Systems and methods for a client-side remote presentation of a multimedia stream

A proxy streaming module executes on a first computing machine to stream multimedia data from a virtual channel that is established between the first computing machine and a second computing machine. In some instances, the multimedia data is generated by a multimedia device that communicates with the second computing machine. The proxy streaming module forwards the multimedia data to a presentation application that is executing on the first computing machine. A remoting application that executes on the first computing machine then captures the application output generated by the presentation application while the presentation application presents the multimedia data. The remoting application then transmits the application output to the second computing machine which displays the application output in an application output window.

FIELD OF THE DISCLOSURE

This application generally relates to remotely providing data. In particular, this application relates to remotely providing multimedia data generated by a multimedia device.

BACKGROUND OF THE DISCLOSURE

Over the past couple of years, there has been a steady increase in demand for video conferencing applications. Typically video conferencing requires an enormous amount of bandwidth and suffers from poor quality, latency and other similar issues. Many new technologies have been introduced to reduce some of the user experience problems inherent in past video conferencing applications including video codecs and anti jitter algorithms and protocols. These new technologies have allowed companies to rely on video conferencing as a tool to communicate with employees, vendors and clients remotely while reducing travel costs.

In many cases, employees do not have local access to video conferencing or other multimedia applications. Furthermore, many companies may require employees to use a particular video conferencing or multimedia application that is available only on a company's internal network. In these situations, employees who work remotely are unable to access the required applications. Thus, there is a need for a solution by which users can access remote display applications to display multimedia data generated locally by a multimedia device located remote from the display application. Similarly, there exists a need for a solution by which users can receive and display multimedia data on a local display application, where the multimedia data is generated remotely by a multimedia device located remote from the display application.

While there exists a number of different methods for permitting the remote display of multimedia output, none of these solutions take advantage of the technological advances in multimedia processing that reduce the undesired qualities typically present in a remote multimedia display application. Thus, there exists a need for a solution that takes advantage of the multimedia processing technologies such as those described above.

SUMMARY OF THE DISCLOSURE

The methods and systems described herein are embodiments of methods and systems for remotely providing multimedia data. Often times a user of a client computer connected to a multimedia device may wish to use an application remotely executing on a remote server, to display or otherwise modify output generated by the multimedia device. Access to the application, in many instances, can be provided via a thin client protocol. The application can receive the multimedia output from the client computer via a virtual channel over which the client computer can transmit the multimedia output using the thin client protocol. Transmitting multimedia data from one computer to another can be taxing on both systems because multimedia data can require a great deal of storage resources, computing (e.g. CPU) resources, memory resources and bandwidth resources.

In one aspect, described herein is a method for remotely presenting multimedia data generated by a multimedia device connected to a second computing machine. The method includes streaming multimedia data from a virtual channel established between a first computing machine and a second computing machine, where the multimedia data is generated by a multimedia device that communicates with a second computing machine. The multimedia data is streamed by a proxy streaming module that executes on the first computing machine and that forwards the multimedia data to a presentation application executing on the first computing machine. A first remoting application that executes on the first computing machine can capture the application output generated by the presentation application during the presentation of the multimedia data. The first remoting application can also transmit the application output to the second computing machine which can then display the application output in an application output window.

In some embodiments, the proxy streaming module can stream the multimedia data in response to receiving a request from a user of the second computing machine to execute the presentation application.

In other embodiments, a second remoting application that executes on the second computing machine can transmit the multimedia data from the second computing machine to the first computing machine over the virtual channel.

In one embodiment, a streaming module executing on the second computing machine, streams the multimedia data from a multimedia device interface, and then streams the multimedia data to the remoting application executing on the second computing machine.

Other embodiments include an encoder that executes on the second computing machine to encode the multimedia data before transmitting the multimedia data to the first computing machine. Still other embodiments include an encryption agent that executes on the second computing machine to encrypt the multimedia data before transmitting the multimedia data to the first computing machine.

The remoting application, in some embodiments, encapsulates the multimedia data in a protocol wrapper before transmitting the multimedia data to the first computing machine.

In some embodiments, a decoder executing on the first computing machine can decode the multimedia data before forwarding the multimedia data to the presentation application. The decoder, in some embodiments, can include a decryption agent.

In still other embodiments, the remoting application can un-encapsulate the multimedia data before forwarding the multimedia data to the presentation application.

The presentation application can, in some embodiments, store the multimedia data in a storage repository.

In yet another aspect, described herein is a system for remotely presenting multimedia data generated by a multimedia device connected to a second computing machine. This system, in some embodiments, can include a first computing machine and a second computing machine communicating with the first computing machine over a virtual channel established between the first computing machine and the second computing machine. The system can further include a multimedia device communicating with the second computing machine, and a proxy streaming module executing on the first computing machine to stream multimedia data from the virtual channel. The multimedia data, in some embodiments, is generated by the multimedia device, and forwarded by the proxy streaming module to a presentation application executing on the first computing machine. A remoting application executing on the first computing machine can capture application output generated by the presentation application during presentation of the multimedia data, and transmit the application output to the second computing machine.

In some embodiments, the second computing machine can display the application output in an application output window.

In yet another embodiment, the second computing machine can directly, or locally, display the multimedia data captured by the local multimedia device in an application output window.

In one aspect, the present application relates to a method for displaying on a local computing device, by an application executing on a remote computing device, multimedia data generated by a multimedia device connected to the local computing device. The remote computing device may be in communication with the local computing device via a virtual channel. A proxy streaming module executing on a remote computing device may stream multimedia data received from a local computing device via a virtual channel. The multimedia data may be generated by a multimedia device associated with the local computing device. The proxy streaming module may forward the multimedia data to a presentation application executing on the remote computing device, the presentation application generating multimedia application output. A remoting application executing on the remote computing device may capture the generated multimedia application output. The remoting application executing on the remote computing device may transmit the generated multimedia application output to the local computing device for display in an application output window on the local computing device.

In some embodiments, multimedia data is streamed responsive to receiving a request to execute the presentation application from a user of the local computing device. In other embodiments, a local streaming module executing on the local computing device transmits the multimedia data to the remote computing device via the virtual channel. In further embodiments, a local streaming module executing on the local computing device streams the multimedia data from a multimedia device interface. The local streaming module executing on the local computing device may stream the multimedia data to a local remoting application executing on the local computing device.

In some embodiments, an encoder executing on the local computing device encodes the multimedia data before transmitting the multimedia data to the remote computing device. In further embodiments, a decoder executing on the remote computing device decodes the multimedia data before forwarding the multimedia data to the presentation application. In some embodiments, a local remoting application on the local computing device constructs a packet to include the multimedia data in a protocol wrapper before transmitting the packet comprising the multimedia data to the remote computing device. In further embodiments, the remoting application executing on the remote computing device deconstructs the packet to extract the multimedia data from the packet before forwarding the multimedia data to the presentation application. In further embodiments, an encoder executing on the local computing device encrypts the multimedia data before transmitting the multimedia data to the remote computing device. In further embodiments, a decoder executing on the remote computing device decrypts the multimedia data before forwarding the multimedia data to the presentation application. In some embodiments, the presentation application stores the multimedia data in a storage repository.

In some aspects, the present disclosure relates to a system for displaying on a local computing device, by an application executing on a remote computing device. Multimedia data may be generated by a multimedia device connected to the local computing device. The remote computing device may be in communication with the local computing device via a virtual channel. The system may include a local computing device. The system may further include a multimedia device communicating with the local computing device, the multimedia device generating multimedia data. The system may also include a remote computing device hosting the executing of a proxy streaming module to stream multimedia data received from the local computing device via a virtual channel. The remote computing device may forward the multimedia data to a presentation application executing on the remote computing device. The presentation application may generate multimedia application output. The remoting application may capture the generated multimedia application output and transmit the multimedia application output to the local computing device for displaying in an application output window of the local computing device.

In some embodiments, the proxy streaming module streams the multimedia data responsive to receiving a request from a user of the local computing device to execute the presentation application. In other embodiments, a local remoting application executing on the local computing device transmits the multimedia data to the remote computing device over the virtual channel. In further embodiments, a streaming module executing on the local computing device streams the multimedia data from a multimedia interface to the remote application executing on the local computing device.

In some embodiments, an encoder executing on the local computing device encodes the multimedia data before transmitting the multimedia data to the remote computing device. In further embodiments, a decoder executing on the remote computing device decodes the multimedia data before forwarding the multimedia data to the presentation application. In other embodiments, the local remoting application executing on the local computing device constructs a packet to include the multimedia data in a protocol wrapper before transmitting the packet comprising the multimedia data to the remote computing device. In further embodiments, the remoting application executing on the remote computing device deconstructs the packet by extracting the multimedia data from the packet before forwarding the multimedia data to the presentation application. In further embodiments, the presentation application stores the multimedia data in a storage repository.

In some aspects, the present disclosure relates to a method for displaying on a client device, by an application executing on a remote server, multimedia data generated by a multimedia device connected to the client device. One or more filters of the client device may transform multimedia data to conform to a protocol of a virtual channel established between the client device and a remote server. A streaming module executing on the client device may forward compressed multimedia data to the remote server via the virtual channel. A proxy streaming module executing on the remote server may stream multimedia data received from the client device via the virtual channel. The proxy streaming module may forward multimedia data to a presentation application executing on the remote server. A remoting application executing on the remote server may capture application output generated by the presentation application during presentation of the multimedia data. The remoting application executing on the remote computing device may transmit the application output to the local computing device. The client device may display the application output in an application output window.

In some aspects, the present disclosure relates to methods and systems for displaying on multiple client devices, by one or more applications executing on one or more remote servers, multimedia data generated by a multimedia device connected to each of the remote client devices. For example, two or more clients may wish to communicate with each other via audio/video conferencing using their locally connected web cameras by processing the data from these cameras on one or more remote applications executing on one or more remote servers.

In such embodiments, a first multimedia data is generated by a multimedia device connected to a first client computing device. Second multimedia data may be generated by a second multimedia device connected to a second client computing device. The first and the second client computing devices may each be in communication with a remote server via one or more virtual channels. A first proxy streaming module executing on the remote server may stream multimedia data received from a first client computing device via a first virtual channel. A second proxy streaming module executing on the remote server may stream multimedia data received from a second client computing device via a second virtual channel. In some embodiments, a single proxy streaming module streams the multimedia data from both the first and the second client computing devices. The one or more proxy streaming modules may forward the multimedia data received from the first and the second client via the one or more virtual channels to a presentation application executing on the remote computing device. The presentation application may generate first multimedia application output for the first multimedia data and the second multimedia data application output for the second multimedia data. In some embodiments, multiple presentation applications generate the first and the second multimedia application outputs.

A first remoting application executing on the remote computing device may capture the generated first multimedia application output for the first client. A second remoting application executing on the remote computing device may capture the generated second multimedia application output for the second client. The first remoting application executing on the remote computing device may transmit the generated first multimedia application output to the first client. The second remoting application executing on the remote computing device may transmit the generated second multimedia application output to the second client. The first client may display in an application output window on the first client the generated first multimedia application output. The second client may display in an application output window on the second client the generated second multimedia application output.

However, in some embodiments, the first and the second clients may each receive and display the first and the second generated multimedia application outputs. For example, the first client may receive from the first and the second remoting application both the first and the second generated multimedia application outputs. Similarly, the second client may receive both the first and the second generated multimedia application outputs. In such embodiments, the first client displays in one or more local application output windows the generated first multimedia application output and the second multimedia application output. The second client may also display in one or more local application output windows the generated first multimedia application output and the second multimedia application output. The first client and the second client may thus implement audio/video conferencing while processing their audio/video data generated by their locally connected multimedia capture devices on one or more applications executing on one or more remote servers.

In some embodiments, the remote server includes one or more filters or functions enabling the operation of the presentation application with the multimedia data from the remote clients. The one or more filters may comprise or utilize any of the proxy streaming modules and remoting applications to ensure that the presentation application treats the multimedia data from each of the remote clients as multimedia data generated by a locally connected multimedia capture device. For example, the one or more filters may cause the presentation application to register the one or more filters as a multimedia capture device, such as a web camera, locally connected to the remote client or the server. The presentation application which may be designed to operate with locally connected multimedia capture devices only may continue to operate with a multimedia capture device connected to a remote client without any modifications to the presentation application. The presentation application may treat and communicate with the one or more filters in a manner in which it communicates with a locally connected multimedia capture device.

Similarly, on the client side, the client may include one or more filters or functions enabling the client to receive the multimedia data generated by a locally connected multimedia capture device and transmit the received multimedia data to the remote server. The one or more filters may also enable the client to receive the generated multimedia application output from the remote server and display the received generated multimedia application output locally. The one or more filters may satisfy all the requirements of the presentation application executing on the remote server. The one or more filters on the client and the server side may enable the client and the server to process, modify and/or edit the multimedia data received from the locally stored multimedia capture device in a manner in which it can be received, processed and transmitted by the presentation application executing on the remote server.

In some aspects, the present disclosure relates to a method for displaying on a local computing device, by an application executing on a remote computing device, multimedia data generated by a multimedia device connected to the local computing device. The remote computing device may be in communication with the local computing device via a virtual channel. A local computing device may stream multimedia data to a remote computing device via a virtual channel. The multimedia data may be generated by a multimedia device associated with the local computing device and comprising input to a presentation application executing on the remote computing device. Application output generated may be received from the remote computing device by the presentation application responsive to the transmitted multimedia data. The received application output may include the multimedia data generated by the multimedia device and a second stream of multimedia data generated by a third computing device.

In some embodiments, the multimedia data is streamed responsive to receiving a request to execute the presentation application from a user of the local computing device. In some embodiments, a local streaming module executing on the local computing device transmits the multimedia data to the remote computing device via the virtual channel. A local streaming module executing on the local computing device may stream the multimedia data from a multimedia device interface. The local streaming module executing on the local computing device may stream the multimedia data to a local remoting application executing on the local computing device. In some embodiments, an encoder executing on the local computing device encodes the multimedia data before transmitting the multimedia data to the remote computing device. In further embodiments, a local remoting application on the local computing device constructs a packet to include the multimedia data in a protocol wrapper before transmitting the packet comprising the multimedia data to the remote computing device. In other embodiments, an encoder executing on the local computing device encrypts the multimedia data before transmitting the multimedia data to the remote computing device.

