GB2491852A

GB2491852A - Rendering Active Speaker Image at Higher Resolution than Non-active Speakers at a Video Conference Terminal

Info

Publication number: GB2491852A
Application number: GB1109938.9A
Authority: GB
Inventors: David K Linsdall
Original assignee: Thales Holdings UK PLC
Current assignee: Thales Holdings UK PLC
Priority date: 2011-06-13
Filing date: 2011-06-13
Publication date: 2012-12-19
Also published as: GB201109938D0

Abstract

A collaborative working environment is established between a plurality of client units. Each client unit is operable to collect a video input and to generate a scalable video signal therefrom for use in others of the client units. The client units are each configured to display images generated at one or more of the other client units, and at least one of the client units is operable to display images from two or more of the client units. An active participant is determined (e.g. using participant identification information), corresponding to one of said client units, and, at a client unit displaying more than one participant image, the image corresponding to the active participant is rendered at a high resolution (PARTICIPANT 2) while the or each other participant image is rendered at a lower resolution (PARTICIPANT 3). Each client unit may comprise first and second rendering means to render the first and second resolution images.

Description

I

Multi-way collaboration The present invention relates to multi-way collaboration, and particularly, but not exclusively, to video-conferencing based collaboration.

Multi-way collaboration involves the provision of communication facilities at three or more locations, to enable communication by users with each other. A simple multi-way collaboration is exemplified by a telephone conference call. Such is relatively easy to establish, and merely requires user level usage protocols to avoid interruption of a speaker by another. Such protocols are innate to standard human behaviour.

While the reader will appreciate that collaboration can also be implemented at merely two locations, the issues addressed in this disclosure tend not to be exhibited in that

trivial example

It is also known to provide video-conferencing on the same basis. That is, a user experience is established whereby a user can be presented with video images of other participants in the multi-way collaboration, alongside an audio stream.

Video conferencing between two participants is well established. A user would be presented with an image of the other participant, together with an audio stream to enable telephonic communication. The use of video conferencing between three or more participants introduces an added level of complexity, in that there is then a need to present several video images to a user. For example, in a three way collaboration, each user has to be provided with a facility to view images from the other two user sites. This may require the use of multiple video display units, or sub-divisions of a screen presented on a single video display unit, in order to display the video images from all of the other users.

Conventional, single screen systems generally allow either a fixed division of the screen to display several smaller images, or they incorporate software to provide an operational feature which detects the current speaker in a video-conferencing session, and to switch the video feed to show only that speaker. However, this is not ideal, as repeated switching of a video presentation tends to be very intrusive when a lively debate is underway. Most people who experience this effect soon disable the feature as a result.

It is also known that the provision of video-conferencing facilities, or the quality of such facilities when provided, depends substantially on the bandwidth available for communication between sites. This applies of course to two-way communication, but even more so to multi-way conferencing where the number of channels is increased.

To provide context, in a peer-to-peer arrangement, the number of channels required to establish multiway conferencing is governed by the following formula: n(n-i) where n is the number of conferencing nodes, and c is the number of bi-directional channels required.

Thus, whereas two-way conferencing involves one bi-directional channel, three-way conferencing involves three bi-directional channels, four-way conferencing involves six bi-directional channels and so on. The number of channels required is 0(n2) and thus the complexity of such a system is an obstacle to effective communication between multiple participants.

Of course, if a hub-and-spoke arrangement can be implemented, the complexity issue does not arise, but on the other hand, more infrastructure is required in order to manage the hub of the hub-and-spoke arrangement.

The limitation imposed by bandwidth is particularly applicable to instances where one or more of the channels is implemented at least in part using a radio link. One approach to tackling this is to configure the bandwidth of the video codecs used in the video-conferencing implementation such that the sum of the video feeds being transmitted fits within the available bandwidth of the slowest link in the network.

However, this strategy is not particularly effective if the available bandwidth is so low that only a single reasonable quality video feed can be supported. It also means that the quality of a multi-way collaboration is set by the capability of the poorest communications link, thus imposing an artificial limitation on performance of higher bandwidth links in a multi-node conferencing implementation.

