Patent Publication Number: US-8970661-B2

Title: Routing for video in conferencing

Description:
BACKGROUND 
     Video conferencing is a technology that has been instrumental in the advancement and development of global commerce. Video conferencing can facilitate meetings and collaborations between parties in different geographic locations, including different cities, states or provinces, and even different continents. Video conferencing can be conducted using dedicated video conferencing applications, or integrated into applications or websites for collaboration, social networking, public forums, and the like. In addition, dedicated and secured video conferencing systems can be used in business environments. 
     A video conferencing system typically includes one or more video capture devices in communication with a video conferencing server over a network. Some video conferencing systems even allow users to view multiple video streams at the same time. Video conferencing systems also typically include an audio capture device in communication with the video conferencing server. 
     The video and audio streams are generally communicated to the video conferencing server as digital data streams, such as Internet Protocol (IP) data streams. In other systems, the video is communicated independently of the audio. For example, some systems only communicate the video to the video conferencing server, while the audio is communicated via a telephone bridge. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
     Regardless of the actual system configuration, it is often valuable to be able to link the audio and video signals coming from the same user in a video conferencing system. Multiview systems allow video streams from several video conferencing participants to be displayed simultaneously to users. In such systems, it is helpful to identify the last few Dominant Speakers (DS) so that the video associated with the DS may be displayed to users. A variety of criteria may be used to identify the DS, for example the speaker with the highest volume audio signal may be selected as a DS. Alternatively, a speaker with a most active audio signal may be selected as a DS. 
     Once the DS is identified by the video conferencing server, the video conferencing server may then push the video stream associated with the DS to the participants, and each participant&#39;s video conferencing application may indicate the DS in some way. For example, the video of the DS may be rendered in a larger window. Alternatively, the video of the DS may be highlighted or tagged in some manner. 
     Embodiments of methods and systems for active speaker identification in video conferencing are described. Such methods and systems identify a list of DSs. In one embodiment, the list includes identification of a group of most recent DSs. In another embodiment, the DS list includes identification of a group of most active DSs. In one embodiment, the DS list may include a Media Source Identifier (MSID) associated with each of the DSs on the list. The DS list may be distributed to each client in the video conference. 
     In one embodiment, each of the clients may request a set of video streams for rendering by the client. In one embodiment, the client may request the set of video streams associated with the DSs identified on the DS list. Alternatively, each participant may request a set of video streams associated with a user selection. In still another embodiment, a combination of the DSs on the DS list and the user selection may be requested by the client. 
     A computer-implemented method performing one embodiment receives one or more data stream identifiers. Each data stream identifier is associated with a data stream available from a media source. A media source identifier (MSID) is assigned to the media source. The data stream identifiers available from the media source are mapped to the media source identifier assigned to the media source. 
     A source may generate multiple video streams. Each stream may be at a different resolution and/or produced by a different codec. The video streams may be labeled with a video stream identifier. One or more stream identifiers may be associated with a requested media source identifier. One or more stream identifiers may be associated with the requested media source identifier and a requested video quality. Video streams associated with the one or more stream identifiers may be provided to a remote device in response to a media request. 
     In other embodiments, a list of dominant speakers may be generated. The list of dominant speakers may be provided to a client. The list of dominant speakers may comprise a media source identifier for each of the dominant speakers. One or more data streams associated with each of the media source identifiers on the dominant speaker list may be automatically provided to a client device. 
    
    
     
       DRAWINGS 
       To further clarify the above and other advantages and features of embodiments of the present invention, a more particular description of embodiments of the present invention will be rendered by reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  is a schematic block diagram illustrating one embodiment of a system for active speaker identification in video conferencing. 
         FIG. 2  is a schematic block diagram illustrating one embodiment of signal communications in a system for active speaker identification in video conferencing. 
         FIG. 3  is a schematic block diagram illustrating another embodiment of a system for active speaker identification in video conferencing. 
         FIG. 4  is a schematic block diagram illustrating another embodiment of signal communications in a system for active speaker identification in video conferencing. 
         FIG. 5  is a schematic block diagram illustrating one embodiment of a computer system suitable for use in a system for active speaker identification in video conferencing. 
