Patent Publication Number: US-9843455-B2

Title: Conferencing system with spatial rendering of audio data

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority and the benefits of the earlier filed Provisional U.S. application Ser. No. 61/495,984, filed 11 Jun. 2011, which is incorporated by reference for all purposes into this specification. 
     Additionally, this application is a continuation of U.S. application Ser. No. 13/493,934, filed 11 Jun. 2012, which is incorporated by reference for all purposes into this specification. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to a conferencing system. More particularly, this present disclosure relates to a conferencing system with spatial rendering of audio data from a local room to a remote or far end room. 
     BACKGROUND ART 
     Voice over internet protocol (VoIP) is a technique for delivering voice information using an internet protocol (IP) network, such as the Internet. Generally, VoIP is not a traditional protocol based on a link, as in a public switched telephone network (PSTN), but rather is a protocol that transmits voice information in a digital form within discrete packets. In conventional VoIP devices, audio data may be mixed, encoded, and transmitted from one VoIP device to another VoIP device, such as in a VoIP conferencing application. For situations in which the microphone elements and the speaker elements do not align on a point-to-point basis, the sound field produced in a remote room may lose the effect of the location of the sound source within the local room. This problem also occurs when using non-IP networks such as Asynchronous Transfer Mode networks or InfiniBand networks. 
     This application is related to U.S. application Ser. No. 13/398,662, filed 16 Feb. 2012, which claims the benefit of U.S. application Ser. No. 61/443,471, filed 16 Feb. 2011, both of which are incorporated by reference for all purposes into this disclosure. 
     SUMMARY OF INVENTION 
     This disclosure describes a conferencing system with spatial rendering of audio data. The conferencing system includes a local conferencing device that includes a plurality of microphones, an audio encoder, and a spatial encoder that are associated with a local endpoint, where the local conferencing device is configured to: generate a set of spatial information for said local endpoint, implement a call set up procedure; encode audio data and said spatial information; and transmit said audio data and said spatial information to a remote endpoint. The conferencing system further includes a remote conferencing device that includes a plurality of speakers, an audio decoder, and a spatial renderer that are associated with the remote endpoint, where the remote conferencing device is configured to: receive said audio data and said spatial information; decode said audio data and said spatial information; and render said audio data among said plurality of speakers based, at least in part, on said spatial information of the local endpoint. The spatial renderer is configured to superimpose a coordinate system for the plurality of speakers and a coordinate system for the plurality of microphones during spatial rendering of the audio data. 
     The conferencing system further provides that the audio data includes mixed audio data and includes a plurality of audio streams. 
     The conferencing system further provides that the quantity of the plurality of microphones and the quantity of the plurality of speakers are not necessarily equal. 
     The conferencing system further provides that the spatial configuration of the plurality of microphones and the spatial configuration of the plurality of speakers may be substantially different. 
     The conferencing system further provides that the spatial information may be represented in cylindrical or spherical coordinates in a coordinate system. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To further aid in understanding the disclosure, the attached drawings help illustrate specific features and embodiments of the disclosure and the following is a brief description of the attached drawings: 
         FIG. 1  is a schematic block diagram of a conferencing device according to an embodiment of the present disclosure. 
         FIG. 2  is a schematic block diagram of a conferencing device according to an embodiment of the present disclosure. 
         FIG. 3  is a schematic block diagram of a conferencing device according to another embodiment of the present disclosure. 
         FIG. 4  is a schematic representation of a point-to-point surround sound call between two rooms according to an embodiment of the present disclosure. 
         FIG. 5  is a schematic representation of a point-to-point surround sound call between two rooms according to an embodiment of the present disclosure. 
         FIG. 6  is a schematic representation of a point-to-point mono sound bridge call between four near rooms and a far room according to an embodiment of the present disclosure. 
         FIG. 7  is a schematic representation of a point-to-point stereo sound bridge call between four near rooms and a far room according to an embodiment of the present disclosure. 
         FIG. 8  is a schematic block diagram representing a call setup involving a plurality of endpoints according to an embodiment of the present disclosure. 
         FIG. 9  is a media path for a plurality of endpoints according to an embodiment of the present disclosure. 
         FIG. 10  is an illustration of a room including a plurality of speakers according to an embodiment of the present disclosure. 
         FIG. 11  is an illustration of a room including a plurality of microphones according to an embodiment of the present disclosure. 
         FIG. 12  is an illustration of a room including a microphone according to an embodiment of the present disclosure. 
         FIG. 13  is an illustration of a room including a plurality of microphones according to an embodiment of the present disclosure. 
         FIG. 14  is an illustration of a room including a plurality of microphones according to an embodiment of the present disclosure. 
     
    
    
     DISCLOSURE OF EMBODIMENTS 
     This disclosure describes a conferencing system with spatial rendering of audio data. The disclosed embodiments are intended to describe aspects of the disclosure in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and changes may be made without departing from the scope of the disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined only by the included claims. 
     Furthermore, specific implementations shown and described are only examples and should not be construed as the only way to implement or partition the present disclosure into functional elements unless specified otherwise herein. It will be readily apparent to one of ordinary skill in the art that the various embodiments of the present disclosure may be practiced by numerous other partitioning solutions. 
