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 plurality of destination devices, each comprising a local clock and connected to a network and configured to render media received over the network; and a synchronization module operating on a device connected to the network and configured to communicate with the plurality of destination devices, the synchronization module periodically transmitting a common event En, with a unique event identifier n, to each of the plurality of destination devices; wherein each destination device records a time Dxn when event En is received and transmits an acknowledgement message comprising at least the time Dxn and the unique event identifier n; wherein the synchronization module, for each of the plurality of destination devices, carries out the steps of:
(a) determining a frequency difference between the local clock of the respective destination device and the local clock of a first destination device;(b) computing a frequency adjustment to compensate for the difference determined in (a) between the first destination device and the respective device; and(c) directing the respective destination device to do one or both of:
adjust its clock frequency by an amount related to the value determined in (b); orperform a sample rate conversion on media received from the media source device to carry out a frequency adjustment related to the value determined in (b); and each destination device thereby synchronously renders media received over the network from a media source configured to stream audio or video media.