A video conferencing system, using a server which acts as a hub for the whole system, can address this problem by re-coding the outgoing stream to a site constructed by some performance issue, to a lower quality than those streams sent to sites with a high bandwidth connection. However, this leads to a deleterious quality of service to a particular user.

In general terms, an aspect of the present invention links participant detection software to dynamic bandwidth video encoding.

An aspect of the invention provides a system for establishing a collaborative working environment, the system comprising a plurality of client units, each client unit being operable to collect a video input and to generate a scalable video signal therefrom for use in others of said client units, each client unit being configured to display images generated at one or more of the other client units, at least one of said client units being operable to display images from two or more of said client units, the system further comprising active participant determining means, for determining one participant, corresponding to one of said client units, as an active participant, and image rendering means operable to render images corresponding to one or more of said video signals at said client units, such that, at a client unit displaying, in use, more than one image, an image corresponding to said active participant is rendered at a first resolution, whereas any other image rendered at said client unit is rendered at a second resolution lower than said first resolution.

An aspect of the invention provides a method for establishing a collaborative working environment between a plurality of client units, each client unit being operable to collect a video input and to generate a scalable video signal therefrom for use in others of said client units, each client unit being configured to display images generated at one or more of the other client units, at least one of said client units being operable to display images from two or more of said client units, the method further comprising determining one participant, corresponding to one of said client units, as an active participant, and rendering images corresponding to one or more of said video signals at said client units, such that, at a client unit displaying, in use, more than one image, an image corresponding to said active participant is rendered at a first resolution, whereas any other image rendered at said client unit is rendered at a second resolution lower than said first resolution.

An aspect of the invention provides a computer apparatus for use in a establishing a collaborative working environment with at least two other cooperative apparatus, the apparatus being operable to collect a video input and to generate a scalable video signal therefrom for use by other apparatus as required, the apparatus being configured to receive scalable video signals from said other computer apparatus to which said apparatus is connected, in use, and including display means operable to display images on the basis of said received scalable video signals, the apparatus further being operable to receive information identifying another computer apparatus as an active participant, corresponding to one of the scalable video signals and wherein said display means includes image rendering means operable to render said images such that, an image corresponding to a scalable video signal from a computer apparatus designated as an active participant is rendered at a first resolution, whereas any other image is rendered at a second resolution lower than said first resolution.

An aspect of the invention provides a method performed at a computer apparatus in a establishing a collaborative working environment with at least two other cooperative apparatus, the method comprising collecting a video input and generate a scalable video signal therefrom for use by other apparatus as required, receiving scalable video signals from said other computer apparatus to which said apparatus is connected, in use, and displaying images on the basis of said received scalable video signals, receiving information identifying another computer apparatus as an active participant, corresponding to one of the scalable video signals and rendering said images such that, an image corresponding to a scalable video signal from a computer apparatus designated as an active participant is rendered at a first resolution, whereas any other image is rendered at a second resolution lower than said first resolution.

Whereas aspects of the invention have been described in terms of apparatus and or methods, either can be implemented by means of the use of computer software. That is, suitable computer software implemented on suitable, general purpose, computer equipment can be used to arrive at an apparatus, or a method, in accordance with the invention. In particular, a computer program product can be used to implement the invention. Such a computer program product can comprise a computer readable storage medium, or a computer receivable signal, bearing computer executable instructions which, when executed by a computer, cause that computer to be configured either as apparatus in accordance with the invention or to perform a method in accordance with the invention.

While it may be possible to implement a computer program product to implement all of the functionality of a described aspect of the invention, it may also be possible to use software and/or hardware components of a suitable computer to make use of facilities already provided in the computer to arrive at an embodiment of the invention. That is, an operating system, possibly also including libraries of functions for reference by a computer program product, may be used to achieve technical effects in line with an aspect of the invention. It is not necessary to describe here the exact implementation of the invention in software, in that the reader will appreciate that such can be achieved with programming techniques known in the art.

