JP2024509416A - Camera control data for virtual cameras in virtual interactive scenes defined by streamed media data - Google Patents

Abstract

An exemplary device for retrieving media data includes a memory configured to store media data and one or more processors implemented with circuitry and configured to execute a presentation engine. the presentation engine is configured to receive streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and to receive camera control data for the three-dimensional scene, the presentation engine comprising: a camera; The control data includes data defining constraints for preventing the virtual camera from passing through the at least one virtual solid object, and requiring the virtual camera to move within the at least one virtual solid object. and, in response to the camera movement data, using the camera control data to prevent the virtual camera from passing through the at least one virtual solid object. It is composed of

Description

This application claims priority to and claims priority to U.S. Patent Application No. 17/654,020, filed on March 8, 2022, and U.S. Provisional Application No. 63/159,379, filed on March 10, 2021. The entire contents of each are incorporated herein by reference. U.S. Patent Application No. 17/654,020, filed March 8, 2022, claims the benefit of U.S. Provisional Application No. 63/159,379, filed March 10, 2021.

TECHNICAL FIELD This disclosure relates to the storage and transfer of encoded video data.

Digital video capabilities include digital television, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, digital cameras, digital recording devices, digital media players, video game devices, and video game consoles. It can be incorporated into a wide range of devices, including cellular or satellite radio telephones, video conferencing devices, and more. Digital video devices use MPEG-2, MPEG-4, ITU-T H.263 or ITU-T H.264/MPEG-4, Part 10, Advanced Video Coding ( AVC), the standards set forth by ITU-T H.265 (also known as High Efficiency Video Coding (HEVC)), and extensions to such standards.

Video compression techniques perform spatial and/or temporal prediction to reduce or eliminate redundancy inherent in video sequences. For block-based video coding, video frames or slices may be partitioned into macroblocks. Each macroblock may be further partitioned. Intra-coded (I) Macroblocks in a frame or slice are encoded using spatial prediction on neighboring macroblocks. Macroblocks in an inter-coded (P or B) frame or slice may use spatial prediction with respect to neighboring macroblocks in the same frame or slice or temporal prediction with respect to other reference frames.

After the video data is encoded, it may be packetized for transmission or storage. Video data may be assembled into video files that conform to any of a variety of standards, such as the International Organization for Standardization (ISO) base media file format and its extensions, such as AVC.

R. Fielding et al., RFC 2616, "Hypertext Transfer Protocol-HTTP/1.1", Network Working Group, IETF, June 1999. T. Paila et al., “FLUTE-File Delivery over Unidirectional Transport”, Network Working Group, RFC 6726, November 2012

Generally, this disclosure describes techniques related to streaming interactive media data. Such interactive media data may be, for example, virtual reality, augmented reality, or other such interactive content, such as other three-dimensional video content. Recent MPEG scene description elements include support for timed media in glTF2.0. A media access function (MAF) provides an application programming interface (API) to the presentation engine through which the presentation engine can request timed media. A retrieval unit executing MAF may process the retrieved timed media data and pass the processed media data through a circular buffer to a presentation engine in a desired format. Current MPEG scene descriptions allow users to consume scene media data in six degrees of freedom (6DoF). Therefore, a user is generally able to move freely within the 3D scene (eg, through walls displayed in the 3D scene). However, content creators may wish to impose limits on viewer movement to some areas, for example to prevent movement through displayed walls or other objects. This disclosure describes techniques for imposing such limits, which may make the user's experience more realistic by preventing the user from passing through obstacles in the virtual world. So the experience can be improved.

In one example, a method for retrieving media data includes receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving control data, the camera control data comprising data defining constraints for preventing the virtual camera from passing through the at least one virtual solid object; receiving camera movement data from a user requesting that the camera move within the at least one virtual solid object; and in response to the camera movement data, the virtual camera is moved by the presentation engine using the camera control data. and preventing passage through at least one virtual solid object.

In another example, a device for retrieving media data is implemented with memory configured to store media data and one or more circuitry configured to execute a presentation engine. a processor, the presentation engine receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and receiving camera control data for the three-dimensional scene. , the camera control data includes data defining constraints for preventing the virtual camera from passing through the at least one virtual solid object; and the virtual camera moving within the at least one virtual solid object. and, in response to the camera movement data, using the camera control data to prevent the virtual camera from passing through the at least one virtual solid object. configured to do so.

In another example, a computer-readable storage medium having instructions stored thereon, the instructions, when executed, transmit to a processor of a client device a streamed media representing a virtual three-dimensional scene including at least one virtual solid object. receiving data; and receiving camera control data for a three-dimensional scene, the camera control data defining constraints to prevent the virtual camera from passing through the at least one virtual solid object. receiving from a user camera movement data requesting that the virtual camera move within the at least one virtual solid object; and in response to the camera movement data, using the camera control data; and preventing the virtual camera from passing through the at least one virtual solid object.

In another example, the device for retrieving media data includes means for receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object, and camera control data for the three-dimensional scene. means for receiving, wherein the camera control data includes data defining constraints for preventing the virtual camera from passing through the at least one virtual solid object; means for receiving camera movement data from a user requesting movement through the at least one virtual solid object; and, in response to the camera movement data, preventing the virtual camera from passing through the at least one virtual solid object. and means for using the camera control data to.

In another example, a method for retrieving media data includes the steps of: receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving, by a presentation engine, camera movement data from a user requesting that a virtual camera move within the at least one virtual solid object; and, in response to the data, using the object collision data to prevent the virtual camera from passing through the at least one virtual solid object by the presentation engine.

In another example, a device for retrieving media data is implemented with memory configured to store media data and one or more circuitry configured to execute a presentation engine. a processor and a presentation engine receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and receiving object collision data representing a boundary of the at least one virtual solid object. receiving from a user camera movement data requesting that the virtual camera move within the at least one virtual solid object; and in response to the camera movement data, using the object collision data, the virtual camera is configured to prevent the object from passing through the at least one virtual solid object.

In another example, a computer-readable storage medium stores instructions that, when executed, cause a processor of a client device to stream media data representing a virtual three-dimensional scene including at least one virtual solid object. receiving object collision data representing a boundary of at least one virtual solid object; and receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object. and, in response to the camera movement data, using the object collision data to prevent the virtual camera from passing through the at least one virtual solid object.

In another example, the device for retrieving media data includes means for receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object, and a boundary of the at least one virtual solid object. means for receiving object collision data representing a virtual solid object, means for receiving from a user camera movement data requesting that a virtual camera move within the at least one virtual solid object; and means responsive to the camera movement data; and means for using the object collision data to prevent the virtual camera from passing through the at least one virtual solid object.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

FIG. 1 is a block diagram illustrating an example system implementing techniques for streaming media data over a network. 2 is a block diagram illustrating an exemplary set of components of the extraction unit of FIG. 1 in more detail; FIG. FIG. 2 is a conceptual diagram illustrating elements of example multimedia content. FIG. 2 is a block diagram illustrating elements of an example video file that may correspond to segments of a representation. FIG. 2 is a conceptual diagram illustrating an example camera path segment with a bounding volume in accordance with the techniques of this disclosure. 1 is a conceptual diagram illustrating an exemplary virtual object, in this example a chair; FIG. 3 is a flowchart illustrating an example method for retrieving media data in accordance with techniques of this disclosure. 3 is a flowchart illustrating an example method for retrieving media data in accordance with techniques of this disclosure.

Interactive media data may be streamed over a network. For example, a client device may retrieve interactive media data using unicast, broadcast, multicast, etc. The interactive media data may be, for example, three-dimensional (3D) media data for extended reality (XR), augmented reality (AR), virtual reality (VR), etc. Thus, when presented to a user, the user can navigate the rendered 3D virtual scene according to the interactive media data.

An MPEG scene description may describe a three-dimensional (3D) scene for a virtual world or experience, eg, for an XR, VR, AR, or other interactive media experience. According to the techniques of this disclosure, the MPEG scene description may describe objects in the 3D scene, such as chairs, walls, tables, counters, doors, windows, or other solid objects. The present disclosure allows the MPEG scene description (or other such description set of data) to impose restrictions on virtual camera movement, e.g., to prevent the camera from passing through solid objects such as walls. describes techniques that can be enhanced thereby.

In particular, the scene description may describe a set of paths along which the camera is allowed to move. A route may be described as a set of anchor points connected through route segments. For enhanced expressivity of camera control, each path segment can be enriched with bounding volumes that allow some degree of freedom of movement along the path.

Additionally or alternatively, the scene description may describe virtual solid objects within the scene. The scene description includes, for example, the boundaries of the object, whether the object can be affected by collisions with the user or other objects (whether the object moves or remains stationary in response to such collisions, ), provides information representing the material for the object, describing how the colliding object interacts with the object, and/or animation data representing the animation that should be played or applied to the object in response to the collision. It is possible.

The techniques of this disclosure may be applied to ISO base media file formats, Scalable Video Coding (SVC) file formats, Advanced Video Coding (AVC) file formats, 3rd Generation Partnership Project (3GPP(R)) file formats, and/or multi-view It may be applied to video files that conform to video data encapsulated according to any of the Video Coding (MVC) file formats, or other similar video file formats.

In HTTP streaming, frequently used operations include HEAD, GET, and partial GET. A HEAD operation retrieves the header of a file associated with a given uniform resource locator (URL) or uniform resource name (URN) without retrieving the payload associated with the URL or uniform resource name (URN). A GET operation retrieves the entire file associated with a given URL or URN. A partial GET operation receives a byte range as an input parameter and retrieves a consecutive number of bytes of the file, where the number of bytes corresponds to the received byte range. Accordingly, movie fragments may be provided for HTTP streaming because a partial GET operation can retrieve one or more individual movie fragments. In a movie fragment, there may be several track fragments of different tracks. In HTTP streaming, a media presentation can be a structured collection of data that is accessible to the client. Clients can request and download media data information to present streaming services to users.

In the example of streaming 3GPP data using HTTP streaming, multiple representations may exist for the video and/or audio data of the multimedia content. As explained below, different representations may be based on different coding characteristics (e.g. different profiles or levels of a video coding standard), different coding standards or extensions of the coding standard (e.g. multi-view and/or scalable extensions), or different bit rates. can correspond to A manifest of such representations may be defined in a media presentation description (MPD) data structure. A media presentation may correspond to a structured collection of data accessible to an HTTP streaming client device. An HTTP streaming client device can request and download media data information to present streaming services to a user of the client device. Media presentations may be described in MPD data structures, which may include MPD updates.

A media presentation may include a sequence of one or more time periods. Each time period may extend until the start of the next time period or, in the case of the last time period, until the end of the media presentation. Each time period may include one or more representations for the same media content. The representation may be one of several alternative encoded versions of audio, video, timed text, or other such data. The representation may vary depending on the type of encoding, eg, the bit rate, resolution, and/or codec of video data, and the bit rate, language, and/or codec of audio data. The term representation may be used to refer to a section of encoded audio or video data that corresponds to a particular period of multimedia content and is encoded in a particular manner.

A representation for a particular time period may be assigned to a group indicated by an attribute in the MPD indicating the adaptation set to which the representation belongs. Representations within the same adaptation set are generally considered substitutes for each other in that a client device can dynamically and seamlessly switch between these representations to perform bandwidth adaptation, for example. For example, each representation of video data for a particular time period may be assigned to the same adaptation set so that any of the representations does not contain media data, such as video data or audio data, of multimedia content for the corresponding time period. may be selected for decoding as presented. In some examples, media content within one time period is represented by either one representation from group 0, if present, or a combination of at most one representation from each non-zero group. obtain. Timing data for each representation of a time period may be expressed relative to the start time of the time period.

A representation may include one or more segments. Each representation may include an initialization segment, or each segment of the representation may be self-initializing. The initialization segment, if present, may include initialization information for accessing the representation. Generally, the initialization segment does not include media data. A segment may be uniquely referenced by an identifier, such as a uniform resource locator (URL), uniform resource name (URN), or uniform resource identifier (URI). MPD may provide an identifier for each segment. In some examples, the MPD may also provide a byte range in the form of a range attribute, which may correspond to data for a segment within a file that is accessible by a URL, URN, or URI.

Different representations may be selected for substantially simultaneous retrieval for different types of media data. For example, a client device may select an audio representation, a video representation, and a timed text representation from which to retrieve segments. In some examples, a client device may select a particular adaptation set to perform bandwidth adaptation. That is, the client device may select an adaptation set that includes a video representation, an adaptation set that includes an audio representation, and/or an adaptation set that includes timed text. Alternatively, a client device can select an adaptation set for one type of media (eg, video) and directly select a representation for another type of media (eg, audio and/or timed text).

