System for synchronization with nonstreaming device controller and a streaming data handler each supplying current location for synchronizing slave data and master data flow

摘要

Disclosed are apparatus and methods for synchronized presentation of analog and digital data by applying a common synchronization scheme to both types of data. Digital data is "streamed" by transferring the data in blocks from a source to a series of memory buffers, where it accumulates for subsequent transfer to an output device driver. The control module responsible for data streaming periodically reports a temporal location within the presentation represented by the data. A supervisory module designates one of the control modules a "master", and periodically compares the values reported by the various other control modules against that reported by the master. If a comparison exceeds a threshold tolerance value associated with each control module, a sync pulse is delivered to that control module, causing it to correct the synchronization mismatch. This approach is applied to analog sources through the use of control modules that behave in a manner consistent with the digital control modules, but which are capable of directing the operation of analog devices and re-establishing their synchronization with other data sources despite limited modes of device control. Specifically, the control modules that handle analog information also periodically report a presentation location based solely on temporal information, react to sync pulses by altering the playback rate of the analog devices they control within user-tolerable limits, and can act as master control modules.