Abstract: Disclosed is a networked multimedia information system which may be utilized to record, store and distribute multimedia presentations together with any supplemental materials that may be referenced during the presentation. The recorded presentation, together with the associated supplemental materials, may be simultaneously presented on a display containing two separate viewing windows. The effects of network congestion are minimized by prefetching audio and video data for storage in audio and video buffers. An adaptive control algorithm compensates for network congestion by dynamically varying the rate at which video frames are retrieved over the network, in response to network traffic conditions. The audio playback speed is reduced if the audio data does not arrive fast enough over the network to maintain the desired size of the audio buffer after the amount of video data transmitted across the network has been reduced to a minimum value.

Abstract: Disclosed is a networked multimedia information system which may be utilized to record, store and distribute multimedia presentations together with any supplemental materials that may be referenced during the presentation. The recorded presentation, together with the associated supplemental materials, may be simultaneously presented on a display containing two separate viewing windows. The effects of network congestion are minimized by prefetching audio and video data for storage in audio and video buffers. An adaptive control algorithm compensates for network congestion by dynamically varying the rate at which video frames are retrieved over the network, in response to network traffic conditions. The audio playback speed is reduced if the audio data does not arrive fast enough over the network to maintain the desired size of the audio buffer after the amount of video data transmitted across the network has been reduced to a minimum value.

Abstract: A method and apparatus for recording and indexing audio information exchanged during an audio conference call, or video, audio and data information exchanged during a multimedia conference. For a multimedia conference, the method and apparatus utilize the voice activated switching functionality of a multipoint control unit (MCU) to provide a video signal, which is input to the MCU from a workstation from which an audio signal is detected, to each of the other workstations participating in the conference. A workstation and/or participant-identifying signal generated by the multipoint control unit is stored, together or in correspondence with the audio signal and video information, for subsequent ready retrieval of the stored multimedia information. For an audio conference, a computer is connected to an audio bridge for recording the audio information along with an identification signal for correlating each conference participant with that participant's statements.

Abstract: Video image quality is preserved in an asynchronous network by providing a synchronizing arrangement in which the input of video data from an asynchronous network to a video data buffer is synchronized with the reading of information from the video data buffer. Synchronizing video data transfers to and from a video data buffer ensures that video data from only a single frame from a source is displayed on a display monitor at one time, thus maintaining image quality. Furthermore, multiple video data streams from several asynchronous sources can be displayed simultaneously on a single display screen using the synchronization technique. The synchronization arrangement synchronizes receipt of the different data streams into the frame buffer with the output of data from the frame buffer to the display screen.