FIG. 1 is a block diagram illustrating an example system 10 implementing techniques for streaming media data over a network. In this example, system 10 includes a content preparation device 20, a server device 60, and a client device 40. Client device 40 and server device 60 are communicatively coupled by a network 74, which may include the Internet. In some examples, content preparation device 20 and server device 60 may also be coupled by network 74 or another network, or may be coupled in direct communication. In some examples, content preparation device 20 and server device 60 may include the same device.

In the example of FIG. 1, content preparation device 20 includes an audio source 22 and a video source 24. In the example of FIG. Audio source 22 may include, for example, a microphone that generates electrical signals representing captured audio data to be encoded by audio encoder 26. Alternatively, audio source 22 may comprise a storage medium storing previously recorded audio data, an audio data generator such as a computerized synthesizer, or any other source of audio data. Video source 24 may be a video data generating unit such as a video camera that produces video data to be encoded by video encoder 28, a storage medium encoded with previously recorded video data, a computer graphics source, or Any other source of video data may be provided. Content preparation device 20 is not necessarily communicatively coupled to server device 60 in all instances, but may store multimedia content on a separate medium that is read by server device 60.

Raw audio and video data may include analog or digital data. Analog data may be digitized before being encoded by audio encoder 26 and/or video encoder 28. Audio source 22 may obtain audio data from a speaking participant while the speaking participant is speaking, and video source 24 may simultaneously obtain video data of the speaking participant. Can be done. In other examples, audio source 22 may comprise a computer-readable storage medium containing stored audio data, and video source 24 may comprise a computer-readable storage medium containing stored video data. As such, the techniques described in this disclosure may be applied to live, streaming, real-time audio data, and real-time video data, or to archived pre-recorded audio data and archived pre-recorded audio data. can be applied to video data that has been

Audio frames corresponding to video frames generally include audio data captured (or generated) by audio source 22 at the same time as video data captured (or generated) by video source 24 contained within the video frame. It is an audio frame. For example, while a speaking participant is generally generating audio data by speaking, audio source 22 is capturing audio data and video source 24 is capturing audio data at the same time, i.e., audio source 22 is capturing audio data. In between, capture video data of the speaking participant. Thus, an audio frame may correspond in time to one or more particular video frames. Thus, an audio frame that corresponds to a video frame generally corresponds to a situation where audio data and video data were captured simultaneously, and for which situation an audio frame and a video frame correspond to simultaneously captured audio data and video data, respectively. Contains data.

In some examples, audio encoder 26 may encode, in each encoded audio frame, a timestamp that represents the time the audio data for the encoded audio frame was recorded; In each encoded video frame, a timestamp may be encoded that represents the time that video data for the encoded video frame was recorded. In such an example, an audio frame that corresponds to a video frame may include an audio frame that includes a timestamp and a video frame that includes the same timestamp. Content preparation device 20 may have internal clocks that audio encoder 26 and/or video encoder 28 may generate time stamps, or that audio source 22 and video source 24 use to associate audio and video data with time stamps, respectively. may include an internal clock that may be

In some examples, audio source 22 may send data to audio encoder 26 that corresponds to the time that the audio data was recorded, and video source 24 may send data that corresponds to the time that the video data was recorded to video It can be sent to encoder 28. In some examples, audio encoder 26 uses encoded audio data to indicate the relative time order of the encoded audio data, but not necessarily the absolute time at which the audio data was recorded. , a sequence identifier may be encoded, and similarly, video encoder 28 may also use the sequence identifier to indicate the relative temporal order of encoded video data. Similarly, in some examples, sequence identifiers may be mapped with or correlated with timestamps.

Audio encoder 26 generally produces a stream of encoded audio data, and video encoder 28 generally produces a stream of encoded video data. Each individual stream of data (whether audio or video) is sometimes called an elementary stream. An elementary stream is a single digitally coded (possibly compressed) component of a representation. For example, the coded video or audio portion of the representation may be an elementary stream. Elementary streams may be converted to packetized elementary streams (PES) before being encapsulated within a video file. Within the same representation, a stream ID may be used to distinguish PES packets belonging to one elementary stream from PES packets belonging to other elementary streams. The basic unit of elementary stream data is a packetized elementary stream (PES) packet. Thus, coded video data generally corresponds to an elementary video stream. Similarly, audio data corresponds to one or more respective elementary streams.

Many video coding standards, such as ITU-T H.264/AVC and the upcoming High Efficiency Video Coding (HEVC) standard, define syntax, semantics, and decoding processes for error-free bitstreams, and all conform to a certain profile or level. Although video coding standards generally do not specify encoders, the encoder is tasked with ensuring that the generated bitstream complies with the standards for the decoder. In the context of video coding standards, a "profile" corresponds to a subset of algorithms, features, or tools and the constraints applied to them. As defined by the H.264 standard, for example, a "profile" is a subset of the overall bitstream syntax specified by the H.264 standard. A "level" corresponds to a limit on the decoder's resource consumption, such as decoder memory and computation, which is related to picture resolution, bit rate, and block processing speed. A profile may be signaled by a profile_idc (profile indicator) value, whereas a level may be signaled by a level_idc (level indicator) value.

For example, within the limits imposed by the syntax of a given profile, the performance of the encoder and decoder can vary depending on the values taken by syntax elements in the bitstream, such as the specified size of the picture to be decoded. The H.264 standard recognizes that it is still possible to determine variations. The H.264 standard further recognizes that in many applications it is neither practical nor economical to implement a decoder that can handle all hypothetical uses of the syntax within a particular profile. Accordingly, the H.264 standard defines a "level" as a specified set of constraints placed on the values of syntax elements within a bitstream. These constraints can be simple limits on values. Alternatively, these constraints may take the form of constraints on arithmetic combinations of values (eg, the product of the number of pictures decoded per second, the picture height, and the picture width). The H.264 standard further specifies that individual implementations may support different levels of supported profiles.

A decoder that conforms to a profile typically supports all features defined within the profile. For example, as a coding feature, B-picture coding is not supported in the baseline profile of H.264/AVC, but is supported in other profiles of H.264/AVC. A decoder compliant with a level should be able to decode any bitstream that does not require more resources than the limits defined within the level. Profile and level definitions may be useful for explainability. For example, during video transmission, a pair of profile and level definitions may be negotiated and agreed upon for the entire transmission session. More specifically, in H.264/AVC, the level depends on the number of macroblocks that need to be processed, the size of the decoded picture buffer (DPB), the size of the coded picture buffer (CPB), and the vertical motion. A range of vectors, a limit on the maximum number of motion vectors per two consecutive MBs, and whether a B block can have sub-macroblock partitions smaller than 8x8 pixels can be defined. In this way, the decoder can determine whether it is capable of properly decoding the bitstream.

In the example of FIG. 1, encapsulation unit 30 of content preparation device 20 receives an elementary stream containing coded video data from video encoder 28 and an elementary stream containing coded audio data from audio encoder 26. do. In some examples, video encoder 28 and audio encoder 26 may each include a packetizer to form PES packets from encoded data. In other examples, video encoder 28 and audio encoder 26 may each interface with a respective packetizer for forming PES packets from encoded data. In yet other examples, encapsulation unit 30 may include a packetizer for forming PES packets from encoded audio data and encoded video data.

Video encoder 28 encodes video data of the multimedia content in a variety of ways, including pixel resolution, frame rate, compliance with various coding standards, and various profiles and/or levels of profiles for various coding standards. multimedia content of different bitrates with different characteristics, such as conformance, representation with one or more views (e.g. for two-dimensional or three-dimensional playback), or other such characteristics It is possible to generate various representations of . The representations used in this disclosure may include one of audio data, video data, text data (eg, for closed captioning), or other such data. This representation may include an elementary stream, such as an audio elementary stream or a video elementary stream. Each PES packet may include a stream_id that identifies the elementary stream to which the PES packet belongs. The encapsulation unit 30 is responsible for assembling the elementary streams into various representations of video files (eg, segments).

Encapsulation unit 30 receives PES packets for elementary streams of representations from audio encoder 26 and video encoder 28 and forms corresponding network abstraction layer (NAL) units from the PES packets. Coded video segments may be organized into NAL units that enable addressing applications for "network-friendly" video representations, such as video telephony, storage, broadcasting, or streaming. NAL units may be classified into video coding layer (VCL) NAL units and non-VCL NAL units. A VCL unit may include a core compression engine and may include block, macroblock, and/or slice level data. Other NAL units may be non-VCL NAL units. In some examples, coded pictures at one time instance may be contained within an access unit, which is typically presented as a primary coded picture and may include one or more NAL units.

Non-VCL NAL units may include parameter set NAL units and SEI NAL units, among others. The parameter sets may include sequence level header information (in a sequence parameter set (SPS)) and picture level header information that does not change frequently (in a picture parameter set (PPS)). With parameter sets (eg, PPS and SPS), this infrequently changing information does not need to be repeated for each sequence or picture, thus improving coding efficiency. Additionally, the use of parameter sets can enable out-of-band transmission of critical header information, eliminating the need for redundant transmission for error recovery. In an example of out-of-band transmission, a parameter set NAL unit may be transmitted on a different channel than other NAL units, such as SEI NAL units.

Supplemental Enhancement Information (SEI) may contain information that is not necessary to decode coded picture samples from a VCL NAL unit, but may assist processes related to decoding, display, error recovery, and other purposes. obtain. SEI messages may be included in non-VCL NAL units. SEI messages are a normative part of some standard specifications and are therefore not always mandatory in standard-compliant decoder implementations. The SEI message may be a sequence level SEI message or a picture level SEI message. Some sequence level information may be included within SEI messages, such as scalability information SEI messages in the SVC example and view scalability information SEI messages in MVC. These example SEI messages may convey information regarding operating point extraction and operating point characteristics, for example. In addition, encapsulation unit 30 may form a manifest file, such as a media presentation descriptor (MPD), that describes characteristics of the representation. Encapsulation unit 30 may format the MPD according to Extensible Markup Language (XML).

Encapsulation unit 30 may provide data for one or more representations of multimedia content to output interface 32 along with a manifest file (eg, MPD). The output interface 32 is an interface for writing to a storage medium, such as a network interface or a Universal Serial Bus (USB) interface, a CD or DVD writer or burner, an interface to a magnetic storage medium or a flash storage medium, or an interface for transmitting media data. Other interfaces for storage or transmission may be included. Encapsulation unit 30 may provide data for each representation of multimedia content to output interface 32, which may send the data to server device 60 via network transmission or storage media. In the example of FIG. 1, server device 60 includes a storage medium 62 that stores various multimedia content 64, each of which includes a respective manifest file 66 and one or more representations 68A-68N (representation 68). In some examples, output interface 32 can also send data directly to network 74.

In some examples, representations 68 may be separated into adaptation sets. That is, the various subsets of representations 68 are determined by the codec, profile and level, resolution, number of views, file format of the segment, e.g. by the speaker, the representation to be decoded and presented and/or the text to be displayed along with the audio data. text type information, which may identify the language or other characteristics of the content; camera angle information, which may represent the real-world camera field of view of the scene of the representation in the camera angle or adaptation set; Each may include a common set of characteristics, such as rating information representing suitability.

Manifest file 66 may include data indicating a subset of representations 68 that correspond to a particular adaptation set, as well as common characteristics of the adaptation sets. Manifest file 66 may also include data representing individual characteristics, such as bit rate, for individual representations of the adaptation set. In this way, the adaptation set may enable simplified network bandwidth adaptation. Representations within the adaptive set may be indicated using child elements of the adaptive set element in the manifest file 66.

Server device 60 includes a request processing unit 70 and a network interface 72. In some examples, server device 60 may include multiple network interfaces. Additionally, any or all of the features of server device 60 may be implemented on other devices of the content delivery network, such as routers, bridges, proxy devices, switches, or other devices. In some examples, intermediate devices of the content distribution network may include components that cache multimedia content 64 data and substantially conform to components of server device 60. Generally, network interface 72 is configured to send and receive data over network 74.

Request processing unit 70 is configured to receive network requests for data on storage medium 62 from a client device, such as client device 40 . For example, request processing unit 70 may use Hypertext Transfer Protocol (HTTP), as described in R. Fielding et al. ) Version 1.1 may be implemented. That is, request processing unit 70 may be configured to receive HTTP GET or partial GET requests and provide data for multimedia content 64 in response to those requests. The request may specify a segment of one of the representations 68 using, for example, the segment's URL. In some examples, the request may also specify one or more byte ranges of the segment, and thus includes a partial GET request. Request processing unit 70 may be further configured to respond to an HTTP HEAD request to provide header data for one segment of representation 68. In either case, request processing unit 70 may be configured to process the request to provide the requested data to a requesting device, such as client device 40.

