WO2023144594A1

WO2023144594A1 - Scene change acceleration in cloud gaming

Info

Publication number: WO2023144594A1
Application number: PCT/IB2022/050832
Authority: WO
Inventors: Dmitri KRYLOV; Jonathan Lynam; Joel L. Wittenberg; Lars ERNSTRÖM
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2022-01-31
Filing date: 2022-01-31
Publication date: 2023-08-03

Abstract

A method of video stream management by an encoder manager includes loading configuration for a video stream to be sent to a user device, receiving a user action from the user device, determining whether the user action correlates with a scene change, and storing a preceding frame of the video stream into a long-term reference (LTR) set, in response to the user action correlating with the scene change.

Description

SPECIFICATION

SCENE CHANGE ACCELERATION IN CLOUD GAMING

TECHNICAL FIELD

[0001] Embodiments of the invention relate to the field of video stream management; and more specifically, to the processes and mechanisms for predicting scene changes for a video stream based on monitored user input.

BACKGROUND ART

[0002] Cloud gaming is a type of gaming where a user plays a video game that is executed on a remote server. The remote server streams the video and other content of the video game to the user where a local application displays the video stream through a user interface. The user interface of the client application also receives user inputs that are relayed to the remote server that is executing the video game. This differs from traditional video gaming where the video game executes on a user device and in some cases interacts with servers that support multiplayer functionality.

[0003] Cloud gaming is supported by cloud gaming platforms. Cloud gaming platforms execute and store video games on behalf of a user who can access them over a network from a user device. Cloud gaming enables a user to play video games that may require expensive computer hardware to execute locally. Cloud gaming can be accessed through a wide range of user devices such as mobile devices, desktop system, tablets, smart televisions, and similar user devices.

[0004] Cloud gaming relies on a reliable, high-speed connection to the Internet to reach the cloud gaming platform and to ensure a low latency experience for the user. Even in cases where high-speed connections are available, traffic congestion and other issues affecting network latency can affect the performance of cloud gaming such as the responsiveness and quality of the video stream.

SUMMARY

[0005] In one embodiment, a method of video stream management by an encoder manager is set forth. The method includes loading configuration for a video stream to be sent to a user device, receiving a user action from the user device, determining whether the user action correlates with a scene change, and storing a preceding frame of the video stream into a longterm reference (LTR) set, in response to the user action correlating with the scene change. [0006] In another embodiment, an electronic device is set forth that can execute the method of the encoder manager. The electronic device includes a non-transitory computer-readable storage medium having stored therein the encoder manager, and a processor coupled to the non- transitory computer-readable storage medium. The processor can execute the encoder manager, the encoder manager can load configuration for a video stream to be sent to a user device, receive a user action from the user device, determine whether the user action correlates with a scene change, and store a preceding frame of the video stream into a LTR set, in response to the user action correlating with the scene change.

[0007] In a further embodiment, a computing device is set forth that can execute a method of an encoder manager in a network, the computing device to execute a plurality of virtual machines, the plurality of virtual machines implementing network function virtualization (NFV). The computing device includes a non-transitory computer-readable storage medium having stored therein the encoder manager, and a processor coupled to the non-transitory computer- readable storage medium. The processor can execute one of the plurality of virtual machines. The one of the plurality of virtual machines can execute the encoder manager. The encoder manager can load configuration for a video stream to be sent to a user device, receive a user action from the user device, determine whether the user action correlates with a scene change, and store a preceding frame of the video stream into a LTR set, in response to the user action correlating with the scene change.

[0008] In one embodiment, a control plane device is set forth that can execute the method of an encoder manager in a software defined networking (SDN) network. The control plane device includes a non-transitory computer-readable storage medium having stored therein the encoder manager, and a processor coupled to the non-transitory computer-readable storage medium. The processor can execute the encoder manager. The encoder manager can load configuration for a video stream to be sent to a user device, receive a user action from the user device, determine whether the user action correlates with a scene change, and store a preceding frame of the video stream into a LTR set, in response to the user action correlating with the scene change.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. In the drawings:

[0010] Figure 1 is a diagram of one embodiment of a system that supports an encoder manager.

[0011] Figure 2 is a diagram illustrating an example of the process of the encoder manager. [0012] Figure 3 is a flowchart of one embodiment of the process of the encoder manager. [0013] Figure 4A illustrates connectivity between network devices (NDs) within an exemplary network, as well as three exemplary implementations of the NDs, according to some embodiments of the invention.

[0014] Figure 4B illustrates an exemplary way to implement a special-purpose network device according to some embodiments of the invention.

[0015] Figure 4C illustrates various exemplary ways in which virtual network elements (VNEs) may be coupled according to some embodiments of the invention.

[0016] Figure 4D illustrates a network with a single network element (NE) on each of the NDs, and within this straight forward approach contrasts a traditional distributed approach (commonly used by traditional routers) with a centralized approach for maintaining reachability and forwarding information (also called network control), according to some embodiments of the invention.

[0017] Figure 4E illustrates the simple case of where each of the NDs implements a single NE, but a centralized control plane has abstracted multiple of the NEs in different NDs into (to represent) a single NE in one of the virtual network(s), according to some embodiments of the invention.

[0018] Figure 4F illustrates a case where multiple VNEs are implemented on different NDs and are coupled to each other, and where a centralized control plane has abstracted these multiple VNEs such that they appear as a single VNE within one of the virtual networks, according to some embodiments of the invention.

[0019] Figure 5 illustrates a general purpose control plane device with centralized control plane (CCP) software, according to some embodiments of the invention.

DETAILED DESCRIPTION

[0020] The following description describes methods and apparatus for improving the operation of cloud gaming systems by utilizing user inputs to predict video scene changes. Predicting video scene changes can enable more efficient and responsive video stream encoding to improve user quality of experience. In the following description, numerous specific details such as logic implementations, opcodes, means to specify operands, resource partitioning/sharing/duplication implementations, types and interrelationships of system components, and logic partitioning/integration choices are set forth in order to provide a more thorough understanding of the present invention. It will be appreciated, however, by one skilled in the art that the invention may be practiced without such specific details. In other instances, control structures, gate level circuits and full software instruction sequences have not been shown in detail in order not to obscure the invention. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

[0021] References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0022] Bracketed text and blocks with dashed borders (e.g., large dashes, small dashes, dotdash, and dots) may be used herein to illustrate optional operations that add additional features to embodiments of the invention. However, such notation should not be taken to mean that these are the only options or optional operations, and/or that blocks with solid borders are not optional in certain embodiments of the invention.

[0023] In the following description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. “Coupled” is used to indicate that two or more elements, which may or may not be in direct physical or electrical contact with each other, co-operate or interact with each other. “Connected” is used to indicate the establishment of communication between two or more elements that are coupled with each other.

