2D image may be called a video frame or a frame.
  • the present invention proposes metadata for the region-specific packing process and a signaling method of the metadata according to the projection scheme.
  • the region-specific packing process may be performed more efficiently based on the metadata.
  • 8 exemplarily illustrates a 2D image to which a region-specific packing process according to a 360-degree processing process and a projection format is applied.
  • 8A illustrates a process of processing input 360 video data.
  • 360 video data of an input viewpoint may be stitched and projected onto a 3D projection structure according to various projection schemes, and the 360 video data projected on the 3D projection structure may be represented as a 2D image. . That is, the 360 video data may be stitched and projected into the 2D image.
  • the 2D image projected with the 360 video data may be referred to as a projected frame.
  • the above-described region-specific packing process may be performed on the projected frame.
  • the region-specific packing process may represent a process of mapping the projected frame to one or more packed frames.
  • the region-specific packing process may be optional. When the region-specific packing process is not applied, the packed frame and the projected frame may be the same. When the region-specific packing process is applied, each region of the projected frame may be mapped to a region of the packed frame, and the position and shape of a region of the packed frame to which each region of the projected frame is mapped. And metadata indicative of the size can be derived.
  • the 360 video data may be projected on a 2D image (or frame) according to a panoramic projection scheme.
  • the top region, the middle region and the bottom region of the projected frame may be rearranged as shown in the figure on the right by applying region-specific packing processes.
  • the top region may be a region representing a top surface of the panorama on a 2D image
  • the middle surface region may be a region representing a middle surface of the panorama on a 2D image
  • the bottom region is It may be a region representing a bottom surface of the panorama on a 2D image.
  • FIG. 8B the 360 video data may be projected on a 2D image (or frame) according to a panoramic projection scheme.
  • the top region, the middle region and the bottom region of the projected frame may be rearranged as shown in the figure on the right by applying region-specific packing processes.
  • the top region may be a region representing a top surface of the panorama on a 2D image
  • the middle surface region may be a region representing a middle surface of the panorama on a
  • the 360 video data may be projected onto a 2D image (or frame) according to a cubic projection scheme.
  • Region-specific packing processes are applied to the front region, the back region, the top region, the bottom region, the right region, and the left region of the projected frame. It can be rearranged as shown in the figure on the right.
  • the front region may be a region representing the front side of the cube on a 2D image
  • the back region may be a region representing the back side of the cube on a 2D image.
  • the top region may be a region representing a top surface of the cube on a 2D image
  • the bottom region may be a region representing a bottom surface of the cube on a 2D image.
  • the right side region may be a region representing the right side surface of the cube on a 2D image
  • the left side region may be a region representing the left side surface of the cube on a 2D image.
  • the 3D projection formats may include tetrahedron, cube, octahedron, dodecahedron, and icosahedron.
  • 2D projections illustrated in FIG. 8D may represent projected frames representing 2D images of 360 video data projected to the 3D projection format.
  • the projection formats are exemplary, and according to the present invention, some or all of the following various projection formats (or projection schemes) may be used. Which projection format is used for 360 video may be indicated, for example, via the projection format field of metadata.
  • Figure 9a (a) may represent an isotropic projection format.
  • the offset value with respect to the x-axis and the offset value with respect to the y-axis may be expressed through the following equation.
  • data having (r, ⁇ / 2, 0) on the spherical plane may be mapped to a point of (3 ⁇ K x r / 2, ⁇ K x r / 2) on the 2D image.
  • 360 video data on the 2D image can be re-projected onto the spherical plane.
  • this as a conversion equation may be as follows.
  • FIG. 9A (b) may show a cubic projection format.
  • stitched 360 video data may be represented on a spherical face.
  • the projection processor may divide the 360 video data into cubes and project them on a 2D image.
  • 360 video data on a spherical face may be projected onto the 2D image as shown in (b) left or (b) right in FIG. 9A, corresponding to each face of the cube.
  • Figure 9a (c) may represent a cylindrical projection format. Assuming that the stitched 360 video data can be represented on a spherical surface, the projection processor may divide the 360 video data into a cylinder to project it on a 2D image. 360 video data on a spherical face correspond to the side, top and bottom of the cylinder, respectively, as shown in (c) left or (c) right in FIG. 8A on the 2D image. Can be projected together.
  • FIG. 9A (d) may represent a tile-based projection format.
  • the above-described projection processing section may project 360 video data on a spherical surface into 2 or more detail regions by dividing it into one or more detail regions as shown in (d) of FIG. 9A. Can be.
  • the detail region may be called a tile.
  • the projection processor can view the 360 video data in a pyramid form and divide each face to project on a 2D image.
  • the 360 video data on the spherical face correspond to the front of the pyramid and the four sides of the pyramid (Left top, Left bottom, Right top, Right bottom), respectively, on the 2D image. It can be projected as shown on the left or (e) right.
  • the bottom surface may be an area including data acquired by a camera facing the front.
  • FIG. 9B (f) may represent the panoramic projection format.
  • the above-described projection processing unit may project only the side surface of the 360 video data on the spherical surface on the 2D image as shown in FIG. 9B (f). This may be the same as in the case where there is no top and bottom in the cylindrical projection scheme.
  • FIG. 9B (g) may represent a case where projection is performed without stitching.
  • the projection processing unit described above may project 360 video data onto a 2D image as it is shown in FIG. 9B (g). In this case, stitching is not performed, and each image acquired by the camera may be projected onto the 2D image as it is.
  • each image may be a fish-eye image obtained through each sensor in a spherical camera (or fish-eye camera).
  • image data obtained from camera sensors at the receiving side can be stitched, and the spherical video, i.e. 360 video, is rendered by mapping the stitched image data onto a spherical surface. can do.
  • 10A and 10B illustrate a tile according to an embodiment of the present invention.
  • 360 video data projected onto a 2D image or 360 video data performed up to region-specific packing may be divided into one or more tiles.
  • 10a shows a form in which one 2D image is divided into 16 tiles.
  • the 2D image may be the above-described projected frame or packed frame.
  • the data encoder can encode each tile independently.
  • the region-specific packing and tiling may be distinguished.
  • the region-specific packing described above may mean processing the 360 video data projected on the 2D image into regions in order to increase coding efficiency or to adjust resolution.
  • Tiling may mean that the data encoder divides a projected frame or a packed frame into sections called tiles, and independently encodes corresponding tiles.
  • the user does not consume all parts of the 360 video at the same time.