         FIG. 6  is a schematic block diagram illustrating one embodiment of an apparatus for active speaker identification in video conferencing. 
         FIG. 7  is a schematic block diagram illustrating a further embodiment of an apparatus for active speaker identification in video conferencing. 
         FIG. 8  is a schematic flowchart diagram illustrating one embodiment of a method for active speaker identification in video conferencing. 
         FIG. 9  is a schematic block diagram illustrating another embodiment of system for active speaker identification in video conferencing. 
         FIG. 10  is a diagram illustrating one embodiment of a video conferencing participant&#39;s screen view. 
         FIG. 11  is a schematic flowchart diagram illustrating another embodiment of a method for active speaker identification in video conferencing. 
         FIG. 12  is a diagram illustrating another embodiment of a video conferencing participant&#39;s screen view. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments disclosed herein are directed to methods, systems, and software for active speaker identification in video conferencing. These systems and methods may be incorporated into a wide range of systems and solutions for video conferencing, including for example, dedicated video conferencing systems, web-based video conferencing systems, and application-driven video conferencing systems. Certain embodiments may be incorporated into applications with additional content, such as collaboration software, and may provide a significant commercial benefit over previous versions of such software because of an enhanced overall user experience. 
       FIG. 1  is a schematic block diagram illustrating one embodiment of a system  100  for active speaker identification in video conferencing. The system  100  may include one or more media sources  102   a - n  coupled to a Multipoint Control Unit (MCU)  106 . In one embodiment, the media sources  102   a - n  are coupled to the MCU  106  through a network  104 . In addition, one or more media requestors  108   a - n  may be coupled to the network  104 . One of ordinary skill in the art may recognize various topologies of system  100  that may be more or less suitable for use with the present embodiments. 
     In one embodiment, the media sources  102   a - n  may include video capture devices. The video capture devices may include, for example, a video camera, webcam, or other specialized video conferencing capture device. In certain embodiments, the video capture device may be coupled to a computer or other hardware suitable for running a video codec which may generate one or more data streams from the video captured by the video capture device. The media sources  102   a - n  may then each transmit the data streams through the network  104 . In one embodiment, the media sources  102   a - n  may transmit the data streams to the MCU  106 . Alternatively, the media sources  102   a - n  may transmit the data streams to the media requestors  108   a - n  at a destination device upon receiving instructions from the MCU or a direct request from one of the media requestors  108   a - n.    
     In one embodiment, the network  104  may include one or more network routing devices. For example, the network  104  may include one or more Internet routing devices configured to route traffic from the media sources  102   a - n  to, for example, the MCU  106 . 
     The MCU  106  may be configured to route audio and/or video from the media sources  102   a - n  to the media requestors  108   a - n . Because the MCU  106  handles routing of audio and video data streams, the MCU  106  is sometimes referred to as an Audio Video MCU (AVMCU). In one embodiment, the MCU  106  may be configured as a bridge to connect calls from multiple sources. Participants in a video conference may call the MCU  106 , or alternatively the MCU  106  may call the participants once video conference configuration information has been set. The MCU  106  may use various communication protocols, such as IP, Voice Over IP (VOIP), or Plain Old Telephone Service (POTS) networks for communication of video and/or audio data streams. In one embodiment, the MCU  106  may be configured as a web-based server of a web-based video conferencing application. In another embodiment, the MCU  106  may operate in the background, participating only in the routing of data streams between the media sources  102   a - n  and media requestors  108   a - n.  The MCU may be configured in software, hardware, or a combination of the two. 
     A media requestor  108   a - n  may be a computing device configured to receive media data streams originating from the media sources  102   a - n  and render the data streams into displayed video. In one embodiment, a media requestor  108   a - n  may be a desktop computer. In another embodiment, the media requestor  108   a - n  may be a laptop, tablet, or mobile Personal Computer (PC). In still a further embodiment, the media requestor  108   a - n  may be a smartphone, Personal Data Assistant (PDA), mobile phone, or the like. One of ordinary skill in the art will recognize various embodiments of a media requestor  108   a - n  that may be adapted for use with the present embodiments. 
       FIG. 2  is a schematic block diagram illustrating one embodiment of signal communications in a system  100  for active speaker identification in video conferencing. In the depicted embodiment, a first media source  102   a  is configured to send a plurality of data streams to the MCU  106 . 