[0024] An electronic device stores and transmits (internally and/or with other electronic devices over a network) code (which is composed of software instructions and which is sometimes referred to as computer program code or a computer program) and/or data using machine-readable media (also called computer-readable media), such as machine-readable storage media (e.g., magnetic disks, optical disks, solid state drives, read only memory (ROM), flash memory devices, phase change memory) and machine-readable transmission media (also called a carrier) (e.g., electrical, optical, radio, acoustical or other form of propagated signals - such as carrier waves, infrared signals). Thus, an electronic device (e.g., a computer) includes hardware and software, such as a set of one or more processors (e.g., wherein a processor is a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, other electronic circuitry, a combination of one or more of the preceding) coupled to one or more machine-readable storage media to store code for execution on the set of processors and/or to store data. For instance, an electronic device may include non-volatile memory containing the code since the non-volatile memory can persist code/data even when the electronic device is turned off (when power is removed), and while the electronic device is turned on that part of the code that is to be executed by the processor(s) of that electronic device is typically copied from the slower nonvolatile memory into volatile memory (e.g., dynamic random access memory (DRAM), static random access memory (SRAM)) of that electronic device. Typical electronic devices also include a set of one or more physical network interface(s) (NI(s)) to establish network connections (to transmit and/or receive code and/or data using propagating signals) with other electronic devices. For example, the set of physical NIs (or the set of physical NI(s) in combination with the set of processors executing code) may perform any formatting, coding, or translating to allow the electronic device to send and receive data whether over a wired and/or a wireless connection. In some embodiments, a physical NI may comprise radio circuitry capable of receiving data from other electronic devices over a wireless connection and/or sending data out to other devices via a wireless connection. This radio circuitry may include transmitter(s), receiver(s), and/or transceiver s) suitable for radiofrequency communication. The radio circuitry may convert digital data into a radio signal having the appropriate parameters (e.g., frequency, timing, channel, bandwidth, etc.). The radio signal may then be transmitted via antennas to the appropriate recipient(s). In some embodiments, the set of physical NI(s) may comprise network interface controller(s) (NICs), also known as a network interface card, network adapter, or local area network (LAN) adapter. The NIC(s) may facilitate in connecting the electronic device to other electronic devices allowing them to communicate via wire through plugging in a cable to a physical port connected to a NIC. One or more parts of an embodiment of the invention may be implemented using different combinations of software, firmware, and/or hardware.

[0025] A network device (ND) is an electronic device that communicatively interconnects other electronic devices on the network (e.g., other network devices, end-user devices). Some network devices are “multiple services network devices” that provide support for multiple networking functions (e.g., routing, bridging, switching, Layer 2 aggregation, session border control, Quality of Service, and/or subscriber management), and/or provide support for multiple application services (e.g., data, voice, and video).

[0026] Video streams are composed of a set of frames. A ‘set,’ as used herein, refers to any positive whole number of items including one item. The frames of a video stream have varying types. There are three types of frames used in most forms of video compression. An I-frame (Intra-coded picture) is a complete image. A P-frame (Predicted picture) holds only the changes in the image relative to a reference frame, which in a simplest case is the previous frame. P- frames reuse pieces (macroblocks) from the reference frame, and so typically use much less space (i.e., are smaller in terms of an amount of data) than I-frames. A B-frame (Bidirectional predicted picture) uses the same approach as P-frame, but uses both previous and next frames as reference frames. The embodiments operate primarily with I-frames and P-frames. However, one skilled in the art would appreciate that some of the features, structures, and processes of the embodiments can also be used in conjunction with B-frames.

[0027] H.264 is a video compression standard for encoding video frames. H.264 and later standard codecs (i.e., coder s/decoders) allow the video stream encoder to use several reference frames, arbitrarily choosing between the reference frames for encoding of a particular frame (i.e., a P-frame). By default, an encoder would use the previous frame (i.e., an immediately preceding frame in a sequence of frames for a given video stream) as reference frame, but some encoders allow an application to explicitly manage the set of reference frames. Management of the reference frames can be used to determine which frames should be saved as reference frames, and when the saved reference frames should be used to encode new frames. This set of reference frames is known as the Long-Term Reference (LTR) set.

[0028] In most cases, sequentially encoded frames (P-frames) are of relatively small size compared to 1-frames. This is because from one video frame to the next, there are often only small changes, so many of the macroblocks from preceding frames can be reused and don’t have to be resent. However, when a video stream (e.g., for a movie, game, or similar source) has a sudden scene change (e.g., switching to a new camera view), encoding the first frame of the new scene as a delta against a frame of the previous scene (i.e., as a P-frame) can result in the frame requiring many more bits than an average P-frame to encode. Frames for scene changes can be tens of times larger than an average P-frame. These frames, when encoded as P-frames can be even larger than they would be if encoded as an I-frame. However, if the encoder can encode a scene change frame as a P-frame, but as a delta against an LTR reference frame from when the new scene was last shown, the resulting P-frame can be significantly smaller. This saving in bandwidth however is not trivial to achieve in real world conditions. The embodiments address this issue and provide an effective approach to detect scene changes and determine when and how to save and reuse reference frames to improve encoding efficiency and conserve network resources, in the context of a cloud gaming application managing or working in coordination with a video stream encoder.

[0029] The embodiments utilize user input (such as keystrokes or button presses) in order to make an intelligent guess about impending scene changes, which can be referred to as a “top- down” approach, to proactively know when to save the current frame into the LTR set, instead of only trying to infer when a scene change has already taken place by constantly examining the raw frame pixels. [0030] The embodiments are particularly applicable to the context of cloud gaming. In cloud gaming, a video game is executed on a remote server in a cloud datacenter or similar cloud computing environment. The game video, instead of being sent directly to an attached monitor, is instead encoded and streamed to a remote user device, e.g., a smartphone. User input (keystrokes, button presses, gamepad movements, and similar input) are captured on the user device and relayed back to the server executing the game. The embodiments are able to make use of these user inputs and can correlate them with scene changes that can be used to guide frame selection to be stored into the LTR set.

[0031] The existing art treats any video stream as a movie and does not take advantage of distinguishing features of different kinds of video, like sports, video games, training courses, slideshows, and other types of video streams. Without any special case handling, a video encoder will often produce a large frame (e.g., either I-frame or P-frame with an arbitrarily big difference from the previous frame) upon a scene change. Large and small frames in this context relate to number of bytes of data in the frame for a given resolution or dimensions. Most video encoders do not have any mechanism for knowing that a scene change will take place, which results in inefficient encoding of the frames. In the case of cloud gaming, when a game is being executed at a server in a cloud, the video output is encoded, and then streamed over a network to a user device. Large frame sizes consume additional network bandwidth and can take longer to transit the network, creating latency, which can result in a human-noticeable “freeze” or stilted playback in the video stream.

[0032] Some existing video encoders attempt to smoothen out the bitrate of the video stream by reducing video quality. When a scene change occurs, which would normally result in a large frame, the encoder will heavily compress the large video frame to keep the size smaller. This results in scene changes incurring reduced video quality due to compression. In one example, an existing video encoder encodes each frame twice at two different bitrates, using the smaller frame in case the larger one exceeds the bandwidth budget. In case of scene change such an approach can cause a quality loss due to the nature of highly compressed frames.

[0033] The embodiments overcome these limitations of the existing art for video encoders by providing a mechanism for predicting scene changes. In the context of a cloud gaming streaming application, the embodiments observe user activity (e.g., keystrokes and other game input) to learn when scene changes are about to take place and use this knowledge for reference frame- controlled encoding. When a scene change happens, the current frame (from “Scene A”) is saved to the video encoder’s LTR frame list, just before the video switches to the new scene (“Scene B”). When the video stream switches back to a prior scene or view (“Scene A”), this saved LTR frame can be reused as a reference frame for the next P-frame, which can compress well and have fewer changes, because the reference frame was from the same scene. One benefit of the embodiments is that the encoder produces smaller P-frames for repetitive scene changes without quality loss. Frame size is important for low-latency streaming over a network, and in particular for gaming applications. The embodiments can also be used for any other types of video streaming involving multiple views when switching between them is caused by user keystrokes (for example, video from several surveillance cameras).