In some aspects, the present disclosure relates to a local computing device for use in a system in which multimedia data generated by a multimedia device connected to the local computing device is displayed on the local computing device by an application executing on a remote computing device. The local computing device may comprise a multimedia interface acquiring multimedia data from a multimedia device associated with the local computing device. The multimedia data may comprise input to a presentation application executing on a remote computing device. The local computing device may also comprise a streaming module transmitting the acquired multimedia data to the remote computing device via a virtual channel. The local computing device may further comprise a local agent receiving, from the remote computing device, application output generated by the presentation application responsive to the transmitted multimedia data. The received application output may include the multimedia data generated by the multimedia device and a second stream of multimedia data generated by a third computing device. The streaming module may stream the multimedia data responsive to receiving a request from a user of the local computing device to execute the presentation application. The streaming module may execute on the local computing device and streams the multimedia data directly from the multimedia interface.

In some embodiments, the encoder executing on the local computing device encodes the acquired multimedia data before transmission to the remote computing device. In other embodiments, a packet engine executes on the local computing device and constructs a packet including the acquired multimedia data in a protocol wrapper before transmitting the packet comprising the multimedia data to the remote computing device.

In some aspects, the present disclosure relates to a local computing device for use in a system in which multimedia data generated by a multimedia device connected to the local computing device is displayed on the local computing device by an application executing on a remote computing device. The local computing device may comprise a means for streaming, by a local computing device, multimedia data to a remote computing device via a virtual channel, the multimedia data generated by a multimedia device associated with the local computing device and comprising input to a presentation application executing on the remote computing device. The local computing device may also include a means for receiving, from the remote computing device, application output generated by the presentation application responsive to the transmitted multimedia data, the received application output including the multimedia data generated by the multimedia device and a second stream of multimedia data generated by a third computing device.

DETAILED DESCRIPTION OF THE DRAWINGS

For purposes of reading the description of the various embodiments below, the following descriptions of the sections of the specification and their respective contents may be helpful:Section A describes a network environment and computing environment which may be useful for practicing embodiments described herein;Section B describes embodiments of systems and methods for virtualizing a computing environment; andSection C describes embodiments of systems and methods for remotely presenting a multimedia data stream.
A. Network and Computing Environment

FIG. 1Aillustrates one embodiment of a computing environment101that includes one or more client machines102A-102N (generally referred to herein as “client machine(s)102”) that are in communication with one or more servers106A-106N (generally referred to herein as “server(s)106”). Installed in between the client machine(s)102and server(s)106is a network104.

In one embodiment, the computing environment101can include an appliance installed between the server(s)106and client machine(s)102. This appliance can manage client/server connections, and in some cases can load balance client connections amongst a plurality of backend servers.

The client machine(s)102can in some embodiment be referred to as a single client machine102or a single group of client machines102, while server(s)106may be referred to as a single server106or a single group of servers106. In one embodiment a single client machine102communicates with more than one server106, while in another embodiment a single server106communicates with more than one client machine102. In yet another embodiment, a single client machine102communicates with a single server106.

A client machine102can, in some embodiments, be referenced by any one of the following terms: client machine(s)102; client(s); client computer(s); client device(s); client computing device(s); local machine; remote machine; client node(s); endpoint(s); endpoint node(s); a second machine; a first machine; or a third machine. The server106, in some embodiments, may be referenced by any one of the following terms: server(s), local machine; remote machine; server farm(s), host computing device(s), a first machine(s); or a second machine(s).

In one embodiment, the client machine102can be a virtual machine102C. The virtual machine102C can be any virtual machine, while in some embodiments the virtual machine102C can be any virtual machine managed by a hypervisor developed by XenSolutions, Citrix Systems, IBM, VMware, or any other hypervisor. In other embodiments, the virtual machine102C can be managed by any hypervisor, while in still other embodiments, the virtual machine102C can be managed by a hypervisor executing on a server106or a hypervisor executing on a client102.

The client machine102can in some embodiments execute, operate or otherwise provide an application that can be any one of the following: software; a program; executable instructions; a virtual machine; a hypervisor; a web browser; a web-based client; a client-server application; a thin-client; an ActiveX control; a Java applet; software related to voice over internet protocol (VoIP) communications like a soft IP telephone; an application for streaming video and/or audio; an application for facilitating real-time-data communications; a HTTP client; a FTP client; an Oscar client; a Telnet client; or any other set of executable instructions. Still other embodiments include a client device102that displays application output generated by an application remotely executing on a server106or other remotely located machine. In these embodiments, the client device102can display the application output in an application window, a browser, or other output window. In one embodiment, the application is a desktop, while in other embodiments the application is an application that generates a desktop.

The server106, in some embodiments, executes a remote presentation client or other client or program that uses a thin-client or remote-display protocol to capture display output generated by an application executing on a server106and transmits the application display output to a remote client102. The thin-client or remote-display protocol can be any one of the following protocols: the Independent Computing Architecture (ICA) protocol manufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla.; or the Remote Desktop Protocol (RDP) manufactured by the Microsoft Corporation of Redmond, Wash.

The computing environment101can include more than one server106A-106N such that the servers106A-106N are logically grouped together into a server farm106. The server farm106can include servers106that are geographically dispersed and logically grouped together in a server farm106, or servers106that are located proximate to each other and logically grouped together in a server farm106. Geographically dispersed servers106A-106N within a server farm106can, in some embodiments, communicate using a WAN, MAN, or LAN, where different geographic regions can be characterized as: different continents; different regions of a continent; different countries; different states; different cities; different campuses; different rooms; or any combination of the preceding geographical locations. In some embodiments the server farm106may be administered as a single entity, while in other embodiments the server farm106can include multiple server farms106.

In some embodiments, a server farm106can include servers106that execute a substantially similar type of operating system platform (e.g., WINDOWS NT, manufactured by Microsoft Corp. of Redmond, Wash., UNIX, LINUX, or SNOW LEOPARD.) In other embodiments, the server farm106can include a first group of servers106that execute a first type of operating system platform, and a second group of servers106that execute a second type of operating system platform. The server farm106, in other embodiments, can include servers106that execute different types of operating system platforms.

The server106, in some embodiments, can be any server type. In other embodiments, the server106can be any of the following server types: a file server; an application server; a web server; a proxy server; an appliance; a network appliance; a gateway; an application gateway; a gateway server; a virtualization server; a deployment server; a SSL VPN server; a firewall; a web server; an application server or a master application server; a server106executing an active directory; or a server106executing an application acceleration program that provides firewall functionality, application functionality, or load balancing functionality. In some embodiments, a server106may be a RADIUS server that includes a remote authentication dial-in user service. In embodiments where the server106comprises an appliance, the server106can be an appliance manufactured by any one of the following manufacturers: the Citrix Application Networking Group; Silver Peak Systems, Inc; Riverbed Technology, Inc.; F5 Networks, Inc.; or Juniper Networks, Inc. Some embodiments include a first server106A that receives requests from a client machine102, forwards the request to a second server106B, and responds to the request generated by the client machine102with a response from the second server106B. The first server106A can acquire an enumeration of applications available to the client machine102and well as address information associated with an application server106hosting an application identified within the enumeration of applications. The first server106A can then present a response to the client's request using a web interface, and communicate directly with the client102to provide the client102with access to an identified application.

The server106can, in some embodiments, execute any one of the following applications: a thin-client application using a thin-client protocol to transmit application display data to a client; a remote display presentation application; any portion of the CITRIX ACCESS SUITE by Citrix Systems, Inc. like the METAFRAME or CITRIX PRESENTATION SERVER; MICROSOFT WINDOWS Terminal Services manufactured by the Microsoft Corporation; or an ICA client, developed by Citrix Systems, Inc. Another embodiment includes a server106that is an application server such as: an email server that provides email services such as MICROSOFT EXCHANGE manufactured by the Microsoft Corporation; a web or Internet server; a desktop sharing server; a collaboration server; or any other type of application server. Still other embodiments include a server106that executes any one of the following types of hosted servers applications: GOTOMEETING provided by Citrix Online Division, Inc.; WEBEX provided by WebEx, Inc. of Santa Clara, Calif.; or Microsoft Office LIVE MEETING provided by Microsoft Corporation.

Client machines102can, in some embodiments, be a client node that seeks access to resources provided by a server106. In other embodiments, the server106may provide clients102or client nodes with access to hosted resources. The server106, in some embodiments, functions as a master node such that it communicates with one or more clients102or servers106. In some embodiments, the master node can identify and provide address information associated with a server106hosting a requested application, to one or more clients102or servers106. In still other embodiments, the master node can be a server farm106, a client102, a cluster of client nodes102, or an appliance.

One or more clients102and/or one or more servers106can transmit data over a network104installed between machines and appliances within the computing environment101. The network104can comprise one or more sub-networks, and can be installed between any combination of the clients102, servers106, computing machines and appliances included within the computing environment101. In some embodiments, the network104can be: a local-area network (LAN); a metropolitan area network (MAN); a wide area network (WAN); a primary network104comprised of multiple sub-networks104located between the client machines102and the servers106; a primary public network104with a private sub-network104; a primary private network104with a public sub-network104; or a primary private network104with a private sub-network104. Still further embodiments include a network104that can be any of the following network types: a point to point network; a broadcast network; a telecommunications network; a data communication network; a computer network; an ATM (Asynchronous Transfer Mode) network; a SONET (Synchronous Optical Network) network; a SDH (Synchronous Digital Hierarchy) network; a wireless network; a wireline network; or a network104that includes a wireless link where the wireless link can be an infrared channel or satellite band. The network topology of the network104can differ within different embodiments, possible network topologies include: a bus network topology; a star network topology; a ring network topology; a repeater-based network topology; or a tiered-star network topology. Additional embodiments may include a network104of mobile telephone networks that use a protocol to communicate among mobile devices, where the protocol can be any one of the following: AMPS; TDMA; CDMA; GSM; GPRS UMTS; or any other protocol able to transmit data among mobile devices.

Illustrated inFIG. 1Bis an embodiment of a computing device100, where the client machine102and server106illustrated inFIG. 1Acan be deployed as and/or executed on any embodiment of the computing device100illustrated and described herein. Included within the computing device100is a system bus150that communicates with the following components: a central processing unit121; a main memory122; storage memory128; an input/output (I/O) controller123; display devices124A-124N; an installation device116; and a network interface118. In one embodiment, the storage memory128includes: an operating system, software routines, and a client agent120. The I/O controller123, in some embodiments, is further connected to a key board126, and a pointing device127. Other embodiments may include an I/O controller123connected to more than one input/output device130A-130N.

FIG. 1Cillustrates one embodiment of a computing device100, where the client machine102and server106illustrated inFIG. 1Acan be deployed as and/or executed on any embodiment of the computing device100illustrated and described herein. Included within the computing device100is a system bus150that communicates with the following components: a bridge170, and a first I/O device130A. In another embodiment, the bridge170is in further communication with the main central processing unit121, where the central processing unit121can further communicate with a second I/O device130B, a main memory122, and a cache memory140. Included within the central processing unit121, are I/O ports, a memory port103, and a main processor.

Embodiments of the computing machine100can include a central processing unit121characterized by any one of the following component configurations: logic circuits that respond to and process instructions fetched from the main memory unit122; a microprocessor unit, such as: those manufactured by Intel Corporation; those manufactured by Motorola Corporation; those manufactured by Transmeta Corporation of Santa Clara, Calif.; the RS/6000 processor such as those manufactured by International Business Machines; a processor such as those manufactured by Advanced Micro Devices; or any other combination of logic circuits. Still other embodiments of the central processing unit122may include any combination of the following: a microprocessor, a microcontroller, a central processing unit with a single processing core, a central processing unit with two processing cores, or a central processing unit with more than one processing core.

One embodiment of the computing machine100includes a central processing unit121that communicates with cache memory140via a secondary bus also known as a backside bus, while another embodiment of the computing machine100includes a central processing unit121that communicates with cache memory via the system bus150. The local system bus150can, in some embodiments, also be used by the central processing unit to communicate with more than one type of I/O device130A-130N. In some embodiments, the local system bus150can be any one of the following types of buses: a VESA VL bus; an ISA bus; an EISA bus; a MicroChannel Architecture (MCA) bus; a PCI bus; a PCI-X bus; a PCI-Express bus; or a NuBus. Other embodiments of the computing machine100include an I/O device130A-130N that is a video display124that communicates with the central processing unit121. Still other versions of the computing machine100include a processor121connected to an I/O device130A-130N via any one of the following connections: HyperTransport, Rapid I/O, or InfiniBand. Further embodiments of the computing machine100include a processor121that communicates with one I/O device130A using a local interconnect bus and a second I/O device130B using a direct connection.

The computing device100, in some embodiments, includes a main memory unit122and cache memory140. The cache memory140can be any memory type, and in some embodiments can be any one of the following types of memory: SRAM; BSRAM; or EDRAM. Other embodiments include cache memory140and a main memory unit122that can be any one of the following types of memory: Static random access memory (SRAM), Burst SRAM or SynchBurst SRAM (BSRAM); Dynamic random access memory (DRAM); Fast Page Mode DRAM (FPM DRAM); Enhanced DRAM (EDRAM), Extended Data Output RAM (EDO RAM); Extended Data Output DRAM (EDO DRAM); Burst Extended Data Output DRAM (BEDO DRAM); Enhanced DRAM (EDRAM); synchronous DRAM (SDRAM); JEDEC SRAM; PC100 SDRAM; Double Data Rate SDRAM (DDR SDRAM); Enhanced SDRAM (ESDRAM); SyncLink DRAM (SLDRAM); Direct Rambus DRAM (DRDRAM); Ferroelectric RAM (FRAM); or any other type of memory. Further embodiments include a central processing unit121that can access the main memory122via: a system bus150; a memory port103; or any other connection, bus or port that allows the processor121to access memory122.