     In the following description, elements, circuits, and functions may be shown in block diagram form in order not to obscure the present disclosure in unnecessary detail. Additionally, block definitions and partitioning of logic between various blocks is exemplary of a specific implementation. It will be readily apparent to one of ordinary skill in the art that the present disclosure may be practiced by numerous other partitioning solutions. Those of ordinary skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. Some drawings may illustrate signals as a single signal for clarity of presentation and description. It will be understood by a person of ordinary skill in the art that the signal may represent a bus of signals, wherein the bus may have a variety of bit widths and the present disclosure may be implemented on any number of data signals including a single data signal. 
     The various illustrative functional units includes logical blocks, modules, devices, and circuits described in connection with the embodiments disclosed herein so as to more particularly emphasize their implementation independence. The functional units may be implemented or performed with a general purpose processor, a special purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, any conventional processor, controller, microcontroller, or state machine. A general purpose processor may be considered a special purpose processor while the general purpose processor is configured to fetch and execute instructions (e.g., software code) stored on a computer readable medium such as any type of memory, storage, and/or storage devices. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     In addition, the various illustrative functional units previously described above may include software or programs such as computer readable instructions that may be described in terms of a process that may be depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. The process may describe operational acts as a sequential process, many of these acts can be performed in another sequence, in parallel, or substantially concurrently. Further, the order of the acts may be rearranged. In addition, the software may comprise one or more objects, agents, threads, lines of code, subroutines, separate software applications, two or more lines of code or other suitable software structures operating in one or more software applications or on one or more processors. The software may be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices. 
     Elements described herein may include multiple instances of the same element. These elements may be generically indicated by a numerical designator (e.g.  110 ) and specifically indicated by the numerical indicator followed by an alphabetic designator (e.g.,  110 A) or a numeric indicator preceded by a “dash” (e.g.,  110 - 1 ). For ease of following the description, for the most part element number indicators begin with the number of the drawing on which the elements are introduced or most fully discussed. For example, where feasible elements in  FIG. 3  are designated with a format of 3xx, where 3 indicates  FIG. 3  and xx designates the unique element. 
     It should be understood that any reference to an element herein using a designation such as “first,” “second,” and so forth does not limit the quantity or order of those elements, unless such limitation is explicitly stated. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second element does not mean that only two elements may be employed or that the first element must precede the second element in some manner. In addition, unless stated otherwise, a set of elements may comprise one or more elements. 
     Reference throughout this specification to “one embodiment”, “an embodiment” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “one embodiment”, “an embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     A “stream” and a “channel” may be used interchangeably in this specification. Additionally, “microphone” and a “microphone element” may be used interchangeably in this specification. Further, “speaker” and a “speaker element” may be used interchangeably in this specification. 
       FIG. 1  is a schematic block diagram of a conferencing device  100  according to an embodiment of the present disclosure. The conferencing device  100  may be configured to connect to a VoIP-based private branch exchange (PBX) phone system via an IP network. The conferencing device may also be configured to connect to non-IP networks such as Asynchronous Transfer Mode networks or InfiniBand networks as the transport mechanism. One skilled in the art will appreciate that the disclosed invention may work on various types of transport mechanisms for the audio data. 
     The conferencing device  100  may deliver wideband audio signals over networks that implement transport layer security (TLS), advanced encryption standard (AES), secure real-time transport protocol (SRTP), or other similar encryption. In addition, the conferencing device  100  may be further configured to provide a session initiation protocol (SIP) transport method for connecting with a far end device, such as in a far end conference room. 
     The conferencing device  100  includes an application processor  110 , and may also include a distribution processor  120 , and a processor farm  130 . The application processor  110  may be coupled to the distribution processor  120 , which may be coupled to the processor farm  130 . 
     The application processor  110  may be configured as a main processor running the application code for the conferencing device  100 , as well as being configured to function as the voice engine for the conferencing device  100 . The application processor  110  may be configured to perform a variety of different audio processing operations, such as data compression, handling the communication protocol (e.g., session initiation protocol (SIP)), etc. As an example, the application processor  110  may be a microprocessor having an integrated silicon platform (e.g., system on a chip) configured for VoIP and broadband applications, such as the TNETV1050 microprocessor available from Texas Instruments, Inc. of Dallas, Tex. Other similar microprocessors may also be employed to implement embodiments of the disclosure. 
     The distribution processor  120  may be configured to distribute commands between the application processor  120  to the processor farm  130 . For example, in one operation (e.g., the conferencing device  100  receiving data through Ethernet, USB, or other external ports), the application processor  110  may transmit signals (e.g., commands, data, etc.) to the processor farm  130 . The signals may be transmitted through an address bus  111  (e.g., parallel address bus) and a first communication bus  113  (e.g., multi-channel buffered serial port (McBSP)) to the distribution processor  120 , and the distribution processor  120  may distribute the signals to the processor farm  130  via one or more communication buses  121 ,  123 . The communication busses  121 ,  123  may include a serial peripheral interface (SPI) bus  121  or a time-division multiplexing (TDM) bus  123 . In the reverse operation (e.g., the conferencing device  100  transmitting data through Ethernet, USB, or other external port), the distribution processor  120  may distribute the signals from the processing farm  130  to the application processor  110 . 