  • Tiling may enable transmitting or consuming only the tiles corresponding to the critical part or a certain part, such as the viewport currently viewed by the user, on the limited bandwidth. Tiling allows for more efficient use of limited bandwidth and reduces the computational load on the receiving side compared to processing all 360 video data at once.
  • Regions and tiles are distinct, so the two regions do not have to be the same. However, in some embodiments, regions and tiles may refer to the same area. According to an exemplary embodiment, region-specific packing may be performed according to tiles so that regions and tiles may be the same. Further, according to an embodiment, when each side and region according to the projection scheme are the same, each side, region and tile according to the projection scheme may refer to the same region. Depending on the context, a region may be called a VR region, a tile region.
  • the Region of Interest may mean a region of interest of users, which the 360 content provider suggests.
  • a 360 content provider produces a 360 video
  • a certain area may be considered to be of interest to users, and the 360 content provider may produce a 360 video in consideration of this.
  • the ROI may correspond to an area where important content is played on the content of the 360 video.
  • the receiving feedback processor may extract and collect the viewport information and transmit it to the transmitting feedback processor.
  • viewport information can be delivered using both network interfaces.
  • the viewport 1000 is displayed in the 2D image of 10a shown.
  • the viewport may span nine tiles on the 2D image.
  • the 360 video transmission device may further include a tiling system.
  • the tiling system may be located after the data encoder (10b shown), may be included in the above-described data encoder or transmission processing unit, or may be included in the 360 video transmission apparatus as a separate internal / external element.
  • the tiling system may receive viewport information from the feedback feedback processor.
  • the tiling system may select and transmit only the tiles including the viewport area. In the 2D image of FIG. 10A, only nine tiles including the viewport area 1000 among the total 16 tiles may be transmitted.
  • the tiling system may transmit tiles in a unicast manner through broadband. This is because the viewport area is different for each user.
  • the transmitter-side feedback processor may transmit the viewport information to the data encoder.
  • the data encoder may perform encoding on tiles including the viewport area at higher quality than other tiles.
  • the feedback feedback processor may transmit the viewport information to the metadata processor.
  • the metadata processor may transmit the metadata related to the viewport area to each internal element of the 360 video transmission apparatus or may include the metadata related to the 360 video.
  • Embodiments related to the viewport area described above may be applied in a similar manner to specific areas other than the viewport area.
  • the above-described gaze analysis may be used to determine areas of interest, ROI areas, and areas that are first played when the user encounters 360 video through a VR display (initial viewpoint).
  • the processes may be performed.
  • the transmission processor may perform processing for transmission differently for each tile.
  • the transmission processor may apply different transmission parameters (modulation order, code rate, etc.) for each tile to vary the robustness of the data transmitted for each tile.
  • the transmitting-side feedback processor may transmit the feedback information received from the 360 video receiving apparatus to the transmission processor so that the transmission processor performs the differential transmission process for each tile.
  • the transmitter feedback processor may transmit the viewport information received from the receiver to the transmitter.
  • the transmission processor may perform transmission processing on tiles including the corresponding viewport area to have higher robustness than other tiles.
  • the 360 degree video-related metadata may include various metadata about the 360 degree video.
  • 360 degree video related metadata may be referred to as 360 degree video related signaling information.
  • the 360-degree video related metadata may be included in a separate signaling table for transmission, may be included in the DASH MPD for transmission, and may be included in a box format in a file format such as ISOBMFF.
  • the file, fragment, track, sample entry, sample, etc. may be included in various levels to include metadata about data of a corresponding level.
  • some of the metadata to be described later may be configured as a signaling table, and the other may be included in a box or track in the file format.
  • the 360-degree video-related metadata is a basic metadata related to the projection scheme, stereoscopic related metadata, the initial view (Initial View / Initial Viewpoint) Related metadata, ROI related metadata, Field of View (FOV) related metadata, and / or cropped region related metadata.
  • the 360 degree video related metadata may further include additional metadata in addition to the above.
  • Embodiments of 360 degree video related metadata according to the present invention include the aforementioned basic metadata, stereoscopic related metadata, initial viewpoint related metadata, ROI related metadata, FOV related metadata, cropped region related metadata and / or the like. Or it may be a form containing at least one or more of the metadata that can be added later.
  • Embodiments of the 360-degree video-related metadata according to the present invention may be configured in various ways according to the number of detailed metadata included in each case. According to an embodiment, the 360 degree video related metadata may further include additional information in addition to the above.
  • the stereo_mode field may indicate a 3D layout supported by the corresponding 360 degree video. Only this field may indicate whether the corresponding 360 degree video supports 3D. In this case, the above-described is_stereoscopic field may be omitted. If this field value is 0, the corresponding 360 degree video may be in mono mode. That is, the projected 2D image may include only one mono view. In this case, the 360-degree video may not support 3D.
  • the 360 degree video may be based on a left-right layout and a top-bottom layout, respectively.
  • the left and right layouts and the top and bottom layouts may be referred to as side-by-side format and top-bottom format, respectively.
  • 2D images projected from the left image and the right image may be positioned left and right on the image frame, respectively.
  • the 2D images projected from the left image and the right image may be positioned up and down on the image frame, respectively. If the field has the remaining values, it can be reserved for future use.
  • the initial view-related metadata may include information about a view point (initial view point) seen when the user first plays the 360 degree video.
  • the initial view related metadata may include an initial_view_yaw_degree field, an initial_view_pitch_degree field, and / or an initial_view_roll_degree field.
  • the initial view-related metadata may further include additional information.
  • the initial_view_yaw_degree field, the initial_view_pitch_degree field, and the initial_view_roll_degree field may indicate an initial time point when playing the corresponding 360 degree video.
  • the center point of the viewport that is first seen upon playback can be represented by these three fields.
  • the initial_view_yaw_degree field may indicate a yaw value for the initial time. That is, the initial_view_yaw_degree field may indicate the position of the center point in the direction (sign) and the degree (angle) rotated with respect to the yaw axis.
  • the initial_view_pitch_degree field may indicate a pitch value for the initial time.
  • the initial_view_pitch_degree field may indicate the position of the positive center point in the direction (sign) and the degree (angle) rotated with respect to the pitch axis.
  • the initial_view_roll_degree field may indicate a roll value for the initial time. That is, the initial_view_roll_degree field may indicate the position of the positive center point in the direction (sign) and the degree (angle) rotated with respect to the roll axis.
  • an initial time point when playing the corresponding 360 degree video that is, a center point of the viewport that is first displayed when playing the corresponding 360 degree video may be indicated.