One embodiment of the computing device100provides support for any one of the following installation devices116: a CD-ROM drive, a CD-R/RW drive, a DVD-ROM drive, tape drives of various formats, USB device, a bootable medium, a bootable CD, a bootable CD for GNU/Linux distribution such as KNOPPIX®, a hard-drive or any other device suitable for installing applications or software. Applications can in some embodiments include a client agent120, or any portion of a client agent120. The computing device100may further include a storage device128that can be either one or more hard disk drives, or one or more redundant arrays of independent disks; where the storage device is configured to store an operating system, software, programs applications, or at least a portion of the client agent120. A further embodiment of the computing device100includes an installation device116that is used as the storage device128.

The computing device100may further include a network interface118to interface to a Local Area Network (LAN), Wide Area Network (WAN) or the Internet through a variety of connections including, but not limited to, standard telephone lines, LAN or WAN links (e.g., 802.11, T1, T3, 56 kb, X.25, SNA, DECNET), broadband connections (e.g., ISDN, Frame Relay, ATM, Gigabit Ethernet, Ethernet-over-SONET), wireless connections, or some combination of any or all of the above. Connections can also be established using a variety of communication protocols (e.g., TCP/IP, IPX, SPX, NetBIOS, Ethernet, ARCNET, SONET, SDH, Fiber Distributed Data Interface (FDDI), RS232, RS485, IEEE 802.11, IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, CDMA, GSM, WiMax and direct asynchronous connections). One version of the computing device100includes a network interface118able to communicate with additional computing devices100′ via any type and/or form of gateway or tunneling protocol such as Secure Socket Layer (SSL) or Transport Layer Security (TLS), or the Citrix Gateway Protocol manufactured by Citrix Systems, Inc. Versions of the network interface118can comprise any one of: a built-in network adapter; a network interface card; a PCMCIA network card; a card bus network adapter; a wireless network adapter; a USB network adapter; a modem; or any other device suitable for interfacing the computing device100to a network capable of communicating and performing the methods and systems described herein.

Embodiments of the computing device100include any one of the following I/O devices130A-130N: a keyboard126; a pointing device127; mice; trackpads; an optical pen; trackballs; microphones; drawing tablets; video displays; speakers; inkjet printers; laser printers; and dye-sublimation printers; or any other input/output device able to perform the methods and systems described herein. An I/O controller123may in some embodiments connect to multiple I/O devices103A-130N to control the one or more I/O devices. Some embodiments of the I/O devices130A-130N may be configured to provide storage or an installation medium116, while others may provide a universal serial bus (USB) interface for receiving USB storage devices such as the USB Flash Drive line of devices manufactured by Twintech Industry, Inc. Still other embodiments include an I/O device130that may be a bridge between the system bus150and an external communication bus, such as: a USB bus; an Apple Desktop Bus; an RS-232 serial connection; a SCSI bus; a FireWire bus; a FireWire 800 bus; an Ethernet bus; an AppleTalk bus; a Gigabit Ethernet bus; an Asynchronous Transfer Mode bus; a HIPPI bus; a Super HIPPI bus; a SerialPlus bus; a SCI/LAMP bus; a FibreChannel bus; or a Serial Attached small computer system interface bus.

In some embodiments, the computing machine100can connect to multiple display devices124A-124N, in other embodiments the computing device100can connect to a single display device124, while in still other embodiments the computing device100connects to display devices124A-124N that are the same type or form of display, or to display devices that are different types or forms. Embodiments of the display devices124A-124N can be supported and enabled by the following: one or multiple I/O devices130A-130N; the I/O controller123; a combination of I/O device(s)130A-130N and the I/O controller123; any combination of hardware and software able to support a display device124A-124N; any type and/or form of video adapter, video card, driver, and/or library to interface, communicate, connect or otherwise use the display devices124A-124N. The computing device100may in some embodiments be configured to use one or multiple display devices124A-124N, these configurations include: having multiple connectors to interface to multiple display devices124A-124N; having multiple video adapters, with each video adapter connected to one or more of the display devices124A-124N; having an operating system configured to support multiple displays124A-124N; using circuits and software included within the computing device100to connect to and use multiple display devices124A-124N; and executing software on the main computing device100and multiple secondary computing devices to enable the main computing device100to use a secondary computing device's display as a display device124A-124N for the main computing device100. Still other embodiments of the computing device100may include multiple display devices124A-124N provided by multiple secondary computing devices and connected to the main computing device100via a network.

In some embodiments, the computing machine100can execute any operating system, while in other embodiments the computing machine100can execute any of the following operating systems: versions of the MICROSOFT WINDOWS operating systems such as WINDOWS 3.x; WINDOWS 95; WINDOWS 98; WINDOWS 2000; WINDOWS NT 3.51; WINDOWS NT 4.0; WINDOWS CE; WINDOWS XP; WINDOWS VISTA; WINDOWS 7; WINDOWS SERVER 2008 R2; and the different releases of the Unix and Linux operating systems; any version of the MAC OS manufactured by Apple Computer; OS/2, manufactured by International Business Machines; any embedded operating system; any real-time operating system; any open source operating system; any proprietary operating system; any operating systems for mobile computing devices; or any other operating system. In still another embodiment, the computing machine100can execute multiple operating systems. For example, the computing machine100can execute PARALLELS or another virtualization platform that can execute or manage a virtual machine executing a first operating system, while the computing machine100executes a second operating system different from the first operating system.

The computing machine100can be embodied in any one of the following computing devices: a computing workstation; a desktop computer; a laptop or notebook computer; a server; a handheld computer; a mobile telephone; a portable telecommunication device; a media playing device; a gaming system; a mobile computing device; a netbook; a device of the IPOD family of devices manufactured by Apple Computer; any one of the PLAYSTATION family of devices manufactured by the Sony Corporation; any one of the Nintendo family of devices manufactured by Nintendo Co; any one of the XBOX family of devices manufactured by the Microsoft Corporation; or any other type and/or form of computing, telecommunications or media device that is capable of communication and that has sufficient processor power and memory capacity to perform the methods and systems described herein. In other embodiments the computing machine100can be a mobile device such as any one of the following mobile devices: a JAVA-enabled cellular telephone or personal digital assistant (PDA), such as the i55sr, i58sr, i85s, i88s, i90c, i95cl, or the im1100, all of which are manufactured by Motorola Corp; the 6035 or the 7135, manufactured by Kyocera; the i300 or i330, manufactured by Samsung Electronics Co., Ltd; the TREO 180, 270, 600, 650, 680, 700p, 700w, or 750 smart phone manufactured by Palm, Inc; any computing device that has different processors, operating systems, and input devices consistent with the device; or any other mobile computing device capable of performing the methods and systems described herein. In still other embodiments, the computing device100can be any one of the following mobile computing devices: any one series of Blackberry, or other handheld device manufactured by Research In Motion Limited; the iPhone manufactured by Apple Computer; Palm Pre; a Pocket PC; a Pocket PC Phone; or any other handheld mobile device.

Referring now toFIG. 1D, in some embodiments more than one server106can be logically linked to create a server farm38, where each server106can include a network-side interface202and a farm-side interface204. The network-side interface202can be in communication with one or more clients102or a network104. The network104can be a WAN, LAN, or any other network described herein.

In one embodiment, each server106has a farm-side interface204that can connect with one or more servers106in the farm38. In some embodiments, each server106can connect with another server106in the farm38via the other server's farm-side interface and such that both servers' farm-side interfaces204are interconnected. When connected, servers106within the server farm38can communicate with one another.

In some embodiments, the farm-side interface204can communicate with the network-side interface202, a persistent store230and, in some embodiments, with a dynamic store240. The farm38, in some embodiments, can include a combination of servers106, a persistent store230, and a dynamic store240. The server106, in some embodiments, can communicate with the persistent store230, while other servers106′ communicate with the server106to access information stored in the persistent store.

In one embodiment, the persistent store230may be physically implemented on a disk, disk farm, a redundant array of independent disks (RAID), writeable compact disc, or any other device that allows data to be read and written and that maintains written data if power is removed from the storage device. A single physical device may provide storage for a plurality of persistent stores, i.e., a single physical device may be used to provide the persistent store230for more than one farm38. The persistent store230can maintain static data associated with each server106in the farm38, as well as the global data used by the servers106within the farm38. In one embodiment, the persistent store230may maintain the server data in a Lightweight Directory Access Protocol (LDAP) data model. In other embodiments, the persistent store230can store the server data in an ODBC-compliant database. For the purposes of this description, the term “static data” can refer to data that does not change frequently, i.e., data that changes only on an hourly, daily, or weekly basis, or data that never changes. Each server can, in some embodiments, use a persistent storage subsystem to read data from and write data to the persistent store230.

The data stored by the persistent store230may be replicated for reliability purposes either physically or logically. For example, physical redundancy may be provided using a set of redundant, mirrored disks, where each disk provides a copy of the data. In other embodiments, the database itself may be replicated using standard database techniques to provide multiple copies of the database. In further embodiments, both physical and logical replication may be used concurrently.

The dynamic store240can be centralized such that the runtime data is stored in the memory of one server106in the farm38. That server can then operate as a master network node with which all other servers106in the farm38communicate when seeking access to runtime data. In another embodiment, each server106in the farm38can keep a full copy of the dynamic store240such that each server106communicates with every other server106to keep its copy of the dynamic store240up to date. In still another embodiment, each server106maintains its own runtime data and communicates with other servers106when seeking to obtain runtime data from them. Thus, for example, a server106attempting to find an application program requested by the client102may communicate directly with every other server106in the farm38to identify one or more servers hosting the requested application.

In some embodiments, heavy network traffic generated by farms38that have a large number of servers106, can be alleviated by designating a subset of the servers106in the farm38, typically two or more, as “collector points.” A collector point, in some embodiments, can be a server106that collects and stores runtime data collected from other servers106in the farm38. In some embodiments, each collector point can store a copy of the entire dynamic store240, while in other embodiments, each collector point stores a portion of the dynamic store240, i.e. the collector point maintains runtime data of a particular data type. The type of data stored by a server106may be predetermined according to one or more criteria. For example, servers106may store different types of data based on their boot order. Alternatively, the type of data stored by a server106may be configured by an administrator using an administration tool (Not Shown.) In these embodiments, the dynamic store240can be distributed amongst two or more servers106in the farm38.

Servers106not designated as collector points can, in some embodiments, identify servers106that have been designated as collector points. Upon identifying these collector points, the servers106can communicates with the identified collector points to deliver and request runtime data. Using collector points, in one embodiment, can mitigate traffic caused by a large server farm38by allowing servers106to communicate with one or more collector points rather than every other server106. Thus, requesting and delivering access to runtime data can be a less bandwidth intensive process.

Each server106can operate as a collector point for more than one type of data. For example, a first server106″ can operate as a collector point for licensing information and for loading information. In these embodiments, each collector point may amass a different type of run-time data. For example, a second server106′″ can collect licensing information, while the first server106″ collects loading information.

In some embodiments, each collector point can store data that is shared between all servers106in a farm38. In these embodiments, each collector point of a particular type of data exchanges the data collected by that collector point with every other collector point for that type of data in the farm38. Thus, upon completion of the exchange of such data, each collector point106″ and106possesses the same data. Also in these embodiments, each collector point106and106″ also keeps every other collector point abreast of any updates to the runtime data.

A client102, in some embodiments, can view applications executing within the farm38and can access available information and application sessions executing within the farm38, by browsing the contents and activity within a farm38. In some embodiments, each server106can include an ICA browsing subsystem260that can provide the client102with browsing capabilities. After the client102establishes a connection with the ICA browser subsystem260of any of the servers106, that browser subsystem can support a variety of client requests. Such client requests can include: (1) enumerating names of servers in the farm, (2) enumerating names of applications published in the farm, (3) resolving a server name and/or application name to a server address that is useful the client102. The ICA browser subsystem260can also support requests made by clients102running a program neighborhood application that provides the client102, upon request, with a view of those applications within the farm38for which the user is authorized. In some embodiments, the ICA browser subsystem260can forward all of the above-mentioned client requests to the appropriate subsystem in the server106.

In one embodiment, each server106in the farm38that has a program neighborhood subsystem270can provide the user of a client102with a view of applications within the farm38. The program neighborhood subsystem270may limit the view to those applications for which the user of the client102has authorization to access. Typically, this program neighborhood service presents the applications to the user as a list or a group of icons.

The functionality provided by the program neighborhood subsystem270can be available to two types of clients, (1) program neighborhood-enabled clients that can access the functionality directly from a client desktop, and (2) non-program neighborhood-enabled clients (e.g., legacy clients) that can access the functionality by running a program neighborhood-enabled desktop on the server.

Communication between a program neighborhood-enabled client and the program neighborhood subsystem270may occur over a dedicated virtual channel that is established on top of an ICA virtual channel. In other embodiments, the communication occurs using an XML service. In one of these embodiments, the program neighborhood-enabled client communicates with an XML subsystem.

In one embodiment, the program neighborhood-enabled client does not have a connection with the server with a program neighborhood subsystem270. For this embodiment, the client102sends a request to the ICA browser subsystem260to establish an ICA connection to the server106in order to identify applications available to the client102. The client102then runs a client-side dialog that acquires the credentials of a user. The credentials are received by the ICA browser subsystem260and sent to the program neighborhood subsystem270. In one embodiment, the program neighborhood subsystem270sends the credentials to a user management subsystem for authentication. The user management subsystem may return a set of distinguished names representing the list of accounts to which the user belongs. Upon authentication, the program neighborhood subsystem270establishes the program neighborhood virtual channel. This channel remains open until the application filtering is complete. The program neighborhood subsystem270can then request the program neighborhood information from the common application subsystem524associated with those accounts. The common application subsystem524can then obtain the program neighborhood information from the persistent store230. On receiving the program neighborhood information, the program neighborhood subsystem270formats and returns the program neighborhood information to the client over the program neighborhood virtual channel. Then, in some embodiments, the partial ICA connection is closed.