     In addition, the distribution processor  120  may be further configured to perform other operations, such as format conversion of the signals, in addition to simply distributing the signals. The distribution processor  120  may be further configured to serve as the master time source and router for the audio slots associated with the various audio buses. The audio signals received by the processor farm  130  may be sampled and processed at a sampling rate and resolution. The application processor  110  may also be operated at a certain rate and resolution. For example, audio samples may be processed using 24 bit resolution at 48 KHz in the processor farm  130 , and using 16 bit resolution at 16 KHz in the application processor  110 . In embodiments using different sampling rates, the distribution processor  120  may include a sample rate converter. 
     The processor farm  130  may include a plurality of processing resources  132  configured for conferencing, transcoding, and media termination point (MTP) services. For example, the processor farm  130  may be configured to handle operations, such as echo cancellation, gain control, noise reduction, etc. In some embodiments, the processor farm  130  may be a DSP farm including a plurality of DSP resources. 
     Data and commands may be sent over the McBSP bus  113  between the application processor  110  and the distribution processor  120 . Between the distribution processor  120  and the processor farm  130 , data may be sent over the TDM bus  123  and commands may be sent over the SPI bus  121 . In some embodiments, the distribution processor  120  may be configured to act as a memory bank to temporarily store information during operation of the conferencing device  100 . The address bus  111  may be used to provide addresses to the distribution processor  120  to access such information. 
     Thus, to receive audio streams, the conferencing device  100  may receive the audio streams at the application processor  110  (e.g., via Ethernet, USB, etc.), which may decompress the audio streams, decode, and perform other processing. The audio streams may be further transmitted to the processor farm  130  for other processing, such as noise cancellation. In transmit mode for transmitting audio streams, sound may be captured by microphone elements coupled with the processing farm  130 , which may sample the audio signals and send the audio signals to the application processor  110 . The application processor may perform compression of the audio signals, encoding, packetizing, and other processing. The compressed audio stream may be transmitted to a remote or far end endpoint (e.g., via Ethernet, USB, etc.). 
     The conferencing device  100  may be further configured to determine spatial information for the microphone elements and/or speaker elements associated therewith. As a result, in transmit mode as a local endpoint, the conferencing device  100  may be configured to determine how to encode audio data for maintaining an appropriate spatial effect for the audio data having knowledge of the spatial information of the speaker elements of the remote endpoint. In receive mode, the conferencing device  100  may be configured to determine how to render the audio data to produce a sound field that maintains at least some of the spatial effects. Additional detail regarding such spatial rendering is described below with reference to  FIGS. 8 through 14 . 
       FIG. 2  is a schematic block diagram of a conferencing device  200  according to an embodiment of the present disclosure. The conferencing device  200  includes the application processor  110 , the distribution processor  120 , and the processor farm  130  (of  FIG. 1 ), which may be configured generally as described elsewhere. The application processor  110  further includes a session initiation protocol (SIP) user agent  212 , an internal processor  214 , and a McBSP port  216 . 
     The SIP user agent  212  may be implemented as a software program configured to manage a SIP session. The SIP user agent  212  may receive data from or transmit data to a plurality of different callers  202  over an external link (e.g., Ethernet, USB, etc.). The data streams between the callers  202  and the SIP user agent may include real-time transport protocol (RTP) packets (i.e., RTP streams). 
     The internal processor  214  may be a DSP core (e.g., a Texas Instruments TMS320C55 DSP). The internal processor  214  may execute a plurality of codecs  215  used to process the data. In particular, the codecs  215  may be configured to encode and decode the data input and output from the application processor  110 . As an example, the codecs  215  may configured for compression and/or decompression of data depending on the flow of data. The codecs  215  may also be configured for various communications standards, including G.722, G.711, and G.729AB. 
     The codecs  215  may be further configured for supporting other features, such as Advanced Audio Coding-Low Delay (AAC-LD). Such a feature may be configured as a single instance to support a single call, or may be instantiated multiple times to support multiple simultaneous callers  202 . The AAC-LD codec can be configured to support higher quality audio than communication standards such as G.722, G.711, and G.729AB. For example, the resolution may be increased to 24-bit resolution at a sampling rate of 48 kHz. As a result, the resolution and sampling rate of the application processor  110  and the processor farm  130  may be the same, such that full bandwidth audio from the processor farm  130  may be transmitted from the conferencing device  200  rather than down sampled audio. As a result, the full bandwidth audio may be transmitted out of the conferencing device  200  to another device as a full band audio stream covering the full range of human hearing. 
     With data being received from a plurality of callers  202 , the conferencing device  200  may be configured for supporting a bridge call. For example, the plurality of data streams from each caller  202  may be received as independent audio samples on dedicated audio slots. The mixing of the plurality of data streams may be performed within the processor farm  130 . 
       FIG. 3  is a schematic block diagram of conferencing device  300  according to another embodiment of the present disclosure. The conferencing device  300  includes an application processor  110 , a distribution processor  120 , and a processor farm  130  configured generally as described elsewhere. The conferencing device  300  may further include another application processor  310  operably coupled with the distribution processor  120 . The application processor  310  may be a dedicated processor configured for mixing data received by the first application processor  110  and the processor farm  130 . 