  • the width and height of the initial viewport may be determined based on the indicated initial viewpoint through the field of view (FOV). That is, by using these three fields and the FOV information, the 360 degree video receiving apparatus can provide a user with a certain area of the 360 degree video as an initial viewport.
  • FOV field of view
  • the initial view point indicated by the initial view-related metadata may be changed for each scene. That is, the scene of the 360 degree video changes according to the temporal flow of the 360 content, and the initial view point or the initial viewport that the user first sees may change for each scene of the 360 degree video.
  • the metadata regarding the initial view may indicate the initial view for each scene.
  • the initial view-related metadata may further include a scene identifier for identifying a scene to which the initial view is applied.
  • the initial view-related metadata may further include scene-specific FOV information indicating the FOV corresponding to the scene.
  • the ROI related metadata may include information related to the above-described ROI.
  • the ROI related metadata may include a 2d_roi_range_flag field and / or a 3d_roi_range_flag field.
  • the 2d_roi_range_flag field may indicate whether the ROI related metadata includes fields representing the ROI based on the 2D image
  • the 3d_roi_range_flag field indicates whether the ROI related metadata includes fields representing the ROI based on the 3D space. Can be indicated.
  • the ROI related metadata may further include additional information such as differential encoding information according to ROI and differential transmission processing information according to ROI.
  • the ROI-related metadata may include min_top_left_x field, max_top_left_x field, min_top_left_y field, max_top_left_y field, min_width field, max_width field, min_height field, max_height field, min_x Field, max_x field, min_y field and / or max_y field.
  • the min_top_left_x field, max_top_left_x field, min_top_left_y field, and max_top_left_y field may indicate minimum / maximum values of coordinates of the upper left end of the ROI. That is, the fields may sequentially indicate a minimum x coordinate, a maximum x coordinate, a minimum y coordinate, and a maximum y coordinate of the upper left end.
  • the min_width field, the max_width field, the min_height field, and the max_height field may indicate minimum / maximum values of the width and height of the ROI. That is, the fields may sequentially indicate a minimum value of a horizontal size, a maximum value of a horizontal size, a minimum value of a vertical size, and a maximum value of a vertical size.
  • the min_x field, max_x field, min_y field, and max_y field may indicate minimum / maximum values of coordinates in the ROI. That is, the fields may sequentially indicate a minimum x coordinate, a maximum x coordinate, a minimum y coordinate, and a maximum y coordinate of coordinates in the ROI. These fields may be omitted.
  • the ROI related metadata may include min_yaw field, max_yaw field, min_pitch field, max_pitch field, min_roll field, max_roll field, min_field_of_view field and / or It may include a max_field_of_view field.
  • the min_yaw field, max_yaw field, min_pitch field, max_pitch field, min_roll field, and max_roll field may represent the area occupied by the ROI in 3D space as the minimum / maximum values of yaw, pitch, and roll. That is, the fields in order are the minimum value of the yaw axis rotation amount, the maximum value of the yaw axis reference amount, the minimum value of the pitch axis reference amount, the maximum value of the pitch axis reference amount, the minimum value of the roll axis reference amount, and the roll axis. It can represent the maximum value of the reference rotation amount.
  • the min_field_of_view field and the max_field_of_view field may indicate minimum / maximum values of the field of view (FOV) of the corresponding 360 degree video data.
  • the FOV may refer to a field of view displayed at a time when the 360 degree video is played.
  • the min_field_of_view field and the max_field_of_view field may indicate minimum and maximum values of the FOV, respectively. These fields may be omitted. These fields may be included in FOV related metadata to be described later.
  • the FOV related metadata may include information related to the above-described FOV.
  • the FOV related metadata may include a content_fov_flag field and / or a content_fov field.
  • the FOV-related metadata may further include additional information such as the minimum / maximum value-related information of the above-described FOV.
  • the content_fov_flag field may indicate whether or not information on the intended FOV exists during the production of the corresponding 360 degree video. If this field value is 1, there may be a content_fov field.
  • the content_fov field may indicate information about an FOV intended for producing the 360 degree video.
  • an area displayed at one time from among 360 images may be determined according to a vertical or horizontal FOV of the corresponding 360 degree video receiving apparatus.
  • an area of the 360 degree video displayed to the user at one time may be determined by reflecting the FOV information of the field.
  • the cropped region related metadata may include information about an region including actual 360 degree video data on an image frame.
  • the image frame may include an active video area that is projected 360 degrees video data and an area that is not.
  • the active video region may be referred to as a cropped region or a default display region.
  • This active video area is an area shown as 360 degree video on the actual VR display, and the 360 degree video receiving device or the VR display can process / display only the active video area. For example, if the aspect ratio of an image frame is 4: 3, only the part except the upper part and the lower part of the image frame may contain 360-degree video data, which is called the active video area. have.
  • the cropped region related metadata may include an is_cropped_region field, a cr_region_left_top_x field, a cr_region_left_top_y field, a cr_region_width field, and / or a cr_region_height field. According to an embodiment, the cropped region related metadata may further include additional information.
  • the is_cropped_region field may be a flag indicating whether the entire region of the image frame is used by the 360 degree video receiving apparatus or the VR display.
  • the region where the 360-degree video data is mapped or the region shown on the VR display may be called an active video area.
  • the is_cropped_region field may indicate whether the entire image frame is an active video region. If only a part of the image frame is an active video area, the following four fields may be added.
  • the cr_region_left_top_x field, cr_region_left_top_y field, cr_region_width field, and cr_region_height field may indicate an active video region on an image frame. These fields may indicate the x coordinate of the upper left of the active video area, the y coordinate of the upper left of the active video area, the width of the active video area, and the height of the active video area, respectively. The width and height may be expressed in pixels.
  • the 360 video-based VR system may provide a visual / audio experience for different viewing orientations based on the user's position for the 360 video based on the 360 video processing described above.
  • a VR system that provides a starting / aural experience for different viewing orientations at a fixed location of a user for 360 video may be referred to as a three degree of freedom (VR) based VR system.
  • VR systems that can provide extended visual and audio experiences for different viewing orientations at different viewpoints and at different viewing positions can be called 3DoF + or 3DoF plus based VR systems. Can be.
  • FIG. 12 schematically illustrates the concept of a viewpoint, a viewing position, a viewing orientation.
  • each of the displayed circles may represent different viewpoints.
  • Video / audio provided from each viewpoint positioned in the same space may be associated with each other in the same time zone.
  • different visual and audio experiences may be provided to the user according to a change in the user's gaze at a specific viewpoint. That is, it is possible to assume spheres of various viewing positions as shown in (b) for a specific viewpoint, and to provide image / audio / text information reflecting the relative position of each viewing position.