For another example in which the program neighborhood-enabled client establishes a partial ICA connection with a server, consider the user of the client102who selects a farm38. The selection of the farm38sends a request from the client102to the ICA browser subsystem260to establish an ICA connection with one of the servers106in the selected farm38. The ICA browser subsystem260can then send a request to the program neighborhood subsystem270, which selects a server106in the farm38. Address information associated with the server106can be identified and returned to the client102by way of the ICA browser subsystem260. The client102can then subsequently connect to the server106corresponding to the received address information.

In another embodiment, the program neighborhood-enabled client102establishes an ICA connection upon which the program neighborhood-virtual channel can be established, where the connection can remain open for as long as the ICA connection persists. Over this program neighborhood virtual channel, the program neighborhood subsystem270can push program neighborhood information updates to the client102. To obtain updates, the program neighborhood subsystem270subscribes to events from the common application subsystem524to allow the program neighborhood subsystem270to detect changes to published applications.

B. Virtualized Computing Environment

Referring now toFIG. 2A, a block diagram depicts one embodiment of a virtualization environment400. In brief overview, a computing device100includes a hypervisor layer, a virtualization layer, and a hardware layer. The hypervisor layer includes a hypervisor401(also referred to as a virtualization manager) that allocates and manages access to a number of physical resources in the hardware layer (e.g., the processor(s)421, and disk(s)428) by at least one virtual machine executing in the virtualization layer. The virtualization layer includes at least one operating system410and a plurality of virtual resources allocated to the at least one operating system410. Virtual resources may include, without limitation, a plurality of virtual processors432a,432b,432c(generally432), and virtual disks442a,442b,442c(generally442), as well as virtual resources such as virtual memory and virtual network interfaces. The plurality of virtual resources and the operating system410may be referred to as a virtual machine406. A virtual machine406may include a control operating system405in communication with the hypervisor401and used to execute applications for managing and configuring other virtual machines on the computing device100.

In greater detail, a hypervisor401may provide virtual resources to an operating system in any manner which simulates the operating system having access to a physical device. A hypervisor401may provide virtual resources to any number of guest operating systems410a,410b(generally410). In some embodiments, a computing device100executes one or more types of hypervisors. In these embodiments, hypervisors may be used to emulate virtual hardware, partition physical hardware, virtualize physical hardware, and execute virtual machines that provide access to computing environments. Hypervisors may include those manufactured by VMWare, Inc., of Palo Alto, Calif.; the XEN hypervisor, an open source product whose development is overseen by the open source Xen.org community; HyperV, VirtualServer or virtual PC hypervisors provided by Microsoft, or others. In some embodiments, a computing device100executing a hypervisor that creates a virtual machine platform on which guest operating systems may execute is referred to as a host server. In one of these embodiments, for example, the computing device100is a XEN SERVER provided by Citrix Systems, Inc., of Fort Lauderdale, Fla.

In some embodiments, a hypervisor401executes within an operating system executing on a computing device. In one of these embodiments, a computing device executing an operating system and a hypervisor401may be said to have a host operating system (the operating system executing on the computing device), and a guest operating system (an operating system executing within a computing resource partition provided by the hypervisor401). In other embodiments, a hypervisor401interacts directly with hardware on a computing device, instead of executing on a host operating system. In one of these embodiments, the hypervisor401may be said to be executing on “bare metal,” referring to the hardware comprising the computing device.

In some embodiments, a hypervisor401may create a virtual machine406a-c(generally406) in which an operating system410executes. In one of these embodiments, for example, the hypervisor401loads a virtual machine image to create a virtual machine406. In another of these embodiments, the hypervisor401executes an operating system410within the virtual machine406. In still another of these embodiments, the virtual machine406executes an operating system410.

In some embodiments, the hypervisor401controls processor scheduling and memory partitioning for a virtual machine406executing on the computing device100. In one of these embodiments, the hypervisor401controls the execution of at least one virtual machine406. In another of these embodiments, the hypervisor401presents at least one virtual machine406with an abstraction of at least one hardware resource provided by the computing device100. In other embodiments, the hypervisor401controls whether and how physical processor capabilities are presented to the virtual machine406.

A control operating system405may execute at least one application for managing and configuring the guest operating systems. In one embodiment, the control operating system405may execute an administrative application, such as an application including a user interface providing administrators with access to functionality for managing the execution of a virtual machine, including functionality for executing a virtual machine, terminating an execution of a virtual machine, or identifying a type of physical resource for allocation to the virtual machine. In another embodiment, the hypervisor401executes the control operating system405within a virtual machine406created by the hypervisor401. In still another embodiment, the control operating system405executes in a virtual machine406that is authorized to directly access physical resources on the computing device100. In some embodiments, a control operating system405aon a computing device100amay exchange data with a control operating system405bon a computing device100b, via communications between a hypervisor401aand a hypervisor401b. In this way, one or more computing devices100may exchange data with one or more of the other computing devices100regarding processors and other physical resources available in a pool of resources. In one of these embodiments, this functionality allows a hypervisor to manage a pool of resources distributed across a plurality of physical computing devices. In another of these embodiments, multiple hypervisors manage one or more of the guest operating systems executed on one of the computing devices100.

In one embodiment, the control operating system405executes in a virtual machine406that is authorized to interact with at least one guest operating system410. In another embodiment, a guest operating system410communicates with the control operating system405via the hypervisor401in order to request access to a disk or a network. In still another embodiment, the guest operating system410and the control operating system405may communicate via a communication channel established by the hypervisor401, such as, for example, via a plurality of shared memory pages made available by the hypervisor401.

In some embodiments, the control operating system405includes a network back-end driver for communicating directly with networking hardware provided by the computing device100. In one of these embodiments, the network back-end driver processes at least one virtual machine request from at least one guest operating system110. In other embodiments, the control operating system405includes a block back-end driver for communicating with a storage element on the computing device100. In one of these embodiments, the block back-end driver reads and writes data from the storage element based upon at least one request received from a guest operating system410.

In one embodiment, the control operating system405includes a tools stack404. In another embodiment, a tools stack404provides functionality for interacting with the hypervisor401, communicating with other control operating systems405(for example, on a second computing device100b), or managing virtual machines406b,406con the computing device100. In another embodiment, the tools stack404includes customized applications for providing improved management functionality to an administrator of a virtual machine farm. In some embodiments, at least one of the tools stack404and the control operating system405include a management API that provides an interface for remotely configuring and controlling virtual machines406running on a computing device100. In other embodiments, the control operating system405communicates with the hypervisor401through the tools stack104.

In one embodiment, the hypervisor401executes a guest operating system410within a virtual machine406created by the hypervisor401. In another embodiment, the guest operating system410provides a user of the computing device100with access to resources within a computing environment. In still another embodiment, a resource includes a program, an application, a document, a file, a plurality of applications, a plurality of files, an executable program file, a desktop environment, a computing environment, or other resource made available to a user of the computing device100. In yet another embodiment, the resource may be delivered to the computing device100via a plurality of access methods including, but not limited to, conventional installation directly on the computing device100, delivery to the computing device100via a method for application streaming, delivery to the computing device100of output data generated by an execution of the resource on a second computing device100′ and communicated to the computing device100via a presentation layer protocol, delivery to the computing device100of output data generated by an execution of the resource via a virtual machine executing on a second computing device100′, or execution from a removable storage device connected to the computing device100, such as a USB device, or via a virtual machine executing on the computing device100and generating output data. In some embodiments, the computing device100transmits output data generated by the execution of the resource to another computing device100′.

In one embodiment, the guest operating system410, in conjunction with the virtual machine on which it executes, forms a fully-virtualized virtual machine which is not aware that it is a virtual machine; such a machine may be referred to as a “Domain U HVM (Hardware Virtual Machine) virtual machine”. In another embodiment, a fully-virtualized machine includes software emulating a Basic Input/Output System (BIOS) in order to execute an operating system within the fully-virtualized machine. In still another embodiment, a fully-virtualized machine may include a driver that provides functionality by communicating with the hypervisor401. In such an embodiment, the driver may be aware that it executes within a virtualized environment. In another embodiment, the guest operating system410, in conjunction with the virtual machine on which it executes, forms a paravirtualized virtual machine, which is aware that it is a virtual machine; such a machine may be referred to as a “Domain U PV virtual machine”. In another embodiment, a paravirtualized machine includes additional drivers that a fully-virtualized machine does not include. In still another embodiment, the paravirtualized machine includes the network back-end driver and the block back-end driver included in a control operating system405, as described above.

Referring now toFIG. 2B, a block diagram depicts one embodiment of a plurality of networked computing devices in a system in which at least one physical host executes a virtual machine. In brief overview, the system includes a management component404and a hypervisor401. The system includes a plurality of computing devices100, a plurality of virtual machines406, a plurality of hypervisors401, a plurality of management components referred to as tools stacks404, and a physical resource421,428. The plurality of physical machines100may each be provided as computing devices100such as those described herein.

In greater detail, a physical disk428is provided by a computing device100and stores at least a portion of a virtual disk442. In some embodiments, a virtual disk442is associated with a plurality of physical disks428. In one of these embodiments, one or more computing devices100may exchange data with one or more of the other computing devices100regarding processors and other physical resources available in a pool of resources, allowing a hypervisor to manage a pool of resources distributed across a plurality of physical computing devices. In some embodiments, a computing device100on which a virtual machine406executes is referred to as a physical host100or as a host machine100.

The hypervisor executes on a processor on the computing device100. The hypervisor allocates, to a virtual disk, an amount of access to the physical disk. In one embodiment, the hypervisor401allocates an amount of space on the physical disk. In another embodiment, the hypervisor401allocates a plurality of pages on the physical disk. In some embodiments, the hypervisor provisions the virtual disk442as part of a process of initializing and executing a virtual machine450.

In one embodiment, the management component404ais referred to as a pool management component404a. In another embodiment, a management operating system405a, which may be referred to as a control operating system405a, includes the management component. In some embodiments, the management component is referred to as a tools stack. In one of these embodiments, the management component is the tools stack404described above in connection withFIG. 2A. In other embodiments, the management component404provides a user interface for receiving, from a user such as an administrator, an identification of a virtual machine406to provision and/or execute. In still other embodiments, the management component404provides a user interface for receiving, from a user such as an administrator, the request for migration of a virtual machine406bfrom one physical machine100to another. In further embodiments, the management component404aidentifies a computing device100bon which to execute a requested virtual machine406dand instructs the hypervisor401bon the identified computing device100bto execute the identified virtual machine; such a management component may be referred to as a pool management component.

Referring now toFIG. 2C, embodiments of a virtual application delivery controller or virtual appliance450are depicted. In brief overview, any of the functionality and/or embodiments of the appliance200(e.g., an application delivery controller) described above in connection withFIGS. 2A and 2Bmay be deployed in any embodiment of the virtualized environment described above in connection withFIGS. 4A and 4B. Instead of the functionality of the application delivery controller being deployed in the form of an appliance200, such functionality may be deployed in a virtualized environment400on any computing device100, such as a client102, server106or appliance200.

Referring now toFIG. 2C, a diagram of an embodiment of a virtual appliance450operating on a hypervisor401of a server106is depicted. As with the appliance200ofFIGS. 2A and 2B, the virtual appliance450may provide functionality for availability, performance, offload and security. For availability, the virtual appliance may perform load balancing between layers4and7of the network and may also perform intelligent service health monitoring. For performance increases via network traffic acceleration, the virtual appliance may perform caching and compression. To offload processing of any servers, the virtual appliance may perform connection multiplexing and pooling and/or SSL processing. For security, the virtual appliance may perform any of the application firewall functionality and SSL VPN function of appliance200.

Any of the modules of the appliance200as described in connection withFIG. 2Amay be packaged, combined, designed or constructed in a form of the virtualized appliance delivery controller450deployable as one or more software modules or components executable in a virtualized environment300or non-virtualized environment on any server, such as an off the shelf server. For example, the virtual appliance may be provided in the form of an installation package to install on a computing device. With reference toFIG. 2A, any of the cache manager232, policy engine236, compression238, encryption engine234, packet engine240, GUI210, CLI212, shell services214and health monitoring programs216may be designed and constructed as a software component or module to run on any operating system of a computing device and/or of a virtualized environment300. Instead of using the encryption processor260, processor262, memory264and network stack267of the appliance200, the virtualized appliance400may use any of these resources as provided by the virtualized environment400or as otherwise available on the server106.

Still referring toFIG. 2C, and in brief overview, any one or more vServers275A-275N may be in operation or executed in a virtualized environment400of any type of computing device100, such as any server106. Any of the modules or functionality of the appliance200described in connection withFIG. 2Bmay be designed and constructed to operate in either a virtualized or non-virtualized environment of a server. Any of the vServer275, SSL VPN280, Intranet UP282, Switching284, DNS286, acceleration288, App FW280and monitoring agent may be packaged, combined, designed or constructed in a form of application delivery controller450deployable as one or more software modules or components executable on a device and/or virtualized environment400.

In some embodiments, a server may execute multiple virtual machines406a-406nin the virtualization environment with each virtual machine running the same or different embodiments of the virtual application delivery controller450. In some embodiments, the server may execute one or more virtual appliances450on one or more virtual machines on a core of a multi-core processing system. In some embodiments, the server may execute one or more virtual appliances450on one or more virtual machines on each processor of a multiple processor device.

