WO2012089832A1

WO2012089832A1 - Communication system and method

Info

Publication number: WO2012089832A1
Application number: PCT/EP2011/074304
Authority: WO
Inventors: Manrique Brenes; Derek Macdonald
Original assignee: Skype
Priority date: 2010-12-31
Filing date: 2011-12-30
Publication date: 2012-07-05
Also published as: EP2649753A1; EP2649753B1; CN103416023A; CN103416023B; US10291660B2; US20120207147A1

Abstract

There is provided an instance of a client application enabling a first user terminal to access a packet-based communication system to conduct voice or video calls over a packet-based network. The client application is configured to receive an input from one or more audio and/or video input transducers of the first terminal, and to operate in conjunction with one or more other instances of the client application executed on one or more respective second terminals so as to participate in an analysis of the one or more inputs in relation to an input from one or more audio and/or video input transducers of the one or more second terminals; thereby enabling selection of one of the first and second terminals for use by a near-end user in conducting a call with a far-end user of a third user terminal via the respective client instance and packet-based communication system.

Description

Communication System and Method

Field of the Invention The present invention relates to a communication system and a corresponding method for handling voice and/or video calls when multiple audio or video transducers or terminals are potentially available for use in the call.

Background

Communication systems exist which allow a live voice and/or video call to be conducted between two or more end-user terminals over a packet-based network such as the Internet, using a packet-based protocol such as internet protocol (IP). This type of communication is sometimes referred to as "voice over IP" (VoIP) or "video over IP".

To use the communication system, each end user first installs a client application onto a memory of his or her user terminal such that the client application is arranged for execution on a processor of that terminal. To establish a call, one user (the caller) indicates a username of at least one other user (the callee) to the client application. When executed the client application can then control its respective terminal to access a database mapping usernames to IP addresses, and thus uses the indicated username to look up the IP address of the callee. The database may be implemented using either a server or a peer-to-peer (P2P) distributed database, or a combination of the two,. Once the caller's client has retrieved the callee's IP address, it can then use the IP address to request establishment of a live voice and/or video stream between the caller and callee terminals via the Internet or other such packet-based network, thus establishing a call. An authentication procedure is typically also required, which may involve the user providing credentials via the client to be centrally authenticated by a server, and/or may involve the exchange of authentication certificates between the two or more users' client applications according to a P2P type authentication scheme.

In the simple case where each of the end users has only one client application installed on one terminal with only one microphone, one speaker, one webcam and one screen, then the handling of the call is relatively straightforward in this respect.

However, with the increasing prevalence of electronic devices capable of executing communication software, both around the home and in portable devices on the move, then it is possible that the same end user may have multiple instances of the same client application installed on different terminals, and/or that a user may have an instance of the client application installed on a terminal with multiple means of audio and/or video input and/or output, i.e.

multiple audio or video transducers. In such cases it may be necessary to consider how to coordinate the operation of the multiple transducers and/or multiple terminals when making or receiving a call, or rather how to best exploit these multiple resources to improve the user's experience of the communication system.

The matter has been explored to some extent in some preceding patent applications by the applicant: GB 1005386.6, US 12/843527 (GB 1005462.5), and GB 0919592.6. Further, there are some existing arrangements that provide a remote interface for a call. For example Bluetooth headsets provide an input/output interface that is remote from the phone that handles the call. DECT phones (Digital Enhanced Cordless Telephones) provide handsets that are remote from the base station. Nonetheless, the inventors believe there is scope to further improve the coordination between the operation of multiple audio or video transducers or terminals for the purpose of making or receiving packet-based calls. Summary

The present invention provides at least three different aspects, each relating to a communication system, terminal and client application. The communication system is a packet-based communication system such as the Internet and the terminal and client are arranged to conduct the calls via the packet based network using a suitable packet-based protocol such as internet protocol (IP).

According to a first aspect of the present invention, there is provided a

communication system, terminal and/or client application configured to receive an input from multiple different audio and/or video input transducers of the same terminal, to analyse said inputs in relation to one another, and based on said analysis to select at least one audio and/or video input transducer and/or output transducer of that terminal for use in conducting a voice or video call. According to a second aspect of the present invention, there is provided a communication system configured to receive an input from multiple different audio or video input transducers of different terminals of the same user, to analyse said inputs in relation to one another, and based on said analysis to select a suitable one of multiple instances of the client application running on the different terminals for use in conducting a voice or video call. The different instances may be logged in with the same user identity.

According to a third aspect of the present invention there is provided a first user terminal installed with an instance of a client application configured to determine an availability of one or more other secondary user terminals installed with other instances of the client application, and to present the user with an option to select one of said other secondary terminals for use in conducting a voice or video call in conjunction with the first terminal.

The first, second and third aspects of the invention may be used either independently or in combination.