  • the specific viewing position of the specific viewpoint may transmit initial / aural information in various directions as in the existing 3DoF.
  • the main source ex. Video / audio / text
  • additional various sources may be integrated and provided.
  • information may be delivered independently or in association with the viewing orientation of the user.
  • FIG. 13 is a diagram schematically illustrating an example of an architecture for providing 3DoF + video according to the present invention.
  • FIG. 13 is a flow diagram of a 3DoF + end-to-end system including 3DoF + image acquisition, preprocessing, transmission, (post) processing, rendering and feedback.
  • an acquisition process may mean a process of acquiring 360 video through a process of capturing, synthesizing, or generating 360 video.
  • the image information may include not only visual information (ex. Texture) but also depth information (depth).
  • depth depth
  • a plurality of pieces of information of different viewing positions according to different viewpoints may be obtained.
  • the composition process includes not only the information obtained through the video / audio input device, but also the video (video / image, etc.), voice (audio / effect sound, etc.), text (subtitle, etc.) from external media in the user experience. And methods and methods for synthesizing risks.
  • the pre-procesing process is a preparation (preprocessing) process for transmitting / delivering the obtained 360 video, and may include the aforementioned stitching, projection, region packing process, and / or encoding process. That is, this process may include a preprocessing process and an encoding process for changing / supplementing data according to the intention of the producer for video / audio / text information.
  • the mapping of the acquired visual information onto the 360 sphere the editing that removes the boundary of the area, reduces the color / brightness difference, or gives the visual effect of the image ,
  • Image segmentation (view segmentation) according to viewpoint projection process (ma- tion) to map the image on 360 sphere (sphere) to 2D image, region-wise packing according to region (region-wise packing), image information
  • the encoding process may be included.
  • a plurality of projection images of viewing positions of each other according to different viewpoints may be generated.
  • the transmission process may mean a process of processing image and audio data and metadata that have been prepared (preprocessed).
  • a method of transmitting a plurality of video / audio data and related metadata of different viewing positions according to different viewpoints a broadcasting network, a communication network, or a one-way transmission method may be used as described above. Can be used.
  • Post-processing and synthesis may refer to post-processing for decoding received / stored video / audio / text data and for final playback.
  • the post-processing process may include an unpacking process of unpacking the packed image and a re-projection process of restoring the 2D projected image to the 3D spherical image as described above.
  • the rendering process may refer to a process of rendering and displaying re-projected image / video data in 3D space.
  • the video / audio signal can be reconstructed into a form for finally outputting.
  • the viewing orientation, the viewing position / head position, and the viewpoint of the user's region of interest may be tracked, and only the necessary video / audio / text information may be selectively used according to this information.
  • different viewpoints may be selected as shown in 1330 according to the ROI of the user, and finally, as shown in 1340, images of a specific direction of a specific viewpoint at a specific position may be output.
  • 3DoF + end-to-end system architectures are examples of 3DoF + end-to-end system architectures. 3D0F + 360 content as provided by the architecture of FIGS. 14A and 14B may be provided.
  • a 360 video transmission apparatus includes a portion acquisition unit through which 360 video (image) / audio data is obtained, a portion processing video data (video / audio pre-processor), and additional information.
  • a composition for synthesizing the data an encoding unit for encoding text, audio, and projected 360-degree video, and an encapsulation unit for encapsulating the encoded data.
  • the encoded data may be output in the form of a bitstream, and the encoded data may be encapsulated in a file format such as ISOBMFF, CFF, or processed in the form of other DASH segments.
  • the encoded data may be delivered to the 360 video receiving apparatus through a digital storage medium, or although not explicitly illustrated, the encoded data may be processed through a transmission processor as described above, and then the broadcasting network or the broadband may be used. Can be sent through.
  • different information depends on the sensor orientation (viewing orientation in the image), the sensor position (viewing position in the image), and the sensor information acquisition position (in the viewpoint in the image). Can be obtained simultaneously or continuously, and video, image, audio, and location information can be obtained.
  • texture and depth information may be obtained, respectively, and different video pre-processing may be performed according to characteristics of each component.
  • texture information the 360 omnidirectional image may be configured by using images of different viewing orientations of the same viewing position acquired at the same location using image sensor position information.
  • an image stitching process may be performed.
  • projection and / or region-specific packing may be performed to change the image into a format for encoding the image.
  • depth image an image may be generally acquired through a depth camera, and in this case, the depth image may be made in the form of a texture.
  • depth data may be generated based on separately measured data.
  • a sub-picture generation may be performed by further packing (packing) into a video format for efficient compression or dividing it into necessary parts.
  • Information on the video composition used in the video pre-processing stage is delivered as video metadata.
  • the composition generation unit synthesizes externally generated media data (video / image for video, audio / effect sound for audio, subtitles for text, etc.) at the final playback stage based on the intention of the creator. Generates information for the application, which is passed to the composition metadata.
  • the processed video / audio / text information is compressed using each encoder and encapsulated in file or segment units depending on the application. At this time, only the necessary information can be extracted (file extractor) according to the video, file or segment composition method.
  • information for reconstructing each data at the receiver is delivered at the codec or file format / system level, where information for video / audio reconstruction (video / audio metadata), composition metadata for overlay, video / Audio playable positions and viewing position information (viewing position and viewpoint metadata) according to each position are included.
  • the processing of such information may be generated through a separate metadata processing unit.
  • the 360 video receiving apparatus decapsulates a largely received file or segment (file / segment decapsulation unit), and generates a video / audio / text information from a bitstream (decoding unit).
  • a post-processor for reconstructing a video / audio / text a tracking unit for tracking a user's region of interest, and a display, which is a playback device.
  • the bitstream generated through decapsulation may be separately decoded into a playable form by dividing into video / audio / text according to the type of data.
  • the tracking portion generates information on a location of a region of interest of a user, a viewing position at a corresponding position, and a viewing orientation at a corresponding viewpoint based on a sensor and input information of the user.
  • This information may be used for selecting or extracting a region of interest in each module of the 360 video receiving apparatus or may be used for a post-processing process for emphasizing information of the region of interest.
  • it when delivered to the 360 video transmission device, it can be used for file selection or sub-picture selection for efficient bandwidth usage, and various image reconstruction methods based on the region of interest (viewport / viewing position / viewpoint dependent processing).
  • the decoded video signal may be processed according to various processing methods according to the video composition method.