Specific embodiments will now be described, with reference to the accompanying drawings, in which: Figure 1 is a graphical representation of a high resolution video image; Figure 2 is a graphical representation of a relatively low resolution rendering of the image illustrated in figure 1; Figure 3 is a graphical representation of a screen shot at a client unit of a video conferencing system in a first configuration; Figure 4 is a graphical representation of a screen shot at a client unit of a video conferencing system in a second configuration; Figure 5 is a schematic diagram of a video conferencing system in accordance with a first described embodiment; Figure 6 is a schematic diagram of a client unit of the system illustrated in figure 5; Figure 7 is a schematic diagram of a processing unit of the client unit illustrated in figure 6; Figure 8 is a schematic diagram of a server of the system illustrated in figure 5; Figure 9 is a schematic diagram of a server of a system in accordance with a second described embodiment; and Figure 10 is a schematic diagram of a server of a system in accordance with a third described embodiment.

The various embodiments disclosed herein are concerned with video-conferencing between a plurality of video conference apparatus, each apparatus being located at a "site". Each embodiment involves provision of an active participant detection system controlling quality, and hence bandwidth, of a video signal sent to each of the sites.

The active participant detection system is intended to identify an "active participant", namely a site at which a user, participating in the video conferencing session, is located, whose use of local video conference apparatus is drawing the most attention from users of the other video conference apparatus.

The site determined to be the active participant will be set to use the best quality image and the others set to some lesser quality depending upon the bandwidth constraints.

Thus, at any time, only one high quality stream is received from the participant of most interest; the remaining video streams are received at a lower resolution and/or frame rate.

However, in accordance with the described embodiments, the switching between active streams is intended to be more subtle than in conventional solutions. When the active participant detection system determines a change in the designation of active participant, the resultant user experience at a site is that the image of the newly designated active participant simply becomes clearer, and the others reduce in clarity.

Figures 1 and 2 show this effect in practice. Figure 1 shows a line drawing intended to illustrate an image which might be viewed at a video-conferencing suite in accordance with the described embodiments, of a participant designated as the active participant.

Then, figure 2 shows the same image, but at a lower degree of resolution, corresponding to the user not being designated as the active participant.

A benefit of this arrangement, in accordance with the described embodiments, is that images, presented to a participant, do not switch around or jump in size or location to distract the participant in the collaboration.

Thus, in accordance with the described embodiments, an image may be presented to a user substantially in line with figure 3. In figure 3, a schematic representation is shown of a video display 10 offered to a user, denoted participant 1, in a video collaboration comprising three participants, the other two participants being denoted participant 2 and participant 3. The video conferencing system identifies participant 2 as the active participant, and so the image of participant 2 is shown at high resolution. The image of participant 3 is shown in low resolution. Thus, the data required to generate the low resolution image makes less bandwidth demand than would be the case if a high resolution image were required.

Correspondingly, if the identity of the active participant changes, then the image shown in high resolution will change accordingly. In figure 4, a schematic representation of the video display 10' is shown, wherein the video conferencing system has re-evaluated the identity of the active participant as participant 3, and so the corresponding image of participant 3 is therefore presented to participant I in high resolution, with the image of participant 2 relegated to low resolution.

The described embodiments operate on the basis of an assumption that the identity of an "active participant" can be deduced by a system on the basis that the other participants will naturally tend to look at the image of the active participant. Thus, techniques for determining which of the participants is "active" should focus on criteria which map most closely to identifying the participant in which all or most of the other participants are expected to show most active interest.

As illustrated in Figure 5, a server based video conferencing system 20 comprises a server 30 and a plurality of client units 32. In the illustrated example, three client units are shown, though the reader will appreciate that more or fewer such units could be provided. Further, the reader will appreciate that the server 30 can be collocated with one of the client units in practice.

Each client unit 32 is connected to the server via a communications link 34. Each communications link 34 will have an inherent limitation on the communication of data from the client unit 32 to the server 30 and vice versa. The intended outcome of implementation of the present embodiment is that these inherent limitations can be accommodated.

This therefore represents a hub and spoke arrangement. As in any hub and spoke configuration, the server 30 acts as the communications gateway and router. Each of the participating sites implemented by a client units 32 exchanges image streams to and from the server 30. A multi-way collaboration would be configured in the usual manner with a video feed from each of the client units 32 being sent to the server 30 and then routed to the other client unit 32. Software at the server 30 analyses the audio signal, and any other sensors that can detect the active participant, to determine the most active participant. In the case of shared desktop systems, such as nuVa (by Thales Research and Technology Ltd), this may not necessarily be the person speaking.