According to the second aspect of the present invention, there may be provided a method comprising: providing a packet-based communication system for conducting voice or video calls over a packet-based network; and providing an instance of a client application enabling a first user terminal to access the packet- based communication system, the client application being configured so as when executed on the first terminal to receive an input from one or more audio and/or video input transducers of the first terminal, and to operate in conjunction with one or more other instance of the client application executed on one or more respective second terminals so as to participate in an analysis of said one or more inputs in relation to an input from one or more audio and/or video input transducers of the one or more second terminals; thereby enabling selection of one of the first and second terminals, based on said analysis, for use by a near- end user in conducting a voice or video call with a far-end user of a third user terminal via the respective client instance and packet-based communication system.

In embodiments the analysis may relate to a relative proximity of a user to the first and second terminals.

The analysis may comprise a comparison of the energy or power level of the audio input from audio input transducers of the first and second terminals.

The analysis may comprise a Fourier analysis applied the input audio or video inputs of the first and second terminals. The analysis may comprise a voice recognition algorithm applied to the audio input audio input transducers of the first and second terminals.

The analysis may comprise a facial recognition algorithm applied to the video input from video input transducers of the first and second terminals.

The analysis may comprise a motion recognition algorithm applied to the video input from video input transducers of the first terminal. Said selection may be made upon answering or initiating a call.

Said selection may be made during an ongoing call.

The client application may be configured to recognise voice commands for controlling the call, and said selection may be made based on the analysis of audio inputs received due to one or more voice commands.

The instance of the client application on the first terminal may be configured to determine a local selection of a most relevant input from one a plurality of said input transducers of the first terminal, and said analysis may comprise comparing the local selection from the first terminal with a local selection from the one or more other instances on the respective one or more second terminals, said selection of one of the first and second terminals being based on the comparison of the selected local inputs.

The client application may be configured to perform an initial calibration process to determine relative input response properties of the different input transducers.

The instance of the client on the first user terminal may be configured to automatically discover a respective identity of each of the one or more second user terminals. The instance of the client on the first user terminal may be configured to automatically discover a respective address of each of the one or more second user terminals for use in said analysis and/or call.

The instance of the client on the first user terminal may be configured to automatically discover a respective media capability of each of the one or more second user terminals for use in said call. The instance of the client on the first user terminal may be configured to automatically discover a respective online status of each of the one or more second user terminals for the purpose of said analysis and/or call.

The method may comprise making involvement of the one or more second terminals in conjunction with the first user terminal conditional on an authorisation procedure.

According to another aspect of the invention there may be provided a terminal or system comprising apparatus configured in accordance with any of the above features.

According to another aspect, there may be provided a computer program product comprising code embodied on a non-transient computer-readable medium and configured so as when executed on a processing apparatus to operate in accordance with any of the above features. Brief Description of the Drawings

For a better understanding of the present invention and to show how it may be put into effect, reference will be made by way of example to the accompanying drawings in which:

Figure 1 is a schematic representation of a communication network,

Figure 2 is a schematic block diagram of a user terminal, and

Figure 3 is a schematic illustration of a headset.

Detailed Description of Preferred Embodiments

Figure 1 is a schematic diagram of a communication system implemented over a packet-based network such as the Internet 101 . The communication system comprises respective end-user communication apparatus 103 for each of a plurality of users. The communication apparatus 103 of each user is connected to or communicable with the Internet 101 via a suitable transceiver such as a wired or wireless modem. Each communication apparatus 103 comprises at least one user terminal 102. Each terminal 102 is installed with an instance of the client application for accessing the communication system and thereby establishing a live packet-based voice or video call with the client of another user running on another such terminal 102.

Furthermore, in the case of at least one user of the communication system, that user's respective communication apparatus 103 comprises an arrangement or collection of multiple terminals 102. For example, in the illustrative embodiment of Figure 1 the communication apparatus 103 of one user comprises: a mobile handset type terminal 102a such as a mobile phone, a laptop computer 102b, a desktop computer 102c, and a television set or television with set-top box 102d. Other types of terminal 102 that may be installed with a communication client include photo frames, tablets, car audio systems, printers, home control systems, cameras, or other such household appliances or end-user devices, etc. Each of the multiple terminals 102a-102d of the same user is installed with a respective instance of the communication client application which the same user may be logged into concurrently, i.e. so the same user may be logged into multiple instances of the same client application on two or more different terminals 102a- 102d simultaneously. This will be discussed in more detail below.

Each of the different end-user terminals 102a-102d of the same user may be provided with individual connections to the internet 101 and packet-based communication system, and/or some or all of those different terminals 102a-102d may connect via a common router 105 and thus form a local network such as a household network. Either way, it envisaged that in certain preferred

embodiments some or all of the different terminals 102a-102d of the same user will be located at different points around the house, e.g. with the television 102d in the living room, the desktop 102c in the study, the laptop 102b open in the kitchen, and the handheld 102a at any other location the user may happen to find themselves (e.g. garden or WC).