     The data from received by the first application processor  110  (e.g., via Ethernet, USB, etc.) may remain uncompressed for mixing with the data from the processor farm  130 . For example, an audio signal may be received from either the USB port or the Ethernet port to the first application processor  110 . The audio signal may be transmitted to the second application processor  310  via the distribution processor  120  and the McBSP busses  113 ,  313 . The processor farm  130  may also have microphone inputs such that the processor farm  130  may also receive an audio signal that is transmitted to the second application processor  310  via the distribution processor  120 , the TDM bus  123  and the McBSP bus  313 . 
     Embodiments of the present disclosure may further include conferencing systems that are configured to generate a spatial audio representation from a local room to a far end room. To enable such a spatial audio representation, the devices may include a transport layer (e.g., VoIP transport layer) configured to send multiple audio streams to the far end site. 
       FIG. 4  is a schematic representation of a point-to-point surround sound call  400  between two rooms  410 ,  420  according to an embodiment of the present disclosure. The first room  410  includes a plurality of microphones  412  for transmitting RTP streams of audio data to a plurality of speakers  422  in the second room  420 . Each of the plurality of microphones  412  and the plurality of speakers  422  may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. As shown in  FIG. 4 , each audio channel corresponds to an individual microphone  412  and speaker  422  in a point-to-point manner. The four audio streams may be implemented in a surround mode with independent audio streams, while in some embodiments, the one or more of the audio streams may be implemented in a stereo mode that includes a left channel and right channel in the encoded packet. In addition to audio data, additional data may be transmitted, such as metering data used for room acoustical signal processing. Such additional data may be transmitted over a separate real-time control protocol (RTCP) channel. 
       FIG. 5  is a schematic representation of a point-to-point stereo sound call  500  between two rooms  510 ,  520  according to an embodiment of the present disclosure. The first room  510  includes a plurality of microphones  512  for transmitting RTP streams of audio data to a plurality of speakers  522  in the second room  520 . Each of the plurality of microphones  512  and the plurality of speakers  522  may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. As shown in  FIG. 5 , each audio channel corresponds to an individual microphone  512  and speaker  522  in a point-to-point manner. The two audio streams may be implemented in a stereo mode with having a left channel and a right channel in the encoded RTP packets of the RTP streams. 
       FIG. 6  is a schematic representation of a point-to-point mono sound bridge call  600  between four near rooms  610 A,  610 B,  610 C,  610 D and a far room  620  according to an embodiment of the present disclosure. Each of the near rooms  610 A,  610 B,  610 C,  610 D include a microphone  612 A,  612 B,  612 C,  612 D, respectively, for transmitting RTP streams of audio data to a plurality of speakers  622  in the far room  620 . Each of the plurality of microphones  612 A,  612 B,  612 C,  612 D and the plurality of speakers  622  may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. As shown in  FIG. 6 , each audio channel corresponds to an individual microphone  612 A,  612 B,  612 C,  612 D and speaker  622  in a point-to-point manner. 
       FIG. 7  is a schematic representation of a point-to-point stereo sound bridge call  700  between four near rooms  710 A,  710 B,  710 C,  710 D and a far room  720  according to an embodiment of the present disclosure. Each of the near rooms  710 A,  710 B,  710 C,  710 D include a stereo microphone  712 A,  712 B,  712 C,  712 D, respectively, for transmitting RTP streams of audio data to a plurality of speaker pairs  722  in the far room  720 . Each of the plurality of microphones  712 A,  712 B,  712 C,  712 D and the plurality of speaker pairs  722  may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. As shown in  FIG. 7 , each audio channel corresponds to an individual microphone  712 A,  712 B,  712 C,  712 D and a speaker pair  722  in a point-to-point manner. Each audio stream may include two channels (e.g., a right channel and a left channel) corresponding to the two speakers of the speaker pair  722  for the encoded RTP packets of the RTP streams as a stereo bridge call. 
       FIG. 8  is a schematic block diagram representing a call setup  800  involving a plurality of endpoints  810 ,  820  according to an embodiment of the present disclosure. Although two endpoints  810 ,  820  are shown, embodiments are contemplated that may include any number of endpoints. The endpoints  810 ,  820  may include one or more microphone elements and/or speaker elements and other components that are included within a conferencing device. The microphone elements of one endpoint (e.g.,  810 ) may be located at different relative positions than the speaker elements of the other endpoint (e.g.,  820 ). In addition, the number of microphone elements of one endpoint (e.g.,  810 ) may not equal the number of speaker elements of the other endpoint (e.g.,  820 ). In other words, the microphone elements and the speaker elements may not correspond to a point-to-point basis with each other either in number or in relative locations. 
     In some of the embodiments, a conferencing situation is described in which the first endpoint  810  is described as having microphones, while the second endpoint  820  is described as having speakers. In addition, the first endpoint  810  having microphones may be described as a local endpoint, while the second endpoint  820  having speakers may be described as a remote endpoint. Such a description should not be construed to imply that the first endpoint  810  does not have speakers, or that the second endpoint  820  does not have microphones. In many conferencing situations, each endpoint  810 ,  820  may both send and receive audio signals, and may act as a local endpoint and a remote endpoint during the same call. 