Additionally or alternatively, request processing unit 70 may be configured to deliver media data via a broadcast or multicast protocol such as eMBMS. Content preparation device 20 may create DASH segments and/or subsegments in substantially the same manner as described, but server device 60 may create DASH segments and/or subsegments in eMBMS or another broadcast format. Alternatively, it can be distributed using a multicast network transport protocol. For example, request processing unit 70 may be configured to receive multicast group join requests from client devices 40. That is, server device 60 may advertise to client devices, including client device 40, Internet Protocol (IP) addresses associated with multicast groups associated with particular multimedia content (eg, a live event broadcast). Client device 40 can then submit a request to join the multicast group. This request may be propagated through network 74, eg, to the routers that make up network 74, such that the routers direct traffic destined for the IP address associated with the multicast group to participating client devices, such as client device 40.

As shown in the example of FIG. 1, multimedia content 64 includes a manifest file 66, which may correspond to a media presentation description (MPD). Manifest file 66 may include descriptions of various alternative representations 68 (e.g., video services of varying quality), which descriptions may include, for example, codec information, profile values, level values, bitrates, and representations 68. Other explanatory characteristics may be included. Client device 40 may retrieve the MPD of the media presentation to determine how to access segments of representation 68.

Specifically, retrieval unit 52 may retrieve configuration data (not shown) of client device 40 to determine the decoding capabilities of video decoder 48 and the rendering capabilities of video output 44. Video output 44 may be included in a display device for extended reality, augmented reality, or virtual reality, such as a headset. Similarly, configuration data may indicate whether video output 44 is capable of rendering 3D video data for extended reality, augmented reality, virtual reality, etc., for example. The configuration data may also include a language preference selected by a user of client device 40, one or more camera fields of view corresponding to a depth preference set by a user of client device 40, and/or a language preference selected by a user of client device 40. It may include any or all of the rating preferences selected by the user.

Retrieval unit 52 may comprise, for example, a web browser or media client configured to submit HTTP GET and partial GET requests. Retrieval unit 52 may correspond to software instructions executed by one or more processors or processing units (not shown) of client device 40. In some examples, all or some of the functionality described with respect to the extraction unit 52 may be implemented in hardware or a combination of hardware, software, and/or firmware, in which case the required hardware may be provided to execute instructions for software or firmware.

Retrieval unit 52 may compare the decoding and rendering capabilities of client device 40 to the characteristics of representation 68 indicated by information in manifest file 66. Retrieval unit 52 may first retrieve at least a portion of manifest file 66 to determine characteristics of representation 68. For example, retrieval unit 52 may request a portion of manifest file 66 that describes characteristics of one or more adaptation sets. Retrieval unit 52 may select a subset (eg, an adaptive set) of representations 68 that have characteristics that can be satisfied by the coding and rendering capabilities of client device 40. The retrieval unit 52 then determines the bitrate for the representations in the adaptation set, determines the currently available amount of network bandwidth, and extracts the bitrate from one of the representations that has a bitrate that can be satisfied by the network bandwidth. Segments can be extracted.

In general, a higher representation bitrate will result in a higher quality video playback, while a lower representation bitrate will provide sufficient video playback quality when the available network bandwidth is reduced. There is. Therefore, when the available network bandwidth is relatively high, the retrieval unit 52 can retrieve data from a representation with a relatively high bit rate, and when the available network bandwidth is low, the retrieval unit 52 can retrieve data from a representation with a relatively high bit rate. Data can be retrieved from representations with relatively low rates. In this manner, client device 40 may stream multimedia data over network 74 while also adapting to changing network bandwidth availability on network 74.

Additionally or alternatively, retrieval unit 52 may be configured to receive data according to a broadcast or multicast network protocol, such as eMBMS or IP multicast. In such an example, retrieval unit 52 may submit a request to join a multicast network group associated with particular media content. After retrieval unit 52 joins a multicast group, it can receive data of the multicast group without issuing further requests to server device 60 or content preparation device 20. The retrieval unit 52 may submit a request to leave the multicast group when the data of the multicast group is no longer needed, for example to stop playback or to change the channel to a different multicast group. can.

Network interface 54 may receive and provide data for the segment of the selected representation to retrieval unit 52, which in turn may provide the segment to decapsulation unit 50. Decapsulation unit 50 decapsulates the elements of the video file into constituent PES streams and depackets the PES streams to retrieve encoded data, e.g., as indicated by the PES packet header of the stream. As such, the encoded data can be sent to either audio decoder 46 or video decoder 48, depending on whether the encoded data is part of an audio stream or a video stream. Audio decoder 46 decodes the encoded audio data and sends the decoded audio data to audio output 42, while video decoder 48 decodes the encoded video data and sends the decoded video data, which may include multiple views of the stream. Send to video output 44.

Video encoder 28, video decoder 48, audio encoder 26, audio decoder 46, encapsulation unit 30, decapsulation unit 52, and decapsulation unit 50 each include one or more microprocessors, digital signal processors, if applicable. any of a variety of suitable processing circuitry, such as (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), discrete logic circuitry, software, hardware, firmware, or any combination thereof. It can be implemented as Each of video encoder 28 and video decoder 48 may be included within one or more encoders or decoders, any of which may be integrated as part of a composite video encoder/decoder (codec). Similarly, each of audio encoder 26 and audio decoder 46 may be included within one or more encoders or decoders, any of which may be integrated as part of a composite codec. The device including video encoder 28, video decoder 48, audio encoder 26, audio decoder 46, encapsulation unit 30, retrieval unit 52, and/or decapsulation unit 50 may include an integrated circuit, a microprocessor, and/or a cellular phone. wireless communication devices such as

Client device 40, server device 60, and/or content preparation device 20 may be configured to operate in accordance with the techniques of this disclosure. By way of example, this disclosure describes these techniques with respect to client device 40 and server device 60. However, it should be understood that content preparation device 20 may be configured to implement these techniques instead of (or in addition to) server device 60.

Encapsulation unit 30 may form a NAL unit that includes a header that identifies the program to which the NAL unit belongs, as well as a payload, such as audio data, video data, or data that describes the transport or program stream to which the NAL unit corresponds. can. For example, in H.264/AVC, a NAL unit includes a 1-byte header and a variable-sized payload. A NAL unit that includes video data within its payload may include various granularity levels of video data. For example, a NAL unit may include a block of video data, multiple blocks, a slice of video data, or an entire picture of video data. Encapsulation unit 30 may receive encoded video data from video encoder 28 in the form of PES packets of an elementary stream. Encapsulation unit 30 can associate each elementary stream with a corresponding program.

Encapsulation unit 30 can also assemble access units from multiple NAL units. Generally, an access unit may include one or more NAL units to represent a frame of video data, as well as audio data corresponding to the frame when such audio data is available. An access unit generally includes all NAL units for one output time instance, eg, all audio data and video data for one time instance. For example, if each view has a frame rate of 20 frames per second (fps), each time instance may correspond to a time interval of 0.05 seconds. During this time interval, a particular frame for all views of the same access unit (same time instance) may be rendered simultaneously. In one example, an access unit may include coded pictures within one time instance, which may be presented as a primary coded picture.

Thus, an access unit may include all audio and video frames of a common time instance, e.g., all views corresponding to time X. This disclosure also refers to encoded pictures of a particular view as "view components." That is, a view component may include encoded pictures (or frames) for a particular view at a particular time. Thus, an access unit may be defined as containing all view components of a common time instance. The decoding order of access units does not necessarily have to be the same as the output or display order.

A media presentation may include a media presentation description (MPD) that may include descriptions of different alternative representations (e.g., video services with different qualities), where the description includes, for example, codec information, profile values, and level values. may be included. MPD is an example of a manifest file, such as manifest file 66. Client device 40 can retrieve the MPD of a media presentation to determine how to access movie fragments of various presentations. Movie fragments may be placed within a movie fragment box (moof box) of a video file.

Manifest file 66 (which may include an MPD, for example) may advertise the availability of segments of representation 68. That is, the MPD may include information indicating the wall clock time at which the first segment of one of the representations 68 will be available, as well as information indicating the duration of the segments within the representation 68. In this way, the retrieval unit 52 of the client device 40 can determine when each segment is available based on the start time as well as the duration of the segments that precede a particular segment.

After encapsulation unit 30 assembles the NAL units and/or access units into a video file based on the received data, encapsulation unit 30 passes the video file to output interface 32 for output. In some examples, instead of sending the video file directly to client device 40, encapsulation unit 30 may store the video file locally or send the video file to a remote server via output interface 32. . Output interface 32 can include, for example, a transmitter, a transceiver, a device for writing data to a computer-readable medium, such as an optical drive, a magnetic media drive (e.g., a floppy drive), a universal serial bus (USB) port, a network interface, or other output interfaces. Output interface 32 outputs the video file to a computer readable medium, such as, for example, a transmitted signal, magnetic media, optical media, memory, flash drive, or other computer readable medium.

Network interface 54 can receive NAL units or access units via network 74 and provide NAL units or access units to decapsulation unit 50 via retrieval unit 52 . Decapsulation unit 50 decapsulates the elements of the video file into constituent PES streams and depackets the PES streams to retrieve encoded data, e.g., as indicated by the PES packet header of the stream. As such, the encoded data may be sent to either audio decoder 46 or video decoder 48, depending on whether the encoded data is part of an audio stream or a video stream. Audio decoder 46 decodes the encoded audio data and sends the decoded audio data to audio output 42, while video decoder 48 decodes the encoded video data and sends the decoded video data, which may include multiple views of the stream. to video output 44.

According to techniques of the present disclosure, a user of client device 40 may obtain media data related to a 3D virtual scene, e.g., for extended reality (XR), augmented reality (AR), virtual reality (VR), etc. can. A user may navigate through a 3D virtual scene using one or more devices, such as a controller, that communicate with client device 40. Additionally or alternatively, client device 40 may include sensors, cameras, etc. for determining that the user has moved within real-world space, and client device 40 may translate such real-world movement into virtual space movement. It is possible.

A 3D virtual scene may include one or more virtual solid objects. Such objects may include, for example, walls, windows, tables, chairs, or any other such objects that may appear within the virtual scene. According to the techniques of this disclosure, media data retrieved by retrieval unit 52 may include a scene description that describes such virtual solid objects. The scene description may be compliant with the MPEG scene description element of glTF2.0, for example.

In some examples, the scene description may include a description of allowable camera movements. For example, the scene description defines one or more bounding volumes within which the virtual camera is allowed to move (e.g., according to volumes shaped like spheres, cubes, cones, cones, etc.), and the virtual camera can be written such that it is not allowed to move beyond the limits of its shape. That is, the bounding volume may describe the permissible camera movement volume within which the virtual camera is allowed to move. Additionally or alternatively, the scene description may describe one or more vertices or anchor points and allowed paths (eg, segments) between the vertices or anchor points. Client device 40 may only allow the virtual camera to move along the allowed path and/or within the bounding volume.

In some examples, the scene description may additionally or alternatively describe one or more virtual solid objects in the scene that the virtual camera cannot pass through.

FIG. 2 is a block diagram illustrating an exemplary set of components of extraction unit 52 of FIG. 1 in more detail. In this example, retrieval unit 52 includes an eMBMS middleware unit 100, a DASH client 110, a media application 112, and a presentation engine 114.

In this example, eMBMS middleware unit 100 further includes an eMBMS receiving unit 106, a cache 104, and a proxy server 102. In this example, the eMBMS receiving unit 106 is configured as described in T. Paila et al., "FLUTE-File Delivery over Unidirectional Transport," Network Working Group, RFC 6726, 2012, available at, for example, tools.ietf.org/html/rfc6726. Data can be received by eMBMS according to File Delivery over Unidirectional Transport (FLUTE), which was described in November. That is, eMBMS receiving unit 106 may receive files via broadcast, for example, from server device 60, which may act as a broadcast/multicast service center (BM-SC).

When eMBMS middleware unit 100 receives data for a file, eMBMS middleware unit may store the received data in cache 104. Cache 104 may include a computer-readable storage medium such as flash memory, hard disk, RAM, or any other suitable storage medium.

Proxy server unit 102 may act as a server for DASH client 110. For example, proxy server unit 102 may provide an MPD file or other manifest file to DASH client 110. Proxy server unit 102 can advertise availability times for segments within the MPD file as well as within hyperlinks from which the segments can be retrieved. These hyperlinks may include local host address prefixes corresponding to client device 40 (eg, 127.0.0.1 for IPv4). In this manner, DASH client 110 may request a segment from proxy server unit 102 using an HTTP GET or partial GET request. For example, for a segment available from the link http://127.0.0.1/rep1/seg3, DASH client 110 constructs an HTTP GET request that includes a request for http://127.0.0.1/rep1/seg3 and can be submitted to the proxy server unit 102. Proxy server unit 102 can retrieve requested data from cache 104 and provide the data to DASH client 110 in response to such requests.