Also shown connected to the internet 101 is a data store 104 in the form of either a server, a distributed peer-to-peer database, or a combination of the two. A peer-to-peer database is distributed amongst a plurality of end-user terminals of a plurality of different users, typically including one or more users who are not actually participants of the call. However, this is not the only option and a central server can be used as an alternative or in addition. Either way, the data store 104 is connected so as to be accessible via the internet 101 to each of the client applications or instances of client applications running on each of the terminals 102 of each user's communication apparatus 103 . The data store 104 is arranged to provide a mapping of usernames to IP addresses (or other such network addresses) so as to allow the client applications of different users to establish communication channels with one another over the Internet 101 (or other packet-based network) for the purpose of establishing voice or video calls, or indeed other types of communication such as instant messaging (IM) or voicemail.

In the case where the same user can be simultaneously logged in to multiple instances of the same client application on different terminals 102a-102d, in embodiments the data store 104 may be arranged to map the same username (user ID) to all of those multiple instances but also to map a separate sub- identifier (sub-ID) to each particular individual instance. Thus the communication system is capable of distinguishing between the different instances whilst still maintaining a consistent identity for the user within the communication system.

Figure 2 shows a schematic block diagram of an exemplary end-user terminal 102 according to embodiments of the present invention, which may correspond to any of those mentioned above. The user terminal 102 comprises a memory 202 such as an internal or external hard drive or flash memory, and a processing apparatus 204 in the form of a single or multi core processor. The memory 202 is installed with an instance of the communication client 206, is coupled to the processing apparatus 204, and is arranged such that the communication client 206 can be executed on the processing apparatus 204. The terminal 102 also comprises a transceiver 220 for communicating data on the up and downlink to and from the client 206 via the Internet 101 or other such packet-based network, e.g. a wireless transceiver for wirelessly connecting to the Internet 1010 via the wireless router 105. The terminal 102 further comprises a plurality of AV transducers e.g. an internal microphone 104, an internal speaker 210, an internal camera 212 and a screen 214. The terminal 102 may then also comprise further AV transducers plugged into the main body of the terminal 102, e.g. an external or peripheral webcam 216 and a headset 218. As shown in Figure 3 the headset 218 preferably comprises an earpiece or headphones 302 and microphone 304 integrated into the same unit. The term AV transducer may be used herein to refer to any means of audio or video input or output. Terminal is meant as a discrete unit of user equipment whereas a transducer is a component or peripheral of a given terminal. In some situations such as that of a handset and docking station the categorisation may not be immediately apparent, but for the purpose of this application a terminal is considered distinct if it executes its own instance of the communication client.

Each of the transducers 208-218 is operatively coupled to the processing apparatus 204 such that the client is able to receive input from any or all of the input transducers 208, 212, 216, 218 and supply outputs to any or all of the output transducers 210, 214, 218. The terminal of Figure 2 is therefore notable in one respect in that it comprises multiple audio input transducers, multiple audio output transducers and/or multiple video input transducers, and that each of these is potentially available to the client application 206 for conducting voice or video calls over the packet-based network. Multiple video output transducers are also a possibility.

According to a first aspect of the present invention, the client application 206 is configured so as when executed to receive an input from multiple different input transducers of the same terminal 102, to analyse the input signals from the different input transducers in relation to one another, and based on the analysis to select a suitable input transducer and/or output transducer of that terminal for use in conducting a call. According to a second aspect of the present invention, the instances of the client application 206 on the different terminals 102a-102d of the same user are configured so as when executed to operate in conjunction with one another, to thereby receive an input from input transducers of the different terminals 102a- 102d, analyse the input signals from the different terminals 102a-102d in relation to one another, and select a suitable one of the multiple instances of the client application 206 running on different terminals 102a-102d for use in conducting a call. That is to say, the second aspect is concerned not just with the selection of a particular input or output transducer 208-218, but also with the routing of the voice and/or video stream of a call to and from a selected terminal 102a-102d. In this case the terminals 102a-102d together form one end of a call (the "near end") communicating with the client running on a further, third user terminal 102f (the "far end") via the Internet 101 or other such packet-based network.

In either case, the analysis applied to the inputs may include:

• a comparison of the energy or power level of the received audio signal from two or more audio input transducers from the same terminal 102 and/or from different terminals 102;

• comparison of a Fourier analysis of the input signal received from two or more different audio or video inputs from the same terminal and/or different terminals;

· a voice recognition algorithm applied to the received audio signal from two or more audio input transducers from the same terminal 102 and/or from different terminals 02;

• a facial recognition algorithm applied to the received video signal from two or more video input transducers from the same terminal 102 and/or from different terminals 02; and/or

• a motion recognition algorithm applied to the received video signal from two or more video input transducers from the same terminal 102 and/or from different terminals 102. The client application 206 is arranged to perform one or more such analysis processes and, based on the said analysis, to select one or more of the following for use in conducting the packet-based voice or video call: an input audio transducer, an input video transducer, an output audio transducer, an output video transducer, and/or an instance of the client application running on one of multiple terminals of the same user. This process may be performed upon making a call, answering a call, and/or dynamically during an ongoing call. For example, in one embodiment the invention may advantageously be used in conjunction with a client 206 or terminal 102 capable of recognising voice activated commands, e.g. so that the user can control the client 206 vocally with commands such as "call "answer call", and "hang up". Depending on the approximate location of a user within a room, or depending on whether or not the user is wearing his or her headset 218, then the optimal microphone for use in making or answering a call may vary. The client 206 may therefore analyse the inputs from two or microphones 208, 304 of the same terminal in the same room to determine which input signal has the largest energy in the human vocal frequency range, e.g. when the user speaks to answer the call using a voice command, and then select that microphone to use in the call.