  • image packing is performed in a 360 video transmission device, a process of reconstructing an image based on information transmitted through metadata is required.
  • video metadata generated by the 360 video transmission device may be used.
  • the decoded image includes a plurality of viewing positions, a plurality of viewing positions, or images of various viewing orientations, the location of the region of interest of the user generated through tracking, Information matching the viewpoint and direction information may be selected and processed.
  • the viewing position and viewpoint related metadata generated by the transmitter may be used.
  • a rendering process according to each may be included.
  • Video data (texture, depth, overlay) that has been subjected to a separate rendering process is subjected to composition, and at this time, composition metadata generated by a transmitter may be used.
  • information for playing in the viewport may be generated according to the ROI of the user.
  • the decoded voice signal generates a playable voice signal through an audio renderer and / or post-processing process, based on information about the user's region of interest and metadata delivered to the 360 video receiving device. You can generate the right information.
  • the decoded text signal may be delivered to the overlay renderer and processed as text-based overlay information such as a subtitle. If necessary, a separate text post-process may be included.
  • FIG. 15 schematically illustrates an example of a Framework for Live Uplink Streaming (FLUS) architecture.
  • FLUS Live Uplink Streaming
  • FIG. 14A and 14B The detailed blocks of the transmitter and the receiver described above with reference to FIG. 14 (FIGS. 14A and 14B) may be classified as functions of a source and a sink in the framework for live uplink streaming (FLUS).
  • FLUS live uplink streaming
  • the 360 video acquisition apparatus implements the function of a source and sinks on a network.
  • sink can be implemented, or the source / sink can be implemented within a network node.
  • FIGS. 15 and 16 For example, a transmission and reception process based on the aforementioned architecture may be schematically illustrated as shown in FIGS. 15 and 16.
  • the transmission / reception process of FIGS. 15 and 16 is described based on the image signal processing process, and when processing other signals such as voice or text, some parts (eg stitcher, projection processing unit, packing processing unit, subpicture processing unit, Packing / selection, rendering, composition, viewport creation, etc.) may be omitted, or may be modified and processed to suit voice or text processing.
  • some parts eg stitcher, projection processing unit, packing processing unit, subpicture processing unit, Packing / selection, rendering, composition, viewport creation, etc.
  • 16 schematically shows the configuration at the 3DoF + transmitter.
  • the transmitting end 360 may perform stitching for constituting a sphere image for each location / viewpoint / component.
  • projection may be performed as a 2D image for coding.
  • a plurality of images may be generated as sub-pictures divided into packings or sub-pictures for making integrated images.
  • the region-specific packing process may not be performed as an optional process, and in this case, the packing process unit may be omitted. If the input data is video / audio / text additional information, the additional information may be added to the center image to display a method, and additional data may also be transmitted.
  • An encoding process of compressing the generated image and the added data into a bit stream may be performed through an encapsulation process of converting the generated image and the added data into a file format for transmission or storage.
  • a process of extracting a file required by the receiver according to an application or system request may be processed.
  • the generated bitstream may be transmitted after being converted into a transport format through a transport processor.
  • the feedback feedback processor may process the location / view / direction information and necessary metadata based on the information transmitted from the receiver, and transmit the processed metadata to the associated transmitter.
  • the receiving end may extract a necessary file after receiving a bitstream transmitted from the transmitting end.
  • the video stream in the generated file format may be selected using location / view / direction information and video metadata delivered from the feedback processor, and the selected bitstream may be reconstructed into video information through a decoder.
  • unpacking may be performed based on packing information transmitted through metadata. If the packing process is omitted in the transmitter, unpacking of the receiver may also be omitted.
  • a process of selecting an image and a necessary component suitable for a viewpoint / viewing position / viewing orientation transmitted from the feedback processor may be performed.
  • a rendering process of reconstructing a texture, depth, overlay information, etc. of an image into a format suitable for playing may be performed.
  • a composition process of integrating information of different layers may be performed, and an image suitable for a display viewport may be generated and reproduced.
  • a subpicture based processing method of 360 image data may be provided.
  • an embodiment of the present invention may support processing based on a user's viewpoint in a 360 image processing system.
  • One embodiment of the present invention may correspond to some functions of decoding and post-processing of the 3DoF + end-to-end system, and the 3DoF + end-to-end system according to FIG. 14B. It may correspond to an architecture and / or some functions of unpacking / selection of the 3DoF + receiver of FIG. 17.
  • An embodiment of the present invention provides a method for selecting a required stream among a plurality of streams having different high quality regions for supporting processing dependent on a viewport, and a method for selecting a required subpicture among a plurality of subpictures. It can be provided, each method will be described in detail sequentially.
  • the stream may refer to a track including omnidirectional video data or omnidirectional video data for providing to the user.
  • the 360 video format (or omnidirectional media format) can provide signaling information about region-wise quality ranking, which is handled by a viewport dependent processing scheme using this signaling information. Can lose.
  • the 360 image format may include a plurality of tracks with respect to the input image, and the plurality of tracks may each include omnidirectional video or data of all omnidirectional images, and all omnidirectional directions of the plurality of tracks. Videos can have different high quality regions.
  • the 360 image format may be the same as the format of the above-described media file, and may have a file format based on ISO BMFF (ISO base media file format).
  • each projected 2D picture may have regions encoded with different high quality (HQ) encoded regions, and may be ERP (EquiRectangular Projection) frames of 360 images.
  • HQ high quality
  • ERP EquiRectangular Projection
  • the 360 video may be selected from any one of a plurality of tracks for playback, and the plurality of tracks may be used for switching to another track while the 360 video is playing. have.
  • the initially selected track can be switched with the other one of the plurality of tracks.
  • the 360 image format may provide signaling information for selectable and switchable track groups.
  • the 360 video format may provide signaling information for the selectable and switchable track groups for the 360 video playback through the alternate_group field in the TrackHeaderBox, the switch_group field in the TrackSelectionBox, and the attribute_list field.
  • TrackHeaderBox may be included as shown in Table 1, for example.
  • TrackSelectionBox may be included as shown in Table 2, for example.
  • the 360 image format has a non-zero alternate_group field in the TrackHeaderBox of one track, and if the attribute_list field in the TrackSelectionBox has a rwqr value, the track is SphereRegionQualityRankingBox.
  • the track group of each track contains full omnidirectional video having different high quality encoded regions indicated by 2DRegionQualityRankingBox.
  • the 360 image format may specify that if the switch_group field in the TrackSelectionBox has a non-zero value, the corresponding track is included in a switching group that can be switched while the 360 image is played.