DASH client 110 provides the retrieved media data to media application 112. Media application 112 may be, for example, a web browser, game engine, or another application that receives and presents media data. Additionally, presentation engine 114 represents an application that interacts with media application 112 to present retrieved media data within a 3D virtual environment. Presentation engine 114 may, for example, map two-dimensional media data onto a 3D projection. Presentation engine 114 may also receive input from other elements of client device 40 to determine the user's position within the 3D virtual environment and the orientation the user is facing at that position. For example, presentation engine 114 may determine the X, Y, and Z coordinates for the user's location and the user's viewing orientation to determine the appropriate media data to display to the user. Additionally, presentation engine 114 may receive camera movement data representing real-world user movement data and translate the real-world user movement data into 3D virtual space movement data.

According to techniques of this disclosure, eMBMS middleware unit 100 may receive media data (e.g., via glTF2.0) via broadcast or multicast, and then DASH client 110 receives media data from eMBMS middleware unit 100. It can be taken out. The media data may include a scene description that includes camera control information indicating how the virtual camera can move through the virtual scene. For example, a scene description may include data describing allowable paths through the virtual scene, eg, along defined paths between anchor points. Additionally or alternatively, the scene description may include data describing a bounding volume that represents the volume within which the virtual camera is allowed to move. Additionally or alternatively, the scene description may include data describing one or more solid virtual objects within the 3D virtual environment, such as walls, tables, chairs, etc. For example, the scene description data may define collision boundaries for 3D virtual objects. A scene description describes whether an object is static (as in the case of a wall, for example) or dynamic (as in the case of a chair, for example), an animation is played using the object, etc. It may further include data representing what will happen if a collision with such an object occurs.

Presentation engine 114 may use the scene description to determine what to present in the event of a collision with a 3D virtual object and/or an attempt to exit the allowed path or volume. For example, if the scene description includes data about permissible paths or bounding volumes and the user attempts to move beyond the permissible paths or bounding volumes, presentation engine 114 need only avoid updating the display; indicates that such movement is not permitted. As another example, if the scene description includes data about a 3D virtual solid object and the user attempts to move within the 3D virtual solid object, if the 3D virtual solid object is static, the presentation engine 114 may avoid updating the display. If the 3D virtual solid object is not static, presentation engine 114 may determine animation to display for the object, such as translational and/or rotational movement to be applied to the object. For example, if the 3D virtual solid object is a chair, the animation data may indicate that the chair will be pushed along the floor or will fall if a collision occurs.

FIG. 3 is a conceptual diagram illustrating elements of example multimedia content 120. Multimedia content 120 may correspond to multimedia content 64 (FIG. 1) or other multimedia content stored on storage medium 62. In the example of FIG. 3, multimedia content 120 includes a media presentation description (MPD) 122 and a plurality of representations 124A-124N (representations 124). Representation 124A includes optional header data 126 and segments 128A-128N (segment 128), while representation 124N includes optional header data 130 and segments 132A-132N (segment 132). The letter N is conveniently used to designate the last movie fragment of each of representations 124. In some examples, there may be different numbers of movie fragments between representations 124.

MPD 122 may include data structures separate from representation 124. MPD 122 may correspond to manifest file 66 of FIG. Similarly, representation 124 may correspond to representation 68 of FIG. In general, the MPD 122 includes coding and rendering characteristics, an adaptation set, the profiles that the MPD 122 supports, text type information, camera angle information, rating information, trick mode information (e.g., information indicating representations that include temporal subsequences), and/or or may include data generally representative of characteristics of the representation 124, such as information for retrieving remote time periods (eg, for insertion of targeted advertisements into the media content being played).

Header data 126, when present, includes characteristics of segments 128, such as the temporal location of random access points (RAPs, also referred to as stream access points (SAPs)), which of segments 128 contain random access points, It may describe a byte offset to a random access point within segment 128, a uniform resource locator (URL) for segment 128, or other aspects of segment 128. Header data 130, when present, may describe similar characteristics of segment 132. Additionally or alternatively, such characteristics may be contained entirely within MPD 122.

Segments 128, 132 include one or more coded video samples, each of which may include a frame or slice of video data. Each of the coded video samples in segment 128 may have similar characteristics, such as height, width, and bandwidth requirements. Such characteristics could be described by data of MPD 122, but such data is not shown in the example of FIG. 3. MPD 122 may include characteristics as described by the 3GPP specifications, plus any or all of the signaled information described in this disclosure.

Each of segments 128, 132 may be associated with a unique uniform resource locator (URL). Accordingly, each of segments 128, 132 may be separately retrievable using a streaming network protocol such as DASH. In this manner, a destination device, such as client device 40, can retrieve segment 128 or 132 using an HTTP GET request. In some examples, client device 40 may retrieve a particular range of bytes of segment 128 or 132 using an HTTP partial GET request.

FIG. 4 is a block diagram illustrating elements of an example video file 150 that may correspond to a segment of a representation, such as one of segments 128, 132 of FIG. Each of segments 128, 132 may include data that substantially conforms to the organization of data shown in the example of FIG. Video file 150 may be said to encapsulate segments. As explained above, the ISO-based media file format and its extensions to video files store data in a series of objects called "boxes." In the example of Figure 4, a video file 150 has a file type (FTYP) box 152, a movie (MOOV) box 154, a segment index (sidx) box 162, a movie fragment (MOOF) box 164, and a movie fragment random access box. (MFRA) box 166. Although Figure 4 represents an example video file, other media files may be configured similarly to the data in the video file 150 according to the ISO-based media file format and its extensions (e.g., audio data , timed text data, etc.).

File type (FTYP) box 152 generally represents the file type of video file 150. File type box 152 may include data identifying specifications that represent the best use of video file 150. File type box 152 may alternatively be placed before MOOV box 154, movie fragment box 164, and/or MFRA box 166.

In some examples, a segment such as video file 150 may include an MPD update box (not shown) before FTYP box 152. The MPD update box may include information indicating that the MPD corresponding to the representation that includes video file 150 should be updated, along with information for updating the MPD. For example, an MPD update box may provide the URI or URL of the resource used to update the MPD. As another example, an MPD update box may include data to update the MPD. In some examples, the MPD update box may immediately follow a segment type (STYP) box (not shown) for video file 150, which may define the segment type for video file 150.

In the example of FIG. 4, MOOV box 154 includes a movie header (MVHD) box 156, a track (TRAK) box 158, and one or more movie extension (MVEX) boxes 160. Generally, MVHD box 156 may describe general characteristics of video file 150. For example, MVHD box 156 contains data representing when video file 150 was first created, data representing when video file 150 was last modified, data representing the timescale of video file 150, and data representing the timescale of video file 150. or other data representative of video file 150 in general.

TRAK box 158 may contain data for tracks of video file 150. TRAK box 158 may include a track header (TKHD) box that describes characteristics of the track corresponding to TRAK box 158. In some examples, TRAK box 158 may include coded video pictures, while in other examples, the track's coded video pictures may be referenced by data in TRAK box 158 and/or data in sidx box 162. May be included within movie fragment 164.

In some examples, video file 150 may include two or more tracks. Accordingly, MOOV box 154 may include a number of TRAK boxes equal to the number of tracks in video file 150. TRAK box 158 may describe characteristics of the corresponding track of video file 150. For example, TRAK box 158 may describe temporal and/or spatial information for the corresponding track. A TRAK box, similar to TRAK box 158 of MOOV box 154, may describe characteristics of a parameter set track if encapsulation unit 30 (FIG. 3) includes the parameter set track in a video file, such as video file 150. Encapsulation unit 30 may signal the presence of a sequence level SEI message in a parameter set track in a TRAK box that describes the parameter set track.

MVEX box 160 describes the characteristics of corresponding movie fragment 164, e.g., to signal that video file 150 includes movie fragment 164 in addition to the video data contained within MOOV box 154, if any. obtain. In the context of streaming video data, coded video pictures may be contained within movie fragments 164 rather than within MOOV boxes 154. Therefore, all coded video samples may be contained within movie fragments 164 rather than within MOOV box 154.

MOOV box 154 may include a number of MVEX boxes 160 equal to the number of movie fragments 164 in video file 150. Each of the MVEX boxes 160 may describe the characteristics of a corresponding one of the movie fragments 164. For example, each MVEX box may include a movie extension header box (MEHD) box that describes the duration of a corresponding one of movie fragments 164.

As mentioned above, encapsulation unit 30 may store sequence data sets within video samples that do not contain actual coded video data. Video samples may generally correspond to access units, where an access unit is a representation of a coded picture at a particular time instance. In the context of AVC, a picture encodes one or more VCL NAL units, containing information for constructing all pixels with access units and other associated non-VCL NAL units such as SEI messages. include. Accordingly, encapsulation unit 30 may include within one of movie fragments 164 a sequence data set that may include sequence-level SEI messages. Encapsulation unit 30 further identifies the presence of a sequence data set and/or a sequence level SEI message in one of movie fragments 164 in one of MVEX boxes 160 corresponding to one of movie fragments 164. As such, it can be signaled.

SIDX box 162 is an optional element of video file 150. That is, a video file that conforms to the 3GPP file format or other such file format does not necessarily include a SIDX box 162. According to an example 3GPP file format, SIDX boxes may be used to identify subsegments of a segment (eg, a segment contained within video file 150). The 3GPP file format is a "self-contained set of one or more contiguous movie fragment boxes with corresponding media data boxes, such that the media data box containing the data referenced by the movie fragment box Define a subsegment as ``following a fragment box and must precede the next movie fragment box containing information about the same track.'' The 3GPP file format also specifies that a SIDX box "contains a series of references to subsegments of the (sub)segment documented by the box. The referenced subsegments are consecutive in presentation time. Similarly, the segment The bytes referenced by the index box are always contiguous within the segment.The referenced size gives a count of the number of bytes in the referenced material.

SIDX box 162 generally provides information representing one or more subsegments of the segments contained within video file 150. For example, such information may include the playback time at which the sub-segment starts and/or ends, the byte offset with respect to the sub-segment, whether the sub-segment contains (e.g. starts by) a stream access point (SAP), the SAP's type (for example, whether the SAP is an instantaneous decoder refresh (IDR) picture, clean random access (CRA) picture, broken link access (BLA) picture, etc.), (playback time and/or byte offset within the subsegment) (regarding) the location of the SAP, etc.

Movie fragment 164 may include one or more coded video pictures. In some examples, movie fragment 164 may include one or more groups of pictures (GOPs), and each GOP may include multiple coded video pictures, eg, frames or pictures. Additionally, as explained above, movie fragment 164 may include sequence data sets in some examples. Each of movie fragments 164 may include a movie fragment header box (MFHD, not shown in FIG. 4). The MFHD box may describe characteristics of the corresponding movie fragment, such as the sequence number of the movie fragment. Movie fragments 164 may be included in sequence number order within video file 150.

MFRA box 166 may describe random access points within movie fragment 164 of video file 150. This may assist in implementing trick modes, such as performing a search for a particular temporal location (ie, playback time) within a segment encapsulated by video file 150. MFRA box 166 is generally optional in some examples and does not need to be included in the video file. Similarly, a client device, such as client device 40, does not necessarily need to reference MFRA box 166 to accurately decode and display the video data of video file 150. MFRA box 166 may include a number of track fragment random access (TFRA) boxes (not shown) equal to the number of tracks of video file 150, or in some examples, media tracks of video file 150 (e.g., may contain a number of TFRA boxes equal to the number of non-hint tracks).

In some examples, movie fragment 164 may include one or more stream access points (SAPs), such as IDR pictures. Similarly, MFRA box 166 may provide an indication of the location within video file 150 of the SAP. Accordingly, a temporal subsequence of video file 150 may be formed from the SAP of video file 150. The temporal subsequence may also include other pictures such as P frames and/or B frames that are dependent on the SAP. Frames and/or slices of the temporal subsequence may be ordered into segments such that frames/slices of the temporal subsequence that depend on other frames/slices of the subsequence may be properly decoded. For example, in a hierarchical organization of data, data used in predictions for other data may also be included within temporal subsequences.

FIG. 5 is a conceptual diagram illustrating an example camera path segment 212 with bounding volumes in accordance with the techniques of this disclosure. In particular, in 3D scene 200, camera 202 represents a viewpoint from which a user can view portions of 3D scene 200. In this example, path segment 212 is defined between points 204 and 206. Additionally, a bounding volume is defined by the extrusion of points from bounding box 208 to bounding box 210 along path segment 212. Thus, in this example, camera 202 is allowed to move within the bounding volume along path segment 212, but is restricted from moving beyond the bounding volume.

A scene description may describe a set of paths along which a camera, such as camera 202, is allowed to move. A path may be described as a set of anchor points, such as points 204, 206, connected by path segments, such as path segment 212. In some examples, such as the example of FIG. 5, each path segment may be reinforced with a bounding volume that allows some degree of freedom of movement along the path.

The scene camera, and thus the viewer, are allowed to move freely within the bounding volume along the path segments. Path segments may be described using more complex geometries to allow finer control of the path.

Additionally, camera parameters may be constrained at each point along the route. Parameters can be provided for every anchor point and then used with an interpolation function to calculate the corresponding parameters for every point along the path segment. Interpolation functions can be applied to all parameters, including bounding volumes.