The audio inputs from the microphones may also determine a suitable audio output transducer, e.g. by selecting between a loudspeaker 210 and the headphones 302 of a headset 218 depending on which microphone is generating the most vocal energy.

In another example, detection of a rustling or scrabbling sound at the headset microphone 304 may be taken as indicative of the user fumbling for their headset to answer an incoming call, and this can be used to select the headset 218 for audio input and/or output.

In yet another embodiment, the audio inputs from the microphones may be used to switch between different audio or video output transducers during the call, e.g. if the user moves around the room or puts on or removes the headset

In an example of the second aspect of the invention, it is envisaged that the invention will have an application in situations where the user has different terminals 102a, 102b, etc. located in different places around the house. In this case an analysis of the energy levels from different microphones or cameras of different terminals may be used to determine the presence of the user in a particular room or the proximity to a particular terminal, and hence determine the best terminal for answering or making a call, or to switch between the terminals during an ongoing call as the user roams about the house. Other techniques that can be used to detect the presence or proximity of a particular user include motion estimation to detect the presence of a suitably sized moving object (which may be taken as a human moving between rooms), a Fourier analysis to determine an overall colour property of an image or moving object (e.g. based on the assumption that the moving user wears the same colour clothes as they move between rooms), or a voice or facial recognition algorithm (to help distinguish between multiple people and/or background noise), or indeed any combination of these.

In the case of the second aspect of the invention, it will be necessary for the client instance 206 on at least one of the terminals to send information about the input received from its respective transducer(s) to one or more other terminals or other network elements for comparison. To achieve this, both (or all) of the user's client instances 206 that are involved in the comparison are preferably logged into with the same username and have the concept of being in the same call.

For example, communication between the instances and/or controller may be enabled by reference to the system of user IDs and sub-IDs mapped to IP addresses or other such network addresses by the data store 104. Thus the list of sub-IDs for each user allows the different client instances to be identified, and the mapping allows a client instance, server or other network element to determine the address of each terminal on which one or more other different instances is running. In this manner it is possible to establish communications between one client and another or between the client and a server or other network element for the purpose of sharing information on the input signals from the audio and/or video input transducers, e.g. to share input energy levels, motion vectors or FFT results. The same mechanism may also be used to signal or negotiate the selection of the required instance for conducting the call.

Alternatively, communication set up may be enabled by maintaining a list of only the terminal identities rather than the corresponding client identities, the list being maintained on an accessible network element for the purpose of address look-up. For example a list of all the different terminals 102a-102d may be maintained on an element of the local home network, 105, 102a-102d, in which case only the local network addresses and terminal identities need be maintained in the list, and a system of IDs and separate sub-IDs would then not necessarily be required. The local list could be stored at each terminal 102a-102d or on a local server of the home network (not shown), and each client instance would be arranged to determine the necessary identities and addresses of the other instances' terminals by accessing the list over the local network.

Once a suitable mechanism has been put in place for identifying the different client instances and the addresses of their respective terminals 102a-102d, the selection may be performed in a number of ways. For example, in one

implementation all of the client instances 206 in question may be arranged to transmit their respective transducer input information (e.g. input energy levels, motion vectors or an FFT result) to a central server or other central control element, which could be implemented on a server along with the data store 104 or on an element of the local home network. The central controller would then be arranged to run an algorithm to analyse the different received inputs in relation to one another and thereby select the instance of a particular terminal, e.g. 102b, to make or answer the call. The controller then instructs the instances 206 on their behaviour (are they involved in the call or not and to what extent) using the chosen signalling mechanism. In another implementation, the different client instances 206 may share the information directly between each other and either mutually negotiate the selected terminal according to some predetermined protocol or act under the control of one instance that has been designated as the master instance (e.g. by the user or by default).

As mentioned, in some embodiments the analysis of the transducer inputs may be used to switch between different instances of the client 206 running on different terminals 02a, 102b of the same user during an ongoing call, e.g. as the user walks between rooms (rather than just selecting an instance to initiate an outgoing call or answer an incoming call). This may involve each client instance 206 periodically sampling or otherwise monitoring its respective input transducer or transducers 208, 212, 218 and sharing the monitored information throughout the call in a similar manner to that described above. Alternatively each client may only share new transducer input information in response to some detected event such as the input energy level or motion vector exceeding some threshold. Either way, the controller or master instance may thus apply the selection algorithm to the received input information at multiple times throughout the call, in either a scheduled or event-based manner, in order to make an ongoing, dynamic selection as to which instance 206 on which terminal 102 should be used for the call. In one implementation of the dynamic switching case, once the desired instance has been identified as the selected endpoint for the call, then the switchover may be completed in a similar manner to known call forwarding techniques as described for example in US application no. 12/290232, publication no. US 2009- 0136016, but with the call being transferred between different terminals of the same user based on different sub-IDs, rather than the call being transferred between different users based on different user IDs. In another implementation, the client 206 on the initial terminal, e.g. 102b, may continue to receive the audio and/or video stream of the call but then route the audio and/or video stream onwards to the newly selected terminal, e.g. 102c (such that the endpoint of the call appears to be the same, 102b, from the perspective of the client on the other end of the call). This latter option would be particularly applicable if the initial and new terminals 102b and 102c have a local wireless connection such as a wi-fi or Bluetooth connection available between them.