     The plurality of endpoints  810 ,  820  may establish a call (e.g., a conference call) there between. For example, the first endpoint  810  may initiate a call with the second endpoint  820 . During call set up  800 , the endpoints  810 ,  820  may pass call setup messages there between. Call setup messages may include information regarding the media capabilities of the endpoints  810 ,  820 . For example, media capabilities may include the type of media (e.g., audio, video) supported by the endpoints  810 ,  820 , as well as other information, such as formats supported, number of channels supported, which ports may be used for communication, etc. Media capabilities may be transmitted using Media Descriptions and SDP Attributes in SIP, Capability Exchange in H.323 protocol, or using other similar methods based on the media transport protocol, or other protocols that may be designed in the future. 
     A call set up message may further include spatial information regarding how the room for each endpoint  810 ,  820  is set up. Spatial information may include information regarding the relative positions and orientations of the speaker elements and microphone elements relative to a coordinate system within the rooms, as well as other information, such as directionality of the microphone elements and speaker elements. Such information may be defined by an installer of the audio system. In some embodiments, at least some of the spatial information may be dynamic, and may change over time during use of the audio system. In some embodiments, additional information regarding how sound may be reflected or absorbed within the room may be shared by the endpoints  810 ,  820 . Such information may include, for example, dimensions and materials that are present in the room and may enable modeling of reflections within the room. Such information may assist in the spatial rendering to more accurately reconstruct the audio signals and maintain the spatial sound effects. 
       FIG. 9  is a media path  900  for a plurality of endpoints  902 ,  904  according to an embodiment of the present disclosure. The plurality of endpoints  902 ,  904  may be coupled together through network  905 . One skilled in the arts will appreciate that the network may be an IP Network, or non-IP networks such as Asynchronous Transfer Mode networks or InfiniBand networks The first or local endpoint  902  may include a spatial encoder  910 , an audio encoder  920 , and an RTP packetizer  930 . The second or remote endpoint  904  may include an RTP depacketizer  940 , an audio decoder  950 , and a spatial renderer  960 . As discussed above, the local endpoint  902  may include a plurality of microphone elements, and the remote endpoint  904  may include a plurality of speaker elements. The components of each of the endpoints  902 ,  904  may be incorporated within one or more conferencing devices such as first or local conferencing device  912  and a second or remote conferencing device  914  both of which may use the processing components described elsewhere to perform one or more of the functions described in this disclosure. 
     The spatial encoder  910  may capture audio data from the plurality of microphone elements and encode the audio data into separate audio streams. The input audio data may be mixed and encoded into a number of channels (i.e., streams) supported by the remote endpoint  904 , and based on the spatial rendering capabilities and output locations of the speaker elements for the remote endpoint  904 . 
     The audio encoder  920  may receive the individual audio streams from the spatial encoder  910  and compress the audio streams into different channels in a known audio transport protocol (e.g., AAC-LD, G.722, etc.) or future protocol yet to be developed. 
     The RTP packetizer  930  may receive the compressed individual audio streams from the audio encoder and form the compressed individual audio streams into RTP packet streams to be sent over the IP network  905  to the remote endpoint  904 , such as by using RTP/RTCP protocol for such transmission. 
     Referring to the second endpoint  904 , the RTP depacketizer  940  may receive the RTP packet streams from the first endpoint  902 . The RTP depacketizer  940  may further handle jitter buffering between RTP packets for each RTP packet stream, and time align the outputs handed off to the audio decoder  950 . 
     The audio decoder  950  may receive each RTP packet stream from the RTP depacketizer  940 , and decode each RTP packet stream from a known audio transport protocol format to a supported uncompressed format that may be used by the spatial renderer  960 . 
     The spatial renderer  960  may receive the individual uncompressed data streams from the audio decoder  950 , and reconstruct the individual uncompressed data streams to be played out on speaker elements of the second or remote endpoint  904 . The spatial renderer may render the audio signals based on the spatial information for the microphone elements and the speaker elements in their respective rooms. As a result, the audio outputs played by the speaker elements of the second or remote endpoint  904  may sound like it is being replicated spatially in the remote room as it was captured in the local room. 
     In summary, the spatial encoder  910  may define how each audio stream is created (e.g., including mixing the raw audio data from various individual microphones). The spatial encoder  910  may also map each audio stream to a particular location in the remote room to which the audio stream would be targeted. In other words, the local endpoint  902  may be configured to recommend placement of the audio stream within the sound field of the remote or far end endpoint  904 . The spatial renderer  960  may receive each audio stream and know which part of the remote room the audio stream is targeted for. The spatial renderer  960  may segment the remote room and determine which audio stream is played by which speaker element, as well as perform other controls such as adjusting volume and/or direction for the speaker elements located in the different targeted areas. Such a determination may be assisted by geometrically mapping coordinate systems for each set of spatial information. Defining coordinate systems and determining the spatial information will be discussed in further detail below. 