[0034] In a cloud gaming scenario, the embodiments, in the form of an encoder manager, can be a part of the video encoding software executing on the server of the cloud gaming platform. The encoder manager can be responsible for receiving user input (e.g., keystrokes) from the user device and feeding them to the game, as well as managing the video encoder. The embodiments track the user inputs as the encoder manager relays them to the game, in order to predict a coming scene change. When a game-specific user input action is received that changes views (e.g., an input that switches direction a character is looking in the game, opens an inventory window or map, or similar view change), the encoder manager captures the current video frame and associates it with a current view or scene, just before the view or scene change takes place. [0035] The encoder manager maintains a mapping between game scenes (e.g., camera views, menus, maps, and similar scene changes) and their latest reference frames (saved in LTR). When switching back to a view where a reference frame has been saved, the saved reference frame is used for encoding the next frame, thus compressing more efficiently, and reducing the cost of delivering the frame over the network.

[0036] The embodiments provide advantages over existing video encoding schemes. In case of frequent and repetitive scene changes, the embodiments enable the video encoder to produce smaller frames (i.e., lower bitrate). This reduces frame delay and network resources requirements compared to the encoding of I-frames or P-frames based directly on the previous frame (which belongs to a previous scene). The top-down approach, being based on user activity (e.g., keystrokes and other game input), provides the encoder manager with a hint of when to start scene change detection without low-level frame analysis on every frame. The encoder manager can operate without software integration for a class of games where the state of the player can be tracked by the sequence of keystrokes. In some embodiments, the encoder manager doesn't require any additional interface with the video encoder, and instead the encoder manager can use a video encoder’s LTR frame management mechanism.

[0037] In the embodiments, the encoder manager can track different user input or content variations. User input variations in addition to keystrokes can include, mouse button clicks, game pad inputjoystick moves, head tracking (e.g., with virtual reality (VR) headset), touchscreen input, camera or positional tracking, motion or positional sensors (e.g., global positioning system (GPS) locations), and similar input.

[0038] Content variations can include multiple video cameras from a live stream, correlated or alternate video streams, haptic feedback signaling, and similar content variations. Scene change detection can be based on tracking user actions (e.g., camera or menu selections), or on extracting of camera identifiers from the video stream metadata. An example of input parameters could be keystrokes (e.g., Alt F1-F4) with semantics of changes of in-game first- person perspective (back, forward, right, left). Another example would be keystrokes which bring up inventory screens, maps, game settings, communication commands, and similar user interfaces. The information on the correlation of inputs with activation of certain scene changes can be provided in a configuration file as a mapping of keystrokes or inputs to the view changes. [0039] Refined and optimized scene detection options include switching on peak signal to noise ratio (PSNR)-based comparisons for several subsequent frames after detecting user inputs or actions. While such analysis could be too resource and time consuming to run it for each new frame, it can be used sparingly using the keystroke hints as described above. The specific keystroke match determines which saved frame or set of frames to use for comparison.

[0040] Figure 1 is a diagram of one embodiment of a system that supports an encoder manager. In the example, a user device 101 is in communication with an application service 117 (e.g., a cloud video game service) executed at a cloud platform (e.g., a cloud computing platform 115). The user device 101 can be any type of electronic device capable of communicating over a network 111 with a cloud computing platform 115 and capable of processing and displaying a video stream. The user device 101 can be a mobile device (e.g., a smartphone), tablet, computer, console device, VR device, or similar electronic device.

[0041] The user device 101 can execute a remote client application 103 and a decoder 105. These programs can run in an execution environment including an operating system that manages the hardware resources of the user device 101 or a similar execution environment. The remote client application 103 can be a general purpose program that can provide a user interface for a variety of cloud computing platform applications (e.g., application service 117). In other embodiments, the remote client application 103 is a special purpose program designed to provide a local user interface for the application service 117. The remote client application 103 collects user input at the user device 101 (e.g., mouse click, touchscreen input, gamepad input, or similar user input) and sends the user input to the application service 117 to be processed. [0042] The remote client application 103 can also display a video stream received from the application service 117 and cloud computing platform 115 that is decoded by a decoder 105. Any type of video encoding format can be utilized (e.g., H.264 or similar video encoding formats) that utilizes LTRs or the equivalent.

[0043] The user device 101 can include a network interface component (not illustrated) that enables wired or wireless communication over the network 111. The network 111 can be a wide area network (WAN) such as the Internet, a cellular telecommunication network, similar networks, and combinations thereof. In some example embodiments, the application service 117 can be positioned in edge cloud services proximate to the user device 101 using cellular telecommunication networks.

[0044] The cloud computing platform 115 can be any cloud computing environment including a centralized, distributed, or hybrid cloud computing environment. The cloud computing platform 115 can execute an application service 117 (e g., a cloud gaming service) where a single application service 117 can service multiple remote client applications 103 or where the application service 117 is instanced for each remote client application 103. The application service 117 receives user actions from the user device 101 over the network 111 using any set of communication protocols. The application service 117 can directly receive the user input in parallel with an encoder manager or the encoder manager 119 can pass the user input to the application service 117. The processing of the user input by the application service 117 is application specific and contextual. In one example, where the application service 117 is a cloud video game service, the user inputs can guide a character in the video game environment provided by the application service 117 and the user inputs can interact with the video game mechanics including camera viewpoint, movement, navigation, and similar types of video game interaction. Some of these actions can cause a change of scene in the video game and the resulting raw video frames to be output from the application service 117. For example, if a user inputs a keystroke or gamepad button that opens a full screen map, then the scene changes responsive to that input and changes back to a prior scene in response to that same input or another input (e.g., that closes the map).

[0045] The encoder manager 119 receives the same sequence of user actions as the application service 117. The application service 117 also sends raw video frames to the encoder manager 119. Based on the received user actions, the encoder manager can detect inputs that cause a scene change and determines what reference frame should be used to encode the current or subsequent frames received from the application service 117. The encoder manager 119 passes the frames to encode together with an identifier for the appropriate reference frame in the LTRto the encoder 121. The encoder then encodes the set of video frames as P-frames or the equivalent that are encoded relative to the identified reference frame in the LTR, rather than the preceding frames. The encoder 121 can encode the video frames using any encoding format (e.g., H.264) that supports the use of an LTR. The encoded video frames are returned across the network 111 to the user device 101 to be decoded by the decoder 105 and rendered by the remote client application 103.

[0046] Figure 2 is a diagram illustrating an example of the process of the encoder manager. In the illustrated example, the encoder manager process is described with an example where the application service starts with an output of frames having a view A. The application service then switches to output frames having a view B, and then subsequently the application service returns back to outputting frames having a view A. In the example, when the video stream starts, a first frame A0 is sent, which is an instantaneous decoder refresh (IDR) frame (e.g., according to H.264 format). An IDR frame is sent because this is the first appearance of scene A in the video stream. Frames Al and A2 are both P-frames that are encoded relative to the preceding frames of scene A. Each encoded frame is saved as a reference frame, replacing the previously saved frame. When a user action causes the scene to change and the scene change is detected by the encoder manager, the very last saved A-scene frame (e g., frame A2) becomes an entry in the LTR list.