The camera control extension mechanism of the present disclosure may be implemented as a glTF2.0 extension that defines camera control for a scene. Camera control extensions may be identified by the "MPEG_camera_control" tag, which may be included in the extensionsUsed element and may be included in the extensionsRequired element for the 3D scene.

An exemplary "MPEG_camera_control" extension is shown below in Table 1 and may be defined in the "camera" element of the scene description.
Camera control information may be structured as follows.
- For each anchor point, the (x,y,z) coordinates of the anchor point can be represented using floating point values. - For each path segment, the (i,j) coordinates of the first and second anchor points of the path segment ) index can be expressed as an integer value. For bounding volumes,
o If boundingVolume is BV_CONE, the (r1,r2) radius of the circle of the first anchor point and the second anchor point may be given.
o If boundingVolume is BV_FRUSTUM, then ((x,y,z)_topleft,w,h) may be given for each anchor point of the path segment.
o If boundingVolume is BV_SPHERE, then r as the radius of the sphere may be given for each anchor point of the path segment.
- If intrinsicParameters is true, the internal parameters object may be modified.

A presentation engine (e.g., presentation engine 114 of FIG. 2 or another element of client device 40 that may be different from the components shown in FIGS. 1 and 2) may support an MPEG_camera_control extension or other such data structure. . If the scene provides camera control information, the presentation engine controls the camera movement so that the camera's (x,y,z) coordinates are always on the path segment or within the bounding volume of the path segment. may be limited to The presentation engine may provide visual, audio, and/or haptic feedback to the viewer as the viewer approaches the boundary of the bounding volume.

FIG. 6 is a conceptual diagram illustrating an exemplary virtual object 220, which in this example is a chair. In order to provide the viewer with an immersive experience, it is important that the viewer interact appropriately with objects in the scene. Viewers should not be able to walk through solid objects in the scene, such as walls, chairs, and tables, or other such solid objects.

Figure 6 shows a 3D mesh representation of the chair, defined as a set of cuboids, along with collision boundaries. The MPEG_mesh_collision extension data structure may be defined to provide a description of the collision boundaries of such a 3D mesh. An extended data structure may be defined on a mesh object as a set of cuboids around the mesh geometry. Table 2 below represents an exemplary set of properties that may be included in such an extended data structure.

Mesh collision information may include cuboid vertex coordinates (x, y, z) for a cuboid boundary or sphere center and radius for a spherical boundary. The value may be given as a floating point number.

The presentation engine may support the MPEG_mesh_collision extension or other such data structures. The presentation engine may ensure that the camera position (x,y,z) will not fall within one of the defined mesh cuboids at any time. Collisions may be signaled to the viewer through visual, acoustic, and/or haptic feedback. The presentation engine may use information about the boundaries for the nodes to initialize and configure the 3D physics engine that detects collisions.

FIG. 7 is a flowchart illustrating an example method for retrieving media data in accordance with the techniques of this disclosure. The method of FIG. 7 is described with respect to client device 40 of FIG. 1 and retrieval unit 52 of FIG. 2. Other such devices may be configured to perform this or similar methods.

Initially, client device 40 may retrieve media data (250). For example, retrieval unit 52 may retrieve media data that is compliant with glTF2.0, for example. In some examples, retrieval unit 52 may retrieve media data directly by unicast, eg, using DASH. In some examples, a middleware unit of retrieval unit 52, such as eMBMS middleware 100 of FIG. 2, may receive media data via broadcast or multicast, and then a DASH client, e.g., DASH client 110 of FIG. You can extract media data from .

Media data may include scene descriptions. Accordingly, retrieval unit 52 or another component of client device 40 may extract the scene description from the media data (252). The scene description may be an MPEG scene description that includes camera control data in accordance with the techniques of this disclosure. Retrieval unit 52 may provide the scene description to presentation engine 114. Presentation engine 114 may thus receive the scene description and determine camera control data for the three-dimensional scene from the scene description (254). Camera control data may conform to Table 1 above. That is, for example, the camera control data may include one or more anchor points for the camera path, one or more segments between the anchor points for the camera path, a bounding volume such as a cone, cone, or sphere; It may include accessors that provide internal parameters and/or camera control information that may be modified at each anchor point.

Presentation engine 114 may further determine movement constraints from the camera control data (256). For example, presentation engine 114 may determine two or more anchor points and acceptable paths between the anchor points from movement constraints in camera control data. Additionally or alternatively, the presentation engine 114 may determine bounding volumes, such as cubes, spheres, pyramids, cones, etc., from the movement constraints of the camera control data. The presentation engine 114 determines the path along which the virtual camera is allowed to move and/or the virtual camera is allowed to move within the bounding volume but not outside the bounding volume. The acceptance route can be used. Acceptable paths and/or bounding volumes may be defined to ensure that the virtual camera does not exceed 3D solid virtual objects such as walls. That is, a bounding volume or acceptable path may be defined to lie within one or more 3D solid virtual objects, such as walls, floors, ceilings, or other objects within a 3D virtual scene.

Presentation engine 114 may then receive camera movement data (258). For example, the presentation engine 114 may control the orientation of the headset and the headset and/or virtual camera, such as directional and/or rotational movement, from one or more controllers, such as a headset that includes a handheld controller and/or display. may receive data representative of movement of the person. If the presentation engine 114 determines that the camera movement data requires camera movement through the 3D solid virtual object, such as beyond the limits of a bounding volume or along a path that is not one of the defined acceptable paths. There is (260). In response, presentation engine 114 may prevent the virtual camera from passing through the 3D solid virtual object (262).

As such, the method of FIG. 7 includes the steps of receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving control data, the camera control data comprising data defining constraints for preventing the virtual camera from passing through the at least one virtual solid object; receiving camera movement data from a user requesting that the camera move within the at least one virtual solid object; and in response to the camera movement data, the virtual camera is moved by the presentation engine using the camera control data. and preventing passage through at least one virtual solid object.

FIG. 8 is a flowchart illustrating an example method for retrieving media data in accordance with the techniques of this disclosure. The method of FIG. 8 is described with respect to client device 40 of FIG. 1 and retrieval unit 52 of FIG. 2. Other such devices may be configured to implement this or similar methods.

Initially, client device 40 may retrieve media data (280). For example, retrieval unit 52 may retrieve media data that is compliant with glTF2.0, for example. In some examples, retrieval unit 52 may retrieve media data directly by unicast, eg, using DASH. In some examples, a middleware unit of retrieval unit 52, such as eMBMS middleware 100 of FIG. 2, may receive media data via broadcast or multicast, and then a DASH client, e.g., DASH client 110 of FIG. You can extract media data from .

Media data may include scene descriptions. Accordingly, retrieval unit 52 or another component of client device 40 may extract the scene description from the media data (282). The scene description may be an MPEG scene description that includes object collision data in accordance with the techniques of this disclosure. Retrieval unit 52 may provide the scene description to presentation engine 114. Presentation engine 114 may thus receive the scene description and determine object collision data for one or more 3D solid virtual objects from the scene description (284). Object collision data may conform to Table 2 above. That is, object collision data may include, for example, data representing boundaries that represents an array of boundary shapes that define the collision boundaries of a mesh (3D virtual solid) object, data indicating whether the object is static (i.e., movable), It may include materials representing collision materials for the object and/or animations to be presented for the object if a collision occurs.

Presentation engine 114 may further determine object collision data from the camera control data (286). For example, the presentation engine 114 may include mesh (3D virtual solid) boundaries representing an array of boundary shapes that define the collision boundaries of the object, data indicating whether the object is static (i.e., movable), collision materials for the object, etc. may determine the material representing the object and/or the animation to be presented for the object if a collision occurs. Presentation engine 114 may use object collision data to determine how to react in the event of a collision with a 3D solid virtual object.

Presentation engine 114 may then receive camera movement data (288). For example, the presentation engine 114 may control the orientation of the headset and the headset and/or virtual camera, such as directional and/or rotational movement, from one or more controllers, such as a headset that includes a handheld controller and/or display. may receive data representative of movement of the person. Presentation engine 114 may determine that the camera movement data calls for camera movement through the 3D solid virtual object, such as into and through the 3D solid virtual object defined by the object collision data (290). In response, presentation engine 114 may prevent the virtual camera from passing through the 3D solid virtual object (292). For example, if the object is static, as indicated by the object collision data, presentation engine 114 may prevent the virtual camera from moving into and through the object. As another example, if the object is not static (e.g., movable), presentation engine 114 may cause the object to fall or move in response to a collision with the object, e.g. The reaction may be determined from the object collision data, such as an animation to be played against the object.

As such, the method of FIG. 8 includes the steps of receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving, by a presentation engine, camera movement data from a user requesting that a virtual camera move within the at least one virtual solid object; in response, using the object collision data to prevent, by a presentation engine, a virtual camera from passing through at least one virtual solid object.

Some examples of the techniques of this disclosure are summarized in the following sections.

Clause 1: A method for retrieving media data, the method comprising: receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving camera control data of the virtual camera, the camera control data comprising data defining permissible locations for the virtual camera; and the presentation engine moves the virtual camera within the at least one virtual solid object. receiving camera movement data from a user requesting camera movement; and using the camera control data to update, by a presentation engine, the location of the virtual camera to ensure that the virtual camera remains within an acceptable location. and a method including.

Clause 2: The method of Clause 1, wherein updating the location of the virtual camera includes preventing the virtual camera from passing through the at least one virtual solid object.

Clause 3: The method of Clause 1, where the media data to be streamed includes glTF2.0 media data.

Clause 4: The method of Clause 1, wherein receiving the streamed media data comprises requesting the streamed media data from the retrieval unit via an application programming interface (API).

Clause 5: The method of Clause 1, where camera control data is included within the MPEG scene description.

Clause 6: Camera control data includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowable camera movement vectors for a virtual camera, The method of clause 1, wherein updating the camera location includes allowing the virtual camera to traverse only segments between anchor points.

Clause 7: The camera control data includes data defining a bounding volume representing a permissible camera movement volume for the virtual camera, and updating the location of the virtual camera ensures that the virtual camera traverses only the permissible camera movement volume. The method of Clause 1, including the step of recognizing.

Clause 8: The method of Clause 7, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 9: Camera control data is contained within the MPEG_camera_control extension, the method of Clause 1.

Clause 10: MPEG_camera_control extension supports anchor data representing the number of anchor points for the allowed path for the virtual camera, segment data representing the number of path segments for the allowed path between the anchor points, and bounding volume for the virtual camera. clause 9, including one or more of: bounding volume data representing a camera parameter, an internal parameter indicating whether a camera parameter is modified at each of the anchor points, and accessor data representing an index of an accessor providing camera control data. the method of.

Clause 11: The method of Clause 1, wherein the at least one virtual solid object includes one of a virtual wall, a virtual chair, or a virtual table.

Clause 12: The step of updating the location of the virtual camera further comprises determining from the camera control data an allowable path for the virtual camera, the step of updating the location of the virtual camera being such that the virtual camera is within the allowable path defined in the camera control data. The method of clause 1, comprising the step of ensuring movement only along some virtual path.

Clause 13: Camera control data is included in the MPEG_mesh_collision extension, the method of Clause 1.

Clause 14: A device for retrieving media data, the device comprising a memory configured to store the media data and one or more devices implemented with circuitry and configured to run a presentation engine. a processor; the presentation engine is configured to receive streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and to receive camera control data for the three-dimensional scene. , the camera control data includes data defining permissible locations for the virtual camera; and receiving camera movement data from a user that requires the virtual camera to move within the at least one virtual solid object. , using the camera control data to update a location of the virtual camera to ensure that the virtual camera remains within an acceptable location.

Clause 15: The device of Clause 14, wherein the presentation engine is configured to prevent the virtual camera from passing through at least one virtual solid object.

Clause 16: Media data streamed to a Clause 14 device, including glTF2.0 media data.

Clause 17: The device of Clause 14, wherein the presentation engine is configured to request streamed media data from the retrieval unit via an application programming interface (API).

Clause 18: Camera control data is included in the MPEG scene description for Clause 14 devices.

Clause 19: Camera control data includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowable camera movement vectors for a virtual camera and The device of clause 14, wherein the presentation engine is configured to allow the virtual camera to only traverse segments between anchor points in order to update the camera's location.

Clause 20: The camera control data includes data defining a bounding volume representing the allowed camera movement volume for the virtual camera, and in order to update the location of the virtual camera, the presentation engine specifies that the virtual camera has only the allowed camera movement volume. Clause 14 devices configured to permit traversal.

Clause 21: The device of Clause 20, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 22: Camera control data is contained in the MPEG_camera_control extension for Clause 14 devices.