In both the first and second aspects of the invention, note that the type of transducer being selected is not necessarily the same as the type of transducer used to make the selection. E.g. a microphone may indicate the presence of a user in a particular room or location and be used to select a suitably located camera, or a camera may indicate the presence of a user in a particular room or location and be used to select a suitably located microphone, etc.

Further, it is not necessarily the case that the voice and video streams are routed to and from the same user terminals 102a, 120b, etc. In embodiments it could be possible to determine that, say, a television 102d is best placed to display video to the user whilst a laptop 102b or mobile terminal 102a is best placed to handle the audio part of the call. The selection algorithm running on the client instance 206 and/or central controller would then instruct the two streams to be routed to different terminals 102a, 102b.

The first and second aspects of the invention may be used either independently or in combination. For example, it would be possible for the instance of the client application 206 running on each of multiple terminals 102 to determine its own best local input transducer (e.g. highest audio input energy level or best Fourier analysis match), then for the different instances to compare their best local input results to find the best global input result.

In either case, an initial calibration phase may be useful, e.g. to determine the relative levels that the different microphones generate when the user is at different distance from those microphones. That is to say, the client 206 is preferably configured to determine the relative gains of the different microphones. For example upon initial installation the user may be asked to sit or stand at two or more predetermined distances from the terminal and speak at a fixed level, which the client 206 can then use for calibration.

In absence of a clear determination in any of the above examples, the client or system may be configured to use a default transducer and/or terminal for making or answering calls.

According to a third aspect of the present invention, a primary terminal 102 running an instance of the communication client 206 is able to select the resources of one or more secondary terminals 102 installed with or running another instance of the client 206 to be used during a conversation. The user may use the terminal 102 that provides the best interfaces for what they are doing. For example if the user is participating in a video call, he may use his TV 102d for receiving and transmitting video, while using a mobile device 102a for controlling the call and transmitting and receiving the audio stream. Similarly if he wanted to maintain a conversation while working in his living room he may direct the call to a stereo system or speaker phone while he sends/receives video from a handheld or portable device like a photo-frame, he may even chose to send/receive a data file going directly from/to his NAS (network attached storage device).

The term "consume" is sometimes used to generally mean playing a live audio or video stream or storing a file transfer, i.e. using the stream for its ultimate purpose at its end-point destination. Similarly the term "generate" may refer to capturing a live audio or video stream or retrieving a file transfer from memory for transmission over a network , i.e. at the origin of the stream. The third aspect of the invention can be used to allow the second terminal to consume or generate at least one stream of the call whilst the first user terminal concurrently generates or consumes at least another stream of the call. As mentioned, in embodiments one of the streams may be a file transfer performed in conjunction with the voice or video call as part of the same session between the same near and far end users. In other embodiments only live voice and/or video streams may be involved, e.g. with one terminal capturing the outgoing video stream and another terminal playing the incoming video stream, and/or with different terminals handling audio and video streams.

In one example, the client instances could be "network aware" and could be provided with an API enabled to facilitate not only the discovery of the different devices but also the easy transfer/usage of different media streams in a conversation from one end point to the next or the combination of two end points, This allows a user to configure how multi device resources should be allocated for handling communication events.

This third aspect of the present invention advantageously allows a user to be presented with a list of available user terminals 102 and to select at least one secondary terminal 102 with the most appropriate capabilities to handle part of the call or a particular type of communication, for example a live video stream or file transfer. According to an embodiment of the invention, a terminal 102 such as a mobile phone 102a installed with an instance of the client application 206 is arranged to discover other resources that are available on other such user terminals 102. The user may select to use the resources of one or more of the discovered terminals 102.

The selection of "resources" could refer to selecting a particular other

(secondary) user terminal 102, or selecting a particular audio or video output transducer 208-218 of a particular other user terminal 102.

The terminal 102 that is used by a user to perform the selection will be referred to as a primary terminal. Each selected terminal will be referred to as the secondary terminal. In the case of an outgoing call the primary terminal is preferably the initiator of a call, and in the case of an incoming call the primary terminal is preferably the terminal used to answer the call. The primary terminal is also preferably the terminal which controls the call, e.g. to choose when to terminate the call or activate other features. The primary terminal may remain the master terminal for the purpose of controlling the call, or primary status could be transferred during the call to another terminal such as one of the secondary terminals.