The reader will appreciate that numerous software solutions exist, or could be designed, to establish the active participant. This could include identifying the participant who is currently speaking. In the event that the presently described embodiment is implemented with a workspace type CWE, such as disclosed in 0B2473463A, it may be possible to identify that participant who is most actively using the workspace CWE.

A delay could be introduced into the process of identifying the most active participant, to avoid confusing or distracting sequences of transitions from one active participant to another, through false readings. Otherwise, a false input, such as a participant coughing, could trigger a change in the identity of the active participant, even though the actual active participant may not have changed.

Facial recognition software might be used to monitor video image data, firstly to analyse the behaviour of a participant, and secondly to identify the line of sight of the participant. Both of these pieces of information could be used, in one embodiment, to determine the identity of the active participant.

The system may be capable, in one embodiment, of learning from past behaviour of a participant. Like in the manner that a voice recognition tool can develop a signature of the speech characteristics of a user, a system such as proposed could develop, over time, a signature of the physical behavioural characteristics of a user. This acknowledges that some users will be more animated in terms of body language than others, and some users may naturally speak at higher volume than others.

As illustrated in Figure 6, each client unit 32 comprises a processing unit 40, a video monitor 42, and a camera 44. The camera is operable to receive incident light, and convert the same into a video signal, which it then forwards to the processing unit 40.

The video monitor 42 is operable to receive a video signal from the processing unit 40, and convert the same into a rendered video image. The processing unit 40, as indicated, is operable to receive a video signal from an external source, and to send a video signal to an external location, as required. A scalable video codec as in accordance with the H.264 specification is appropriate, to enable transport of different layers of resolution separately if required.

In use, the processing unit 40 comprises codecs which compress and decompress video data as required.

The processing unit 40 is illustrated in further detail in Figure 7. As shown, the processing unit 40 is based upon a general purpose computer with architecture which will be familiar to the user. In essence, the functionality of the processor 40 is provided by the interaction of applications specific software, loaded into the computer to configure the computer to perform particular functions.

To that end, the processing unit 40 comprises a processor 120 operable to execute program instructions. To do this, the processor 120 is in communication with a mass storage unit 122 and a working memory 124.

The working memory 124 is illustrated storing computer programs defining codecs 126 and a communications controller 128. The reader will understand that this is a simplification, and that portions of such programs may be stored in working memory from time to time, but may also be stored in the mass storage 122 too, for convenience.

The exact arrangement of memory management in the computer is immaterial to the

present disclosure.

A bus 130 provides communication facilities to the processor for a communications unit 132, a user input unit 136, a display driver 138 and a camera driver 140. Although not illustrated, computer programs enabling a processor to interact with such units may also be provided.

The communications unit 132 is operable to establish communications channels with the server 30. This may be achieved using standard communications protocols. As previously noted communications encoding standards, such as H.264, may be appropriate for use, in that they provide a scalable video stream, with respect to resolution. The user input unit 136 allows user interaction with the processing unit 40.

The user input unit 136 may be embodied by a keyboard, a mouse (or other pointing device), touch screen facilities, or any other user actuable input device which may come to the mind of the reader.

The display driver 138 is operable to provide, to the video monitor 42, a compatible video signal. The exact form and function of the display driver 138 is not material to

the present disclosure.

Likewise, a camera driver 140 provides facilities for reception of a video signal from the camera 44. The camera driver 140, which may be configured by suitable software, provides an interface between the camera 44 and the processing unit 40.

A functional representation of the server 30 is illustrated in figure 8. The server 30 is operable to receive video streams from each of the participating client units 32, and these are received in a video output stream generator 50. Alongside this, an active participant detector 52 is operable to detect which of the streams is representative of the active participant in the collaboration. On the basis of this, the active participant detector 52 outputs active participant messages to the client units, signalling to each client unit whether it is the active participant. Signalling can be achieved by the sending of short messages using a protocol such as IP. -On the basis of a received active participant message, the codec 126 at a client unit 32 will apply an appropriate compression algorithm, sending data corresponding to a high resolution video image if the client unit 32 in question is designated the active participant, and a data stream corresponding to a lower resolution video signal in the event that the client unit 32 receives a message from the active participant detector 52 that it is not the active participant. To that end, the present embodiment operates on the basis that the codecs 126 at the client unit 32 are capable of operating in two such different modes, or that two codecs 126, one for high resolution encoding, and one for low resolution encoding, are available for selection of one, and then use of the selected codec 126.