     In some embodiments, the raw audio data for each microphone element may be sent to the remote endpoint  904  without spatial encoding. In such an embodiment, the remote endpoint  904  may perform all processing with regard to spatial rendering (including mixing) having each set of spatial information as well as the raw audio data. As a result, the spatial encoder  910  may not be needed for such an embodiment. There may be certain advantages, however, to performing spatial encoding prior to transmitting audio data to the remote endpoint  904 . For example, the remote endpoint  904  may have limited processing capabilities to perform such mixing of audio data. In addition, the remote endpoint  904  may have a limited number of channels available for receiving audio data. As a result, spatial encoding prior to sending audio data may keep more of the audio signal intact. 
     In some embodiments, the local room associated with the first endpoint  902  may have more microphone elements than speaker elements in the remote room associated with the second endpoint  904 . For example, the local room may have ten microphones spaced in a grid configuration. The remote room may have two speakers that are configured to provide two stereo (L/R) channels to the remote room. The first endpoint  902  and the second endpoint  904  may share spatial information regarding their respective elements during call setup and negotiation. The spatial encoder  904  may determine how to mix the audio source data to generate the appropriate number of channels and in the appropriate manner to maintain spatial effects of the audio sources. For example, the spatial encoder may mix the audio signals from the five left-most microphone elements into a left channel, and mix the audio signals from the five right-most microphone elements into a right channel. The spatial renderer  960  may receive the mixed audio signals in the left channel and right channel, and, using the spatial information, the spatial renderer  960  may determine the appropriate speaker elements for playback as well as other playback characteristics. 
     In some embodiments, the local room may include fewer microphone elements than speaker elements in the remote room. Using the spatial information, the spatial encoder  910  may determine how to mix the audio source data to generate the appropriate number of channels and in the appropriate manner to maintain spatial effects of the audio sources. The spatial renderer  960  may receive the mixed audio signals, and, using the spatial information, the spatial renderer  960  may determine the appropriate speaker elements for playback as well as other playback characteristics. 
     In some embodiments, the local room and the remote room may have the same number of microphone elements and speaker elements. While it may be possible to have a one-to-one correspondence of channels between the two endpoints  902 ,  904  (see, e.g.,  FIGS. 4 and 5 ), the relative locations of the microphone elements and speaker elements may be not match from one room to the other room. Thus, without using spatial information for spatial rendering the audio signals, at least some (if not most) spatial effects of the sound may be lost. As a result, using the spatial information, the spatial encoder  910  may determine an appropriate mix for the audio signals based on the spatial information of both the microphone elements and the speaker elements. Likewise, the spatial renderer  920  may use the spatial information to determine the appropriate rendering on the remote endpoint  904 . 
     While certain numbers and configurations are described and shown in the various figures herein, any number or configuration is contemplated as an embodiment of the present disclosure. Such numbers and configurations should not be limited unless specifically described as being so limited. In addition, the different coordinate systems chosen for each room may be roughly the same. As a result, the coordinate systems may be superimposed on each other when mapping the coordinate systems and the spatial information during spatial encoding and spatial decoding. In some embodiments, the coordinate systems may be roughly the same, but that the mapping may be performed by creating a mirror image of the other coordinate system during spatial encoding and spatial decoding. In some embodiments, the coordinate systems may be substantially different (e.g., the rooms have substantially different dimensions). As a result, a more complex mapping (or a simplified estimate of one or more of the rooms) may be performed during spatial encoding and spatial decoding. In some embodiments, room sizes may be substantially different, and a scaling factor may be applied such that the sound may be reproduced in the remote room to sound either closer or further away (as the case may be) than may actually be the case in the local room. 
       FIG. 10  is an illustration of a room  1000  including a plurality of speakers  1020 A- 1020 H according to an embodiment of the present disclosure. Each of the plurality of speakers  1020 A- 1020 H may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The plurality of speakers  1020 A- 1020 H, in conjunction with a conferencing device, may be configured to output spatially encoded audio signals received from an endpoint having a plurality of microphones. In particular,  FIG. 10  shows an example of how the spatial information regarding the speakers may be defined relative to a coordinate system. The coordinate system may be defined as an XY axis. As an example, the relative locations of the speakers may be defined in cylindrical or spherical coordinates. For example, the first speaker  1020 A may have spatial information associated therewith, such as a radius (R 1 ) and an angle relative to the coordinate system. The radius (R 1 ) may be measured from the origin of the coordinate system, and the angle (θ 1 ) may be measured from the positive X axis of the coordinate system. Each of the other speakers  1020 B- 1020 H may have spatial information associated therewith, which may be defined in a similar manner. Of course, other coordinate systems and coordinate systems may be employed for determining positions of the speakers relative to each other using a coordinate system. For example, Cartesian coordinates may be employed, such that an (X,Y) coordinate for each speaker  1020 A- 1020 H may be determined. 