     The first media source  102   a  may include a codec configured to generate multiple layers of video including, but not limited to various Common Intermediate Format (CIF) layers, or high Definition (HD) layers. For example, a common codec may be configured to generate fifty (50) or more video layers, including but not limited to, SQCIF, QCIF, 4CIF, 16CIF, DCIF, HD 720p, HD 1080i, HD 1080p, and the like. One of ordinary skill in the art will recognize a variety of video layers that may be included in separate data streams. The video layers may include video of different frame rates, different resolution, and/or different color schemes. In addition, the data streams may include audio. 
     In the depicted embodiment, the first media source  102   a  sends four different media data streams to the MCU  106 . Each media data stream includes a data stream identifier. For example, in the depicted embodiment the data stream identifier is a Synchronization Source (SSRC) identifier. Each data stream may include data associated with a different layer of media streaming from the first media source  102   a.    
     In one embodiment, the MCU  106  may also receive requests for data streams from a first media requestor  108   a  and a second media requestor  108   b . Due to hardware, or codec limitations, the first media requestor  108   a  and the second media requestor  108   b  may not be able to render the same quality of video. Thus, the first media requestor  108   a  and the second media requestor  108   b  may request different data streams from the MCU  106 . In response to the request, the MCU  106  may send the data streams associated with SSRC 1  and SSRC 2  to the second media requestor  108   b  and the data stream associated with SSRC 3  to the first media requestor. If neither the first media requestor  108   a,  nor the second media requestor  108   b  requests the fourth data stream, the MCU  106  may not pass the data stream associated with SSRC 4  to either media requestor  108   a - b.  As described below, communications between the media requestors  108   a - n  and the MCU  106  may include information, such as MSIDs that may simplify routing of the data streams. 
       FIG. 3  is a schematic block diagram illustrating another embodiment of a system  300  for active speaker identification in video conferencing. In this embodiment, the system  300  may include a network  104  and an MUC  106  substantially as described with relation to  FIG. 1  above. However, in this embodiment, the system may include a plurality of clients  302   a - n  that are configured to operate as both a media source  102   a - n  and a media requestor  108   a - n.  Thus, each client may generate data streams for communication to the MCU  106  and also request data streams originating from other clients  302   a - n  in the system  300 . 
       FIG. 4  is a schematic block diagram illustrating another embodiment of signal communications in a system  400  for active speaker identification in video conferencing. In the depicted embodiment, the system  400  includes four clients  402   a - d.  Each of the clients  402   a - d  may be associated with a participant, for example, Alice, Bob, Charles, and Dave. As discussed above, each client  402   a - d  may both generate audio/video data streams, and also request audio/video data streams from other clients  402   a - d.    
     By way of example, Alice may be operating client  402   a , generates video data streams of her in both CIF (SSRC 1 ) and HD (SSRC 2 ) video formats. Similarly, Bob may be associated with client  402   b , which generates data streams for HD (SSRC 3 ) video format. In such an embodiment, an MSID may be assigned to each client  402   a - d.  For example, the user name (Alice, Bob, Charles, and Dave) may be assigned as the MSID for each respective client  402   a - d . Thus, MCU  106  may map data stream identifiers (SSRC 1 , SSRC 2 , and SSRC 3 ) to the respective MSIDs. 
     In such an example, Charles may request video from Alice. If Charles&#39; client  402   c  is only capable of rendering the CIF video layer, then Charles may only receive data steam SSRC 1 . Thus, Charles may make a request to the MCU  106  for CIF layer video from MSID ‘Alice.’ In such an embodiment, MCU  106  may look up the SSRC associated with CIF video originating from Alice (SSRC 1 ), and provide that data stream to Charles&#39; client  402   c.    
     Similarly, Dave&#39;s client  402   d  may request HD video from both Bob and Alice. In such an embodiment, Dave&#39;s client  402   d  may request MSID ‘Alice’ and MSID ‘Bob’ and specify the HD layer. In response, the MCU  106  may look up the SSRC associated with the HD video stream from both Alice and Bob and send both data streams (SSRC 2  and SSRC 3 ) to Dave&#39;s client  402   d . Beneficially, in such an example each client only uses an MSID and its own capabilities to generate the request to the MCU. Thus, each client need not store and keep updated a list of each SSRC in use on the system  400 . 