The video output stream generator 50 is operable to generate video streams to each of the participating client units. As selection of higher or lower resolution encoding is done at the client units, the video output stream generator 50 need only collate the received video streams, and re-distribute them as appropriate to the participating client units 32. As illustrated, the first client unit requires feeds from the second and third client unit, and so on.

Thus, as described, the server 30 controls the operation of each client unit 32, so that each client unit 32 receives high quality images from the active participant whilst adjusting the resolution of the images of other client participants to a lower quality level to fit the remaining communications bandwidth.

In accordance with this embodiment, the server uses a server based participant detection system to send a message to the video codec of eaOh client unit 32 so as to switch the encoding resolution, frame rate and bandwidth according to whether the client unit 32 in question is that of the active participant.

Although the embodiment has been described as indicating the transmission of an active participant message, merely providing binary information as to whether a client unit is that of the active participant or not, more refined information could be provided if the server has more in-depth knowledge as to channel capacity. That is, if the server detects that a particular communications channel between itself and a client unit 32 is of significantly lower quality than desirable, it may be that the server 30 could send a message to that client unit 32 that the video codec 126 at that client unit should encode to a higher degree of compression, to accommodate the low quality channel.

Using this approach has an advantage in that by switching the capabilities of the source codec, the bandwidth from the source site is also reduced, thus making more bandwidth available for desktop messages and/or reducing the communications costs for mobile clients. However, it does require that the server messages are received correctly to avoid accidentally having two high quality streams active simultaneously.

The reader will appreciate that the server can be implemented as a general purpose computer, configured by suitable software.

A second embodiment of the invention will now be described with reference to figure 9.

In this embodiment, the general principle of operation is that a video decode and re-encode service is implemented at the server to take a full resolution stream at the best rate each client can produce, and reducing the bandwidth sent to the other sites when a participant is not the active participant.

Thus, as illustrated, a modified server 30' comprises a plurality of video stream decoders 62, each being operable to receive a video stream from a respective one of the client units 32 participating in the collaboration. Then, the decoded video streams are passed to codecs 64 appropriate to the designation of active participant made by an active participant detector 52'. It will be noted by the reader that no message needs to be sent in this case to client units 32 giving a designation of active participant -this determination is made and communicated entirely internally of the server 30'.

Thus, the video stream corresponding to the active participant is encoded by a codec specified for relatively high resolution, whereas the other video streams are encoded at relatively low resolution, to give rise to a data stream commensurate with the capabilities of the communications channels to the client units 32.

The video output stream generator 50' then assembles the encoded streams into the appropriate format for transmission to the respective client units, largely as described in respect of the first embodiment, but tailored to the bandwidth of the connection of each client unit to the server 30'.

A third embodiment will now be described with reference to figure 10. In this embodiment, a server 30" is provided, which operates on the basis that each client unit 32 emits to it a video signal encoded with a scalable video codec (such as H.264 as previously discussed). Using a scaleable video codec results in the transmission of a base level stream, defining a low resolution video signal, alongside a high resolution enhancement thereto. Thus, if the higher resolution is not required by a recipient, a relay of such information can strip out' the high resolution enhancement signal, retaining only the lower quality information for further transmission.

In this case, therefore, a stream selector 74 is applied to each of the incoming scalable video streams. Each stream selector 74 is operable on the basis of a signal received from an active participant detector 52", which indicates if a particular stream applies to the active participant in a collaboration or not. In the event that a stream applies to the active participant, then the respective stream selector 74 passes through all information defining the full quality video stream so received from the appropriate client unit 32.

On the other hand, in the event that a stream applies to a client unit 32 which is not the active participant, then the corresponding stream selector 74 passes on only the lower resolution components of the scalable video stream.

It may be that the scalable video codec used in such an arrangement allows more than two levels of quality of resolution. in such a case, the stream selector 74 may make* use of information relating to channel quality to the other client units, to determine channel capacity and thus to determine how much of the stream quality information should be retained.

The selected streams are then passed to a video output stream generator 50", which assembles streams for transmission, as before.