A similar terminology may be used to describe the primary and secondary clients running on the primary and secondary terminals respectively. According to the third aspect of the invention, the client 206 on the other

(secondary) user terminal such as 102c may be of the same user as that on the primary terminal (i.e. logged in with the same user ID), or may be another terminal 102e borrowed from a different user (logged in with a different user ID). Either way, the primary and secondary terminals 102a-102e together form one end of the call (the "near end") communicating with the client running on a further, third user terminal 102f (the "far end") via the Internet 101 or other such packet-based network.

In order for one client instance 206 to use the resources of another client instance 206 it is desirable to require the primary client instance to be authorised to use the resources of the other client instance. There are different methods by which one client instance 206 can authorise another client instance, as follows.

One method is for instances of the client 206 that are logged on with the same username may be automatically authorised to share resources, e.g. the clients on terminals 102b and 102a.

In another authorisation method, if the terminals 102 are logged on using different usernames, it may be necessary for the client on one terminal such as 102b to authorise the client of another terminal 102e to use resources. This may be configured locally at the terminal 102, for example the user may input the usernames of authorised clients 206, or select contacts from the contact list that are authorised to use the terminal resources. Alternatively this may be configured remotely, for example a primary client may send an authorisation request to a secondary client to allow the primary client to use the resources of the secondary client.

Alternatively a client 206 may be configured to authorise any contact to use the resources of the terminal 102 - i.e. any contact that has been approved by the user to be included in a contact list.

As such the primary terminal 102b that initiates a VoIP conversation will have the capability to direct any media stream to any of the secondary terminal that is authorized to use. The media stream of the conversation will be directed to the designated secondary terminal 102e that the primary user selects. The primary user may choose to move all the media streams to a terminal and/or designate an alternative terminal as the primary terminal.

Each client 206 that can act as a primary client, e.g. on primary terminal 102b, is preferably configured with a mechanism for resource discovery for discovering the presence of other potential secondary terminals 102a, 102e, etc. and/or for discovering the media capability of the potential secondary terminals (what input and output transducers they have available). Resources available to the primary client are presented in a list. The list of available resources may indicate the terminal type (e.g. TV, printer) such that the user can select the most appropriate device to handle the communication event. For example the user may select a TV for a video call, a stereo system for a voice call, or a Network Attached Storage (NAS) device for a file transfer.

The available resources of other terminals installed with instances of the client 206 may be discovered using a number of alternative methods, for example as follows. A user terminal 102 installed with a suitable client application 206 or suitable instance of the client application may be referred to in the following as an "enabled terminal".

One such method is server assisted resource discovery. In one embodiment of the invention a server stores the location of each terminal having an instance of the client 206. When a user logs in, the client is arranged to provide its location and terminal type/capabilities to the server. The location could be defined as IP address, NAT or postal address input by the user. In this embodiment of the invention the server is arranged to return a list of proximate terminals to that of the primary client in response to the primary client transmitting a find suitable terminals to the server.

Alternatively the server may provide a client 206 with a list of available terminals 102 enabled with the client 206 in response to receiving a configuration message from a client 206. In this case a client may provide a list of one or more usernames that are authorised to use the resources of the device on which the client is installed. The user of the device may configure access to be limited to certain types of resource, e.g. audio output only, and may additionally control the times during which the resource may be accessed. The server is arranged to provide each authorised client in the list with a message indicating which resources the client is authorised to use and when.

In either of the above options the server could instead be replaced with a distributed database for maintaining the list, or a combination of the two may be used. In the case where the primary and secondary terminals are of the same user, i.e. running clients logged in with the same username, the system of usernames and sub-identifiers may be used to distinguish between the different instances in a similar manner to that discussed above. However, that is not essential and instead other means of listing the available terminals could be used, e.g. by listing only the terminal identity rather than the corresponding client identity, or in the case where the primary and secondary terminals are of different users (e.g. 102b and 102e) then the sub-identifier would not necessarily be needed.

Another possible method is common local network device discovery. In an alternative embodiment the primary client is arranged to present a list of terminals 102a, 102c, 102d enabled with the client 206 to the user that are discovered on the local network, this may be in response to the user actuating a find 'Enabled Terminals' instruction or in response to the user connecting to the network. Any IP enabled terminal that registers into a given network receives a unique IP address within that network. As an enabled terminal joins it will broadcast a presence message to all enabled terminals in that network announcing a given username / ID and a list of authorized users that have rights to access its capabilities. All the enabled terminals 102 that receive this message and have a common authorized user will reply back to authenticate themselves and establish a secure communication channel through which they will announce its IP address and available resources to the primary user. The primary user will have rights to access the media interfaces of all the enabled terminals for which it has been authenticated. Another method is to select resources from the contact list (i.e. a list of contacts approved by the user for communicating with that user, typically maintained via the user's own client 206). In this case resources of other terminals such as 102e may be indicted on the user's contact list. For example each contact listed in the contact list will indicate the type of terminal 102 on which the client is executed. This may be determined automatically, for example the client 206 may detect the type of device by detection of the operating system. Alternatively the user may input the device type directly. The device type may be presented in the contact list in the form of the contact name, 'John's TV ,the mood messages, or an icon. In both the second as well as the third aspects of the invention, the online status of the other or secondary client application may be relevant, e.g. on other user terminal 102a, 102c or 102e. In order for the resources of an other or secondary terminal 102 to be accessed, it will likely be necessary for the device to be online at the time the

communication event is received. If the secondary terminal is not online the primary client should preferably be prevented from selecting the resources of the offline secondary device.

