Abstract: A method for updating a set of presentation images through a single-buffered multipoint dispatcher over a network to multiple clients is provided. Each screen of a set of screens included in the presentation is divided into tiles. Packets respectively corresponding to the tiles of a first screen are stored in a single buffered multipoint dispatcher according to a time sorted hierarchy, a top packet having a most recent time value and a bottom packet having a least recent time value. Each tile of the first screen is compared with a corresponding tile of a second screen to identify any non-matching tile pairs. For each non-matching tile of the second screen, a packet corresponding to that non-matching tile is provided to the single buffered multipoint dispatcher. Then, non-matching tiles of the first screen are replaced with the respective non-matching tiles of the second screen, while maintaining the time sorted hierarchy.

Abstract: A method for efficiently processing image data for display on a computer monitor is provided. The method initiates with reading image data in a compressed format into a memory associated with the computer. Then, at least one scaled copy of the image data is generated in the compressed format. Next, a display scale is determined for an image to be presented on a computer monitor. If the magnification is less than 100% of an image scale associated with the image data, then, either the image data or the at least one scaled copy of the image data is determined as being closest in magnification to the display scale, without being less than the display scale, to provide a closest in magnification image data. Next, the closest in magnification image data in the compressed format is processed. Then, the processed image data is displayed. The method is capable of displaying a portion of the image at any magnification.

Abstract: A method for updating a subset of a frame of an image is provided. The frame of the image is subdivided into a plurality of tiles. The method initiates with providing a fixed-size queue having a stationary last packet at a bottom of the fixed size queue. Then, a plurality of packets is stored in a time sorted order above the last packet, the plurality of packets corresponding to a frame of an image. Next, an updated packet is received, the updated packet corresponds to a previously received packet of the plurality of packets. Then, the previously received packet is replaced with the updated packet while maintaining the time sorted order. Replacing the previously received packet includes: identifying the previously received packet adjusting any pointers pointing at the previously received packet to point at a packet below the previously received packet; and moving the previously received packet to a top of the fixed size queue.

Abstract: A multi-participant videoconference system incorporating a back-channel connection and a client video mixer is disclosed. The multi-participant videoconference system includes a client component and a server component. The server component provides a composite conference video signal to the client component. A region is defined in the composite conference video signal and the size and coordinates of the region are communicated to the client component by the server component over the back-channel. The client component captures local video and mixes local video into the composite conference video signal using the size and coordinates received from the server component for display.

Abstract: A conferencing system supporting active and passive participants is disclosed. The conferencing system includes a client component defining active and passive participants, and a server component having a connection to each active and passive participant defined in the client component. The server component includes a connection manager for managing the connection between each active and passive participant and the server component, a media mixer for receiving conference media and for distributing conference media to active and passive participants, and a virtual producer for selecting conference media to be distributed to passive participants. The conference media provided to the passive participants is dynamically determined based upon activities and selections of a set of active participants.

Abstract: A system configured to playback videoconference data is provided. The system includes a media management server configured to receive videoconference data associated with a videoconference session. The media management server is configured to convert the videoconference data to a common format for storage. An event database configured to capture events occurring during the videoconference session is included. A media analysis server configured to analyze the stored videoconference data to insert indices representing the captured events is provided. A media playback unit configured to establish a connection with the media management server is included. The media playback unit is further configured to enable position control of a video stream delivered to the media playback unit from the media management server while maintaining the connection. A method, a computer readable medium, and a graphical user interface for the play back of videoconference data are also provided.

Abstract: A videoconferencing system configured to utilize peer-to-peer videoconferencing software to provide a multi-participant conference environment for a plurality of participants is provided. The system includes a client component defining a conference client enabled to execute peer-to-peer videoconferencing software. The client component includes a client monitor configured to monitor both, whether the conference channel is active and events within a video window displayed by the conference client, wherein the events within the video window are communicated across a back-channel connection. The back-channel connection is established when the conference channel is active. The system includes a server component having a back-channel controller in communication with the client monitor through the back-channel connection. The server component provides a client configurable audio/video stream for each of a plurality of participants.

