Common event-based multidevice media playback

摘要

A system for event-based synchronized multimedia playback, comprising a media source device and a plurality of destination devices, each destination device comprising a local clock, and a synchronization module on one of the devices. The synchronization module transmits common events, En, each with a unique event number, to each of the plurality of destination devices. Each destination device records time Dxn when event En is received and transmits an acknowledgement message back to the synchronization module comprising time Dxn and event number n. The synchronization module determines phase and frequency differences between clocks of respective destination devices; computes a frequency adjustment to compensate for phase and rate differences; and directs each respective destination device to adjust its clock phase and frequency accordingly. Each destination device adjusts its local clock as directed or may perform a sample rate conversion on sample data in order to enable synchronized media playback.

主权项

1. A system for event-based synchronized multimedia playback, comprising:
a media source device comprising a central processing unit and a memory, connected to a network and adapted to stream media over the network; a plurality of destination devices, each comprising a local clock and connected via the network to the media source device and adopted to render media received over the network; and a synchronization module operating on one of the devices; the synchronization module periodically transmitting a common event En using “multicast messaging”, with a unique event number n, not used as a timestamp, to each of the plurality of destination devices; each destination device recording a time Dxn when event En is received and transmitting an acknowledgement message back to the synchronization module comprising at least the time Dxn and the unique event number n; the synchronization module, for each of the plurality of destination devices, further configured to: (a) determine the frequency difference between the local clock of the respective destination device and the local clock of the first destination device; (b) compute a frequency adjustment to compensate for the differences determined in (a); between the first destination device and the respective device; and (c) direct the respective destination device to adjust its clock frequency by an amount related to the values determined in (b); and each destination device using this adjustment information to synchronously render streaming audio and video media received over the network from the media source device; wherein the media source device is a source for streaming audio or video media.