  • SphereRegionQualityRankingBox or 2DRegionQualityRankingBox can be used as a selection criterion for initial selection and switching within a track group.
  • the 360 video format encodes different high-quality encodings in which the track is indicated by the SphereRegionQualityRankingBox if the alternate_group field in the TrackHeaderBox of any track has a non-zero value and the attribute_list field in the TrackSelectionBox has a sqrg value. It can be specified that it is included in a track group of tracks each containing a full omnidirectional video having a predetermined region.
  • the 360 image format may specify that if the switch_group field in the TrackSelectionBox has a non-zero value, the corresponding track is included in a switching group that can be switched while the 360 image is played.
  • SphereRegionQualityRankingBox can be used as a selection criterion for initial selection and switching in a track group.
  • the 360 video format encodes different high quality encodings in which the track is indicated by 2DRegionQualityRankingBox when the alternate_group field in the TrackHeaderBox of any track has a non-zero value and the attribute_list field in the TrackSelectionBox has a value of 2drg. It can be specified that it is included in a track group of tracks each containing a full omnidirectional video having a predetermined region.
  • the 360 image format may specify that if the switch_group field in the TrackSelectionBox has a non-zero value, the corresponding track is included in a switching group that can be switched while the 360 image is played.
  • 2DRegionQualityRankingBox may be used as a selection criterion for initial selection and switching in a track group.
  • SphereRegionQualityRankingBox may be included as shown in Table 3, for example.
  • 2DRegionQualityRankingBox may be included as shown in Table 4, for example.
  • the quality_ranking field may specify information on a quality ranking of a region among a plurality of tracks in which the track includes the region.
  • quality ranking may be indicated based on sphere area
  • 2DRegionQualityRankingBox quality ranking may be indicated based on 2D area.
  • the quality ranking region A may have a higher quality than the quality ranking region B.
  • the value of the quality ranking region A may mean a value of the quality_ranking field for the corresponding region of the track A
  • the value of the quality ranking region B may mean a value of the quality_ranking field for the corresponding region of the track B.
  • the corresponding region of the track may be empty. In other words, it may mean that data corresponding to the region does not exist in the track.
  • a quality_ranking field value of a track has a value of 0xFF
  • the 360 video format does not have data for the region in the track, so that the 360 video format does not parse the other boxes such as RegionWisePackingBox and CoverageInformationBox of the track. Signaling information on the presence or absence of data in the region can be provided to the track.
  • the track when a 2D picture is spatially divided to form a subpicture, the track may include a subpicture track.
  • the subpicture track may have a spatial relationship with at least one other subpicture track, and may refer to a track representing a subpicture bitstream.
  • the subpicture may refer to a picture representing a spatial subset of the input image
  • the subpicture bitstream may refer to a bitstream representing a spatial subset of the input image.
  • the subset may be obtained by spatially splitting the input image before the encoding process.
  • the subpicture track may include overlapping regions having different quality rankings indicated by other subpicture tracks and region-wise quality ranking metadata.
  • the overlapping regions may be referred to as overlapping regions or overlapping regions.
  • the 360 picture may be selected by any one of a plurality of subpicture tracks including overlapping regions for playback, and the plurality of subpicture tracks may be overwritten while the 360 picture is played. It can be used for switching to other tracks, including lapping regions. In other words, the initially selected subpicture track may be switched with another subpicture track including an overlapping region among the plurality of subpicture tracks while the 360 image is reproduced.
  • the 360 image format may also provide signaling information on subselectable tracks that are selectable and switchable through the above-described process.
  • the selectable and switchable subpicture tracks among the plurality of subpicture tracks may be grouped, and the 360 image format may provide signaling information about the grouped subpicture track group.
  • 19A and 19B illustrate an example in which the same subpicture track is included in two track groups.
  • a 360 picture spatially divided into at least one subpicture may be subjected to a subpicture composition process to be provided to a user.
  • a subpicture composition process to be provided to a user.
  • one subpicture track may be included in a plurality of track groups.
  • the track group may mean a grouping of tracks capable of acquiring one or more pictures through synthesis, and may be different from the track group grouping the switchable tracks described with reference to FIG. 18.
  • a track group 1 having a track group identifier of 1 may be configured as a first sub-picture track and a second track through a sub-picture synthesis process.
  • Side-by-side frame packing format including sub-pic 2 tracks, third sub-pic 3 tracks, and fourth sub-picture 4 tracks.
  • the third subpicture and the fourth subpicture may be included only in the first track group as a picture for the right view, but the first subpicture and the second subpicture are pictures for the left view and the first track group and the second track. Each can be included in a group.
  • Each subpicture in FIG. 19A may have a coverage of 180 degrees * 180 degrees.
  • a first track group Track 1 may be a first sub-picture track, a second sub-picture track, and a first track group through sub-picture synthesis.
  • ERP EquiRectangular Projection
  • the second track group (Track group 2) is a half sphere having a coverage of 180 degrees * 180 degrees, including a second sub-picture track and a third sub-picture track Can be rendered as
  • first subpicture and the fourth subpicture may be included only in the first track group that is rendered in a spherical shape, but the second subpicture and the third subpicture may be included in a spherical first track group and a second track rendered in a hemispherical shape. Each can be included in a group.
  • Each subpicture in FIG. 19B may have a coverage of 90 degrees * 180 degrees.
  • the 360 image format may provide signaling information for a track group including at least one track in which corresponding tracks are spatially arranged, mapped, or synthesized in a subpicture composition process.
  • the 360 image format may provide signaling information about a relationship between a subpicture and a plurality of projected pictures.
  • the 360 picture format may provide signaling information as to whether a corresponding track is included in tracks that can be spatially arranged to obtain a composition picture through a track_group_type field in a TrackGroupTypeBox, and the TrackGroupTypeBox is, for example, a table. May be included as 5.
  • the 360 image format may specify that a corresponding track is included in tracks that may be spatially arranged to obtain a composition picture.
  • a visual track may be grouped with at least one visual track whose track_group_id field in a TrackGroupTypeBox whose track_group_type field has a spco or osdr value has the same value, and the visual tracks that are grouped and mapped may be displayed as visual content ( visual content) collectively.
  • the 360 video format may include a track_group_id field having the same meaning as the TrackGroupTypeBox in the RegionWisePackingBox.
  • the 360 image format may include a track_group_id field only when the version value of the RegionWisePackingBox is 1 to provide compatibility with other RegionWisePackingBox uses.
  • RegionWisePackingBox may be included as shown in Table 6, for example.
