Abstract: An application programming interface (API), implemented on a general-purpose host processor, receives functions calls from an application to control the play of an audio file. The API translates the function calls into host-to-board messages and transmits the host-to-board messages to an audio task, implemented on a digital signal processor. The audio task plays the audio file based on the host-to-board messages received from the API at a higher priority than one or more other audio files. The API and audio task allow the application to select a Microsoft®-standard Wave file for play at a higher priority than other Wave files. By using the API, the application has control of the number of times the file is played back and when playing stops. The application gets notification of playback complete from the audio task via the API.

Abstract: The audio manager provides an interface between one or more upper-level conferencing drivers of the conferencing system and one or more lower-level audio drivers of the conferencing system to isolate the conferencing drivers from the audio drivers. The audio manager is adapted to perform a plurality of functions called by the conferencing drivers. The audio manager comprises a local audio stream state machine and a remote audio stream state machine.

Abstract: Two sequences of signal packets are played. Each signal packet of a first type of signals has been stamped with a sequence number corresponding to the position of the signal packet in the first sequence. Each signal packet of a second type of signals has been stamped with a corresponding sequence number of the first sequence. The playing of the second sequence is synchronized with the playing of the first sequence by comparing the sequence numbers of the second sequence to the sequence numbers of the first sequence. In a preferred embodiment, the two types of signals are audio signals and video signals, and the video signal packets are stamped with sequence numbers for the audio signal packets. Each video signal packet of the video sequence is processed for display based on a comparison of the sequence number for the video signal packet and the sequence number for the current audio signal packet.

Abstract: A computer system for transmitting two or more types of signals. Each type of signal is assigned a priority level. Signals of a particular type are transmitted as they become ready for transmission, unless signals of a different type having a greater priority become ready for transmission. In that case, the transmission of the low-priority signals is interrupted to allow transmission of the high-priority signals. The transmission of the low-priority signals is resumed after the transmission of the high-priority signals is complete. In a preferred embodiment directed to conferencing systems, audio signals are assigned higher priorities than video, data, and control signals in order to provide a high-quality to the audio portion of a conferencing session.