[0047] Subsequently, the scene is changed to scene B in the video stream. This is the first B- scene appearance in the scenario and thus frame B0 is an IDR frame. Frame B0 is followed by several P-frames for scene B (i.e., frames Bl and B2). The process saves each as a reference frame for scene B. A second user action is then received by the encoder manager and application service, which changes the scene back to scene A. At this point in the process the last saved scene B frame is saved as another entry in the LTR list.

[0048] The second user action is correlated with a return to scene A by the encoder manager. The encoder manager then directs the encoder to encode new frames for scene A, namely frames A3-5 using the last saved A-scene LTR frame (A2) as a reference frame. Thus, the process of the encoder manager is able to avoid having to send another I-frame at the point where frame A3 is sent. Instead, frames A3-5 can be P-frames and the correlated bandwidth is preserved without having to send the larger I-frame for frame A3.

[0049] The operations in the flow diagrams will be described with reference to the exemplary embodiments of the other figures. However, it should be understood that the operations of the flow diagrams can be performed by embodiments of the invention other than those discussed with reference to the other figures, and the embodiments of the invention discussed with reference to these other figures can perform operations different than those discussed with reference to the flow diagrams.

[0050] Figure 3 is a flowchart of one embodiment of the process of the encoder manager. The process of an encoder manager can be initiated along with a video stream that is being managed (Block 301). The encoder manager can manage multiple video streams or a separate instance can manage each video stream. The encoder manager loads a configuration for the video stream (Block 303). The configuration can include information identifying each of the user inputs that trigger a scene change as well as an identifier for each scene, such that transitions between different scenes (e.g., from scene A to scene B to scene C and back to scene A) can be identified and handled appropriately. In some embodiments, the encoder manager relies entirely on the configuration to identify and handle user inputs that correlate with scene changes. In other embodiments, the encoder manager can detect correlations between user inputs and scene changes by comparison of the user inputs over time and scene changes in the video streams. Detected correlations can then be added to the configuration for the video stream. Configuration files are selected and can be specific to an application, video stream source, video stream type, or similar classification of the video stream.

[0051] After configuration is determined and loaded, the encoder manager can begin to monitor the received user inputs (Block 305) for an application service. Each received user input is analyzed to determine whether it correlates with a video scene change by comparison with the configuration (Block 307). For example, a particular keystroke or gamepad input can be tied to a scene change to scene B. Upon detection of user action that correlates with a scene change (Block 307), the encoder manager saves the last frame of the current scene into the LTR of the encoder (Block 309). If user inputs do not correlate with a scene change, then the process awaits further user inputs to analyze (Block 305).

[0052] If a user input that correlates with a scene change is detected, then after the storing of the last frame a check is made whether the new scene has a reference frame stored in the LTR (Block 311). The configuration can indicate a new scene after a transition caused by a user input. The encoder manager can track which reference frames in the LTR correlate with each scene. Where a prior saved reference frame is stored in the LTR, then the encoder manager loads the frame and designates it for use as a reference frame (Block 313). Where a prior reference frame for the new scene is not found then the process continues to await further user input (Block 305). The process of the encoder manager can continue during the operation of the application service to improve the efficiency of the bandwidth usage of the video stream and improve the video quality and quality of experience for the user.

[0053] Figure 4A illustrates connectivity between network devices (NDs) within an exemplary network, as well as three exemplary implementations of the NDs, according to some embodiments of the invention. Figure 4A shows NDs 400A-H, and their connectivity by way of lines between 400A-400B, 400B-400C, 400C-400D, 400D-400E, 400E-400F, 400F-400G, and 400A-400G, as well as between 400H and each of 400A, 400C, 400D, and 400G. These NDs are physical devices, and the connectivity between these NDs can be wireless or wired (often referred to as a link). An additional line extending from NDs 400A, 400E, and 400F illustrates that these NDs act as ingress and egress points for the network (and thus, these NDs are sometimes referred to as edge NDs; while the other NDs may be called core NDs).

[0054] Two of the exemplary ND implementations in Figure 4A are: 1) a special-purpose network device 402 that uses custom application-specific integrated-circuits (ASICs) and a special-purpose operating system (OS); and 2) a general purpose network device 404 that uses common off-the-shelf (COTS) processors and a standard OS.

[0055] The special-purpose network device 402 includes networking hardware 410 comprising a set of one or more processor(s) 412, forwarding resource(s) 414 (which typically include one or more ASICs and/or network processors), and physical network interfaces (NIs) 416 (through which network connections are made, such as those shown by the connectivity between NDs 400A-H), as well as non-transitory machine readable storage media 418 having stored therein networking software 420. During operation, the networking software 420 may be executed by the networking hardware 410 to instantiate a set of one or more networking software instance(s) 422. Each of the networking software instance(s) 422, and that part of the networking hardware 410 that executes that network software instance (be it hardware dedicated to that networking software instance and/or time slices of hardware temporally shared by that networking software instance with others of the networking software instance(s) 422), form a separate virtual network element 430A-R. Each of the virtual network element(s) (VNEs) 430A- R includes a control communication and configuration module 432A-R (sometimes referred to as a local control module or control communication module) and forwarding table(s) 434A-R, such that a given virtual network element (e.g., 430A) includes the control communication and configuration module (e.g., 432A), a set of one or more forwarding table(s) (e.g., 434A), and that portion of the networking hardware 410 that executes the virtual network element (e.g., 430A).

[0056] In some embodiments, the networking software 420 can include an encoder manager 465. In other embodiments, the encoder manager 465 is stored in the non-transitory machine readable media 418 separate from the networking software 420. The encoder manager 465 provides the functionality described herein above.

[0057] The special-purpose network device 402 is often physically and/or logically considered to include: 1) a ND control plane 424 (sometimes referred to as a control plane) comprising the processor(s) 412 that execute the control communication and configuration module(s) 432A-R; and 2) a ND forwarding plane 426 (sometimes referred to as a forwarding plane, a data plane, or a media plane) comprising the forwarding resource(s) 414 that utilize the forwarding table(s) 434A-R and the physical NIs 416. By way of example, where the ND is a router (or is implementing routing functionality), the ND control plane 424 (the processor(s) 412 executing the control communication and configuration module(s) 432A-R) is typically responsible for participating in controlling how data (e.g., packets) is to be routed (e.g., the next hop for the data and the outgoing physical NI for that data) and storing that routing information in the forwarding table(s) 434A-R, and the ND forwarding plane 426 is responsible for receiving that data on the physical NIs 416 and forwarding that data out the appropriate ones of the physical NIs 416 based on the forwarding table(s) 434A-R.