Clause 23: MPEG_camera_control extension supports anchor data representing the number of anchor points for the allowed path for the virtual camera, segment data representing the number of path segments for the allowed path between the anchor points, and bounding volume for the virtual camera. clause 22, including one or more of: bounding volume data representing the camera parameters, internal parameters indicating whether the camera parameters are modified at each of the anchor points, and accessor data representing the index of the accessor providing the camera control data. device.

Clause 24: The device of Clause 14, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 25: The presentation engine is further configured to determine, from the camera control data, an allowable path for the virtual camera; and to update the location of the virtual camera, the presentation engine determines that the virtual camera A device according to clause 14 configured to ensure movement only along virtual paths that are within the permissible paths defined in the device.

Clause 26: Camera control data is included in the MPEG_mesh_collision extension for Clause 14 devices.

Clause 27: A computer-readable storage medium having instructions stored thereon, the instructions, when executed, transmitting to a processor executing a presentation engine a streamed media representing a virtual three-dimensional scene including at least one virtual solid object. receiving data; and receiving camera control data for the three-dimensional scene, the camera control data including data defining permissible locations for the virtual camera; Receiving camera movement data from a user that requests movement within the virtual solid object and using camera control data to determine the location of the virtual camera to ensure that the virtual camera remains within acceptable locations. update.

Clause 28: The computer-readable storage medium of Clause 27, wherein the instructions for causing the processor to update the location of the virtual camera include instructions for causing the processor to prevent the virtual camera from passing through the at least one virtual solid object.

Clause 29: Streamed media data is the computer-readable medium of Clause 27, including glTF2.0 media data.

Clause 30: The instructions for causing the processor to receive streamed media data include instructions for causing the processor to request streamed media data from the retrieval unit via an application programming interface (API). Clause 27 computer readable medium.

Clause 31: Camera control data is contained within an MPEG scene description on a Clause 27 computer-readable medium.

Clause 32: Camera control data includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowable camera movement vectors for the virtual camera; 27. The computer-readable medium of clause 27, wherein the instructions cause the processor to update the location of the virtual camera to cause the processor to allow the virtual camera to traverse only segments between anchor points.

Clause 33: The camera control data includes data defining a bounding volume representing an allowable camera movement volume for a virtual camera, and instructions that cause the processor to update the location of the virtual camera cause the processor to specify that the virtual camera has an allowable camera movement volume. Article 27 computer-readable medium containing instructions that permit traversal only.

Clause 34: The computer-readable medium of Clause 20, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 35: Computer-readable medium of Clause 27, where camera control data is contained within the MPEG_camera_control extension.

Clause 36: MPEG_camera_control extension supports anchor data representing the number of anchor points for the allowed path for the virtual camera, segment data representing the number of path segments for the allowed path between anchor points, bounding volume for the virtual camera. clause 22, including one or more of: bounding volume data representing the camera parameters, internal parameters indicating whether the camera parameters are modified at each of the anchor points, and accessor data representing the index of the accessor providing the camera control data. computer readable medium.

Clause 37: The computer-readable medium of Clause 27, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 38: The instructions further include instructions for causing the processor to determine an allowable path for the virtual camera from the camera control data, and the instructions for causing the processor to update the location of the virtual camera further include instructions for causing the processor to determine, from the camera control data, the location of the virtual camera. 27. The computer-readable medium of clause 27 containing instructions for ensuring movement only along virtual paths that are within the permissible paths defined in .

Clause 39: Computer-readable medium of Clause 27, where camera control data is contained within the MPEG_mesh_collision extension.

Clause 40: A device for retrieving media data, the device comprising: means for receiving streamed media data representing a virtual three-dimensional scene comprising at least one virtual solid object; and camera control data for the three-dimensional scene. means for receiving, the camera control data comprising data defining permissible locations for the virtual camera; and means for receiving camera movement requiring the virtual camera to move within the at least one virtual solid object. A device comprising: means for receiving data from a user; and means for using camera control data to update a location of a virtual camera to ensure that the virtual camera remains within an acceptable location.

Clause 41: A method for retrieving media data, the method comprising: receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving, by a presentation engine, from a user object collision data representing a boundary of the solid object; and receiving, by a presentation engine, camera movement data from a user requesting that a virtual camera move within the at least one virtual solid object; and in response to the data, using the object collision data, the presentation engine updates the location of the virtual camera to ensure that the virtual camera remains outside of at least one virtual solid object.

Clause 42: The method of Clause 41, wherein updating the location of the virtual camera includes preventing the virtual camera from passing through the at least one virtual solid object.

Clause 43: The method of Clause 41, wherein receiving object collision data comprises receiving an MPEG_mesh_collision extension.

Clause 44: The method of Clause 43, wherein the MPEG_mesh_collision extension includes data defining at least one 3D mesh for at least one virtual solid object.

Clause 45: The MPEG_mesh_collision extension specifies at least one of the following: a boundary of a 3D mesh for at least one virtual solid object, a material for the 3D mesh, or an animation that should be presented in response to a virtual camera touching the 3D mesh The method of clause 44, including data defining one.

Clause 46: The step of receiving object collision data comprises boundary data representing one or more collision boundaries of the at least one virtual solid object, static data representing whether the at least one virtual solid object is affected by the collision. , one or more of material data representing how the colliding object interacts with the at least one virtual solid object, or animation data representing an animation triggered by the collision with the at least one virtual solid object. The method of clause 41, comprising the step of receiving data comprising:

Clause 47: The method of Clause 41, wherein the at least one virtual solid object includes one of a virtual wall, a virtual chair, or a virtual table.

Clause 48: The method of Clause 41, where the media data to be streamed includes glTF2.0 media data.

Clause 49: The method of Clause 41, wherein receiving the streamed media data comprises requesting the streamed media data from the retrieval unit via an application programming interface (API).

Clause 50: The method of Clause 41, in which object collision data is included within the MPEG scene description.

Clause 51: A device for retrieving media data, the device comprising a memory configured to store the media data and one or more circuitry implemented with circuitry and configured to run a presentation engine. a processor; the one or more processors receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and an object representing a boundary of the at least one virtual solid object. receiving collision data; receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object; and, in response to the camera movement data, using the object collision data. and updating the location of the virtual camera to ensure that the virtual camera remains outside of at least one virtual solid object.

Clause 52: The device of Clause 51, wherein the presentation engine is configured to prevent the virtual camera from passing through at least one virtual solid object in order to update the location of the virtual camera.

Clause 53: The device of Clause 51, wherein the presentation engine is configured to receive the MPEG_mesh_collision extension to receive object collision data.

Clause 54: The MPEG_mesh_collision extension is a Clause 53 device containing data defining at least one 3D mesh for at least one virtual solid object.

Clause 55: The MPEG_mesh_collision extension specifies at least one of the following: a boundary of a 3D mesh for at least one virtual solid object, a material for the 3D mesh, or an animation that should be presented in response to a virtual camera touching the 3D mesh Article 54 device containing data defining one.

Clause 56: To receive object collision data, the presentation engine shall include boundary data representing one or more collision boundaries of at least one virtual solid object, indicating whether the at least one virtual solid object is affected by the collision. static data representing, material data representing how the colliding object interacts with at least one virtual solid object, or animation data representing animation triggered by a collision with at least one virtual solid object. A clause 51 device configured to receive data containing one or more.

Clause 57: The device of Clause 51, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 58: Media data streamed to a Clause 51 device, including glTF2.0 media data.

Clause 59: In order to receive the streamed media data, the presentation engine is configured to request the streamed media data from the retrieval unit via an application programming interface (API), Clause 51 device.

Clause 60: Object collision data is included in the MPEG scene description, Clause 51 devices.

Clause 61: A computer-readable storage medium having instructions stored thereon, the instructions, when executed, causing a processor to receive streamed media data representing a virtual three-dimensional scene including at least one virtual solid object. and receiving object collision data representing a boundary of at least one virtual solid object; and receiving camera movement data from a user requesting that a virtual camera move within the at least one virtual solid object. and, in response to the camera movement data, using the object collision data to update the location of the virtual camera to ensure that the virtual camera remains outside of the at least one virtual solid object. Medium.

Clause 62: The computer-readable medium of Clause 61, wherein the instructions for causing the processor to update the location of the virtual camera include instructions for causing the processor to prevent the virtual camera from passing through the at least one virtual solid object.

Clause 63: The computer-readable medium of Clause 61, wherein the instructions for causing the processor to receive object collision data include instructions for causing the processor to receive an MPEG_mesh_collision extension.

Clause 64: The MPEG_mesh_collision extension is the computer-readable medium of Clause 62 containing data that defines at least one 3D mesh for at least one virtual solid object.

Clause 65: The MPEG_mesh_collision extension specifies at least one of the following: a boundary of a 3D mesh for at least one virtual solid object, a material for the 3D mesh, or an animation that should be presented in response to a virtual camera touching the 3D mesh Article 63 computer-readable medium containing data defining a

Clause 66: Instructions causing the processor to receive object collision data may cause the processor to receive object collision data, including boundary data representing one or more collision boundaries of at least one virtual solid object, whether the at least one virtual solid object is affected by the collision. static data representing whether the colliding object interacts with at least one virtual solid object, material data representing how the colliding object interacts with at least one virtual solid object, or animation data representing animation triggered by a collision with at least one virtual solid object. Article 61 computer-readable medium containing instructions for receiving data containing one or more of the following:

Clause 67: The computer-readable medium of Clause 61, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 68: Streamed media data is a computer-readable medium according to Clause 61, including glTF2.0 media data.

Clause 69: The instructions for causing the processor to receive streamed media data include instructions for causing the processor to request streamed media data from the retrieval unit via an application programming interface (API). Clause 61 computer readable medium.

Clause 70: Object collision data is contained within an MPEG scene description, a Clause 61 computer-readable medium.

Clause 71: A device for retrieving media data, the device representing a virtual three-dimensional scene comprising at least one virtual solid object, with means for receiving streamed media data and boundaries of the at least one virtual solid object. means for receiving object collision data representing a virtual solid object, means for receiving from a user camera movement data requesting that a virtual camera move within the at least one virtual solid object; and means responsive to the camera movement data; and means for updating the location of the virtual camera to ensure that the virtual camera remains outside of at least one virtual solid object.

Clause 72: A method for retrieving media data, the method comprising: receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving camera control data of the virtual camera, the camera control data comprising data defining permissible locations for the virtual camera; and the presentation engine moves the virtual camera within the at least one virtual solid object. receiving camera movement data from a user requesting camera movement data; and using the camera control data to update the location of the virtual camera by a presentation engine to ensure that the virtual camera remains within an acceptable location. and a method including.

Clause 73: The method of Clause 72, wherein updating the location of the virtual camera includes preventing the virtual camera from passing through the at least one virtual solid object.

Clause 74: Streamed media data includes glTF2.0 media data in accordance with any of Clauses 72 and 73.

Clause 75: The step of receiving the streamed media data comprises the step of requesting the streamed media data from the retrieval unit via an application programming interface (API). Method.

Clause 76: Camera control data is included within the MPEG scene description in any of Clauses 72 to 75.

Clause 77: Camera control data includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowable camera movement vectors for a virtual camera and The method of any of clauses 72-76, wherein updating the location of the camera includes allowing the virtual camera to only traverse segments between anchor points.

Clause 78: The camera control data includes data defining a bounding volume representing a permissible camera movement volume for the virtual camera, and updating the location of the virtual camera ensures that the virtual camera traverses only the permissible camera movement volume. any of the methods in clauses 72 to 77, including the step of acknowledging that

Clause 79: The method of Clause 78, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 80: Camera control data is contained within the MPEG_camera_control extension, in any of Clauses 72 to 79.

Clause 81: MPEG_camera_control extension supports anchor data representing the number of anchor points for the allowed path for the virtual camera, segment data representing the number of path segments for the allowed path between the anchor points, and bounding volume for the virtual camera. clause 80, comprising one or more of: bounding volume data representing a camera parameter, an internal parameter indicating whether a camera parameter is modified at each of the anchor points, and accessor data representing an index of an accessor providing camera control data. the method of.

Clause 82: The method of any of Clauses 72 to 81, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 83: The step of updating the location of the virtual camera further comprises determining from the camera control data an allowable path for the virtual camera, the step of updating the location of the virtual camera being such that the virtual camera is within the allowable path defined in the camera control data. The method of clause 72, comprising the step of ensuring movement only along certain virtual paths.

Clause 84: Camera control data is contained within the MPEG_mesh_collision extension, in any of Clauses 72 to 83.

Clause 85: A device for retrieving media data, the device comprising a memory configured to store the media data and one or more circuitry implemented with circuitry and configured to run a presentation engine. a processor; the presentation engine is configured to receive streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and to receive camera control data for the three-dimensional scene. , the camera control data includes data defining permissible locations for the virtual camera; and receiving camera movement data from a user that requires the virtual camera to move within the at least one virtual solid object. , using the camera control data to update a location of the virtual camera to ensure that the virtual camera remains within an acceptable location.