Abstract: A back-channel communication network for a videoconferencing system for a conference between a plurality of participants is provided. The back-channel communication network includes a monitoring agent associated with a client. The client is configured to execute a peer-to-peer videoconferencing application. The monitoring agent monitoring a video display window controlled by the peer-to-peer conferencing application. A back-channel controller in communication with the monitoring agent over a back-channel connection is included. The back-channel controller is configured to enable communication between the client and a plurality of conference clients over a back-channel controller communication link. An event handler configured to enable insertion of server user interface data into an outbound video stream image for the client is also included. A computer readable media and methods for providing a multi-participant conferencing environment are also provided.

Abstract: A method for updating a subset of a frame of an image is provided. The frame of the image is subdivided into a plurality of tiles. The method initiates with providing a fixed-size queue having a stationary last packet at a bottom of the fixed size queue. Then, a plurality of packets is stored in a time sorted order above the last packet, the plurality of packets corresponding to a frame of an image. Next, an updated packet is received, the updated packet corresponds to a previously received packet of the plurality of packets. Then, the previously received packet is replaced with the updated packet while maintaining the time sorted order. Replacing the previously received packet includes: identifying the previously received packet adjusting any pointers pointing at the previously received packet to point at a packet below the previously received packet; and moving the previously received packet to a top of the fixed size queue.

Abstract: A method for efficiently processing image data for display on a computer monitor is provided. The method initiates with reading image data in a compressed format into a memory associated with the computer. Then, at least one scaled copy of the image data is generated in the compressed format. Next, a display scale is determined for an image to be presented on a computer monitor. If the magnification is less than 100% of an image scale associated with the image data, then, either the image data or the at least one scaled copy of the image data is determined as being closest in magnification to the display scale, without being less than the display scale, to provide a closest in magnification image data. Next, the closest in magnification image data in the compressed format is processed. Then, the processed image data is displayed. The method is capable of displaying a portion of the image at any magnification.

Abstract: Image processing techniques which involve direct manipulation of the compressed domain representation of an image to achieve the desired spatial domain processing without having to go through a complete decompression and compression process. The techniques include processing approaches for performing the eight operations in D4 (the dihedral group of symmetries of a square) on JPEG images using the discrete cosine transform (DCT) domain representation of the images directly. For a task such as image rotation by 90° (an operation in D4), DCT-domain based methods can yield nearly a five-fold increase in speed over a spatial-domain based technique. These simple compressed-domain based processing techniques are well suited to the imaging tasks that are needed in a JPEG-based digital still-camera system.

Abstract: A technique that reduces the size of an existing JPEG file or set of DCT coefficients to satisfy a certain bit budget by setting to zero coefficients whose magnitude is below a certain threshold and which occur after a certain ordinal number in the zig-zag scan. The cutoff ordinal number is chosen using a clever savings calculation strategy. This strategy is implemented by filling appropriate savings values in an array of savings values, Savings[1], . . . , Savings[63]. The value Savings[n] is exactly the number of bits saved by reducing the thresholding cutoff ordinal number from n +1 to n. When a non-zero coefficient is set to zero, bits are saved because two runs of zeros (the one preceding it and the one following it) get combined into a single, longer run of zeros. The exact number of bits saved can be calculated by adding the bits needed to code the previous and next runs, and subtracting the bits needed to code the combined run.

Abstract: A fiber optic detection system in which a single optic fiber has a U-shaped configuration. A source of light is disposed at one upper free end of the optic fiber and a light detector is disposed at the other upper free end of the optic fiber. At the bottom of the optic fiber is a light variable loop adapted to be disposed in various media, such as liquids, fluids and air. The light from the source of light is conducted from the source of light through the optic fiber and to the light detector. The quantum of light lost as the light travels through the light variable loop will depend on the medium or the concentration of the medium in which the light variable loop is disposed. The light detector detects the light advancing thereto to produce a signal representative of the medium or the concentration of the medium in which the light variable loop is disposed.