Virtual video driver bridge system for multi-source collaboration within a web conferencing system

1. A system for multi-source collaboration, comprising:

a first client computer of a plurality of client computers, the plurality of client computers in communication with a host computer for sharing content between the plurality of client computers in a multi-source collaboration session, the first client computer including

a web conferencing application, and

a virtual device network interface performing operations of:

receiving an encoded composite image representing a worksurface image hosted by the host computer, the worksurface image including respective video streams from at least two of the plurality of client computers,

emulating a physical device that is communicatively coupled to the first client computer and available as a source for the web conferencing application when running on the first client computer, and

transcoding the encoded composite image into a transcoded video stream that simulates a content source of the physical device,

wherein the web conferencing application transmits the transcoded video stream to a web conferencing computer remote from the first client computer for display thereon.

2. The system of claim 1 , the encoded composite image being a sequence of the worksurface image.

3. The system of claim 1 , the encoded composite image being received from a video source proxy at the host computer.

4. The system of claim 3 , the encoded composite image being received as an encoded video stream from the video source proxy according to a display host-to-client protocol.

5. The system of claim 1 , the simulated device being a video camera.

6. The system of claim 1 , the simulated device being a display device.

7. The system of claim 1 , the simulated device being a device associated with the host computer.

8. A method for multi-source collaboration within a web conferencing system comprising:

receiving, at a host computer, a media stream from each of a first client computer and a second client computer, the first and second client computers connected to the host computer for participating in a multi-source collaboration session;

displaying, with the host computer, the multiple media streams on a shared display as a composite worksurface image;

receiving, with a virtual device network interface of the first client computer, the composite worksurface image as an encoded composite worksurface image;

emulating, with the virtual device network interface, a physical device that is communicatively coupled to the first client computer and available as a source for a web conferencing application running on the first client computer;

transcoding, with the virtual device network interface, the encoded composite worksurface image into at least one transcoded video stream that simulates a content source of the physical device; and

transmitting the at least one transcoded media stream via the web conferencing application, to a web conferencing computer remote from the first client computer.

9. The method of claim 8 , further comprising re-encoding the encoded composite worksurface image prior to the step of transcoding.

10. A method for multi-source collaboration within a web conferencing system comprising:

combining media streams received at a host computer from two or more client computers connected to the host computer for participating in a multi-source collaboration session, the two or more client computers including a first client computer that includes a virtual device network interface;

representing the media streams on a shared worksurface;

sending a composite worksurface image of the shared worksurface to a video source proxy of the host computer;

encoding the composite worksurface image;

displaying the composite worksurface image on a display device, connected to the host computer, to provide a collaborative view of the media streams;

transmitting, via the video source proxy, the encoded composite worksurface image to the virtual device network interface, via a display host-to-client protocol;

emulating, with the first client computer, a physical device that is communicatively coupled to the first client computer and available as a source for web conferencing application running on the first client computer;

exposing, with the virtual device network interface, the received encoded composite worksurface image in a format that is appropriate to the physical device being emulated;

transcoding, with the virtual device network interface, the encoded composite worksurface image into a device-encoded video format that simulates a content source of the physical device;

selecting, via a web conferencing application running on the first client computer, the virtual device network interface as an input source for use in the web conferencing application; and

transmitting the transcoded composite worksurface image to a web conferencing computer remote from the first client computer.

11. The method of claim 10 , wherein the encoded composite worksurface image is the worksurface video image.

12. The method of claim 10 , wherein the encoded composite worksurface image is a sequence of worksurface images.

13. The method of claim 10 , wherein the device being emulated is a display device.

14. The method of claim 10 , wherein the device being emulated is a video camera.