[0058] Figure 4B illustrates an exemplary way to implement the special-purpose network device 402 according to some embodiments of the invention. Figure 4B shows a special-purpose network device including cards 438 (typically hot pluggable). While in some embodiments the cards 438 are of two types (one or more that operate as the ND forwarding plane 426 (sometimes called line cards), and one or more that operate to implement the ND control plane 424 (sometimes called control cards)), alternative embodiments may combine functionality onto a single card and/or include additional card types (e.g., one additional type of card is called a service card, resource card, or multi-application card). A service card can provide specialized processing (e.g., Layer 4 to Layer 7 services (e.g., firewall, Internet Protocol Security (IPsec), Secure Sockets Layer (SSL) / Transport Layer Security (TLS), Intrusion Detection System (IDS), peer-to-peer (P2P), Voice over IP (VoIP) Session Border Controller, Mobile Wireless Gateways (Gateway General Packet Radio Service (GPRS) Support Node (GGSN), Evolved Packet Core (EPC) Gateway)). By way of example, a service card may be used to terminate IPsec tunnels and execute the attendant authentication and encryption algorithms. These cards are coupled together through one or more interconnect mechanisms illustrated as backplane 436 (e.g., a first full mesh coupling the line cards and a second full mesh coupling all of the cards).

[0059] Returning to Figure 4A, the general purpose network device 404 includes hardware 440 comprising a set of one or more processor(s) 442 (which are often COTS processors) and physical NIs 446, as well as non-transitoiy machine readable storage media 448 having stored therein software 450. During operation, the processor(s) 442 execute the software 450 to instantiate one or more sets of one or more applications 464A-R. While one embodiment does not implement virtualization, alternative embodiments may use different forms of virtualization. For example, in one such alternative embodiment the virtualization layer 454 represents the kernel of an operating system (or a shim executing on a base operating system) that allows for the creation of multiple instances 462A-R called software containers that may each be used to execute one (or more) of the sets of applications 464A-R; where the multiple software containers (also called virtualization engines, virtual private servers, or jails) are user spaces (typically a virtual memory space) that are separate from each other and separate from the kernel space in which the operating system is run; and where the set of applications running in a given user space, unless explicitly allowed, cannot access the memory of the other processes. In another such alternative embodiment the virtualization layer 454 represents a hypervisor (sometimes referred to as a virtual machine monitor (VMM)) or a hypervisor executing on top of a host operating system, and each of the sets of applications 464A-R is run on top of a guest operating system within an instance 462A-R called a virtual machine (which may in some cases be considered a tightly isolated form of software container) that is run on top of the hypervisor - the guest operating system and application may not know they are running on a virtual machine as opposed to running on a “bare metal” host electronic device, or through para-virtualization the operating system and/or application may be aware of the presence of virtualization for optimization purposes. In yet other alternative embodiments, one, some or all of the applications are implemented as unikemel(s), which can be generated by compiling directly with an application only a limited set of libraries (e.g., from a library operating system (LibOS) including drivers/libraries of OS services) that provide the particular OS services needed by the application. As a unikemel can be implemented to run directly on hardware 440, directly on a hypervisor (in which case the unikemel is sometimes described as running within a LibOS virtual machine), or in a software container, embodiments can be implemented fully with unikernels running directly on a hypervisor represented by virtualization layer 454, unikernels running within software containers represented by instances 462A-R, or as a combination of unikernels and the above-described techniques (e.g., unikemels and virtual machines both run directly on a hypervisor, unikernels and sets of applications that are run in different software containers).

[0060] In some embodiments, the software 450 can include an encoder manager 465. In other embodiments, the encoder manager 465 is stored in the non-transitory machine readable media 448 separate from the networking software 450. The encoder manager 465 provides the functionality described herein above.

[0061] The instantiation of the one or more sets of one or more applications 464A-R, as well as virtualization if implemented, are collectively referred to as software instance(s) 452. Each set of applications 464A-R, corresponding virtualization construct (e.g., instance 462A-R) if implemented, and that part of the hardware 440 that executes them (be it hardware dedicated to that execution and/or time slices of hardware temporally shared), forms a separate virtual network element(s) 460A-R. [0062] The virtual network element(s) 460A-R perform similar functionality to the virtual network element(s) 430A-R - e.g., similar to the control communication and configuration module(s) 432A and forwarding table(s) 434A (this virtualization of the hardware 440 is sometimes referred to as network function virtualization (NFV)). Thus, NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which could be located in Data centers, NDs, and customer premise equipment (CPE). While embodiments of the invention are illustrated with each instance 462A-R corresponding to one VNE 460A-R, alternative embodiments may implement this correspondence at a finer level granularity (e.g., line card virtual machines virtualize line cards, control card virtual machine virtualize control cards, etc.); it should be understood that the techniques described herein with reference to a correspondence of instances 462A-R to VNEs also apply to embodiments where such a finer level of granularity and/or unikernels are used.

[0063] In certain embodiments, the virtualization layer 454 includes a virtual switch that provides similar forwarding services as a physical Ethernet switch. Specifically, this virtual switch forwards traffic between instances 462A-R and the physical NI(s) 446, as well as optionally between the instances 462A-R; in addition, this virtual switch may enforce network isolation between the VNEs 460A-R that by policy are not permitted to communicate with each other (e g., by honoring virtual local area networks (VLANs)).

[0064] The third exemplary ND implementation in Figure 4A is a hybrid network device 406, which includes both custom ASICs/special-purpose OS and COTS processors/standard OS in a single ND or a single card within an ND. In certain embodiments of such a hybrid network device, a platform VM (i.e., a VM that that implements the functionality of the special-purpose network device 402) could provide for para-virtualization to the networking hardware present in the hybrid network device 406.

[0065] Regardless of the above exemplary implementations of an ND, when a single one of multiple VNEs implemented by an ND is being considered (e.g., only one of the VNEs is part of a given virtual network) or where only a single VNE is currently being implemented by an ND, the shortened term network element (NE) is sometimes used to refer to that VNE. Also in all of the above exemplary implementations, each of the VNEs (e.g., VNE(s) 430A-R, VNEs 460A-R, and those in the hybrid network device 406) receives data on the physical NIs (e.g., 416, 446) and forwards that data out the appropriate ones of the physical NIs (e.g., 416, 446). For example, a VNE implementing IP router functionality forwards IP packets on the basis of some of the IP header information in the IP packet; where IP header information includes source IP address, destination IP address, source port, destination port (where “source port” and “destination port” refer herein to protocol ports, as opposed to physical ports of a ND), transport protocol (e.g., user datagram protocol (UDP), Transmission Control Protocol (TCP), and differentiated services code point (DSCP) values.

[0066] Figure 4C illustrates various exemplary ways in which VNEs may be coupled according to some embodiments of the invention. Figure 4C shows VNEs 470A.1-470A.P (and optionally VNEs 470A.Q-470A.R) implemented in ND 400A and VNE 470H.1 in ND 400H In Figure 4C, VNEs 470A.1-P are separate from each other in the sense that they can receive packets from outside ND 400A and forward packets outside of ND 400A; VNE 470A.1 is coupled with VNE 470H.1, and thus they communicate packets between their respective NDs, VNE 470A.2-470A.3 may optionally forward packets between themselves without forwarding them outside of the ND 400A; and VNE 470A.P may optionally be the first in a chain of VNEs that includes VNE 470A.Q followed by VNE 470A.R (this is sometimes referred to as dynamic service chaining, where each of the VNEs in the series of VNEs provides a different service - e.g., one or more layer 4-7 network services). While Figure 4C illustrates various exemplary relationships between the VNEs, alternative embodiments may support other relationships (e.g., more/fewer VNEs, more/fewer dynamic service chains, multiple different dynamic service chains with some common VNEs and some different VNEs).