C. Systems and Methods for Remote Presentation of a Multimedia Data Stream

Illustrated inFIG. 3Ais one embodiment of a system that retrieves multimedia data generated by a multimedia device302, intercepts that multimedia data, and transmits the multimedia data to a remote computing machine where the data is formatted and sent to a display application314′ where the data can be displayed, played or presented to a user. The system can include two computing machines, a first computing machine301and a second computing machine300, that communicate over a virtual channel306. Each of the first computing machine301and the second computing machine300can execute a version of an application/desktop delivery system322,322′, and the application/desktop delivery system322,322′ can contain any number of codecs324,324′ or other encoding libraries. Additionally, each of the first computing machine301and the second computing machine300may execute a multimedia device driver316,316′ communicating with a multimedia device302,302′, and each machine301,300may execute a display application314,314′. Executing on both the first and second computing machine301,300is a DIRECTSHOW Framework320which can comprise any of the following modules, filters and elements: source filters330,330′ further comprising either a streaming module310or a proxy streaming module308; an application sink filter330,330′; a multimedia sink filter312,312′; a transform filter326,326′; and a renderer filter328,328′. In some embodiments, either or both of the first computing machine301and the second computing machine300can execute a display preview application323,323′.

Multimedia data generated by a multimedia capture device may include any audio and/or video data or format. Multimedia data may include any type and form of graphical presentation. Multimedia data may include portions of audio and/or video. Multimedia data may include digital video data made up of frames or images. Multimedia data may include a key frame, such as a self-contained frame or an encoded frame without any reference to other images. In the MPEG standard, these may include I-frames and D-frames as opposed to P-frames and B-frames that require information of the previous frames, or both the previous and the following frames for encoding and decoding, respectively.

Sometimes, instead of the DIRECTSHOW framework there may be other multimedia framework executing on the first and second computing machines, such as the DirectX Media Object (DMO) and/or Windows Media Foundation (WMF). The framework, such as DIRECTSHOW may include Extensible Core Microsoft Media Technology and may include a streaming architecture designed for audio and video data which offers a high-level application model enabling rapid development of digital media applications. Such framework may also include a low-level plug-in model that enables third parties to create custom audio or video processing components. It may include features, such as DirectDraw and DirectSound of Microsoft Corporation.

Further referring toFIG. 3A, and in more detail, in one embodiment the system can comprise a first computing machine301and a second computing machine300. The first computing machine301, in some embodiments, can be any computing machine, computing machine or computer. The second computing machine300, in some embodiments, can be any computing machine, computing machine or computer. Both the first computing machine301and the second computing machine300can be any computer, computing machine, or device described herein. In one embodiment, the first computing machine301is a server, while the second computing machine300is a client. In another embodiment, the first computing machine301is a client, while the second computing machine300is a server. In still another embodiment, the first computing machine301and the second computing machine300are clients. In one embodiment, the first computing machine301and the second computing machine300are clients that communicate via one or more proxy machines. The proxy machines, in this embodiment, can be a device, a client or a server.

WhileFIG. 3Adepicts a single first computing machine301, in some embodiments the first computing machine301is a server farm comprising a plurality of servers. In this embodiment, the first computing machine301is symbolic for any server within the server farm. Further, the first computing machine301can be symbolic of any server-farm server designated to communicate with the second computing machine300or with a user accessing the server farm via the second computing machine300.

In one embodiment, each of the first computing machine301and the second computing machine300execute an application/desktop delivery system322,322′. This delivery system322,322′ can be any program, module, client, process, or service that, when executing on a computing machine, obtains graphical and non-graphical data and transmits that data to a remote computing machine via a virtual channel306established between the computing machine on which the delivery system322,322′ executes and the remote computing machine. In one embodiment, the application/desktop delivery system322,322′ obtains application output data from applications executing on a local processor, and transmits that application output data to a remote computing machine. In other embodiments, the application/desktop delivery system322,322′ obtains desktop output data from desktops executing on a local processor and transmits that desktop output data to a remote computing machine. In still other embodiments, the application/desktop delivery system322,322′ obtains application or desktop output data from a virtual machine executing on a local processor and transmits that output to a remote computing machine.

In one embodiment, the application/desktop delivery system322,322′ can comprise any number of codecs324,324′ which can be used by the application/desktop delivery system322,322′ to encode or decode multimedia. Encoding or decoding multimedia data can, in some embodiments, include compressing or decompressing multimedia data. In other embodiments, encoding or decoding multimedia data can include encrypting or decrypting multimedia data. Any of the following codecs can be used to encode and decode video data included in a multimedia data stream: Theora; MPEG-4 ASP; VC-1; VC-3; TruDef; Windows Media Video; RealVideo; Apple ProRes 422; Pixlet; MPEG-1; MPEG-2; Cineform; CorePNG; Zip Motion Block Video; DivX Video; JPEG 2000; or any other video codec. Any of the following codecs can be used to encode and decode audio data included in a multimedia data stream: Apple Lossless Audio Codec; Direct Stream Transfer; Dolby TrueHD; RealAudio; WavPack; Windows Media Audio 9 Lossless; Dolby Digital; ADX; MPEG Audio; Windows Media Audio; or any other audio codec. Any of the following codecs can be used to encode and decode textual data included in a multimedia data stream: BiM; MPEG-4 Part 17; Ogg Writ; and any other text codec. In some embodiments the codecs can compress using a lossy compression algorithm, while in other embodiments the codecs can compress using a lossless compression algorithm. When multimedia data is transferred from a local computing machine to a remote computing machine, in some embodiments, the codecs used to encode the multimedia data are bundled together with the encoded multimedia data and sent to the remote computing machine. In turn, the remote computing machine can use the received codecs to decode the encoded multimedia data. In still other embodiments, the codecs324,324′ can use any encryption algorithm to encrypt the data prior to transmitting the data. Similarly, codecs324,324′ can be used to decrypt encrypted data.

The application/desktop delivery system322,322′ can transmit presentation level protocol data from one computing machine to another over a virtual channel306. The virtual channel306, in one embodiment, can be a secure communicative connection between two or more computing machines. This virtual channel306can be established over a network such as any of the networks described herein, and often transmits data via a presentation level protocol such as the CITRIX ICA protocol, or any other presentation level protocol described herein. In some embodiments, the application/desktop delivery system322,322′ further comprises a module that encapsulates formatted multimedia data to form presentation level protocol data. When a remote machine receives the encapsulated multimedia data, the remote machine can un-encapsulate or deconstruct the multimedia data in order to retrieve the multimedia data for processing. In many embodiments, the application/desktop delivery system322,322′ establishes the virtual channel306when a local computing machine requests access to an application executing on a remote computing machine. Establishing the virtual channel306can include any of the following actions: authenticating a user issuing a request to access an application executing on a remote computing machine; verifying privileges associated with the user or the computing machine used by the user to issue the access request; establishing a secure connection between one or more computing machines; and connecting the user to a profile of the user stored on the remote computing machine or stored on a computer accessible by the remote computing machine.

In one embodiment, the second computing machine300can be connected to a multimedia device302, while the first computing machine301is not connected to a multimedia device302. In other embodiments, the first computing machine301can be connected to a multimedia device302′ while the second computing machine300is not connected to a multimedia device302. In still other embodiments, each of the first computing machine301and the second computing machine300are connected to different multimedia devices302. WhileFIG. 3Aillustrates a single multimedia device302,302′, either computing machine can be connected to multiple multimedia devices. The multimedia device(s)302,302′ can be any of the following multimedia devices: web camera; microphone; projector; smart phone; DVD player; CD player; television tuner; musical instrument digital interface; MP3 player; digital cable interface; camera; video camera; infrared camera; optical input device; keyboard; mouse; Blu-Ray Player; satellite interface device; and any other multimedia device.

The multimedia device302,302′, in some embodiments, interfaces with a multimedia driver316,316′ on the computing machine. The multimedia driver316,316′ receives raw multimedia output generated by the multimedia device302,302′ and converts the raw output to a format able to be processed by the DIRECTSHOW framework320,320′ or by any other application for formatting and processing multimedia data. The multimedia driver316,316′ can interface with the DIRECTSHOW framework320,320′, the display application314,314′ or any other application that can input formatted multimedia output in its native form and process the output for eventual presentation to a user. The multimedia data can be any one of the following data: video; audio; text; graphical; or any other type of multimedia data.

WhileFIG. 3Aillustrates a first computing machine301and a second computing machine300where each computing machine can execute a multimedia device driver316,316′. In some embodiments, the computing machine300,301connected to a multimedia device302,302′ can include a multimedia device driver316,316′, while the other computing machine that is not connected to the multimedia device302,302′ does not include a multimedia device driver316,316′. Thus, a multimedia driver316,316′, in some embodiments, is not needed by a computing machine300,301unless that computing machine300,301communicates directly with a multimedia device302,302′. For example, in an embodiment where the second computing machine300communicates directly with a multimedia device302to obtain multimedia data from the multimedia device302, the second computing machine300can include a multimedia device driver316. Upon obtaining the multimedia data from the multimedia device302via the multimedia device driver316, the second computing machine300can transmit the multimedia data to a first computing machine301over a virtual channel306. In this embodiment, the first computing machine301does not communicate with a multimedia device302, therefore the first computing machine301does not include a multimedia device driver316. The first computing machine301, in this embodiment, does not require a multimedia device driver316in order to receive and process the multimedia data transferred to the machine301from the second computing machine300.

The display application314,314′ can be any application able to display, play or otherwise present multimedia. In some embodiments, the display application314can execute on the first computing machine301, and not on the second computing machine300. In other embodiments, the display application314′ can execute on the second computing machine300and not on the first computing machine301. The system compensates for the lack of a display application on one of the computing machines, therefore in many embodiments, at least one computing machine within the system does not have an instance of the display application and therefore cannot execute the display application314. The display application314,314′ can by any of the following display applications: Microsoft Communicator; Skype; Windows Media Player; AOL Instant Messenger; Google Chat; RealPlayer; QuickTime; Adobe Media Player; DivX Video Player; Gmail Voice and Video Chat; iVideoChat; Camfrog; TokBox; NetMeeting; Yahoo Messenger; and any other multimedia player. In some embodiments, the display application is a multimedia player for playing audio such as Windows Media Player, iTunes, or any other audio player. In other embodiments, the display application is a video or web conference system able to replay audio, video and text. In still other embodiments, the display application314,314′ is an application for displaying web camera data, or an application for facilitating web chats. The display application314,314′, in still another embodiment, is an application for displaying video or a combination of video and audio.

In some embodiments, either or both of the first computing machine301and the second computing machine300can execute a display preview application323,323′. In one embodiment, the display preview application323,323′ can be a stand-alone application, while in other embodiments the display preview application323,323′ can be included in the display application314. In other embodiments, the display preview application323,323′ can be included within the application/desktop delivery system322. The display preview application323,323′ receives multimedia data processed within the framework320,320′ and locally displays the multimedia data within an application output window. In some embodiments, the display preview application323,323′ can communicate with the application/desktop delivery system322,322′ on the remote computing machine to receive control information about the presentation window. Control information can include: parent application window properties; application window size and position; in-remote session clipping, or any other control information used by the presentation window to display the multimedia data. In some embodiments, the parent application or remote presentation application is a display application314,314′ executing on a computing machine located remote from the computing machine receiving the multimedia data. One example of local preview via the display preview application323,323′ includes a second computing machine300receiving multimedia data from a multimedia device302. The second computing machine300receives an instruction to display the multimedia data in a remote application executing on a first computing machine301. Rather than transmit the multimedia data to the first computing machine301, the display preview application323queries the application/desktop delivery system321′ executing on the first computing machine301for control information about the remote display application314′. The application/desktop delivery system312′ can then retrieve this information from an operating system executing on the first computing machine301and transmit the relevant control information to the display preview application323executing on the second computing machine300. The display preview application323can then use the control information to generate an application output window for displaying the received multimedia data.

Each of the first computing machine301and the second computing machine300execute an instance of the DIRECTSHOW framework320,320′. In other embodiments, the framework can be a framework based on either of the following technologies DIRECTX MEDIA OBJECT (DMO), MEDIA FOUNDATION (MJ) or any other multimedia technology suitable for the methods and systems described herein. In some embodiments, the first computing machine can execute a first framework320′ based on a first type of multimedia technology, while the second computing machine can execute a second framework320based on a second type of multimedia technology. For example the first computing machine can execute a DIRECTSHOW framework320′ while the second computing machine can execute a framework320based on DMO multimedia technology. In another example, the first computing machine can execute a framework320′ based on MJ multimedia technology, while the second computing machine can execute a framework320based on DMO multimedia technology.

The DIRECTSHOW framework320,320′, in many embodiments, is a software development kit or application program interface that can be used to format, modify and manipulate multimedia data and more specifically, multimedia data streams. In some embodiments, the DIRECTSHOW framework320,320′ can be used to perform operations on multimedia data inputted by a source filter330,330′. Filters, modules, clients or programs included within the framework can receive raw data, format the raw data, modify the raw data and perform other complex processing operations on inputted data. In some embodiments, the processing operations are performed within the DIRECTSHOW framework320. Outside applications can interface with data inputted and manipulated within the DIRECTSHOW framework via communication interfaces included within the DIRECTSHOW framework320,320′. These communication interfaces, in some embodiments, can use COM technology developed by Microsoft. In other embodiments, the communication interfaces can be any communication interface able to relay information from modules, filters, clients or other programs executing within the DIRECTSHOW framework320,320′ to programs interfacing with the framework320,320′.

In one embodiment, the DIRECTSHOW framework320,320′ executes source filters330,330′ which can retrieve information from multimedia driver(s)316,316′ and forward that information on to other filters and modules executing within the framework320,320′. In some embodiments, the source filters are modules, clients or programs executing on a computing machine and within the framework320,320′. In other embodiments, the source filters are services and processes executed by a processor and executed by a processor within the kernel space of a computing machine. The source filters330,330′, in some embodiments, stream data from any of the following sources: a driver; a device interface; a device; a communication module; a virtual channel306; a network; a memory repository; or any other information source. In many embodiments, the source filters330,330′ stream the multimedia data from a source at the kernel level rather than at the user level. In other embodiments, the source filters330,330′ can stream data at the user or program level. Data streamed by the source filters330,330′ is often forwarded to additional modules, programs, clients or filters executing within the framework320,320′. Just as the source filter330,330′ streams the multimedia data from a driver or other source, the source filter330,330′ can also stream the multimedia data to additional modules, clients, filters and programs executing within the framework320,320′.