Clause 86: The device of Clause 85, wherein the presentation engine is configured to prevent the virtual camera from passing through at least one virtual solid object.

Clause 87: Media data streamed to any device in clauses 85 and 86, including glTF2.0 media data.

Clause 88: The device of any of Clauses 85 to 87, wherein the presentation engine is configured to request streamed media data from the retrieval unit via an application programming interface (API).

Clause 89: Camera control data is included in the MPEG scene description for any device in clauses 85 to 88.

Clause 90: Camera control data includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowable camera movement vectors for a virtual camera, Any device in clauses 85-89, wherein the presentation engine is configured to allow the virtual camera to traverse only segments between anchor points to update the camera's location.

Clause 91: The camera control data includes data defining a bounding volume representing the allowed camera movement volume for the virtual camera, and in order to update the location of the virtual camera, the presentation engine specifies that the virtual camera any device in clauses 85 to 90 so constructed as to permit it to cross.

Clause 92: A clause 91 device, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 93: Camera control data is contained within the MPEG_camera_control extension for any device in clauses 85 to 92.

Clause 94: MPEG_camera_control extension supports anchor data representing the number of anchor points for an allowed path for a virtual camera, segment data representing the number of path segments for an allowed path between anchor points, and bounding volume for a virtual camera. clause 93, comprising one or more of: bounding volume data representing a camera parameter, an internal parameter indicating whether a camera parameter is modified at each of the anchor points, and accessor data representing an index of an accessor providing camera control data. device.

Clause 95: The at least one virtual solid object is a device according to any of Clauses 85 to 94, including one of a virtual wall, a virtual chair, or a virtual table.

Clause 96: The presentation engine is further configured to determine, from the camera control data, an acceptable path for the virtual camera, and to update the location of the virtual camera, the presentation engine is configured to determine, from the camera control data, A device according to any of clauses 85 to 95 configured to ensure that it moves only along virtual paths that are within the permissible paths defined in the device.

Clause 97: Any device in clauses 85 through 96, where camera control data is contained within the MPEG_mesh_collision extension.

Clause 98: A computer-readable storage medium having instructions stored thereon, the instructions, when executed, transmitting to a processor executing a presentation engine a streamed media representing a virtual three-dimensional scene including at least one virtual solid object. receiving data; and receiving camera control data for the three-dimensional scene, the camera control data including data defining permissible locations for the virtual camera; Receiving camera movement data from a user that requests movement within the virtual solid object and using camera control data to determine the location of the virtual camera to ensure that the virtual camera remains within acceptable locations. update.

Clause 99: The computer-readable storage medium of Clause 98, wherein the instructions for causing the processor to update the location of the virtual camera include instructions for causing the processor to prevent the virtual camera from passing through the at least one virtual solid object.

Clause 100: Streamed media data is a computer-readable medium according to any of clauses 98 and 99, including glTF2.0 media data.

Clause 101: The instructions for causing the processor to receive streamed media data include instructions for causing the processor to request streamed media data from a retrieval unit via an application programming interface (API), Clause 98 on any computer-readable medium from 100 to 100.

Clause 102: Camera control data is contained within an MPEG scene description on a computer-readable medium according to any of Clauses 98 to 101.

Clause 103: Camera control data includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowable camera movement vectors for the virtual camera; 102. The computer-readable medium of any of clauses 98-102, wherein the instructions cause the processor to update the location of the virtual camera.

Clause 104: The camera control data includes data defining a bounding volume representing an allowed camera movement volume for a virtual camera, and instructions that cause the processor to update the location of the virtual camera cause the processor to specify that the virtual camera has an allowed camera movement volume. Article 103 computer-readable medium containing instructions authorizing traversal only.

Clause 105: The computer-readable medium of any of Clauses 98 to 104, wherein the data defining a bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 106: Computer-readable medium of Clause 105, where camera control data is contained within the MPEG_camera_control extension.

Clause 107: MPEG_camera_control extension supports anchor data representing the number of anchor points for the allowed path for the virtual camera, segment data representing the number of path segments for the allowed path between the anchor points, and bounding volume for the virtual camera. clause 98, including one or more of: bounding volume data representing the camera parameters, internal parameters indicating whether the camera parameters are modified at each of the anchor points, and accessor data representing the index of the accessor providing the camera control data. Any computer readable medium from 106 to 106.

Clause 108: The computer readable medium of any of Clauses 98 to 107, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 109: The instructions further include instructions for causing the processor to determine an allowable path for the virtual camera from the camera control data, and the instructions for causing the processor to update the location of the virtual camera further include instructions for causing the processor to determine the location of the virtual camera from the camera control data. A computer-readable medium according to any of clauses 98 to 108 containing instructions that ensure movement only along virtual paths that are within the permissible paths defined in .

Clause 110: Camera control data is contained in the MPEG_mesh_collision extension on any computer-readable medium of clauses 98 to 109.

Clause 111: A device for retrieving media data, the device comprising: means for receiving streamed media data representing a virtual three-dimensional scene comprising at least one virtual solid object; and camera control data for the three-dimensional scene. means for receiving, the camera control data comprising data defining permissible locations for the virtual camera; and means for receiving camera movement requiring the virtual camera to move within the at least one virtual solid object. A device comprising: means for receiving data from a user; and means for using camera control data to update a location of a virtual camera to ensure that the virtual camera remains within an acceptable location.

Clause 112: A method for retrieving media data, the method comprising: receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving, by a presentation engine, from a user object collision data representing a boundary of the solid object; and receiving, by a presentation engine, camera movement data from a user requesting that a virtual camera move within the at least one virtual solid object; and in response to the data, using the object collision data, the presentation engine updates the location of the virtual camera to ensure that the virtual camera remains outside of at least one virtual solid object.

Article 113: A method involving a combination of any of the methods of Articles 72 to 84 and the method of Article 112.

Clause 114: The method of any of Clauses 112 and 113, wherein updating the location of the virtual camera includes preventing the virtual camera from passing through the at least one virtual solid object.

Clause 115: The method of any of Clauses 112 to 114, wherein receiving object collision data comprises receiving an MPEG_mesh_collision extension.

Clause 116: The method of Clause 115, wherein the MPEG_mesh_collision extension includes data defining at least one 3D mesh for at least one virtual solid object.

Clause 117: The MPEG_mesh_collision extension specifies at least one of the following: a boundary of a 3D mesh for at least one virtual solid object, a material for the 3D mesh, or an animation that should be presented in response to a virtual camera touching the 3D mesh The method of clause 116, including data defining the

Clause 118: The step of receiving object collision data comprises boundary data representing one or more collision boundaries of the at least one virtual solid object, static data representing whether the at least one virtual solid object is affected by the collision. , one or more of material data representing how the colliding object interacts with the at least one virtual solid object, or animation data representing an animation triggered by the collision with the at least one virtual solid object. any of the methods of clauses 112 to 117, comprising the step of receiving data comprising:

Clause 119: The method of any of Clauses 112 to 118, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 120: The media data to be streamed shall be in the manner of any of Clauses 112 to 119, including glTF2.0 media data.

Clause 121: The step of receiving the streamed media data comprises the step of requesting the streamed media data from the retrieval unit via an application programming interface (API). Method.

Clause 122: Object collision data is included within the MPEG scene description, in any of Clauses 112 to 121.

Clause 123: A device for retrieving media data, comprising a memory configured to store media data and one or more circuitry implemented with circuitry and configured to run a presentation engine. a processor; the one or more processors receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; and an object representing a boundary of the at least one virtual solid object. receiving collision data; receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object; and, in response to the camera movement data, using the object collision data. and updating the location of the virtual camera to ensure that the virtual camera remains outside of at least one virtual solid object.

Clause 124: A device comprising a combination of a device according to clauses 85 to 97 and a device according to clause 123.

Clause 125: The device of any of Clauses 123 and 124, wherein the presentation engine is configured to prevent the virtual camera from passing through at least one virtual solid object, in order to update the location of the virtual camera.

Clause 126: A device according to any of Clauses 123 to 125, wherein the presentation engine is configured to receive the MPEG_mesh_collision extension in order to receive object collision data.

Clause 127: The MPEG_mesh_collision extension includes data defining at least one 3D mesh for at least one virtual solid object for a Clause 126 device.

Clause 128: The MPEG_mesh_collision extension specifies at least one of the following: a boundary of a 3D mesh for at least one virtual solid object, a material for the 3D mesh, or an animation that should be presented in response to a virtual camera touching the 3D mesh Article 127 device containing data defining one.

Clause 129: To receive object collision data, the presentation engine shall include boundary data representing one or more collision boundaries of at least one virtual solid object, indicating whether the at least one virtual solid object is affected by the collision. static data representing, material data representing how the colliding object interacts with at least one virtual solid object, or animation data representing animation triggered by a collision with at least one virtual solid object. A device according to any of clauses 123 to 128, configured to receive data containing one or more of the following:

Clause 130: The at least one virtual solid object is a device according to any of Clauses 123 to 129, including one of a virtual wall, a virtual chair, or a virtual table.

Clause 131: Media data streamed to any device in clauses 123 to 130, including glTF2.0 media data.

Clause 132: In order to receive the streamed media data, the presentation engine is configured to request the streamed media data from the retrieval unit via an application programming interface (API), Clause 123. Any device from 131.

Clause 133: Object collision data is included in the MPEG scene description, any device in clauses 123 to 132.

Clause 134: A computer-readable storage medium having instructions stored thereon, the instructions, when executed, causing a processor to receive streamed media data representing a virtual three-dimensional scene including at least one virtual solid object. and receiving object collision data representing a boundary of at least one virtual solid object; and receiving camera movement data from a user requesting that a virtual camera move within the at least one virtual solid object. and, in response to the camera movement data, using the object collision data to update the location of the virtual camera to ensure that the virtual camera remains outside of the at least one virtual solid object. Medium.

Clause 135: A computer-readable storage medium comprising a combination of the computer-readable storage medium of any of Clauses 98-110 and the computer-readable storage medium of Clause 134.

Clause 136: The computer-readable medium of any of clauses 134 and 135, wherein the instructions for causing the processor to update the location of the virtual camera include instructions for causing the processor to prevent the virtual camera from passing through at least one virtual solid object. .

Clause 137: The computer-readable medium of any of clauses 134-136, wherein the instructions for causing the processor to receive object collision data include instructions for causing the processor to receive an MPEG_mesh_collision extension.

Clause 138: The MPEG_mesh_collision extension is the computer-readable medium of any of Clauses 134 to 137 containing data that defines at least one 3D mesh for at least one virtual solid object.

Clause 139: The MPEG_mesh_collision extension specifies at least one of the following: a boundary of a 3D mesh for at least one virtual solid object, a material for the 3D mesh, or an animation that should be presented in response to a virtual camera touching the 3D mesh A computer-readable medium according to any of clauses 134 to 138 containing data defining a

Clause 140: Instructions causing the processor to receive object collision data may cause the processor to receive object collision data, including boundary data representing one or more collision boundaries of at least one virtual solid object, whether the at least one virtual solid object is affected by the collision. static data representing whether the colliding object interacts with at least one virtual solid object, material data representing how the colliding object interacts with at least one virtual solid object, or animation data representing animation triggered by a collision with at least one virtual solid object. A computer-readable medium according to any of clauses 134 to 139 containing instructions for receiving data containing one or more of the following:

Clause 141: The computer readable medium of any of Clauses 134 to 140, wherein the at least one virtual solid object comprises one of a virtual wall, a virtual chair, or a virtual table.

Clause 142: Streamed media data is a computer readable medium according to any of Clauses 134 to 141, including glTF2.0 media data.

Clause 143: The instructions for causing the processor to receive streamed media data include instructions for causing the processor to request streamed media data from the retrieval unit via an application programming interface (API). Clause 134 142 on any computer-readable medium.

Clause 144: The computer-readable medium of any of Clauses 134 to 143, wherein the object collision data is contained within an MPEG scene description.

Clause 145: A method for retrieving media data, the method comprising: receiving, by a presentation engine, streamed media data representing a virtual three-dimensional scene including at least one virtual solid object; receiving camera control data of the at least one virtual solid object, the camera control data comprising data defining constraints for preventing the virtual camera from passing through the at least one virtual solid object; , receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object; and in response to the camera movement data, using camera control data, the virtual camera moves within the at least one virtual solid object; and preventing passage through two virtual solid objects.

Clause 146: The method of Clause 145, wherein the streamed media data includes glTF2.0 media data.

Clause 147: The step of receiving the streamed media data comprises the step of requesting the streamed media data from the retrieval unit via an application programming interface (API). Method.

Clause 148: Camera control data is included within the MPEG scene description in any of Clauses 145 to 147.

Clause 149: Camera control data is contained within the MPEG_camera_control extension, in any of Clauses 145 to 148.

Clause 150: The method of Clause 149, wherein the MPEG_camera_control extension includes data defining two or more anchor points and one or more segments between the anchor points, where the segments represent allowed camera movement vectors.

