Multimedia wired/wireless content synchronization method

• US 20040068588A1
• Filed: 08/06/2003
• Published: 04/08/2004
• Est. Priority Date: 03/16/2000
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ishii, Atsushi, Kowalski, John Michael
• Granted Patent: US 7,185,090 B2
• Time in Patent Office: Days
• US Class Current: 709/248
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/43615 Interfacing a Home Network, e.g. for connecting the client to a plurality of peripherals home Audio Video Interoperability [HAVI] data switching networks H04L12/2805
• CPC Class Codes: H04N 5/0736 using digital storage buffer techniques

Abstract

A method of synchronizing a multimedia content stream for output to a plurality of wired and wireless output device in a network having plural realms, wherein each realm includes a CTL, includes buffering the multimedia content stream in a first realm; determining a buffer delay; transmitting the buffer delay to all CTLs in all realms of the network; and transmitting the multimedia content stream to all realms in the network.

Claims

1. A system for synchronizing a multimedia content stream signal, emanating from at least one multimedia source, for play through a plurality of output devices, wherein the output devices are connected to the multimedia source by wired connections and wireless connections;

the system comprising;

plural output realms, including wired realms and wireless realms;

wherein said wired realms each include;

a wired realm transceiver;

a wired realm delay synchronizer, including a wired realm buffer for storing said multimedia content stream signal;

an output device connected to said wired realm delay synchronizer; and

a wired realm connection control processor (CTL) connected between said first wired realm transceiver and said wired realm delay synchronizer for exchanging medium access control (MAC) layer messages between said first wired realm transceiver and said wired realm delay synchronizer, and for determining a wired realm buffer delay for streaming the multimedia content stream signal from said wired realm buffer to an output device; and

wherein said wireless realms each includes;

a wireless realm transceiver;

a wireless realm delay synchronizer;

including a wireless realm buffer for storing said multimedia content stream signal;

an output device connected to said wireless realm delay synchronizer and

a wireless realm connection control processor (CTL) connected between said wireless realm transceiver and said wireless realm delay synchronizer for exchanging medium access control (MAC) layer messages between said wireless realm transceiver and said wireless realm delay synchronizer, and for determining a wireless realm buffer delay for streaming the multimedia content stream signal from said wireless realm buffer to an output device; and

wherein said wireless realm buffer delay is transmitted to said wired realm CTL and wherein said wired realm buffer delay is transmitted to said wireless realm CTL.

2. The system of claim 1 wherein said wireless realm includes a second wireless transceiver for relaying the multimedia content stream signal to other wireless realms.

3. The system of claim 1 wherein said wired realm CTL includes a clock which operates at a known rate and wherein data is transmitted from said wired realm buffer at a rate taken from the group of rates consisting of the known rate, an integer multiple of the known rate and an integer divisor of the known rate.

4. A method of synchronizing a multimedia content stream for output to a plurality of wired and wireless output device in a network having plural realms, wherein each realm includes a CTL, the method comprising:

buffering the multimedia content stream in a first realm;

determining a buffer delay;

transmitting the buffer delay to all CTLs in all realms of the network; and

transmitting the multimedia content stream to all realms in the network.

5. The method of claim 4 wherein said determining includes setting a buffer size, T_D, where T_D is the product of the packet length used in the network and the number of packets to be buffered.

6. The method of claim 5 which include determining the packet length and wherein said determining the packet length further includes inserting a coding and formatting delay factor into the packet length.

7. The method of claim 4 wherein said determining includes determining a buffer delay as a function of the buffer delays in all of the realms of the network.