The source filters330,330′ can comprise a single source filter, or can comprise multiple filters. These source filters330,330′ can be associated with a specific multimedia device, or can be associated with a specific multimedia data type, i.e. video, audio, text. In one embodiment, the source filters330,330′ can comprise a streaming module310for streaming multimedia content from a source such as a multimedia device driver316. The streaming module310, in some embodiments can be the KSProxy filter included within the DIRECTSHOW framework320,320′. When the streaming module310is the KSProxy filter or a module, filter or program having substantially the same functionality as the KSProxy filter, the streaming module310will stream multimedia data from a source such as a driver, device interface or other interface or communication port able to relay multimedia data to a program executing within the framework320,320′. In one embodiment, the streaming module310is included in the instance of the framework320,320′ installed on the computing machine connected to or in direct communication with the multimedia device302, just asFIG. 3Adepicts the framework320on the second computing machine300as comprising a streaming module310. In embodiments that include a framework320,320′ or application interface that is not DIRECTSHOW, the streaming module310can be any program able to retrieve raw, un-formatted multimedia data either from a multimedia device or from a driver or other interface communicating with the multimedia device.

In one embodiment, the source filters330,330′ can comprise a proxy streaming module308that corresponds to a streaming module310on a remote computing machine. For example, the proxy streaming module308executing within the instance of the DIRECTSHOW framework320′ executing on the first computing machine301corresponds to the streaming module310executing within the instance of the DIRECTSHOW framework320executing on the second computing machine300. The proxy streaming module308, however, streams multimedia data from one of either a network104, a virtual channel306such as the virtual channel306between the first computing machine301and the second computing machine300and any other multimedia source. The proxy streaming module308, in some embodiments streams the multimedia data from a virtual channel306by streaming the multimedia data from a temporary memory repository or cache on the computing machine. The application/desktop delivery system322or a program communicating with the application/desktop delivery system322stores the multimedia data into the temporary memory repository or cache after the application/desktop delivery system322receives the multimedia data from the remote computing machine, i.e. the second computing machine300. In other embodiments, the proxy streaming module308opens or otherwise establishes a channel within the virtual channel306, and streams multimedia data directly from the remote computing machine, i.e. the second computing machine300, over the established channel.

Other filters included within the framework320are the transform filter326,326′ and the renderer filter328,328′. The transform filter326,326′, in some embodiments, can input raw or formatted multimedia data and further manipulate, modify or transform the inputted data. For example, the transform filter326,326′ can input multiple video streams and splice those streams together according to a combination scheme or according to user instructions. In another embodiment, the transform filter326,326′ can input an audio stream and a video stream, synchronize the streams according to timestamp information included within each stream, and combine the streams into a single multimedia data stream. In yet another embodiment, the transform filter326,326′ can place text within video or perform other similar modifications to the inputted data stream.

The renderer filter328,328′, in some embodiments, can render the multimedia streams. In one embodiment, the renderer filter328,328′ can input an audio stream, and format the audio stream as needed before forwarding the audio stream to a sound card within the local computing machine. The renderer filter328,328′ in other embodiments can forward the audio stream to an audio player such as iTunes or Windows Media Player. In another embodiment, the renderer filter328,328′ can input a video stream, and format the video stream as needed before forwarding the video stream to a video card within the local computing machine. The renderer filter328,328′, in other embodiments, can forward the video stream to a video player such as iVideo or Windows Media Player. In yet another embodiment, the renderer filter328,328′ can draw received video to a screen, draw received graphics to a screen, draw received text to a screen, or write received multimedia data to a memory element.

In some embodiments, the DIRECTSHOW framework320,320′ can comprise an application sink filter330,330′ which can be used to stream formatted multimedia data from the DIRECTSHOW framework320,320′ to a display application314,314′. In one embodiment, there can exist an application sink filter330,330′ for each possible display application. In other embodiments, the application sink filter330,330′ forwards the multimedia data stream according to a file type or according to a configuration setting. In frameworks that use a multimedia technology different from the DIRECTSHOW framework, a renderer filter328can be referred to as a sink filter. Thus, in the DIRECTSHOW framework, the application sink filter330,330′ can be called the application renderer filter330,330′.

In other embodiments, the DIRECTSHOW framework320,320′ can comprise a multimedia sink filter312,312′ which can be used to receive the streamed multimedia data generated by the multimedia device302and transmit the streamed multimedia data over the virtual channel306to the remote computing machine, e.g. the first computing machine301. The multimedia sink filter312,312′, in some embodiments, can be a video/audio sink filter312,312′ that receives, processes and transmits both video and audio data. In other embodiments, the multimedia sink filter312,312′ can be a camera/microphone sink filter312,312′. In one embodiment, the video/audio sink filter312,312′ can be a type of renderer filter328. In frameworks that use a multimedia technology different from the DIRECTSHOW framework, a renderer filter328can be referred to as a sink filter. Thus, in the DIRECTSHOW framework, the video/audio sink filter312,312′ can be called the video/audio renderer filter312,312′.

WhileFIG. 3Billustrates a single multimedia device302,302′, in other embodiments the computing machines300,301can communicate with multiple multimedia devices. Similarly, the multimedia data stream received by the streaming module310and streamed from the virtual channel306by the proxy streaming module308can include one or more data streams originating from one or more multimedia devices. For example, the multimedia data stream can include data generated by two different cameras. The streaming module310can stream data from both cameras and the remoting application or application/desktop delivery system322,322′ can stream both camera data streams over the virtual channel306. The proxy streaming module308can then stream from the virtual channel306a single multimedia data stream that includes both the first and second camera data stream.

Illustrated inFIG. 3Bis an embodiment of the system303illustrating another scheme for the DIRECTSHOW framework320,320′. In one embodiment, the instance of the framework320executing on the second computing machine300comprises a KSProxy filter340, an encoder342and an interceptor344. The multimedia information/data obtained or received by the multimedia driver316executing on the second computing machine300, is streamed to the KSProxy filter340at the kernel level. The interceptor344streams the encoded multimedia information over a virtual channel306installed between the first computing machine301and the second computing machine300. The following components are included within the DIRECTSHOW framework320′ on the first computing machine301, a receiver346, a decoder347and a proxy multimedia device348. The proxy multimedia device348can communicate with a display application314executing on the first computing machine301.

Further referring toFIG. 3B, and in more detail, in one embodiment the KSProxy filter340functions substantially the same as the streaming module310. The KSProxy filter340, in many embodiments, streams multimedia data directly from the multimedia device driver316and streams the received multimedia data to other filters or modules included in the DIRECTSHOW framework320. In one embodiment, the KSProxy filter340streams the multimedia data from the multimedia device driver316at the kernel level. In other embodiments, the KSProxy filter340streams the multimedia data from the multimedia device driver316at the user or application level.

The encoder342can be any encoder. In one embodiment, the encoder342can receive the multimedia data from the KSProxy filter340and encode the multimedia data using any codec. In particular, the encoder342can encode the multimedia data using any codec described herein. The type of codec used to encode the multimedia data can be based on the type of data included in the multimedia data stream. For example, a video encoding codec can be used to encode video data, while an audio encoding codec can be used to encode audio data. In many embodiments, the encoder342can be communicatively connected to the KSProxy filter340or streaming module310such that the encoder342can stream multimedia data from either the filter340or the module310. In one embodiment, the encoder342and decoder347can negotiate security credentials and in some embodiments, can exchange encryption keys or other encryption agents.

The interceptor344can be communicatively connected to the encoder342such that the interceptor344intercepts multimedia data once it is encoded by the encoder342. There may be encoder/decoder negotiation involved. Such negotiation may be in accordance with ICA or RAVE virtual channel protocol. In some embodiments, the interceptor344can stream multimedia data directly from the KSProxy filter340or the streaming module310such that the multimedia data is not encoded by the encoder342. In another embodiment, the interceptor344includes substantially the same functionality as the multimedia sink filter312. The interceptor344, in some embodiments, communicates with the receiver346using a presentation level protocol. Upon receiving the multimedia data either from the encoder342, the KSProxy filter340/streaming module310or some other filter or module; the interceptor344transmits or streams the multimedia data to the receiver346. In one embodiment, the interceptor344encapsulates the multimedia data packets in a presentation level protocol before transmitting the multimedia data to a remote computing machine.

WhileFIG. 3Billustrates a framework320where the encoder342precedes the interceptor344, in other embodiments the interceptor344can intercept multimedia data and forward it to an encoder342. Thus, in this embodiment the interceptor344precedes the encoder342. In other embodiments, the placement of the modules within the frameworks320,320′ illustrated inFIG. 3Bdoes not indicate the order in which actions occur during the process of streaming multimedia data, processing the multimedia data, intercepting the multimedia data and transmitting the multimedia data, or the process of receiving and processing multimedia data transmitted over a virtual channel306.

The receiver346, in some embodiments, receives multimedia data from a remote computing machine and forwards the received data to other filters, modules, clients or programs executing within the DIRECTSHOW framework320′. In at least one embodiment, the receiver346can un-encapsulate multimedia data encapsulated in a presentation level protocol before streaming the multimedia data to other programs executing within the DIRECTSHOW framework320′. In another embodiment, the receiver346can stream the multimedia data to a decoder347or directly to a proxy multimedia device348.

The decoder347, in some embodiments, can decode received multimedia data using the codec used to encode the multimedia data. This codec can be any codec, and more specifically, can be any codec described herein. In one embodiment, the decoder347can decompress, decrypt or otherwise decode the multimedia data before streaming the multimedia data to another program or component executing within the framework320′.

The proxy multimedia device348can stream multimedia data from any of the filters included in the framework320′, but more specifically can stream multimedia data from either the receiver346or the decoder347. In one embodiment, the proxy multimedia device348streams the received multimedia data directly to the display application314so that the display application314can display or present the received multimedia data. In some embodiments, the framework320′ can comprise a proxy multimedia device348for each display application314. In other embodiments, the framework320′ can comprise a proxy multimedia device348for each type of multimedia data.

Illustrated inFIG. 4is an embodiment of a flow diagram that depicts an embodiment of the path350multimedia data travels from the time it is captured by a multimedia device to the point in time that a user views or hears the multimedia data. The path or process350includes a streaming module310or KSProxy filter340streaming multimedia data from a multimedia driver316,316′ that captures multimedia data generated by a multimedia device302,302′ (Step352). The multimedia data is then intercepted by a module within the framework320,320′ (Step354) and streamed to an encoder342or transformation filter326where the multimedia data is encoded using codecs324on the computing machine (Step356). The encoded multimedia data is then transmitted358over the virtual channel306(Step358) to a remote computing machine. Modules executing on the remote computing machine received the transmitted multimedia data and decode the data using codecs corresponding to those codecs used to encode the multimedia data (Step360). A proxy module streams the multimedia data from the application that received the multimedia data (Step362) and then transmits the multimedia data to a display application (Step364). The display application receives the streamed multimedia data and presents the multimedia data to a user. The application/desktop delivery application can then capture the presented data and send it back to the second computing machine300(Step366).

Further referring toFIG. 4, and in more detail, in one embodiment a streaming module310or KSProxy filter340streams multimedia data from a multimedia driver316,316′ that captures multimedia data generated by a multimedia device302,302′. In some embodiments, the streaming module310is a KSProxy filter340, while in other embodiments the streaming module is any application that can stream multimedia data directly from a multimedia driver316,316′. The streaming module310, in some embodiments, executes at the kernel level. In other embodiments, the streaming module301can execute at the user level.

In one embodiment, a module executing within the DIRECTSHOW framework320,320′ intercepts the multimedia data generated by the multimedia device302,302′ (Step354). In some embodiments, this module can be a streaming module310executing on a computing machine. In other embodiments, this module can be a proxy streaming module308executing on a computing machine. The module, in some embodiments, can intercept the multimedia data by streaming the multimedia data directly from a device driver316,316′. In other embodiments, the module can intercept the multimedia data by streaming the data from an intermediary or intermediate application communicating with the device driver316,316′.

In still other embodiments, an encoder342or transformation filter326encodes the multimedia data (Step356) prior to transmission. Encoding can include compressing, transforming or otherwise encrypting the multimedia data. In some embodiments, the encoder342or transformation filter326can encode the multimedia data using any encoding scheme. In other embodiments, the encoder342or transformation filter326can encode the multimedia data using any encryption algorithm, compressing algorithm or encoding algorithm described herein. WhileFIG. 4illustrates a process350that includes encoding the multimedia data stream, in some embodiments, the process350does not include an encoding step during which an encoder encodes the multimedia data.

The computing machine, in some embodiments, can then transmit the encoded multimedia data over the virtual channel306to a remote computing machine (Step358). In one embodiment, the application/desktop delivery system322transmits the encoded multimedia data over the virtual channel306. In other embodiments, the multimedia data is transmitted over a virtual channel306dedicated to a user of the computing machine.

In some embodiments, modules executing on the remote computing machine receive the transmitted multimedia data and decode the data using codecs corresponding to those codecs used to encode the multimedia data (Step360). The codecs, in some embodiments, can be transmitted along with the multimedia data. In other embodiments, the remote computing machine can request the codecs from the local computing machine. Upon receiving the codecs, a decoder or other decoding application can decode the encoded multimedia data. WhileFIG. 4illustrates a process350whereby the multimedia data is decoded, in some embodiments the multimedia data is not encoded and therefore need not be decoded.

Once the remote computing machine receives the multimedia data, in some embodiments a streaming module310or proxy streaming module308streams the multimedia data from the receiving application (Step362). In some embodiments, the proxy streaming module308streams the multimedia data from the application/desktop delivery system322′. In other embodiments, the streaming module310streams the multimedia data from the application/desktop delivery system322. When the streaming module310or proxy streaming module308streams the multimedia data from the application that received the multimedia data, the module310,308can stream the multimedia data into the DIRECTSHOW framework320,320′. In some embodiments, the multimedia data can be further processed by filters or applications executing within the framework320,320′ subsequent to streaming the multimedia data into the framework320,320′.