     In some embodiments, the speakers  1020 A- 1020 H may be non-directional (in other words, they are omnidirectional) and generate sound in all directions rather than favoring a specific direction. For example, the speakers  1020 A- 1020 H may be configured as ceiling speakers in the room  1000 . In some embodiments, speakers may be directional and generate sound to favor a specific direction. For example, speakers may be wall-mounted speakers, mounted to a video screen, etc., and may point in a direction that is different than toward the horizontal plane. In some embodiments, speakers may include a speaker array configured to generate a beam pattern such that the beam pattern is directional. Such speakers may further be configured to steer the beam pattern to be directed and favor a particular direction. In such embodiments including directional speakers, the spatial data may further include directional data in addition to location and orientation of the speakers. In addition, for embodiments where the beam pattern may be steered, the directional data may be combined with the other spatial data during rendering of the incoming audio signals such that the rendering may include steering the beam patterns of one or more of the speakers. 
       FIG. 11  is an illustration of a room  1100  including a plurality of microphones  1110 A- 1110 E according to an embodiment of the present disclosure. Each of the plurality of microphones  1110 A- 1110 E may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The plurality of microphones  1110 A- 1110 E, in conjunction with a conferencing device, may be configured to capture and send outgoing audio signals to a remote endpoint. In particular,  FIG. 11  shows an example of how the spatial information regarding the microphones  1110 A- 1110 E may be defined relative to a coordinate system. The coordinate system may be defined as an XY axis. As an example, the relative locations of the microphones  1110 A- 1110 E may be defined in cylindrical or spherical coordinates. For example, the fourth microphone  1110 D may have spatial information associated therewith, such as a radius (R 4 ) and an angle relative to the coordinate system. The radius (R 4 ) may be measured from the origin of the coordinate system, and the angle may be measured from the positive X axis of the coordinate system. In the example of  FIG. 11 , because the fourth microphone  1110 D is located on the positive X axis, the angle is 0, and therefore, not specifically shown. Each of the other microphones  1110 A,  1110 B,  1110 C,  1110 E may have spatial information associated therewith, which may be defined in a similar manner. Of course, other coordinate systems and coordinate systems may be employed for determining positions of the speakers relative to each other using a coordinate system. For example, Cartesian coordinates may be employed, such that an (X,Y) coordinate for each microphone  1110 A- 1110 E may be determined. 
     In some embodiments, the microphones  1110 A- 1110 E may be non-directional (in other words, they are omnidirectional) and generate sound in all directions rather than favoring a specific direction. For example, the microphones  1110 A- 1110 E may be located along a table  1102  in the room  1100 , such that sound may be captured from participants on each side of the table  1102 . 
       FIG. 12  is an illustration of a room  1200  including a microphone  1210  according to an embodiment of the present disclosure. The microphone  1210  may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The microphone  1210 , in conjunction with a conferencing device, may be configured to output outgoing audio signals to a remote endpoint. The microphone  1210  may be configured as a beam forming microphone array (BMA). Thus, the microphone  1210  will also be referred to as a BMA  1210 . In particular, the microphone  1210  may include a plurality of microphones that capture sound within a field illustrated by a lobe  1212 .  FIG. 12  shows an example of how the spatial information regarding the individual beams of the BMA  1210  may be defined relative to a coordinate system. The BMA  1210  may be located along a table  1202  in the room  1200 , such that sound may be captured from participants on each side of the table  1202 . 
     As in the previous examples, the coordinate system may be defined as an XY axis, and the relative locations of the individual microphones of the microphone array  1210  may be defined in cylindrical or spherical coordinates. For example, each individual beam of BMA  1210  may have spatial information associated therewith, such as a radius and an angle relative to the coordinate system. The radius may be measured from the origin of the coordinate system, and the angle may be measured from the positive X axis of the coordinate system. In addition to the radius and angle representing the location of the individual microphone, the spatial information may further include additional angles (∂, ±φ) representing directional characteristics of the beam. For example, the directional angle (∂) may define the angle between the positive X axis and the general direction  1215  of the beam represented by the lobe  1212 . The width angles (±φ) represent the width of the beam between lines  1211 ,  1213 . These additional angles (Γ, ±φ) may be transmitted to the remote endpoint with the spatial information in order to further assist in spatial rendering of the audio signals. 
       FIG. 13  is an illustration of a room  1300  including a plurality of microphones  1310 A- 1310 E according to an embodiment of the present disclosure. Each of the plurality of microphones  1310 A- 1310 E may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The plurality of microphones  1310 A- 1310 E, in conjunction with a conferencing device, may be configured to capture and send outgoing audio signals to a remote endpoint. As discussed in the previous examples, the spatial information regarding the microphones  1310 A- 1310 E may be defined relative to a coordinate system (e.g., XY axis). In the example shown in  FIG. 13 , the origin for the coordinate system may be at a location different than near the center of the room  1300 . For example, the room  1300  may be a conference room set up for video conferencing having a video screen  1304  near one end of the room  1300 . The origin for the coordinate system in  FIG. 13  may be proximate the front of the room  1300  near the video screen  1304 . 