The second and third embodiments so described do not restrict the available bandwidth and so allow a mixed system to be configured where a collaboration between several well connected client units could operate in conjunction with a client unit limited by a low bandwidth radio link. Such an arrangement would avoid having to restrict the quality experienced by all of the participants to the slowest link in the system.

Each of the above embodiments takes advantage of variation from a good quality image to a lesser quality image and vice-versa ensuring that the overall user experience is maintained whilst accommodating the restrictions of a limited communications network. This variation can be considered smooth, as reductions in image! resolution take place in the peripheral field of vision of a user.

The various embodiments described herein avail themselves of an understanding of the physiology of the human eye. In a human eye, a field of vision is defined, being that range of angles of incident light for which detection of light by retinal light receptors is provided for. The concentration and type of receptors in the retina of an eye varies, such that a generally central region of the retina is provided with receptors to enable high resolution detection at the centre of the field of vision, while the remainder of the retina provides a relatively low resolution detection in the periphery of the field of vision.

The region of the brain concerned with the determination of sight is able to discern an image from such information, so that the central high resolution portion is that on which the brain has primary focus, while the peripheral parts of the image merely provide context. Thus, except for the image actually of interest to a user, there is no real advantage in providing an image rendered to high resolution.

Claims

CLAIMS: 1. A system for establishing a collaborative working environment, the system comprising a plurality of client units, each client unit being operable to collect a video input and to generate a scalable video signal therefrom for use in others of said client units, each client unit being configured to display images generated at one or more of the other client units, at least one of said client units being operable to display images from two or more of said client units, the system further comprising active participant determining means, for determining one participant, corresponding to one of said client units, as an active participant, and image rendering means operable to render images corresponding to one or more of said video signals at said client units, such that, at a client unit displaying, in use, more than one image, an image corresponding to said active participant is rendered at a first resolution, whereas any other image rendered at said client unit is rendered at a second resolution lower than said first resolution.
2. A system in accordance with claim 1 wherein each client unit operable to display images from two or more of said client units comprises first and second rendering means, said first rendering means being operable to render an image at said first resolution and said second rendering means being operable to render an image at said second resolution.
3. A system in accordance with claim 2, wherein each client unit is operable to generate a scalable video signal comprising a low resolution component defining a video image output at said second resolution and a high-resolution component defining said video image output at said first resolution.
4. A system in accordance with claim 3, wherein said high-resolution component defines said video image output at said first resolution in conjunction with said low resolution component.
5. A system in accordance with any preceding claim wherein said active participant determining means is operable, on determining a participant as an active participant, to configure each client unit with active participant identification information enabling said client unit to determine which displayed image is to be displayed at which resolution.
6. A system in accordance with claim 5 wherein said active participant determining means is operable to send a message to each client unit, the message bearing information identifying the client unit at which the active participant is present.
7. A system in accordance with claim 6 wherein said client units each comprise an local active participant determining means, said local active participant determining means being operable to determine if a user of the respective client unit is active, and therefrom determining that said client unit hosts the active participant in a collaborative working environment, each local active participant determining means being operable to send said message to said other client units.
8. A method for establishing a collaborative working environment between a plurality of client units, each client unit being operable to collect a video input and to generate a scalable video signal therefrom for use in others of said client units, each client unit being configured to display images generated at one or more of the other client units, at least one of said client units being operable to display images from two or more of said client units, the method further comprising: determining one participant, corresponding to one of said client units, as an active participant, and rendering images corresponding to one or more of said video signals at said client units, such that, at a client unit displaying, in use, more than one image, an image corresponding to said active participant is rendered at a first resolution, whereas any other image rendered at said client unit is rendered at a second resolution lower than said first resolution.
9. A method in accordance with claim 8 wherein, at each client unit operable to display images from two or more of said client units, the method comprises first and second rendering processes, said first rendering process comprising rendering an image at said first resolution and said second rendering process comprising rendering an image at said second resolution.
10. A method in accordance with claim 9 comprising, at each client unit, generating a scalable video signal comprising a low resolution component defining a video image output at said second resolution and a high-resolution component defining said video image output at said first resolution.