In one embodiment, the proxy streaming module308can forward the multimedia display to a display application for display (Step364). A display application, in some embodiments, can be any display application able to display, play or present multimedia data. In other embodiments, a display application can be any display application described herein. Forwarding the multimedia data to the display application can include streaming, transmitting or otherwise sending the display data to the display application. In some embodiments, forwarding the multimedia data can include formatting the multimedia data using one or more filters included in the DIRECTSHOW framework320,320′. In other embodiments, forwarding the multimedia data can include formatting the multimedia data according to one or more filters of the display application.

In one embodiment, the display application displays, plays or presents the multimedia data upon receiving it from the proxy streaming module308. The display application, in other embodiments, can display and/or present the multimedia data on a display device communicating with the computing machine on which the display application executes. In other embodiments, the display application plays the multimedia data on speakers communicating with the computing machine on which the display application executes.

A remoting application, in some embodiments, intercepts the application output generated by the display application, and sends the display data of the displayed or played multimedia data to a second computing machine or client (Step366). Intercepting the application output can include intercepting graphics generated by the display application, audio data generated by the display application, and or video generated by the display application. In some embodiments, the remoting application is a remote access client such as XEN APPLICATION, OR XEN DESKTOP manufactured by CITRX SYSTEMS, INC. In other embodiments, the remoting application can be any client that uses a presentation level protocol to intercept application output and transmit that output to remote computers or devices.

Illustrated inFIG. 5Ais one embodiment of a method500for remotely presenting multimedia output. In one embodiment, a multimedia device302,302′ generates multimedia data (Step502) and a multimedia device driver316,316′ retrieves or receives the multimedia data from the multimedia device (Step504). A streaming module310executing on a computing machine streams or passes the multimedia data from the multimedia device driver316(Step506) to one or more filers and/or modules executing within a DIRECTSHOW framework320,320′ (Step508). An application/desktop delivery system322,322′ or remoting application then intercepts the multimedia data (Step510) and transmits the multimedia data over a virtual channel306(Step512).

Further referring toFIG. 5A, and in more detail, in one embodiment a multimedia device302,302′ generates multimedia data (Step502). The multimedia device302,302′ can be any multimedia device, while in some embodiments the multimedia device302,302′ can be any multimedia device described herein. In some embodiments, the multimedia device302,302′ can be connected to or communicating with a second computing machine300. In other embodiments, the multimedia device302,302′ can be connected to a first computing machine301, or any other computing machine or computing machine. In some embodiments, the multimedia device302,302′ generates multimedia data by recording video, graphics or audio. For example, the multimedia device302,302′ can be a video or web camera that can capture an image of a scene over a period of time. Capturing the scene can include generating a video and/or an audio representation of events that occur within the scene during a period of time. The period of time, in some embodiments, is a period of time the device302,302′ is set to record the events that occur within the scene. The scene, in some embodiments, can be an area able to be viewed or heard by a lens and/or a microphone of the device302,302′. Thus, the device302,302′ can record the movements and speech of a person who talks in front of the device's lens and microphone.

In some embodiments, a multimedia device driver316,316′ executing on the computing machine can retrieve the multimedia data from the multimedia device302,302′ (Step504). Retrieving the multimedia data, in some embodiments, can include receiving data transmitted by the multimedia device302,302′ to the device driver316,316′. For example, the multimedia device302,302′ can generate multimedia data and substantially at the same time transmit that multimedia data over a connection between the device302,302′ and the computing machine, to the computing machine. In some embodiments, the multimedia device driver316,316′ can receive the raw output from the multimedia device302,302′ and translate it into commands able to be to interpreted by the operating system, the DIRECTSHOW Framework320,320′ and other applications executing on the computing machine. In other embodiments, the multimedia device302,302′ can transmit, stream or otherwise send generated multimedia data to the computing machine where the multimedia data is stored in memory. The multimedia device driver316,316′ can then retrieve the multimedia data from the memory element.

A streaming module310executing on the computing machine can, in some embodiments, stream the multimedia data from the multimedia device driver316,316′ (Step506). WhileFIG. 5Aillustrates a method500where the streaming module310streams data from the multimedia device driver316,316′, in some embodiments the streaming module310can stream the multimedia data directly from the multimedia device302,302′. In other embodiments, the streaming module310can stream the multimedia data from the driver316,316′ at the kernel level rather than at the user level. The streaming module310, in many embodiments, executes within the DIRECTSHOW Framework320,320′ on the computing machine. Thus, the streaming module310can stream multimedia data from the multimedia device driver316,316′ into the framework320,320′.

In some embodiments, the streaming module310streams the multimedia data to other filters or modules executing within the DIRECTSHOW Framework320,320′ (Step508). Streaming the multimedia data to the filters and modules can include passing, transmitting or otherwise sending the multimedia data to the filters and modules. In some embodiments, the streaming module310can stream the multimedia data to a filter or module in response to a request from a filter or module for the multimedia data. In one embodiment, the streaming module310can stream the multimedia data from the multimedia device driver316to any transform filter326,326′, renderer filter328,328′, and/or video/application sink filter. The streaming module310, in some embodiments, in a source filter330such that the streaming module310streams multimedia data from the multimedia device driver316,316′ and provides the streamed multimedia data to any filter or module that wants or tries to access the multimedia data. In some embodiments, the streaming module310streams the multimedia data to filters and modules executing in the framework320,320′ and associated with the display application314,314′.

A remoting application, in some embodiments, can intercept the multimedia data at any time after it is streamed from the multimedia device302,302′ (Step510). In some embodiments, the remoting application can be any remoting application described herein. In other embodiments, the remoting application can be the application/desktop delivery system332. In still other embodiments, the remoting application can be any application, thin client or program that executes on the computing machine and that uses a presentation level protocol to transmit application data to a remote computing machine. Intercepting the multimedia data, in some embodiments, can include hooking into the DIRECTSHOW Framework320,320′ so that any calls made to a local presentation or display application can be intercepted by the remoting application. Upon intercepting or receiving the calls, the remoting application can extract the multimedia data included in the call and transmit the multimedia data to a remote computing machine. In some embodiments, the remoting application can be a module or program that executes within an application/desktop delivery system322,322′. The module or program can register as a display application such that each time multimedia data is processed by the DIRECTSHOW Framework320,320′, the module or program receives the processed multimedia data instead of other display applications executing on the computing machine. In this embodiment, the remoting application can receive or capture the multimedia data.

The remoting application, in some embodiments, transmits the multimedia data over a virtual channel306to a remote computing machine (Step512). In some embodiments, the remoting application can encapsulate or modify the multimedia data using a remote presentation protocol tailored towards transmitting multimedia data. Upon encapsulating the multimedia data using this protocol, the delivery system322,322′ can then transmit the encapsulated data to a remote computing machine. WhileFIG. 5Aillustrates a method500where the multimedia data is transmitted to one remote computing machine, in some embodiments, the multimedia data can be transmitted to one or more remote computing machines communicating with the computing machine via a virtual channel306.

In some embodiments, the method500can further include a step of locally display the captured or intercepted multimedia data. Subsequent to intercepting the multimedia data, the display preview application323,323′ executing on the second computing machine300can receive and process the multimedia data. Instead of transmitting the multimedia data over a virtual channel306(Step512), the display preview application323,323′ can query the This display preview application323,323′ can query a remote computing machine for control information related to a display application, and using this information the display preview application323,323′ can generate an application output window. The display preview application323,323′ can then display the multimedia data in the application output window. Displaying the multimedia data can also include playing audio data included in the multimedia data.

In one embodiment, the remoting application or any application or program executing on a computing machine to transmit the intercepted multimedia data over a virtual channel (Step512) can perform one or more quality control operations. In some embodiments, a quality control operation can include determining an amount of available bandwidth on the virtual channel306, and varying the transmission rate according to the determined bandwidth. For example, when there is a low amount of available bandwidth, the program may transmit multimedia data over the virtual channel306at a slower rate in order to achieve optimal throughput and maximum quality. In other embodiments, a quality control operation can include sending a command to a streaming module310, video filter312or any other program to sample the multimedia data from the multimedia device302at a slower rate. In one embodiment, this command can include data indicating an amount of available bandwidth. In other embodiments, this command can include a sample rate determined based on an amount of available bandwidth.

Illustrated inFIG. 5Bis an embodiment of a method530for receiving remotely provided multimedia data, and processing that multimedia data. In one embodiment, a proxy streaming module308executing within the DIRECTSHOW Framework320,320′ of a remote computing machine streams multimedia data from a virtual channel306(Step532) and decodes the streamed multimedia data (Step534). The proxy streaming module308then passes the multimedia data to other filters and modules within the DIRECTSHOW Framework320,320′ (Step536). A filter or module within the DIRECTSHOW Framework320,320′ then forwards the multimedia data to a display application314,314′ (Step538) which displays the multimedia data (Step540). In some embodiments, a remoting application executing on the remote computing machine intercepts the output generated by the display application (Step542).

Further referring toFIG. 5B, and in more detail, in one embodiment a proxy streaming module308streams multimedia data from the virtual channel306(Step532). In some embodiments, the proxy streaming module308executes on a remote computing machine, and streams the multimedia data from a virtual channel306between a computing machine and the remote computing machine. The multimedia data, in some embodiments, is generated by a multimedia device communicating with the computing machine, transmitted over the virtual channel306to the remote computing machine, and streamed from the virtual channel306by the proxy streaming module308. In some embodiments, an application/desktop delivery system322,322′ or remoting application receives the multimedia data transmitted over the virtual channel306and the proxy streaming module308streams the multimedia data from the application/desktop delivery system322,322′. In this embodiment, the proxy streaming module308can be a part of the application/desktop delivery system322,322′ while being registered as a source filter within the DIRECTSHOW Framework320,320′.

In some embodiments, the multimedia data stream is decoded (Step534). The proxy streaming module308, in some embodiments, decodes the multimedia data stream, while in other embodiments the application/desktop delivery system322,322′ or remoting application decodes the multimedia data stream. In some embodiments, the multimedia data stream is decoded using codecs324,324′.

In some embodiments, the proxy streaming module308passes or streams the multimedia data to other filters or modules executing within the DIRECTSHOW Framework320,320′ (Step536). Passing the multimedia data to the filters and modules can include streaming, transmitting or otherwise sending the multimedia data to the filters and modules. In some embodiments, the proxy streaming module308can stream the multimedia data to a filter or module in response to a request from a filter or module for the multimedia data. In one embodiment, the proxy streaming module308can stream the multimedia data to any transform filter326,326′, renderer filter328,328′, and/or video/application sink filter. The proxy streaming module308, in some embodiments, in a source filter330such that the proxy streaming module308streams multimedia data to any filter or module that wants or tries to access the multimedia data. In some embodiments, the proxy streaming module308streams the multimedia data to filters and modules executing in the framework320,320′ and associated with the display application314,314′.

In one embodiment, the multimedia data is forwarded to the display application (Step538) and displayed by the display application (Step540). Displaying the data can include playing, displaying or otherwise presenting the multimedia data. In one embodiment, displaying the multimedia data can include displaying video chat or web camera output within a display application such as Google Talk®, Microsoft Communicator®, Instant Messenger®, or any other display application.

The remoting application or application/desktop delivery system322,322′ can then intercept the display application output and transmit it back to the computing machine (Step542). For example, the remoting application can intercept output generated by Google Talk®, Microsoft Communicator®, Instant Messenger®, or any other display application and transmit that output to the computing machine. Upon receiving the output, the computing machine can display the output in an application window and/or play the output using one or more audio applications.

In some embodiments, the method530may not include intercepting the output generated by the display application (Step542). Instead, in this embodiment the display application merely displays the multimedia data (Step540). Displaying the multimedia data can include playing audio, display video or any other display or presentation of the multimedia data. In this embodiment, the second computing machine300, (or the local computing machine communicating with the multimedia device) merely supplies the first computing machine301(or the remote computing machine executing the display application) with multimedia data. The first computing machine301displays the multimedia data and does not transmit application output to the second computing machine300for display on a display device connected to the second computing machine300.

Referring now toFIG. 5C, a high level embodiment of a system for delivering support for desktop video conferencing applications on remote network devices, such as XenApp or XenDesktop is illustrated. The present system may, in some embodiments, be referred to as Helios, reverse RAVE or a bi-directional RAVE system. The system may be used for providing video conferencing solutions to users using remote XenApp & XenDesktop machines. The system may include various functions and features, such as codecs and protocols for communicating data and instructions between the client and the servers. The system may support Microsoft Office Communicator (OCS) video and audio communications between the client and the server. In some embodiments, the present system supports conferencing applications like Skype and GoogleTalk. In such embodiments, a client using a locally connected camera may use the instant messenger video conferencing that executes on a remote server. The system may be designed to be functional on multiple platforms and operating systems, including all the operating systems and platforms described herein.

In brief overview toFIG. 5C, the system illustrated may relate to an embodiment in which multiple clients are communicating using a multimedia videoconferencing application hosted on a remote server. A client102A, also referred to as an ICA client, may be connected to a capture device, such as a microphone or a video camera. The capture device may capture and transmit to the client raw audio and/or video data. Client102A may be interested in communicating with another client102B via an audio and/or video conferencing application executing on the server106. Client102may not have or use a locally executing multimedia videoconferencing application and may wish to use such an application executing on the server106. The server106, also referred to as XenApp or XenDesktop server, may host any number of audio and/or video conferencing applications, such as, for example, the Microsoft Office Communicator, Skype, GoogleTalk, Yahoo instant messenger, MSG instant messenger or any other type and form of application enabling audio and/or video conferencing. Clients102A and102B may establish a virtual channel with the server106in order to commence the audio/video conference.