  • a packed picture may refer to a sub picture.
  • the RegionWisePackingBox may include a track_group_id field when the version value is 1, and tracks having the same track_group_id field value are synthesized during the synthesis process. It can be synthesized or mapped to each other.
  • the 360 image format may include a track_group_id field in the TrackGroupBox of the track, and may include the same track_group_id field in the RegionWisePackingBox of the track, which specifies a track group for composition or mapping of the track. can do.
  • the box configuration using the track_group_id field of the first subpicture track included in the first track group and the second track group may be as shown in Table 7.
  • Track 1 indicates the first subpicture track. May be referred to.
  • the box configuration using the track_group_id field of the second subpicture track included in the first track group and the second track group may be as shown in Table 8, and in Table 8, Track 2 indicates the second subpicture track.
  • Track 2 indicates the second subpicture track.
  • the box configuration using the track_group_id field of the third subpicture track included only in the first track group in FIG. 19A may be as shown in Table 9, and in Table 9, Track 3 may refer to the third subpicture track.
  • the box configuration using the track_group_id field of the fourth subpicture track included only in the first track group in FIG. 19A may be as shown in Table 10, and in Table 10, Track 4 may refer to the fourth subpicture track.
  • a packed picture may refer to a subpicture.
  • FIG. 20 schematically illustrates a subpicture based processing method of 360 image data by the 360 image transmitting apparatus according to the present invention.
  • the method disclosed in FIG. 20 may be performed by the 360 video transmitting apparatus disclosed in FIG. 5 or 16.
  • the apparatus for transmitting 360 images acquires 360 images (S2000).
  • the 360 image may be a video / image captured by at least one camera. Alternatively, some or all of the 360 images may be virtual images generated by a computer program or the like.
  • the 360 image may be an independent still image or may be part of the 360 video.
  • the 360 image transmission apparatus processes a 360 image to derive a picture (S2010).
  • the 360 image transmission apparatus may derive a 2D-based picture based on the various projection formats and region-specific packing procedures described above.
  • the derived picture may correspond to the projected picture, or may correspond to a packed picture (when a regional packing process is applied).
  • the 360 image transmission apparatus generates metadata including track group information about a plurality of tracks (S2020).
  • the metadata may include the fields described above in the present specification. Fields may be included in boxes at various levels or as data in separate tracks in a file.
  • the metadata may include some or all of the fields / information described above in Tables 1 to 6, and the track group information may be referred to as track group related metadata (including information / fields).
  • track group-related metadata may include information about an initial selectable track for playback among a plurality of tracks and a track being played when the picture includes a plurality of tracks each including all omnidirectional media data. Information about tracks and whether they can be switched, information about tracks being played and switchable, information about the selection criteria of tracks for initial selection and / or switching during playback, whether each of the plurality of tracks contains a particular region Information about the quality ranking information and a specific region between tracks including the specific region.
  • the track group may refer to a set of switchable tracks.
  • track group-related metadata may include information about an initial selectable subpicture track for reproduction between subpicture tracks of subpictures including an overlapping region when the picture is spatially divided into subpictures.
  • Information on whether the subpicture track being switched is switchable with other subpicture tracks, information on the subpicture track being played back and the switchable subpicture track, and the selection criteria of the subpicture track for initial selection and / or switching during playback.
  • a subpicture may refer to a packed picture.
  • information about an initial selectable track or subpicture track for playback information about whether the track or subpicture track being played is switchable with another track or another subpicture track, and the track or subpicture being played.
  • Information about the track and the switchable track or subpicture track may include an alternate_group field in the TrackHeaderBox and a switch_group field in the TrackSelectionBox.
  • Information about selection criteria of a track or subpicture track for switching during initial selection and / or playback may include an attribute_list field in a TrackSelectionBox.
  • the quality ranking information may include a quality_ranking field in SphereRegionQualityRankingBox or 2DRegionQualityRankingBox, and the quality_ranking field may indicate information about whether each of the plurality of tracks includes a specific region.
  • the track group related metadata may include information about a track group to which a subpicture track of each subpicture belongs or a track group ID when a picture is spatially divided into subpictures and includes a plurality of subpictures. have.
  • track group-related metadata may include version information or region-specific packing-related version indicating that information about a track group or a track group ID is omitted when a picture is spatially divided into sub pictures and includes a plurality of sub pictures. May contain information.
  • Information about the track group or track group ID may include a track_group_id field in the TrackGroupBox and / or a track_group_id field in the RegionWisePackingBox, and the TrackGroupBox may include at least one track_group_id field, but the RegionWisePackingBox may include one track_group_id field. have.
  • the metadata may include the same number of RegionWisePackingBoxes as the number of track groups.
  • the version information may include a version value in the RegionWisePackingBox.
  • the version value is 1
  • the corresponding RegionWisePackingBox may include a track_group_id field.
  • the 360 image transmission device encodes a picture (S2030).
  • the 360 image transmission device may encode at least a partial region of the picture, and may encode the 2D picture and output the encoded 2D picture in a bitstream form.
  • at least a portion of the picture may mean at least one subpicture.
  • the 360 image transmission apparatus performs processing for storing or transmitting the encoded picture and the metadata (S2040).
  • the 360 image transmission apparatus may perform processing for storing or transmitting at least a partial region and metadata of the encoded picture.
  • the 360 image transmission apparatus may generate 360 image data based on data and / or metadata related to the encoded picture.
  • 360 video a series of pictures for a series of images constituting the 360 video may be encoded, and 360 video data including the encoded pictures may be generated.
  • the 360 image transmission device may encapsulate data and / or metadata regarding the encoded picture (s) in the form of a file or the like.
  • the 360 image transmission device may encapsulate the file in ISOBMFF, CFF, or other file formats, or may process other DASH segments.
  • the picture (s) may mean a picture or at least a part of the picture.
  • the 360 image transmission device may include metadata in a file format. For example, metadata may be included in boxes at various levels in the ISOBMFF file format or as data in separate tracks within the file.
  • the 360 video imaging apparatus may encapsulate the metadata itself into a file.
  • the 360 image transmission device may apply processing for transmission to the encapsulated 360 image data according to the file format.
  • the 360 image transmission device may process 360 image data according to an arbitrary transmission protocol.
  • the processing for transmission may include processing for delivery through a broadcasting network, or processing for delivery through a communication network such as broadband.
  • the 360 image transmission device may apply a process for transmission to the metadata.
  • the 360 image transmitting apparatus may transmit the processed 360 image data (including metadata) through a broadcasting network and / or broadband.