The availability of resources may be determined using the presence. In this case the client applications 206 are arranged to search for contacts' network addresses in a peer-to-peer network or server. Once the address is determined the client 206 sends a status request command to the specified address. If the contact is online, it responds with a reply reporting its status. If no reply is received, the contact is deemed to be offline. Presence requests are preferably sent periodically so that the status can be updated when necessary.

In an alternative embodiment, in the case where the secondary terminals 102 are located on the same local network, each client 206 is arranged to transmit "keep alive" messages periodically. If a keep alive message is not received from a client, the client is determined to be offline.

A further matter which may be relevant to the third embodiment is the primary and secondary client status.

When a client is selected as a secondary client, the identity of the primary client is stored at the secondary device. The client will behave as a secondary client for any calls or communication events associated with the primary client. For example, in response to receiving a selection request at the secondary terminal, the secondary client will store the network location/username of the primary terminal. The secondary client will handle media and call set up instructions from the primary client in accordance with predetermined rules configurable by the user. For example the user may configure the TV client to allow the mobile client to use the video input and output resources of the TV. If the TV receives a call set up request from a third party that identifies the mobile client as the primary client, the TV will only handle the video media during the call. In particular the TV client will not attempt to capture and transmit audio during the call. Furthermore the TV will not display a user interface to the user for controlling the call.

The above embodiments provide example mechanisms by which one or more user terminals can be selected for use in conducting a call or part of a call according to the second or third aspects of the invention. Once a suitable mechanism is put in place, Call or communication set up can proceed as follows. By way of example, the following will be described with reference to the laptop or tablet style computer 102b as the primary terminal and the mobile handset type terminal 102a as the secondary terminal.

When a call is received at the primary terminal 102b, the client running on the primary client may be used to answer the call and direct the media stream to the desired selected secondary terminal 102a. Note that the audio and video streams of a video call are not necessarily generated or played out by the same user terminal 102, and nor are the received and outbound streams necessarily generated and played by the same terminal 102. Indeed, it is one advantageous use of the present invention that the primary terminal 102b can be used to generate and/or play out the audio stream whilst the secondary terminal 102a is used to generate and/or play out the video stream, or vice versa - i.e. the second terminal 102a handles whichever of the received and/or outbound audio and/or video streams is not handled by the primary terminal 102b. Other streams such as file transfers forming part of the same session as the call may also be directed to a secondary terminal, e.g. 102c or 102e

In a preferred embodiment of the invention, the primary client on the primary terminal 102b may instruct the far end party (on the other end of the call) to route the relevant media stream directly to the secondary client on the secondary terminal 102a (e.g. by referring the far end terminal to the mapping of user IDs and Sub-IDs to addresses in the data store 104, or by sending the address of the secondary terminal 102a to the far end terminal directly). Alternatively however all streams may be routed via the primary terminal 102b, with the primary client then routing any required streams onwards to and from the secondary terminal 102a (i.e. so from the perspective of the far end client and user terminal the primary terminal 102b is still the end point for all streams of the call, and the routing to or from the secondary terminal is handled solely by the client on the primary terminal 102b).

In order to retain control of the call at the primary device, the secondary client will handle the call in response to instructions received from the client (e.g. end call). These instructions may be sent as IM messages. The primary terminal may input call handling instructions such as 'increase volume', 'answer call', 'turn off webcam' or 'end call' using predetermined IM messages, recognised by the secondary client.

In an alternative embodiment of the invention, call set up may be handled by the server. For example if the user has previously configured the system to send video to the television, the server will provide the address of the TV to the far end node such that video data can be sent directly to the TV client. Again the TV client will be aware that the call is associated with the primary device and will accordingly only use the resources that are authorised for use. Either way, in order to direct control signals to instruct the secondary terminal, the primary client or the server may determine the address of the secondary terminal from a list or database mapping addresses to terminal identities or user IDs and Sub-IDs, which may be implemented on a server, distributed database or local network element. In embodiments the mechanism for transmitting control signals and/or responses in the third aspect of the invention may be the same or a similar mechanism to that used to share information on transducer inputs according to the second aspect of the present invention, or in other embodiments different mechanisms may be used for the two different aspects.

Note that in preferred embodiments a client 206 installed at any terminal 102 may present the user with a list of enabled terminals 102 which are installed with an instance of the client application 206. In this case the terminal on which the user selects a terminal becomes the primary terminal and the selected terminal becomes the secondary device.