       FIG. 5  is a schematic block diagram illustrating one embodiment of a computer system  500  suitable for use in a system  100 ,  300  for active speaker identification in video conferencing. For example, the computer system  500  may be suitable for configuration as an MCU  106 , a media source  102   a - n,  a media requestor  108   a - n,  and/or a client  302   a - n.  Components may include, but are not limited to, various hardware components, such as processing unit  502 , data storage  504 , such as a system memory, and system bus  506  that couples various system components including the data storage  504  to the processing unit  502 . The system bus  506  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus. 
     The computer  500  typically includes a variety of computer-readable media  508 . Computer-readable media  508  may be any available media that can be accessed by the computer  500  and includes both volatile and nonvolatile media, and removable and non-removable media, but excludes propagated signals. By way of example, and not limitation, computer-readable media  508  may comprise computer storage media and communication media. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by the computer  500 . Communication media may include computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of the any of the above may also be included within the scope of computer-readable media. Computer-readable media may be embodied as a computer program product, such as software stored on computer storage media. 
     The data storage or system memory  504  includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) and random access memory (RAM). A basic input/output system (BIOS), containing the basic routines that help to transfer information between elements within computer  500 , such as during start-up, is typically stored in ROM. RAM typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit  502 . By way of example, and not limitation, data storage  504  holds an operating system, application programs, and other program modules and program data. 
     Data storage  504  may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, data storage  504  may be a hard disk drive that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive that reads from or writes to a removable, nonvolatile magnetic disk, and an optical disk drive that reads from or writes to a removable, nonvolatile optical disk such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The drives and their associated computer storage media, described above and illustrated in  FIG. 5 , provide storage of computer-readable instructions, data structures, program modules and other data for the computer  500 . 
     A user may enter commands and information through a user interface  510  or other input devices such as a tablet, electronic digitizer, a microphone, keyboard, and/or pointing device, commonly referred to as mouse, trackball or touch pad. Other input devices may include a joystick, game pad, satellite dish, scanner, or the like. Additionally, voice inputs, gesture inputs using hands or fingers, or other natural user interface (NUI) may also be used with the appropriate input devices, such as a microphone, camera, tablet, touch pad, glove, or other sensor. These and other input devices are often connected to the processing unit  502  through a user input interface  510  that is coupled to the system bus  506 , but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor  512  or other type of display device is also connected to the system bus  506  via an interface, such as a video interface. The monitor  512  may also be integrated with a touch-screen panel or the like. Note that the monitor and/or touch screen panel can be physically coupled to a housing in which the computing device  500  is incorporated, such as in a tablet-type personal computer. In addition, computers such as the computing device  500  may also include other peripheral output devices such as speakers and printer, which may be connected through an output peripheral interface or the like. 
     The computer  500  may operate in a networked or cloud-computing environment using logical connections  514  to one or more media devices, such as a media computer. The media computer may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer  500 . The logical connections depicted in  FIG. 5  include one or more local area networks (LAN) and one or more wide area networks (WAN), but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet. In particular, the network interface  514  may include an interface to network  104  for communication of media signals between the computer and, for example, clients  302   a - n  of the network and/or the MCU  106 . 
     When used in a networked or cloud-computing environment, the computer  500  may be connected to a public or private network through a network interface or adapter  514 . In some embodiments, a modem or other means for establishing communications over the network. The modem, which may be internal or external, may be connected to the system bus  506  via the network interface  514  or other appropriate mechanism. A wireless networking component such as comprising an interface and antenna may be coupled through a suitable device such as an access point or peer computer to a network. In a networked environment, program modules depicted relative to the computer  500 , or portions thereof, may be stored in the media memory storage device. It may be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. 
     The described embodiments may be implemented in the context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, and so forth, which perform particular tasks or implement particular abstract data types. The invention may also be practiced in distributed computing environments where tasks are performed by media processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in local and/or media computer storage media including memory storage devices. 
       FIG. 6  is a schematic block diagram illustrating one embodiment of an MCU  106 . The MCU  106  may be implemented on hardware such as that described in  FIG. 5 , but may be specially programmed using computer readable instructions stored on, for example, computer-readable storage media  508 . 