  • FIG. 21 schematically illustrates a subpicture based processing method of 360 image data by a 360 image receiving apparatus according to the present invention.
  • the method disclosed in FIG. 21 may be performed by the 360 video receiving apparatus disclosed in FIG. 6 or 17.
  • the 360 image receiving apparatus receives 360 image data (or a signal) including information and metadata about an encoded picture (S2100).
  • the 360 image receiving apparatus may receive the 360 image data signaled from the 360 image transmitting apparatus through a broadcasting network.
  • the 360 video receiving apparatus may receive 360 image data through a communication network such as broadband or a storage medium.
  • the 360 image data may be a file format such as ISPBMFF or CFF, and the metadata may be included in boxes of various levels on the ISOBMFF file format or as data in separate tracks in the file.
  • the 360 image receiving apparatus obtains information and metadata about an encoded picture (S2110).
  • Information and metadata about the encoded picture may be obtained through a procedure such as file / segment decapsulation from 360 image data.
  • the information about the encoded picture may mean information on at least some areas when at least some areas of the picture are encoded.
  • the metadata may include the fields described above in the present specification. Fields may be included in boxes at various levels or as data in separate tracks in a file.
  • the metadata may include some or all of the fields / information described above in Tables 1 to 6, and the track group information may be referred to as track group related metadata (including information / fields).
  • track group-related metadata may include information about an initial selectable track for playback among a plurality of tracks and a track being played when the picture includes a plurality of tracks each including all omnidirectional media data. Information about tracks and whether they can be switched, information about tracks being played and switchable, information about the selection criteria of tracks for initial selection and / or switching during playback, whether each of the plurality of tracks contains a particular region Information about the quality ranking information and a specific region between tracks including the specific region.
  • the track group may refer to a set of switchable tracks.
  • track group-related metadata may include information about an initial selectable subpicture track for reproduction between subpicture tracks of subpictures including an overlapping region when the picture is spatially divided into subpictures.
  • Information on whether the subpicture track being switched is switchable with other subpicture tracks, information on the subpicture track being played back and the switchable subpicture track, and the selection criteria of the subpicture track for initial selection and / or switching during playback.
  • a subpicture may refer to a packed picture.
  • information about an initial selectable track or subpicture track for playback information about whether the track or subpicture track being played is switchable with another track or another subpicture track, and the track or subpicture being played.
  • Information about the track and the switchable track or subpicture track may include an alternate_group field in the TrackHeaderBox and a switch_group field in the TrackSelectionBox.
  • Information about selection criteria of a track or subpicture track for switching during initial selection and / or playback may include an attribute_list field in a TrackSelectionBox.
  • the quality ranking information may include a quality_ranking field in SphereRegionQualityRankingBox or 2DRegionQualityRankingBox, and the quality_ranking field may indicate information about whether each of the plurality of tracks includes a specific region.
  • the track group related metadata may include information about a track group to which a subpicture track of each subpicture belongs or a track group ID when a picture is spatially divided into subpictures and includes a plurality of subpictures. have.
  • track group-related metadata may include version information or region-specific packing-related version indicating that information about a track group or a track group ID is omitted when a picture is spatially divided into sub pictures and includes a plurality of sub pictures. May contain information.
  • Information about the track group or track group ID may include a track_group_id field in the TrackGroupBox and / or a track_group_id field in the RegionWisePackingBox, and the TrackGroupBox may include at least one track_group_id field, but the RegionWisePackingBox may include one track_group_id field. have.
  • the metadata may include the same number of RegionWisePackingBoxes as the number of track groups.
  • the version information may include a version value in the RegionWisePackingBox.
  • the version value is 1
  • the corresponding RegionWisePackingBox may include a track_group_id field.
  • the 360 image receiving apparatus decodes the picture (S2120).
  • the decoded picture may correspond to the projected picture, or may correspond to a packed picture (when a regional packing process is applied).
  • the 360 image receiving apparatus may decode at least a partial region of the picture, and at least a partial region of the picture may mean at least one subpicture.
  • the 360 image receiving apparatus may decode a picture based on metadata. For example, the 360 image receiving apparatus may decode a portion of a picture in which a viewport is located. Alternatively, the 360 image receiving apparatus may decode a track having a high quality area in which a viewport is located among a plurality of tracks of a picture.
  • the 360 image receiving apparatus renders the decoded picture based on the metadata (S2130).
  • the decoded picture may be rendered on the 3D surface through a procedure such as reprojection as described above.
  • the 360 image receiving apparatus may render at least a partial region of the decoded picture based on the metadata.
  • the 360 image receiving apparatus may select and provide a track or subpicture track having a high-quality area where a viewport is located based on metadata among a plurality of tracks or a plurality of subpicture tracks, and when the viewport is changed, the changed viewport The region in which the is located can switch the track or subpicture track of high quality to the track or subpicture track being reproduced.
  • the internal components of the apparatus described above may be processors for executing successive procedures stored in a memory, or hardware components configured with other hardware. They can be located inside or outside the device.
  • the above-described modules may be omitted or replaced by other modules performing similar / same operations according to the embodiment.
  • Each part, module, or unit described above may be a processor or hardware part that executes successive procedures stored in a memory (or storage unit). Each of the steps described in the above embodiments may be performed by a processor or hardware parts. Each module / block / unit described in the above embodiments can operate as a hardware / processor.
  • the methods proposed by the present invention can be executed as code. This code can be written to a processor readable storage medium and thus read by a processor provided by an apparatus.
  • the above-described method may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in memory and executed by a processor.
  • the memory may be internal or external to the processor and may be coupled to the processor by various well known means.
  • the processor may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices.
  • the memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Library & Information Science (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

Abstract

Un procédé de traitement de données vidéo à 360° par un dispositif de réception de vidéo à 360° selon la présente invention comprend les étapes suivantes : recevoir des données de vidéo à 360°; obtenir des informations d'une image encodée et des métadonnées à partir des données de vidéo à 360°; décoder au moins une zone partielle de l'image en fonction des informations de l'image encodée; et effectuer le rendu d'au moins une zone partielle de l'image décodée en fonction des métadonnées, où les données de vidéo à 360° contiennent une pluralité de pistes de sous-image, l'image contient une pluralité de sous-image, et les métadonnées contiennent des informations de groupe de pistes de la pluralité de pistes de sous-image.
PCT/KR2019/004212 2018-04-10 2019-04-09 Procédé de traitement de données d'image à 360° en fonction d'une sous-image, et dispositif pour cela WO2019199024A1 (fr)

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