[0067] The NDs of Figure 4A, for example, may form part of the Internet or a private network; and other electronic devices (not shown; such as end user devices including workstations, laptops, netbooks, tablets, palm tops, mobile phones, smartphones, phablets, multimedia phones, Voice Over Internet Protocol (VOIP) phones, terminals, portable media players, GPS units, wearable devices, gaming systems, set-top boxes, Internet enabled household appliances) may be coupled to the network (directly or through other networks such as access networks) to communicate over the network (e.g., the Internet or virtual private networks (VPNs) overlaid on (e.g., tunneled through) the Internet) with each other (directly or through servers) and/or access content and/or services. Such content and/or services are typically provided by one or more servers (not shown) belonging to a service/content provider or one or more end user devices (not shown) participating in a peer-to-peer (P2P) service, and may include, for example, public webpages (e.g., free content, store fronts, search services), private webpages (e.g., usemame/password accessed webpages providing email services), and/or corporate networks over VPNs. For instance, end user devices may be coupled (e.g., through customer premise equipment coupled to an access network (wired or wirelessly)) to edge NDs, which are coupled (e.g., through one or more core NDs) to other edge NDs, which are coupled to electronic devices acting as servers. However, through compute and storage virtualization, one or more of the electronic devices operating as the NDs in Figure 4A may also host one or more such servers (e.g., in the case of the general purpose network device 404, one or more of the software instances 462A-R may operate as servers; the same would be true for the hybrid network device 406; in the case of the special-purpose network device 402, one or more such servers could also be run on a virtualization layer executed by the processor(s) 412); in which case the servers are said to be co-located with the VNEs of that ND.

[0068] A virtual network is a logical abstraction of a physical network (such as that in Figure 4A) that provides network services (e g., L2 and/or L3 services). A virtual network can be implemented as an overlay network (sometimes referred to as a network virtualization overlay) that provides network services (e g., layer 2 (L2, data link layer) and/or layer 3 (L3, network layer) services) over an underlay network (e.g., an L3 network, such as an Internet Protocol (IP) network that uses tunnels (e.g., generic routing encapsulation (GRE), layer 2 tunneling protocol (L2TP), IPSec) to create the overlay network).

[0069] A network virtualization edge (NVE) sits at the edge of the underlay network and participates in implementing the network virtualization; the network-facing side of the NVE uses the underlay network to tunnel frames to and from other NVEs; the outward-facing side of the NVE sends and receives data to and from systems outside the network. A virtual network instance (VNI) is a specific instance of a virtual network on a NVE (e.g., a NE/VNE on an ND, a part of a NE/VNE on a ND where that NE/VNE is divided into multiple VNEs through emulation); one or more VNIs can be instantiated on an NVE (e.g., as different VNEs on an ND). A virtual access point (VAP) is a logical connection point on the NVE for connecting external systems to a virtual network; a VAP can be physical or virtual ports identified through logical interface identifiers (e.g., a VLAN ID).

[0070] Examples of network services include: 1) an Ethernet LAN emulation service (an Ethernet-based multipoint service similar to an Internet Engineering Task Force (IETF) Multiprotocol Label Switching (MPLS) or Ethernet VPN (EVPN) service) in which external systems are interconnected across the network by a LAN environment over the underlay network (e.g., an NVE provides separate L2 VNIs (virtual switching instances) for different such virtual networks, and L3 (e.g., IP/MPLS) tunneling encapsulation across the underlay network); and 2) a virtualized IP forwarding service (similar to IETF IP VPN (e.g., Border Gateway Protocol (BGP)/MPLS IPVPN) from a service definition perspective) in which external systems are interconnected across the network by an L3 environment over the underlay network (e.g., an NVE provides separate L3 VNIs (forwarding and routing instances) for different such virtual networks, and L3 (e.g., IP/MPLS) tunneling encapsulation across the underlay network)). Network services may also include quality of service capabilities (e.g., traffic classification marking, traffic conditioning and scheduling), security capabilities (e.g., filters to protect customer premises from network - originated attacks, to avoid malformed route announcements), and management capabilities (e.g., full detection and processing).

[0071] Fig. 4D illustrates a network with a single network element on each of the NDs of Figure 4A, and within this straight forward approach contrasts a traditional distributed approach (commonly used by traditional routers) with a centralized approach for maintaining reachability and forwarding information (also called network control), according to some embodiments of the invention. Specifically, Figure 4D illustrates network elements (NEs) 470A-H with the same connectivity as the NDs 400 A-H of Figure 4A.

[0072] Figure 4D illustrates that the distributed approach 472 distributes responsibility for generating the reachability and forwarding information across the NEs 470A-H; in other words, the process of neighbor discovery and topology discovery is distributed.

[0073] For example, where the special-purpose network device 402 is used, the control communication and configuration module(s) 432A-R of the ND control plane 424 typically include a reachability and forwarding information module to implement one or more routing protocols (e.g., an exterior gateway protocol such as Border Gateway Protocol (BGP), Interior Gateway Protocol(s) (IGP) (e.g., Open Shortest Path First (OSPF), Intermediate System to Intermediate System (IS-IS), Routing Information Protocol (RIP), Label Distribution Protocol (LDP), Resource Reservation Protocol (RSVP) (including RSVP-Traffic Engineering (TE): Extensions to RSVP for LSP Tunnels and Generalized Multi -Protocol Label Switching (GMPLS) Signaling RSVP-TE)) that communicate with other NEs to exchange routes, and then selects those routes based on one or more routing metrics. Thus, the NEs 470A-H (e.g., the processor(s) 412 executing the control communication and configuration module(s) 432A-R) perform their responsibility for participating in controlling how data (e.g., packets) is to be routed (e.g., the next hop for the data and the outgoing physical NI for that data) by distributively determining the reachability within the network and calculating their respective forwarding information. Routes and adjacencies are stored in one or more routing structures (e.g., Routing Information Base (RIB), Label Information Base (LIB), one or more adjacency structures) on the ND control plane 424. The ND control plane 424 programs the ND forwarding plane 426 with information (e.g., adjacency and route information) based on the routing structure(s). For example, the ND control plane 424 programs the adjacency and route information into one or more forwarding table(s) 434A-R (e.g., Forwarding Information Base (FIB), Label Forwarding Information Base (LFIB), and one or more adjacency structures) on the ND forwarding plane 426. For layer 2 forwarding, the ND can store one or more bridging tables that are used to forward data based on the layer 2 information in that data. While the above example uses the special-purpose network device 402, the same distributed approach 472 can be implemented on the general purpose network device 404 and the hybrid network device 406. [0074] Figure 4D illustrates that a centralized approach 474 (also known as software defined networking (SDN)) that decouples the system that makes decisions about where traffic is sent from the underlying systems that forwards traffic to the selected destination. The illustrated centralized approach 474 has the responsibility for the generation of reachability and forwarding information in a centralized control plane 476 (sometimes referred to as a SDN control module, controller, network controller, OpenFlow controller, SDN controller, control plane node, network virtualization authority, or management control entity), and thus the process of neighbor discovery and topology discovery is centralized. The centralized control plane 476 has a south bound interface 482 with a data plane 480 (sometime referred to the infrastructure layer, network forwarding plane, or forwarding plane (which should not be confused with a ND forwarding plane)) that includes the NEs 470A-H (sometimes referred to as switches, forwarding elements, data plane elements, or nodes). The centralized control plane 476 includes a network controller 478, which includes a centralized reachability and forwarding information module 479 that determines the reachability within the network and distributes the forwarding information to the NEs 470A-H of the data plane 480 over the south bound interface 482 (which may use the OpenFlow protocol). Thus, the network intelligence is centralized in the centralized control plane 476 executing on electronic devices that are typically separate from the NDs. [0075] For example, where the special-purpose network device 402 is used in the data plane 480, each of the control communication and configuration module(s) 432A-R of the ND control plane 424 typically include a control agent that provides the VNE side of the south bound interface 482. In this case, the ND control plane 424 (the processor(s) 412 executing the control communication and configuration module(s) 432A-R) performs its responsibility for participating in controlling how data (e.g., packets) is to be routed (e.g., the next hop for the data and the outgoing physical NI for that data) through the control agent communicating with the centralized control plane 476 to receive the forwarding information (and in some cases, the reachability information) from the centralized reachability and forwarding information module 479 (it should be understood that in some embodiments of the invention, the control communication and configuration module(s) 432A-R, in addition to communicating with the centralized control plane 476, may also play some role in determining reachability and/or calculating forwarding information - albeit less so than in the case of a distributed approach; such embodiments are generally considered to fall under the centralized approach 474, but may also be considered a hybrid approach). [0076] While the above example uses the special-purpose network device 402, the same centralized approach 474 can be implemented with the general purpose network device 404 (e.g., each of the VNE 460A-R performs its responsibility for controlling how data (e.g., packets) is to be routed (e g., the next hop for the data and the outgoing physical NI for that data) by communicating with the centralized control plane 476 to receive the forwarding information (and in some cases, the reachability information) from the centralized reachability and forwarding information module 479; it should be understood that in some embodiments of the invention, the VNEs 460A-R, in addition to communicating with the centralized control plane 476, may also play some role in determining reachability and/or calculating forwarding information - albeit less so than in the case of a distributed approach) and the hybrid network device 406. In fact, the use of SDN techniques can enhance the NFV techniques typically used in the general purpose network device 404 or hybrid network device 406 implementations as NFV is able to support SDN by providing an infrastructure upon which the SDN software can be run, and NFV and SDN both aim to make use of commodity server hardware and physical switches.