Clause 151: The MPEG_camera_control extension includes data defining a bounding volume that represents the allowed camera movement volume, as in any of Clauses 149 and 150.

Clause 152: The method of Clause 151, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere.

Clause 153: The MPEG_camera_control extension conforms to the data in Table 1 above, in any of Clauses 149 to 152.

Clause 154: The method of any of Clauses 149 to 153, wherein the at least one virtual solid object comprises a virtual wall.

Clause 155: Preventing the virtual camera from passing through the at least one virtual solid object comprises preventing the virtual camera from moving along a virtual path that exceeds the allowed path defined in the MPEG_camera_control extension. In any of the ways specified in Articles 149 to 154.

Clause 156: Camera control data is contained within the MPEG_mesh_collision extension, in any of Clauses 145 to 155.

Clause 157: The method of Clause 156, wherein the MPEG_mesh_collision extension includes data defining at least one 3D mesh for at least one virtual solid object.

Clause 158: The MPEG_mesh_collision extension includes data defining at least one of the boundaries of a 3D mesh, the material for the 3D mesh, or an animation to be presented in response to a virtual camera contacting the 3D mesh; Article 157 method.

Clause 159: MPEG_mesh_collision extension conforms to Table 2 above, in any of Clauses 156 to 158.

Clause 160: Preventing the virtual camera from passing through the at least one virtual solid object comprises using the MPEG_mesh_collision extension to prevent the virtual camera from entering the at least one virtual solid object. Clause 156 Any way from 159.

Clause 161: A device for retrieving media data, the device comprising one or more means for implementing any of the methods of Clauses 145 to 160.

Clause 162: The device of Clause 161, wherein the one or more means comprises one or more processors implemented in circuitry.

Clause 163: The device of Clause 161, wherein the apparatus includes at least one of an integrated circuit, a microprocessor, and a wireless communication device.

Clause 164: A device for retrieving media data, the device comprising: means for receiving streamed media data representing a virtual three-dimensional scene comprising at least one virtual solid object; and camera control data for the three-dimensional scene. means for receiving, wherein the camera control data includes data defining a constraint for preventing the virtual camera from passing through the at least one virtual solid object; means for receiving camera movement data from a user requesting movement through the at least one virtual solid object; and, in response to the camera movement data, preventing the virtual camera from passing through the at least one virtual solid object. and means for using the camera control data to.

In one or more examples, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, corresponding to tangible media such as data storage media, or any computer-readable storage medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. communication media, including media. Thus, computer-readable media generally may correspond to (1) non-transitory, tangible computer-readable storage media, or (2) communication media such as a signal or carrier wave. A data storage medium can be accessed by one or more computers or one or more processors to retrieve instructions, code, and/or data structures for implementation of the techniques described in this disclosure. It can be a possible medium. A computer program product may include a computer readable medium.

By way of example and not limitation, such computer-readable storage medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage device, flash memory, or a memory containing instructions or data structures. Any other medium that can be used to store desired form of program code and that can be accessed by a computer can be included. Also, any connection is properly termed a computer-readable medium. For example, if the instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals or other transitory media, but instead refer to non-transitory tangible storage media. Disc and disc, as used herein, refer to compact disc (disc) (CD), laser disc (disc), optical disc (disc), digital versatile disc (disc) (DVD), Includes floppy disks (disks) and Blu-ray disks (discs), with disks typically reproducing data magnetically and discs reproducing data optically using a laser. Combinations of the above should also be included within the scope of computer-readable media.

The instructions may be implemented on one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. may be executed by one or more processors, such as. Accordingly, the term "processor" as used herein may refer to any of the structures described above or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or in combination codecs. can be incorporated. Also, the techniques may be implemented entirely with one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including wireless handsets, integrated circuits (ICs) or sets of ICs (eg, chipsets). Although various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to implement the disclosed techniques, they are not necessarily different hardware units. It does not necessarily need to be realized by Rather, the various units, including one or more processors as described above, together with suitable software and/or firmware, may be combined or interacted with in a codec hardware unit, as described above. It may be provided by a collection of operable hardware units.

Various examples have been described. These and other examples are within the scope of the following claims.

10 systems
20 Content Preparation Device
22 Audio sources
24 video sources
26 Audio encoder
28 video encoder
30 encapsulation units
32 Output interface
40 client devices
42 audio output
44 video output
46 Audio decoder
48 Video decoder
50 Decapsulation Unit
52 Take-out unit
54 Network Interface
60 server devices
62 Storage medium
64 Multimedia Content
66 Manifest file
68 expression
68A~68N expression
70 Request processing unit
72 Network interface
74 Network
100 eMBMS middleware units
102 Proxy server unit
104 Cache
106 eMBMS receiving unit
110 DASH Client
112 Media Applications
114 Presentation Engine
120 Multimedia Content
122 Media Presentation Description (MPD)
124 Expression
124A Expression
124N expression
126 header data
128 segments
128A~128N segment
130 header data
132 segments
132A~132N segment
150 video files
152 File type (FTYP) box
154 Movie (MOOV) Box
156 Movie header (MVHD) box
158 TRAK Box
160 Movie Extension (MVEX) Box
162 Segment index (sidx) box
164 Movie Fragment (MOOF) Box
166 Movie Fragment Random Access (MFRA) Box
202 Camera

Claims (40)

A method for extracting media data, the method comprising:
receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object by a presentation engine;
receiving, by the presentation engine, camera control data for the three-dimensional scene, the camera control data including data defining allowed locations for a virtual camera;
receiving, by the presentation engine, camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object;
using the camera control data to update, by the presentation engine, a location of the virtual camera to ensure that the virtual camera remains within the allowed locations. 2. The method of claim 1, wherein updating the location of the virtual camera includes preventing the virtual camera from passing through the at least one virtual solid object. 2. The method of claim 1, wherein the streamed media data includes glTF2.0 media data. 2. The method of claim 1, wherein receiving the streamed media data comprises requesting the streamed media data from a retrieval unit via an application programming interface (API). 2. The method of claim 1, wherein the camera control data is included in an MPEG scene description. The camera control data includes data defining two or more anchor points and one or more segments between the anchor points, the segments representing allowed camera movement vectors for the virtual camera; 2. The method of claim 1, wherein updating the location of the virtual camera includes allowing the virtual camera to traverse only the segments between the anchor points. The camera control data includes data defining a bounding volume representing an allowable camera movement volume for the virtual camera, and updating the location of the virtual camera includes data that defines a bounding volume representing an allowable camera movement volume for the virtual camera, and updating the location of the virtual camera allows the virtual camera to only move the allowable camera movement volume. 2. The method of claim 1, comprising the step of allowing traversal. 8. The method of claim 7, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere. 2. The method of claim 1, wherein the camera control data is included in an MPEG_camera_control extension. The MPEG_camera_control extension is
anchor data representing the number of anchor points for an allowable path for the virtual camera;
segment data representing the number of route segments for the allowed route between the anchor points;
bounding volume data representing a bounding volume for the virtual camera;
10. An internal parameter indicating whether a camera parameter is modified at each of the anchor points; and accessor data representing an index of an accessor providing the camera control data. Method. 2. The method of claim 1, wherein the at least one virtual solid object includes one of a virtual wall, a virtual chair, or a virtual table. The step of updating the location of the virtual camera further includes determining an allowable path for the virtual camera from the camera control data, and updating the location of the virtual camera includes 2. The method of claim 1, comprising the step of ensuring movement only along virtual paths that are within allowed paths. 2. The method of claim 1, wherein the camera control data is included in an MPEG_mesh_collision extension. A device for extracting media data,
a memory configured to store media data;
one or more processors implemented in circuitry and configured to execute a presentation engine, the presentation engine comprising:
receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object;
receiving camera control data for the three-dimensional scene, the camera control data including data defining allowed locations for a virtual camera;
receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object;
and updating a location of the virtual camera using the camera control data to ensure that the virtual camera remains within the allowed locations. 15. The device of claim 14, wherein the presentation engine is configured to prevent the virtual camera from passing through the at least one virtual solid object. 15. The device of claim 14, wherein the streamed media data includes glTF2.0 media data. 15. The device of claim 14, wherein the presentation engine is configured to request the streamed media data from a retrieval unit via an application programming interface (API). 15. The device of claim 14, wherein the camera control data is included in an MPEG scene description. The camera control data includes data defining two or more anchor points and one or more segments between the anchor points, the segments representing allowed camera movement vectors for the virtual camera; 15. The device of claim 14, wherein to update the location of the virtual camera, the presentation engine is configured to allow the virtual camera to only traverse the segment between the anchor points. . The camera control data includes data defining a bounding volume representing an allowable camera movement volume for the virtual camera, and to update the location of the virtual camera, the presentation engine is configured such that the virtual camera 15. The device of claim 14, configured to allow traversing only a camera movement volume. 21. The device of claim 20, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere. 15. The device of claim 14, wherein the camera control data is included in an MPEG_camera_control extension. The MPEG_camera_control extension is
anchor data representing the number of anchor points for an allowable path for the virtual camera;
segment data representing the number of route segments for the allowed route between the anchor points;
bounding volume data representing a bounding volume for the virtual camera;
23. An internal parameter indicating whether a camera parameter is modified at each of the anchor points; and accessor data representing an index of an accessor providing the camera control data. device. 15. The device of claim 14, wherein the at least one virtual solid object includes one of a virtual wall, a virtual chair, or a virtual table. The presentation engine is further configured to determine an allowable path for the virtual camera from the camera control data, and to update the location of the virtual camera, the presentation engine is configured to: 15. The device of claim 14, configured to ensure movement only along virtual paths that are within the allowed paths defined in the camera control data. 15. The device of claim 14, wherein the camera control data is included in an MPEG_mesh_collision extension. A computer-readable storage medium having instructions stored thereon, the instructions, when executed, causing a processor running a presentation engine to:
receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object;
receiving camera control data for the three-dimensional scene, the camera control data including data defining allowed locations for a virtual camera;
receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object;
and updating a location of the virtual camera using the camera control data to ensure that the virtual camera remains within the allowed locations. 28. The computer of claim 27, wherein the instructions for causing the processor to update the location of the virtual camera include instructions for causing the processor to prevent the virtual camera from passing through the at least one virtual solid object. Readable storage medium. 28. The computer-readable storage medium of claim 27, wherein the streamed media data comprises glTF2.0 media data. The instructions for causing the processor to receive the streamed media data include instructions for causing the processor to request the streamed media data from a retrieval unit via an application programming interface (API). Computer readable storage medium according to paragraph 27. 28. The computer-readable storage medium of claim 27, wherein the camera control data is included in an MPEG scene description. The camera control data includes data defining two or more anchor points and one or more segments between the anchor points, the segments representing allowed camera movement vectors for the virtual camera; 28. The instructions for causing the processor to update the location of the virtual camera include instructions for causing the processor to allow the virtual camera to only traverse the segment between the anchor points. computer readable storage medium. The camera control data includes data defining a bounding volume representing an allowable camera movement volume for the virtual camera, and the instructions causing the processor to update the location of the virtual camera cause the processor to update the location of the virtual camera. 28. The computer-readable storage medium of claim 27, comprising instructions for allowing only the permissible camera movement volume to be traversed. 34. The computer-readable storage medium of claim 33, wherein the data defining the bounding volume includes data defining at least one of a cone, a cone, or a sphere. 28. The computer-readable storage medium of claim 27, wherein the camera control data is included in an MPEG_camera_control extension. The MPEG_camera_control extension is
anchor data representing the number of anchor points for an allowable path for the virtual camera;
segment data representing the number of route segments for the allowed route between the anchor points;
bounding volume data representing a bounding volume for the virtual camera;
36. An internal parameter indicating whether a camera parameter is modified at each of the anchor points; and accessor data representing an index of an accessor providing the camera control data. Computer readable storage medium. 28. The computer-readable storage medium of claim 27, wherein the at least one virtual solid object includes one of a virtual wall, a virtual chair, or a virtual table. The instructions further include instructions for causing the processor to determine an acceptable path for the virtual camera from the camera control data, the instructions for causing the processor to update the location of the virtual camera, the instructions for causing the processor to determine if the virtual camera 28. The computer-readable storage medium of claim 27, comprising instructions for ensuring movement only along virtual paths that are within the allowed paths defined in the camera control data. 28. The computer-readable storage medium of claim 27, wherein the camera control data is included in an MPEG_mesh_collision extension. A device for extracting media data,
means for receiving streamed media data representing a virtual three-dimensional scene including at least one virtual solid object;
means for receiving camera control data for the three-dimensional scene, the camera control data comprising data defining permissible locations for a virtual camera;
means for receiving camera movement data from a user requesting that the virtual camera move within the at least one virtual solid object;
and means for using the camera control data to update a location of the virtual camera to ensure that the virtual camera remains within the allowed locations.

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