     In one embodiment, MCU  106  may be configured to include multiple modules or units. For example, MCU  106  may include a receiver unit  601 , a MSID assignment unit  602 , and a mapping unit  603 . Further, MCU  106  may generate and store a map  604  for mapping MSIDs to SSRCs. 
     In one embodiment, the receiver  601  may utilize the network interface  514 , to receive data streams from clients  302   a - n . Additionally, the receiver  601  may receive requests for data streams from the clients  302   a - n . The receiver may be in communication with the MSID assignment unit  602 . The MSID assignment unit  602  may be configured to assign an MSID to each client  302   a - n . In one embodiment, the MSID assignment unit  602  may assign an MSID that is unique among the group of clients  302   a - n  such that request collisions are avoided. The MSID assignment unit  602  may assign one of a predetermined set of MSIDs. Alternatively, the MSID assignment unit  602  may assign a randomly generated MSID. In another embodiment, the MSID assignment unit  602  may assign an MSID in response to a user input, such as a name, telephone number, email address, user ID, or the like. 
     The mapping unit  603  may then generate map  604  to associate each data stream received from the clients  302   a - n  with a respective MSID associated with the client  302   a - n  . For example, if MSID assignment unit  602  assigns the MSID ‘Alice’ to client  302   a,  them mapping unit  603  may tag, group, or otherwise arrange the SSRCs associated with the data streams received from client  302   a  in association with the MSID ‘Alice.’ Mapping unit  603  may further update the map  604  with additional SSRCs as additional data streams become available from existing clients  302   a - n , or as new clients  302   a - n  join the video conference. 
     In one embodiment, the map  604  may be stored in memory on the MCU  106 . Alternatively, the map  604  may be stored on a data storage disk, such as a hard disk drive. The map  604  may be stored in database format. Alternatively, the map  604  may be stored as a hash table, an array of strings, an array of arrays, an array of pointers to MSIDs and/or SSRCs, or the like. One of ordinary skill in the art will recognize a variety of arrangements that may be suitable for mapping the MSIDs to SSRCs. 
       FIG. 7  is a schematic block diagram illustrating a further embodiment of an MCU  106 . In one embodiment, the MCU  106  includes modules substantially as described in  FIG. 6 . In addition,  FIG. 7  may include a DS list generator  701  a sender  702 , and identification unit  703 . Additionally, the MCU  106  may include an alternative version of the map  604  which includes identification of DSs. 
     In one embodiment, the DS list generator  701  may identify a DS through one or more of multiple methods. For example, the DS list generator  701  may identify a DS by measuring the volume of audio signals received from each client  302   a - n  and identifying an audio signal with the highest volume. Alternatively, the DS list generator  701  may identify an audio signal with a greatest amount of activity within a period of time. In still a further embodiment, the DS list generator  701  may analyze video to determine a DS based upon body or lip motion. One of ordinary skill in the art may recognize alternative methods for identifying the DS. 
     Once the DS list generator  701  identifies the DS, it may add the current DS to a DS list. A DS list may include a file or table of DSs. The DS list may include the MSID of the DSs. In one embodiment, the DS list may include a history of the most recent DSs. Alternatively the DS list may include a history of the most active DSs. In still another embodiment, the DS list may include a list of the MSIDs that are most requested by the clients  302   a - n . One of ordinary skill in the art may recognize additional criteria that may be used to generate the DS list. 
     The DS list may then be distributed to the clients  302   a - n  by sender  702 . For example, the sender  702  may send an initial DS list to a new client  302  in the video conference upon identifying that the new client  302  has joined. In a further embodiment, the sender  702  may distribute updated DS lists to the clients  302   a - n  in response to an update to the list, or on a periodic basis. 
     It will be understood that in other embodiments, dominant or active participants may be selected using criteria other than audio participation. An active participant may be determined not only by the participant&#39;s input audio level or the frequency of input audio (i.e., a dominant speaker) but also by other non-audio inputs, such as changes in a video input, which may reflect movement of the participant, changes in the participant&#39;s location, or gestures by the participant. For example, a participant who does not speak or speaks infrequently may be designated as an active participant if he or she makes certain gestures, such as sign language or other signals, or moves by more than a threshold frequency or amount. Alternatively, an active participant on a video conference may be determined by activity on a non-audio and non-video channel, such as by identifying recent or concurrent email, text, messaging, document editing, document sharing, or other activity by the participant. For example, a participant who does not speak or speaks infrequently may be designated as an active participant if he or she sends email, texts, or other messages to other participants or shares or edits documents with other participants. 