The capture device, such as the webcam connected to client102A, may generate an audio/video stream. The audio/video data may be generated in any number of formats. The ICA client102may pick a particular native format of the audio/video data and may compress the data in order to transmit it over the ICA to the server106. The server106may decompress the data and deliver the data to the hosted application. The application may then process the data and take care of the jitter and conversion of the format as it would normally do with any data from a locally connected capture device. The multimedia application may load Citrix webcam filter which may interface with the multimedia application in a manner in which it appears to the application as a real capture device, or a camera. The filter may communicate with the application and appear as a standard capture device, thus enabling the application to receive the raw data from the remote capture device via the filter while treating the data as if received from a local capture device. In such instances, the application may treat the filter which delivers the data from the remote client102, as the standard, locally connected capture device or a camera. The application may therefore receive the raw data and process the data as if the data was generated from a local video camera, based on the settings by which the application believes that the filter provided is in fact the camera itself.

Referring now toFIG. 5D, an embodiment of a system that uses one or more custom made filters to enable a multimedia application on a remote server to process audio/video data generated by a capture device connected to a client machine is illustrated. In brief overview, the system may leverage DirectShow technology as a part of the Microsoft Windows operating system in order to intercept video from the capture devices, transcode and compress the video is illustrated. Generally, manufacturers of capture devices may supply drivers that plugin to Microsoft's Kernel Streaming architecture. DirectShow may include a layer that sits on top of the Kernel Streaming layer that may exchange data between applications and the capture devices. Such a DirectShow layer may be implemented as a normal filter that interacts with the multimedia topology much the same way other filters do. In some embodiments, a custom made filter may be designed and provided to replace the functionality of the DirectShow capture filter. DirectShow may provide an API for implementing this feature, so no hooks may be needed. In some embodiments, the custom filter may be registered under capture devices category, thus making the filter available to the system device enumerator. When hosted capture applications enumerate the capture devices, such as the cameras or microphones, these hosted capture applications may instantiate the system device enumerator and then enumerate the capture devices category. In essence, the new capture filter may become visible to the hosted applications as just another webcam. In such embodiments, the users may only need to select a selection option associated with the filter in the application options. Once the new capture filter is loaded by the application, the filter may communicate with the client over the ICA protocol.

Typically, capture devices may provide several different formats that capture applications can choose from. DirectShow may provide an interface, such as IAMStreamConfig interface, which applications may use to select the output format of the capture device. The new capture filter may implement this interface and return raw formats that are compatible with the codec being used for the system. The ICA client may then create a filter graph and loads the capture device along with a video sink filter. The video sink filter may be designed to receive the video from the capture device and to communicate with the host-side capture filter over ICA. Such a filter may be visible to the applications as just another webcam, so users only need to select it in the application options. Once this webcam filter is loaded by the application, it may communicate with the client over the ICA protocol.FIG. 5Dillustrates an embodiment of system in which a number of filters of the system are illustrated. In some embodiments, the system supplies3filters that plug-in to the DirectShow filtergraph (pipeline). These filters may include the Citrix interceptor filter, the Citrix receiver filter and the aforementioned webcam capture filter. The rest of the filters illustrated inFIG. 5Dmay be standard Microsoft or third-party components. When a webcam filter gets loaded by the application on the server, this filter may send a message to the client to create a filtergraph and load the real webcam along with the encoder and interceptor filter. When the application begins requesting data from the webcam filter, the request may be forwarded to the client, which then may start pushing media samples upstream. The system may include functionality for audio and video synchronization to ensure that the audio and video streams delivered are in sync. In some embodiments, the application, such as the Microsoft Office Communicator, Skype or GoogleTalk may render the video incoming to the server using a graphics API, which is then remoted as a graphics virtual channel over ICA. In some embodiments, the incoming as well as outgoing stream may be compressed. For example, the multimedia incoming stream, comprising audio and/or video, may be remoted over forward (host to client) RAVE, or the Multimedia Acceleration Virtual Channel. Upon receipt, the client may then decompresses and render the multimedia stream. In some embodiments, the multimedia stream gets rendered in the host session. For video, this may result in GDI/graphics operations to be transmitted to the client rather than the compressed native video. For audio, the data is delivered as raw or PCM format to the Citrix Remote audio endpoint component in the remote session. The Citrix Remote audio endpoint might compress it before sending it over an audio Virtual Channel to the ICA client. The ICA client then may decompress the audio data and render it.

Referring now toFIG. 5E, an embodiment of an ICA engine is illustrated. The ICA engine may be referred to as a high level abstraction of the process operations on a client side with respect to the data capture and transmission to the server106. In brief overview, a driver of a capture device, such as a Webcam KS Driver operates in the kernel space of the client102. Platform abstraction layer may be responsible for setting up the DirectShow pipeline and loading the actual webcam components, such as for example the data generated by the capture device. The webcam KS driver may communicate with KsProxy DirectShow Filter, which may then forward the data to the intermediate conversion filters which finally forward the data to Citrix Video Sink DirectShow filter, which may also be known as CtxDSSink.dll. The data may then be forwarded to Protocol Link, also referred to as ClientMMLink.dll. The protocol link component may abstract the virtual channel implementation details from the video sink filter. The protocol link may also take care of the common tasks, such as for example compression. One or more codecs may be used for compression or decompression. In some embodiments, system may use Theora codec for compression and/or decompression. The data may be forwarded to the virtual channel, which may also be referred to as vdmm.dll. Virtual channel may perform stream aggregation and session management. Virtual channel may also maintain communication with the server106, such as the XenApp/XenDesktop server host using an extended version of RAVE ICA protocol. The data may then be transmitted over to the server106.

The system may compress the video on the client before sending it over the network. Compression may be needed in order to reduce the amount of bandwidth consumed by the video. For example, 30 frames per second of raw RGB24 data at CIF 352×288 resolution may require about 72990720 bps (almost 73 Mbps!). Clients may consume less CPU cycles compressing the video and then sending it over the network compared to just sending huge amounts of uncompressed video.

The codec used may be any codec for processing audio and/or video data. In some embodiments, the codec comprises source code that is editable in order to modify it and incorporate it into the filters/sinks for each multimedia platform. The coded may also need it to be able to control the encoder settings in real-time. In some embodiments, the codec does not have any hard dependencies on the platform which would preclude us from incorporating it into other platforms, such as for example Windows, Linux or Macintosh. In further embodiments, the codec is fast enough to process at least 30 frames per second or more. In some embodiments, the codec processes at any speed, such as 10 frames per second, 20 frames per second, 30 frames per second, 40 frames per second, 50 frames per second, 60 frames per second, 70, frames per second, 80 frames per second, 90 frames per second or 100 frames per second. In further embodiments, the codec processes data at more than 100 frames per second, such as 110, 120, 150, 180, 200 and up 500 frames per second.

Referring now toFIG. 5F, an embodiment of an application space is illustrated. The video may be received from the virtual channel implemented in mmvd.dll. The virtual channel may be hosted in the Wfshell.exe process. The virtual channel may perform stream aggregation and session management and may communicate with the client using the RAVE ICA protocol. Data may be transmitted up to the protocol marshalling interface. The protocol marshalling interface may be a layer that communicates with the virtual channel using a named pipe. Codec may receive data and may compress or decompress the data using Theora functionality. The data may be forwarded to the protocol link, also referred to as HostMMLink.dll. The protocol link component may abstract the virtual channel implementation details from the video sink filter and take care of the compression/decompression, as necessary. Data may be received and processed by Citrix Webcam DirectShow filter, which may forward it to the intermediate conversion filters, which may then forward the data to application sink filter. Application, which had already taken care of the DirectShow pipeline and setup the webcam filter, may receive the data, and display it.

Referring now toFIG. 5G, an embodiment of a protocol sequence is illustrated. The protocol sequence may be designed to minimize the protocol related code inside of the filters. The filters may be modified to handle things that are specific to the multimedia platform, while being as independent from the protocol sequence as possible. All other common functionality may be abstracted out of the filters and put in a common component. Such feature may make it easier to port the filters to other multimedia frameworks, such as, for example Windows Media Foundation and GStreamer. In some embodiments, the system may re-use and leverage the existing RAVE virtual channel instead of creating a new one. In such embodiments, an existing ICA virtual channel system may provide any available virtual channels via which the present system may operate.

Referring toFIG. 5Gin greater detail a protocol sequence between a host and a client is illustrated. A host, such as a server106, may transmit a create stream request to a client102. The client may transmit create stream response back to the server106. The client may create topology and load video sink filter. The host server may load the capture filter, such as the customized filter which the application treats as a capture device. Application on the host may start the capture. The instruction to play may be transmitted from the host server to the client. The client may produce the samples using the capture device and transmit the samples to the host server. The host server may deliver the samples to the application. The application, mistaking the capture filter for the capture device will operate as if the data was being delivered from a locally connected capture device. Once the application sends the instruction to stop the capture, the client tears down the topology. The host server may transmit the request to delete the stream request. The host may also unload the capture filter.

In yet another embodiment, the client machine can directly (locally) display the multimedia data captured by the local multimedia device in an application output window. This operation may be referred to as a local preview and may be an optimization compared to streaming the data from the server machine back to the client machine where it originated. The client machine may need to be made aware of where and how to display the data, such as for example the parent app window, preview window size, position, in-remote-session clipping. The client machine may receive control information instead of the multimedia data from the presentation application running on the server machine.

For example, in some embodiments in which two clients communicate via teleconference the multimedia data captured by a local multimedia capture device on a first client may be processed, rendered and displayed locally on the first client directly, while only the application output multimedia data from a second client processed by the presentation application on the remote server is received from the remote server. In such embodiments, the second client may also process and display the locally generated multimedia data on the second client, while receiving from the remote server the multimedia application output data of the first client from the remote server. In such embodiments, both clients can help save the bandwidth by not requiring the remote server to transmit back the locally generated multimedia stream but instead using the locally generated multimedia to display it locally while relying on the remote server only to deliver the multimedia output data of the multimedia stream generated from the other remote client. Both host server and client machines may be configured to be senders as well as receivers of commands or instructions needed to transmit and/or process the multimedia data. In more detail in reference toFIG. 5G, virtual channel protocol communication between the client and the host server, which may also be referred to as RAVE VC or RAVE virtual channel, may be negotiated in order to facilitate the transmission of multimedia data between the client and server. Client to host (or client to host server) media streams or transmissions may be supported based on a version of protocol or a type of settings.

Client-to-host (C2H) media streams may allow for selection of a specific capture device by the host, negotiation of native media types (including resolution) supported by the device, and negotiation of optional RAVE VC-level compression media types, such as the Theora codec. The Multimedia Virtual Channel Protocol may comprise the support for C2H (capture) media streams, which may be known as reverse-RAVE, which may also be negotiated by means of the CTXMM_TYPE_CAPABILITY_C2H_MEDIA_STREAMS capability. The exact media stream type may be determined by the type of media property elements supplied in the MMVD_CMD_CREATE_CONTEXT_REQUEST command.

In one example, the client may notify the host of media capture devices over the Control Virtual Channel (VC) by means of Plug-and-Play (PnP) notifications. The Control VC may supply a media capture device description and a non-empty list of native media Types supported by the device. As part of a type, the capture resolution may be defined. For example, for clients that do not implement this capability over the Control VC, the host may assume the presence of one default Device with default (uncompressed/raw) native Type and default resolution. The host server, as well as the presentation application may select a specific media device, and also requests the usage of a specific native media type to be used with the selected device, plus the compression media types supported by the host that can be used over the RAVE VC, listed in order of decreasing preference. If only one Type is supplied, then no compression may be applied by the RAVE VC itself, although the native media type supported by the selected device could still be a compressed type. If more than one Type is supplied, the client may decide whether to use compression over the RAVE VC itself by choosing one of the media types supplied by the host.

Any compression type may be used for compressing the data. The compression type capability negotiation may be implemented on a per stream context basis, as opposed to globally for the ICA session in order to provide more flexibility. For example, the RAVE VC might encode directly in a media type format that the host presentation application expects and avoid trans-coding over the VC.

Plug and play notifications may be transmitted between the client and the hosting server in order to enable the server to treat a filter or a function associated with the client and executing on the server as a multimedia capture device. In some embodiments, a plug and play notification is transmitted from the client to the server via a virtual channel. At the server side, an agent, such as a filter associated with multimedia communication between the server and the client, may receive the plug and play notification and pass it on to the relevant presentation application. The application may process the plug and play notification and identify the agent or the function executing on the server as a particular capture device, such as a web camera or a microphone locally connected to the server. In actuality, the agent may only represent a function for the hosted application's communication with a capture device, such as a web camera connected to the client. The application may then communicate with the agent as if it is a multimedia capture device. The agent may forward the communication, instructions and data, as necessary, between the client and the presentation application. As such, the hosted application may process the data from the remote capture device, as necessary. Plug and play features are described in U.S. Pat. No. 7,702,750, entitled “System and Method for Event Detection and Re-direction over a Network using a Presentation Level Protocol”, filed on Sep. 29, 2004 and U.S. patent application Ser. No. 12/763,492, entitled “System and Method for Event Detection and Re-direction over a Network Using a Presentation Level Protocol”, filed on Apr. 20, 2010, both of which are incorporated herein by reference in their entirety.

In some embodiments, in order to set up a direct, client to client streaming, a direct connection between the endpoint A and endpoint B needs to be established. Endpoint A′ (in the virtualized session on the server) may only serve as a proxy for hand-shake and control with Endpoint B, but the video is channeled from the local web cam (Endpoint A) directly to Endpoint B. Endpoint A may be a local Web Cam on the local client machine. Endpoint A′ may be referred to as the application in the virtualized/remote session. Endpoint B may include the entity on the other side of the video/audio communication. In some embodiments, the client side video sampling rate may vary based on bandwidth availability in order to achieve optimal throughput and maximum possible quality.

While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the methods and systems described herein. Additionally, it is possible to implement the methods and systems described herein or some of its features in hardware, programmable devices, firmware, software or a combination thereof. The methods and systems described herein or parts of the methods and systems described herein may also be embodied in a processor-readable storage medium or machine-readable medium such as a magnetic (e.g., hard drive, floppy drive), optical (e.g., compact disk, digital versatile disk, etc), or semiconductor storage medium (volatile and non-volatile).