[0077] Figure 4D also shows that the centralized control plane 476 has a north bound interface 484 to an application layer 486, in which resides application(s) 488. The centralized control plane 476 has the ability to form virtual networks 492 (sometimes referred to as a logical forwarding plane, network services, or overlay networks (with the NEs 470A-H of the data plane 480 being the underlay network)) for the application(s) 488. Thus, the centralized control plane 476 maintains a global view of all NDs and configured NEs/VNEs, and it maps the virtual networks to the underlying NDs efficiently (including maintaining these mappings as the physical network changes either through hardware (ND, link, or ND component) failure, addition, or removal).

[0078] While Figure 4D shows the distributed approach 472 separate from the centralized approach 474, the effort of network control may be distributed differently or the two combined in certain embodiments of the invention. For example: 1) embodiments may generally use the centralized approach (SDN) 474, but have certain functions delegated to the NEs (e.g., the distributed approach may be used to implement one or more of fault monitoring, performance monitoring, protection switching, and primitives for neighbor and/or topology discovery); or 2) embodiments of the invention may perform neighbor discovery and topology discovery via both the centralized control plane and the distributed protocols, and the results compared to raise exceptions where they do not agree. Such embodiments are generally considered to fall under the centralized approach 474, but may also be considered a hybrid approach. [0079] While Figure 4D illustrates the simple case where each of the NDs 400A-H implements a single NE 470A-H, it should be understood that the network control approaches described with reference to Figure 4D also work for networks where one or more of the NDs 400A-H implement multiple VNEs (e.g., VNEs 430A-R, VNEs 460A-R, those in the hybrid network device 406). Alternatively or in addition, the network controller 478 may also emulate the implementation of multiple VNEs in a single ND. Specifically, instead of (or in addition to) implementing multiple VNEs in a single ND, the network controller 478 may present the implementation of a VNE/NE in a single ND as multiple VNEs in the virtual networks 492 (all in the same one of the virtual network(s) 492, each in different ones of the virtual network(s) 492, or some combination). For example, the network controller 478 may cause an ND to implement a single VNE (a NE) in the underlay network, and then logically divide up the resources of that NE within the centralized control plane 476 to present different VNEs in the virtual network(s) 492 (where these different VNEs in the overlay networks are sharing the resources of the single VNE/NE implementation on the ND in the underlay network).

[0080] In some embodiments, the networking controller 478 or application layer 486 can include an encoder manager 481. The encoder manager 481 can be stored in a non-transitory machine readable media and executed in any component of the centralized control plane 476. The encoder manager 481 provides the functionality described herein above.

[0081] On the other hand, Figures 4E and 4F respectively illustrate exemplary abstractions of NEs and VNEs that the network controller 478 may present as part of different ones of the virtual networks 492. Figure 4E illustrates the simple case of where each of the NDs 400 A-H implements a single NE 470A-H (see Figure 4D), but the centralized control plane 476 has abstracted multiple of the NEs in different NDs (the NEs 470A-C and G-H) into (to represent) a single NE 4701 in one of the virtual network(s) 492 of Figure 4D, according to some embodiments of the invention. Figure 4E shows that in this virtual network, the NE 4701 is coupled to NE 470D and 470F, which are both still coupled to NE 470E.

[0082] Figure 4F illustrates a case where multiple VNEs (VNE 470A.1 and VNE 470H.1) are implemented on different NDs (ND 400A and ND 400H) and are coupled to each other, and where the centralized control plane 476 has abstracted these multiple VNEs such that they appear as a single VNE 470T within one of the virtual networks 492 of Figure 4D, according to some embodiments of the invention. Thus, the abstraction of a NE or VNE can span multiple NDs.

[0083] While some embodiments of the invention implement the centralized control plane 476 as a single entity (e.g., a single instance of software running on a single electronic device), alternative embodiments may spread the functionality across multiple entities for redundancy and/or scalability purposes (e.g., multiple instances of software running on different electronic devices).

[0084] Similar to the network device implementations, the electronic device(s) running the centralized control plane 476, and thus the network controller 478 including the centralized reachability and forwarding information module 479, may be implemented a variety of ways (e g., a special purpose device, a general-purpose (e g., COTS) device, or hybrid device). These electronic device(s) would similarly include processor(s), a set of one or more physical NIs, and a non-transitory machine-readable storage medium having stored thereon the centralized control plane software For instance, Figure 5 illustrates, a general purpose control plane device 504 including hardware 540 comprising a set of one or more processor(s) 542 (which are often COTS processors) and physical NIs 546, as well as non-transitory machine readable storage media 548 having stored therein centralized control plane (CCP) software 550.