     In still further embodiments, the receiver  601  may receive requests for data streams from the clients  302   a - n . Each request may include, for example, a list of MSIDs, and identification of a video layer supported by the clients  302   a - n . For example, referring back to the example in  FIG. 4 , Charles  302   c  may send a request to the MCU  106  for CIF layer video from Alice. In response, the mapping unit  603  may check the map  604  to identify one or more SSRCs that satisfy the request. In the present example, the mapping unit may determine that SSRC 1  satisfies the request. The sender  702  may then send the data stream(s) associated with the identified SSRC(s) to the client  302   c . Further details of the operations of the MCU  106  and associated methods are described below. 
       FIG. 8  is a schematic flowchart diagram illustrating one embodiment of a method  800  for active speaker identification in video conferencing. In one embodiment, the method  800  starts when the receiver  601  receives  801  one or more data stream identifiers (e.g., SSRCs). The MSID assignment unit  602  may then assign  802  an MSID to the client  302  transmitting the data stream. The mapping unit  603  may then map  803   
       FIG. 9  is a schematic block diagram illustrating another embodiment of system  900  for active speaker identification in video conferencing. In one embodiment, client  402   a  for Alice ( FIG. 4 ) may include a video capture device  901 , such as a video camera or a webcam. Additionally, client  402   a  may include a codec, such as an MBR encoder  902 . In one embodiment, the MBR encoder  902  may be implemented in a combination of hardware and software. 
     The MBR encoder  902  may generate multiple data streams from the video captured by video capture device  901 . For example, the MBR encoder may generate both an HD  720 p data stream  903  and a CIF data stream  904 . In addition, each of the HD data stream  903  and the CIF data stream  904  may further include one or more layers. In one embodiment, a distinct SSRC may be assigned to each layer in the data streams  903 ,  904 . 
     Client  402   a  may send the data streams  903 ,  904  to the AVMCU  106 . In response to requests from Bob and Charles, AVMCU  106  may pass the HD data stream  903  to Bob  402   b  and the CIF data stream  904  to Charles  402   c . One of ordinary skill in the art will recognize that the present embodiment is merely for illustrative purposes, and that a wide variety of system configuration may be employed for video conferencing in accordance with the present embodiments. 
       FIG. 10  is a diagram illustrating one embodiment of a video conferencing participant&#39;s screen view  1000 . In one embodiment, the view  1000  may include multiple viewing panes or panels. For example, a main viewing pane  1001  may be used to display application sharing, desktop sharing, Instant Messenger (IM) windows, etc. In a further embodiment, the main viewing pane  1001  may be used to render a current DS. 
     Additionally, a side panel  1002  may be used for viewing a list of participants in the video conference. These participants generally would not be DSs. In one embodiment, only a still-frame image of the participant is illustrated in panel  1002 . Alternatively, only a name or MSID of the participant is displayed in the side panel  1002 . 
     In addition, multiple video panels may be used for rendering a group of DSs. For example, the DS list may specify that the most recent DSs are Bob, Charles, Dave, Elliot, and Fabian. These DSs may be displayed in windows  1003 - 1007  respectively. Since this is Alice&#39;s view, her video may also be displayed in window  1008 . In a further embodiment, the view may include a method for identifying the currently active DS in the DS list. For example, if Elliot is currently speaking, Elliot&#39;s video window may be highlighted, enlarged, framed, or otherwise indicated. 
       FIG. 11  is a schematic flowchart diagram illustrating another embodiment of a method  1100  for active speaker identification in video conferencing. In particular, this method  1100  may be used to establish and update the DSs in participant view  1000  ( FIG. 10 ). 