The behaviour of a client 206 as either a primary client or a secondary client will depend on whether it has been selected for use as a secondary client. It will be appreciated that the above embodiments have been described only by way of example. Other variants or implementations may become apparent to a person skilled in the art given the disclosure herein. For example, the invention is not limited by any particular method of resource discovery or authorisation, and any of the above-described examples could be used, or indeed others. Further, any of the first, second and/or third aspects of the invention may be implemented either independently or in combination. Where it is referred to a server this is not necessarily intended to limit to a discrete server unit housed within a single housing or located at a single site. Further, where it is referred to an application, this is not necessarily intended to refer to a discrete, stand-alone, separately executable unit of software, but could alternatively refer to any portion of code such as a plug-in or add-on to an existing application. The invention is not limited by the described embodiments but only by the appendant claims.

Claims

1. A method comprising:

providing a packet-based communication system for conducting voice or video calls over a packet-based network; and

providing an instance of a client application enabling a first user terminal to access the packet-based communication system, the client application being configured so as when executed on the first terminal to receive an input from one or more audio and/or video input transducers of the first terminal, and to operate in conjunction with one or more other instances of the client application executed on one or more respective second terminals so as to participate in an analysis of said one or more inputs in relation to an input from one or more audio and/or video input transducers of the one or more second terminals;

thereby enabling selection of one of the first and second terminals, based on said analysis, for use by a near-end user in conducting a voice or video call with a far-end user of a third user terminal via the respective client instance and packet-based communication system.

2. The method of claim 1 , wherein the analysis relates to a relative proximity of a user to the first and second terminals.

3. The method of claim 1 or 2, wherein the analysis comprises a comparison of the energy or power level of the audio input from audio input transducers of the first and second terminals.

4. The method of any preceding claim, wherein the analysis comprises a Fourier analysis applied the input audio or video inputs of the first and second terminals.

5. The method of any preceding claim, wherein the analysis comprises a voice recognition algorithm applied to the audio input audio input transducers of the first and second terminals.

6. The method of any preceding claim, wherein the analysis comprises a facial recognition algorithm applied to the video input from video input transducers of the first and second terminals.

7. The method of any preceding claim, wherein the analysis comprises a motion recognition algorithm applied to the video input from video input transducers of the first terminal.

8. The method of any preceding claim, wherein said selection is made upon answering or initiating a call.

9. The method of any preceding claim, wherein said selection is made during an ongoing call.

10. The method of any preceding claim, wherein the client application is configured to recognise voice commands for controlling the call, and said selection is made based on the analysis of audio inputs received due to one or more voice commands.

11. The method of any preceding claim, wherein the instance of the client application on the first terminal is configured to determine a local selection of a most relevant input from one a plurality of said input transducers of the first terminal, and said analysis comprises comparing the local selection from the first terminal with a local selection from the one or more other instances on the respective one or more second terminals, said selection of one of the first and second terminals being based on the comparison of the selected local inputs.

12. The method of any preceding claim, wherein the client application is configured to perform an initial calibration process to determine relative input response properties of the different input transducers.

13. The method of any preceding claim, wherein the instance of the client on the first user terminal is configured to automatically discover a respective identity of each of the one or more second user terminals.

14. The method of any preceding claim, wherein the instance of the client on the first user terminal is configured to automatically discover a respective address of each of the one or more second user terminals for use in said analysis and/or call.

15. The method of any preceding claim, wherein the instance of the client on the first user terminal is configured to automatically discover a respective media capability of each of the one or more second user terminals for use in said call.

16. The method of any preceding claim, wherein the instance of the client on the first user terminal is configured to automatically discover a respective online status of each of the one or more second user terminals for the purpose of said analysis and/or call.

17. The method of any preceding claim, comprising making involvement of the one or more second terminals in conjunction with the first user terminal conditional on an authorisation procedure.

18. A client application comprising code embodied on a computer-readable medium and configured so as when executed on a first terminal to perform operations of:

accessing a packet-based communication system to conduct voice or video calls over a packet-based network; receiving an input from one or more audio and/or video input transducers of the first terminal; and

operating in conjunction with one or more other instances of the client application executed on one or more respective second terminals so as to participate in an analysis of said one or more inputs in relation to an input from one or more audio and/or video input transducers of the one or more second terminals; thereby enabling selection of one of the first and second terminals, based on said analysis, for use by a near-end user in conducting a voice or video call with a far-end user of a third user terminal via the respective client instance and packet-based communication system.

19. The client application of claim 18, wherein the code is further configured to perform operations in accordance with any of claims 2 to 17.

20. A first user terminal comprising:

a transceiver operable to access a packet-based communication system to conduct voice or video calls over a packet-based network;

a storage medium storing an instance of a client application enabling the first user terminal to access the packet-based communication system; and

processing apparatus arranged to execute the instance of the client application, the client application being configured so as when executed on the first terminal to receive an input from one or more audio and/or video input transducers of the first terminal, and to operate in conjunction with one or more other instance of the client application executed on one or more respective second terminals so as to participate in an analysis of said one or more inputs in relation to an input from one or more audio and/or video input transducers of the one or more second terminals; thereby enabling selection of one of the first and second terminals, based on said analysis, for use by a near-end user in conducting a voice or video call with a far-end user of a third user terminal via the respective client instance and packet-based communication system.

21 . The first user terminal of claim 20, wherein the client application is further configured to perform operations in accordance with any of claims 2 to 17.