[0085] In embodiments that use compute virtualization, the processor(s) 542 typically execute software to instantiate a virtualization layer 554 (e.g., in one embodiment the virtualization layer 554 represents the kernel of an operating system (or a shim executing on a base operating system) that allows for the creation of multiple instances 562A-R called software containers (representing separate user spaces and also called virtualization engines, virtual private servers, or jails) that may each be used to execute a set of one or more applications; in another embodiment the virtualization layer 554 represents a hypervisor (sometimes referred to as a virtual machine monitor (VMM)) or a hypervisor executing on top of a host operating system, and an application is run on top of a guest operating system within an instance 562A-R called a virtual machine (which in some cases may be considered a tightly isolated form of software container) that is run by the hypervisor ; in another embodiment, an application is implemented as a unikemel, which can be generated by compiling directly with an application only a limited set of libraries (e.g., from a library operating system (LibOS) including drivers/libraries of OS services) that provide the particular OS services needed by the application, and the unikernel can run directly on hardware 540, directly on a hypervisor represented by virtualization layer 554 (in which case the unikemel is sometimes described as running within a LibOS virtual machine), or in a software container represented by one of instances 562A-R). Again, in embodiments where compute virtualization is used, during operation an instance of the CCP software 550 (illustrated as CCP instance 576A) is executed (e.g., within the instance 562A) on the virtualization layer 554. In embodiments where compute virtualization is not used, the CCP instance 576A is executed, as a unikemel or on top of a host operating system, on the “bare metal” general purpose control plane device 504. The instantiation of the CCP instance 576A, as well as the virtualization layer 554 and instances 562A-R if implemented, are collectively referred to as software instance(s) 552.

[0086] In some embodiments, the CCP instance 576A includes a network controller instance 578. The network controller instance 578 includes a centralized reachability and forwarding information module instance 579 (which is a middleware layer providing the context of the network controller 478 to the operating system and communicating with the various NEs), and an CCP application layer 580 (sometimes referred to as an application layer) over the middleware layer (providing the intelligence required for various network operations such as protocols, network situational awareness, and user - interfaces). At a more abstract level, this CCP application layer 580 within the centralized control plane 476 works with virtual network view(s) (logical view(s) of the network) and the middleware layer provides the conversion from the virtual networks to the physical view.

[0087] The centralized control plane 476 transmits relevant messages to the data plane 480 based on CCP application layer 580 calculations and middleware layer mapping for each flow. A flow may be defined as a set of packets whose headers match a given pattern of bits; in this sense, traditional IP forwarding is also flow-based forwarding where the flows are defined by the destination IP address for example; however, in other implementations, the given pattern of bits used for a flow definition may include more fields (e.g., 10 or more) in the packet headers. Different NDs/NEs/VNEs of the data plane 480 may receive different messages, and thus different forwarding information. The data plane 480 processes these messages and programs the appropriate flow information and corresponding actions in the forwarding tables (sometime referred to as flow tables) of the appropriate NE/VNEs, and then the NEs/VNEs map incoming packets to flows represented in the forwarding tables and forward packets based on the matches in the forwarding tables.

[0088] In some embodiments, the control plane device 504 can include an encoder manager 581. The encoder manager 581 can be stored in a non-transitory machine readable media 548 and executed by the processors 542. The encoder manager 581 provides the functionality described herein above.

[0089] Standards such as OpenFlow define the protocols used for the messages, as well as a model for processing the packets. The model for processing packets includes header parsing, packet classification, and making forwarding decisions. Header parsing describes how to interpret a packet based upon a well-known set of protocols. Some protocol fields are used to build a match structure (or key) that will be used in packet classification (e.g., a first key field could be a source media access control (MAC) address, and a second key field could be a destination MAC address). [0090] Packet classification involves executing a lookup in memory to classify the packet by determining which entry (also referred to as a forwarding table entry or flow entry) in the forwarding tables best matches the packet based upon the match structure, or key, of the forwarding table entries. It is possible that many flows represented in the forwarding table entries can correspond/match to a packet; in this case the system is typically configured to determine one forwarding table entry from the many according to a defined scheme (e g., selecting a first forwarding table entry that is matched). Forwarding table entries include both a specific set of match criteria (a set of values or wildcards, or an indication of what portions of a packet should be compared to a particular value/values/wildcards, as defined by the matching capabilities - for specific fields in the packet header, or for some other packet content), and a set of one or more actions for the data plane to take on receiving a matching packet. For example, an action may be to push a header onto the packet, for the packet using a particular port, flood the packet, or simply drop the packet. Thus, a forwarding table entry for IPv4/IPv6 packets with a particular transmission control protocol (TCP) destination port could contain an action specifying that these packets should be dropped.

[0091] Making forwarding decisions and performing actions occurs, based upon the forwarding table entry identified during packet classification, by executing the set of actions identified in the matched forwarding table entry on the packet.

[0092] However, when an unknown packet (for example, a “missed packet” or a “match-miss” as used in OpenFlow parlance) arrives at the data plane 480, the packet (or a subset of the packet header and content) is typically forwarded to the centralized control plane 476. The centralized control plane 476 will then program forwarding table entries into the data plane 480 to accommodate packets belonging to the flow of the unknown packet. Once a specific forwarding table entry has been programmed into the data plane 480 by the centralized control plane 476, the next packet with matching credentials will match that forwarding table entry and take the set of actions associated with that matched entry.

[0093] A network interface (NI) may be physical or virtual; and in the context of IP, an interface address is an IP address assigned to a NI, be it a physical NI or virtual NI. A virtual NI may be associated with a physical NI, with another virtual interface, or stand on its own (e.g., a loopback interface, a point-to-point protocol interface). A NI (physical or virtual) may be numbered (a NI with an IP address) or unnumbered (a NI without an IP address). A loopback interface (and its loopback address) is a specific type of virtual NI (and IP address) of a NE/VNE (physical or virtual) often used for management purposes; where such an IP address is referred to as the nodal loopback address. The IP address(es) assigned to the NI(s) of a ND are referred to as IP addresses of that ND; at a more granular level, the IP address(es) assigned to NI(s) assigned to a NE/VNE implemented on a ND can be referred to as IP addresses of that NE/VNE.

[0094] While the invention has been described in terms of several embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described, can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting.

Claims

CLAIMS What is claimed is:

1. A method of video stream management by an encoder manager, the method comprising: loading (303) configuration for a video stream to be sent to a user device; receiving (305) a user action from the user device; determining (307) whether the user action correlates with a scene change; and storing (309) a preceding frame of the video stream into a long-term reference (LTR) set, in response to the user action correlating with the scene change.

2. The method of claim 1, further comprising: determining (311) whether a frame for a new scene is present in the LTR set.

3. The method of claim 2, further comprising: loading (313) the frame for the new scene, in response to determining the frame is present in the LTR set.

4. The method of claim 1, wherein the configuration is selected based on a source of the video stream or a type of the video stream.

5. The method of claim 1, wherein the user action is an input collected by a client application at the user device, where the input is any one of a keystroke, touchscreen input, a button press, a mouse click, or a virtual reality headset input.

6. The method of claim 1, wherein the user action is passed to an application service that generates the video stream.

7. The method of claim 1, wherein the loaded configuration includes a mapping of input types with scene types.

8. A machine-readable medium comprising computer program code which when executed by a computer carries out the method steps of any of claims 1-7.

9. An apparatus for executing the encoder manager, the apparatus comprising: a machine-readable medium (448) to store computer program code of the encoder manager (465); and a set of processors (442) coupled with the machine-readable medium, the set of processors to execute the encoder manager to perform the method steps of any of claims 1-7.