Multimedia wired/wireless content synchronization method

• US 7,185,090 B2
• Filed: 08/06/2003
• Issued: 02/27/2007
• Est. Priority Date: 03/16/2000
• Status: Expired due to Fees

• 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
• Primary Examiner(s): DINH, KHANH Q
• Application Number:
  US10/635,071
• Publication Number:
  US 20040068588A1
• Time in Patent Office: 1,301 Days
• Field of Search: 709/224, 709/227, 709/238, 709/231, 709/206, 709/228, 370/232, 370/237, 370/253, 370/318, 379/406.08, 379/32.4, 703/13
• US Class Current: 709/224
• 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 method of synchronizing a multimedia content stream for output to a plurality of wired and wireless output devices in a network having plural realms, wherein each realm includes a connection control processor (CTL), the method comprising:

buffering the multimedia content stream in a first realm;

determining a buffer delay as T_D=N*TED*R_p, where T_D is the delay size, N is the byte size of a packet, TED is an end-to-end delay, and R_p is the transmission rate of packets per second;

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.

2. The method of claim 1 wherein said determining includes setting a buffer length which is the product of the packet length used in the network and a number of packets to be buffered.

3. The method of claim 2 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.

4. The method of claim 1 wherein said determining includes determining a buffer delay as a function of the buffer delays in all of the realms of the network.

5. A method 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 method comprising;

providing plural output realms, including wired realms and wireless realms, wherein the wired realms each include;

a wired realm transceiver;

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

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

a wired realm connection control processor (CTL) connected between the first wired realm transceiver and the wired realm delay synchronizer for using delay information measured, signaled and updated from the output realms to synchronize playback at each of the output devices;

determining a wired realm buffer delay for streaming the multimedia content stream signal from the wired realm buffer to an output device; and

providing, for each wireless realms;

a wireless realm transceiver;

a wireless realm delay synchronizer;

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

an output device connected to the wireless realm delay synchronizer and a wireless realm connection control processor (CTL) connected between the wireless realm transceiver and the wireless realm delay synchronizer;

disseminating medium access control (MAC) layer information about delay and jitter between the wireless realm transceiver and the wireless realm delay synchronizer;

determining a wireless realm buffer delay for streaming the multimedia content stream signal from the wireless realm buffer to an output device;

transmitting the wireless realm buffer delay to the wired realm CTL; and

transmitting the wired realm buffer delay to the wireless realm CTL.

6. The method of claim 5 which further includes relaying the multimedia content stream signal to other wireless realms.

7. The method of claim 5 which further includes providing, in the wired realm CTL, a clock which operates at a known rate and transmitting data from the 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.