11. A method in accordance with claim 10, wjierein said high-resolution component defines said video image output at said first resolution in conjunction with said low resolution component.
12. A method in accordance with any one of claims 8 to 11 wherein said determining of said active participant comprises, on determining a participant as an active participant, configuring each client unit with active participant identification information enabling said client unit to determine which displayed image is to be displayed at which resolution.
13. A method in accordance with claim 12 wherein said determining of said active participant comprises sending a message to each client unit, the message bearing information identifying the client unit at which the active participant is present.
14. A method in accordance with claim 13 wherein said determining of said active participant comprises determining, at each client unit, if a user of the respective client unit is active, and therefrom determining that said client unit hosts the actiye participant in a collaborative working environment, such that a client unit so determining locally that its user is active then sends said message to said other client units.
15. A computer apparatus for use in a establishing a collaborative working environment with at least two other cooperative apparatus, the apparatus being operable to collect a video input and to generate a scalable video signal therefrom for use by other apparatus as required, the apparatus being configured to receive scalable video signals from said other computer apparatus to which said apparatus is connected, in use, and including display means operable to display images on the basis of said received scalable video signals, the apparatus further being operable to receive information identifying another computer apparatus as an active participant, corresponding to one of the scalable video signals and wherein said *18 display means includes image rendering means operable to render said images such that, an image corresponding to a scalable video signal from a computer apparatus designated as an active participant is rendered at a first resolution, whereas any other image is rendered at a second resolution lower than said first resolution.
16. Apparatus in accordance with claim 15 comprising first and second rendering means, said first rendering means being operable to render an image at said first resolution and said second rendering means being operable to render an image at said second resolution.
17. Apparatus in accordance with claim 16, operable to generate a scalable video signal comprising a low resolution component defining a video image output at said* second resolUtion and a high-resolution component defining said video image IS output at said first resolution.
18. Apparatus in accordance with claim 17, wherein said high-resolution component defines said video image output at said first resolution in conjunction with said low resolution component.
19. Apparatus in accordance with any one of claims 15 to 17 and comprising active participant determining means operable to determine that said apparatus is in use by an active participant and to send a message to other computer apparatus to which said apparatus is connected, the message bearing information identifying the apparatus at which the active participant is present.
20. A method performed at a computer apparatus in a establishing a collaborative working environment with at least two other cooperative apparatus, the method comprising collecting a video input and generate a scalable video signal therefrom for use by other apparatus as required, receiving scalable video signals from said other computer apparatus to which said apparatus is connected, in use, and displaying images on the basis of said received scalable video signals, receiving information identifying another computer apparatus as an active participant, corresponding to one of the scalable video signals and rendering said images such that, an image corresponding to a scalable video signal from a computer apparatus designated as an active participant is rendered at a first resolution, whereas any other image is rendered at a second resolution lower than said first resolution.
21. A method in accordance with claim 20 comprising first and second rendering processes, said first rendering process comprising rendering an image at said first resolution and said second rendering process comprising rendering an image at said second resolution.
22. A method in accordance with claim 21, comprising generating a scalable video signal comprising a low resolution component defining a video image output at said second resolution and a high-resolution component defining said video image output at said first resolution.
23. A method in accordance with claim 22, wherein said high-resolution component defines said video image output at said first resolution in conjunction with said low resolution component.
24. A method in accordance with any one of claims 20 to 22 and comprising determining that said apparatus is in use by an active participant and sending a message to other computer apparatus to which said apparatus is connected, the message bearing information identifying the apparatus at which the active participant is present.
25. A computer program product comprising computer executable instructions which, when loaded into suitably configured and networked computers, cause said computers to establish a system in accordance with any one of claims I to 7.
26. A computer program product comprising computer executable instructions which, when loaded into suitably configured and networked computers, cause said computers to cooperatively perform a method in accordance with any one of claims 8 to 14.
27. A computer program product comprising computer executable instructions which when executed by a computer apparatus cause said computer apparatus to become configured in accordance with any one of claims 15 to 19.
28. A computer program product comprising computer executable instructions which when executed by a computer apparatus cause said computer apparatus to perform a method in accordance with any one of claims 20 to 24.
29. A computer program product in accordance with any one of claims 25 to 28 comprising a computer readable storage medium.
30. A computer program product in accordance with any one of claims 25 to 28 comprising a computer receivable signal.