     The room  1300  also shows a plurality of speakers  1320 A,  1320 B positioned near the video screen  1304 . Each of the plurality of speakers  1320 A,  1320 B may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The audio signals captured by the plurality of microphones  1310 A- 1310 E may be spatially rendered and output to the plurality of speakers  1320 A,  1320 B of a remote endpoint. The plurality of speakers  1320 A,  1320 B may be directional speakers, which information may be sent to the microphones  1310 A- 1310 E along with the spatial information. It should be understood that the speakers  1320 A,  1320 B may be part of a remote room that is different than the room  1300  including the plurality of microphones  1310 A- 1310 E. In other words, the room  1300  is shown to act as both the local endpoint as well as the remote endpoint, for convenience in illustration to not include a figures for both. Of course, embodiments may include a single room that both captures audio signals through a plurality of microphones as well as outputs the spatially rendered audio signals within the same room. 
     In some embodiments, when the audio signals are spatially rendered, the coordinate system associated with the microphones  1310 A- 1310 E may be constructed as a mirror image of the reference from for the speakers  1320 A,  1320 B. As a result, the sound projected from the speakers  1320 A,  1320 B may provide sound to the remote room such that the location of the person speaking in the local room may be apparent to the listener in the remote room. As a result, such an embodiment may provide an effect to the listeners in the remote room as if they were watching a video conference through a window rather than a two dimensional screen. 
     In some embodiments, a video conference may be configured to include automatic camera tracking based on which microphone is gated on. For example, the camera (not shown) that captures the video for a video conference may be focused to pan and zoom to the person speaking into a microphone (e.g., a microphone may be gated on or off when sound is detected). Having spatial rendering of the audio signals may also enable increasing the gain to an appropriate audio channel during spatial rendering, which may have the effect of the person sounding closer than they actually are. 
       FIG. 14  is an illustration of a room  1400  including a plurality of microphones  1410 A- 1410 H according to an embodiment of the present disclosure. Each of the plurality of microphones  1410 A- 1410 H may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The plurality of microphones  1410 A- 1410 H, in conjunction with a conferencing device, may be configured to capture and send outgoing audio signals to a remote endpoint. As discussed in the previous examples, the spatial information regarding the microphones  1410 A- 1410 H may be defined relative to a coordinate system (e.g., XY axis). In the example shown in  FIG. 14 , the origin for the coordinate system may be at a location different than near the center of the room  1400 . The origin for the coordinate system in  FIG. 14  may be proximate the front of the room  1400 . For example, the room  1400  may be an auditorium or other room (e.g., lecture hall) set up for the primary sound source may be near one end of the room  1400 . The microphones  1410 A- 1410 H may be positioned at locations associated with a plurality of tables  1402 A- 1402 D. The room  1400  also shows a plurality of speakers  1420 A- 1420 D distributed along the ceiling of the room  1400 . Each of the plurality of speakers  1420 A- 1420 D may be coupled to, or incorporated within, a conferencing device that includes other processing components as described above. The other side of the room is configured in a similar manner. 
     The audio signals captured by the plurality of microphones  1410 A- 1410 H may be spatially rendered and output to the plurality of speakers  1420 A- 1420 D of a remote endpoint. The plurality of speakers  1420 A- 1420 D may be omnidirectional speakers. As with  FIG. 13 , a single room is shown having both the plurality of microphones  1410 A- 1410 H and speakers  1420 A- 1420 D. A local endpoint and a remote endpoint for spatially rendering audio signals may be located within the same rooms or different rooms. 
     In some embodiments, when the audio signals are spatially rendered, the coordinate system associated with the microphones  1410 A- 1410 H may be constructed as being superimposed with the coordinate system for the speakers  1420 A- 1420 D. As a result, with the plurality of speakers  1420 A- 1420 D may provide the effect of being spatially accurate. For example, a person speaking near the front of the room  1400  may translate to the speaker  1420 A being louder, with the other speakers  1420 B,  1420 C,  1420 D fading out going down the line. 
     Various embodiments have been described including the locations of the speakers and the microphones being fixed relative to the coordinate system defined for the rooms. In some embodiments, the speakers and/or the microphones may be movable throughout the room, such that the spatial information may be dynamically changing and sent from endpoint to endpoint with the audio streams. 
     The angular and radial information for the microphone may be determined based on determining a position of the microphone within the room. For example, various sensors, transmitters, etc. may be used to determine positional data from which the radial and angular information may be determined. Direction and orientation information may also change dynamically and may be re-sent as such information changes. For example, a person may be wearing a lapel microphone, and may be walking around the room. When streaming the spatially rendered audio to a remote room, the sound may also reflect this movement in the speakers. 
     In another embodiment, sound sources may be part of a virtual environment rather than solely in a physical environment. For example, in a gaming application, a set of players may be gaming on-line with an established conference call within rooms. As virtual players move around a screen in a virtual world, an endpoint for a remote room may be configured to spatially render audio signals speakers in a remote room based on a changing location of the virtual player in the virtual world or of the players in the physical world. 
     While the present disclosure has been described herein with respect to certain illustrated and described embodiments, those of ordinary skill in the art will recognize and appreciate that the present invention is not so limited. Rather, many additions, deletions, and modifications to the illustrated and described embodiments may be made without departing from the scope of the invention as hereinafter claimed along with their legal equivalents. In addition, features from one embodiment may be combined with features of another embodiment while still being encompassed within the scope of the invention as contemplated by the inventor. The disclosure of the present invention is exemplary only, with the true scope of the present invention being determined by the included claims.