     In one embodiment, the method starts when Alice  402   a  ( FIG. 4 ) joins  1101  the conference. The MCU  106  may then receive  1102  notification that Alice  402   a  has joined the conference. For example, Alice  402   a  may send a notification to the MCU  106 . Alternatively, Alice  402   a  may be required to negotiate credentials with the MCU  106  in order to join the conference, thereby notifying the MCU  106 . The MCU  106  may then send  1103  a DS list to Alice  402   a . Alice  402   a  may receive  1104  the DS list in turn, and request  1105  the data streams associated with the DSs on the DS list. For example, the request may include the MSIDs of the DSs as well as an indicator of the supported or requested media layers. 
     The MCU  106  may then receive  1106  the request from Alice  402   a . In response, the mapping unit  603  may identify  1107  the SSRCs to send to Alice  402   a  in response to the request. Sender  702  may then send  1108  data stream(s) associated with the identified SSRCs to Alice  402   a . In turn, Alice  402   a  may then receive  1109  the data stream(s) and render  1110  the data streams. For example, Alice  402   a  may render  1110  the data stream associated with video from Bob, Charles, Dave, Elliot, and Fabian in DS video windows ( 1003 - 1007  respectively). 
     In one embodiment, the DS list generator  701  ( FIG. 7 ) may continue to monitor for changes in the DS list. If the DS list changes, the MCU  106  may send  1111  an updated DS list to Alice  402  via sender  702 . Alice  402   a  may then receive  1112  the updated DS list and request  1113  an updated set of data streams according to the updates to the DS list. Alternatively, Alice  402   a  may request  1113  an updated set of data streams according to a user selection of data streams. In still a further embodiment, Alice  402   a  may request  1113  a combination of data streams associated with the DS list and a set of data streams associated with a user selection. 
     The receiver  601  on the MCU  106  may then receive  1114  the request from Alice  402   a  and the identification unit  703  may identify  1115  the SSRCs associated with the requested MSIDs and layers. The sender  702  may then send  1116  the data streams associated with the identified SSRCs to Alice  402   a.    
     Alice  402   a  may then receive  1117  the new data streams and render video associated with the new data streams in an updated view as illustrated in  FIG. 12 . 
       FIG. 12  is a diagram illustrating another embodiment of a video conferencing participant&#39;s screen view  1200  that provides a modified version of view  1000  ( FIG. 10 ). In this embodiment, the video panels at the bottom of the view may be updated according to the request  1113  ( FIG. 11 ). For example, in this case, a user may have selected video from Bob, Charles, Fabian, and Alice for constant viewing by pinning the videos, flagging the videos, or making some other form of user selection. Pinned videos may be identified with a pin icon  1201  or the like. Additionally, video from George may replace video from Elliot at panel  1202 , because George may have replaced Elliot on the DS list. One of ordinary skill in the art will recognize other possible views, including alternative arrangements of viewing panels or panes and other content within the view. 
     Beneficially, such embodiments may provide greater user flexibility with regard to selection of videos for viewing, allow for frequent updating of DS videos, and avoid communication errors such as SSRC collisions and the like. In general, the present embodiments may provide a user of a video conferencing system a more robust and flexible participation experience. 
     In a computer-implemented method, such as a processor running instructions stored on a memory, a device receives one or more data streams from a media source, where each data stream associated with a data stream identifier. A media source identifier is assigned to each data stream from the media source. The data stream identifiers are mapped to the media source identifiers. At least one of the data streams may be modified by replacing an associated data stream identifier with the media source identifier. The modified data streams are provided to a destination device. 
     A request is received from a destination device for data streams associated with a media source identifier. One or more data stream identifiers are associated with the requested media source identifier. The one or more data streams may be associated with Application sharing/Desktop Sharing, a video quality, a video resolution, a video frame rate, or an audio quality. 
     The data streams may be associated with a different layer of video data. A video capability of a destination device is determined. A plurality of data streams are provided to the destination device. The plurality of data streams are selected based upon the video capability. Each of the plurality of data streams mapped to the media source identifier. 
     The media source identifiers may be assigned to each data stream by a media server to uniquely identify a plurality of media sources. A list of media source identifiers may be provided to a destination device. The list of media source identifiers may correspond to a list of active participants. The list of active participants may comprise, for example, a list of dominant speakers. 
     The one or more data streams associated with each of the media source identifiers may be automatically provided as requested by a destination device. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.