# US 8,782,720 B2 · Method and system for synchronizing content between terminals

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,782,720 B2
- Document ID: US8782720B2
- Status: Granted
- Kind: B2
- Application number: 13/533,151
- Filed: 2012-06-26
- Published: 2013-01-03
- Granted: 2014-07-15
- Earliest claimed: 2011-06-30
- Assignees: Electronics and Telecommunications Research Institute
- Applicants: Hun-Hoi Choi; Hwa-Suk Kim; Kee-Seong Cho; Geun-Hyung Kim; Jae-Chan Shim
- Inventors: Hun-Hoi Choi; Hwa-Suk Kim; Kee-Seong Cho; Geun-Hyung Kim; Jae-Chan Shim
- Web page: https://patentgrep.com/patent/US8782720B2

## CPC

- H04N 21/4302: {Content synchronisation processes, e.g. decoder synchronisation}
- H04L 7/0012: {by comparing receiver clock with transmitter clock}
- H04L 65/4025: {where none of the additional parallel sessions is real time or time sensitive, e.g. downloading a file in a parallel FTP session, initiating an email or combinational services}
- H04L 65/65: Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
- H04L 67/1095: Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
- H04N 7/147: {Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals (selecting H04Q)}
- H04L 65/765: {intermediate}
- H04N 7/17336: {Handling of requests in head-ends}
- H04N 21/2625: {for delaying content or additional data distribution, e.g. because of an extended sport event}
- H04N 21/64322: {IP}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A synchronization apparatus and method for synchronizing playback time of a media provided to multiple devices during service transfer and replication process are provided. The content synchronization system for providing a receiving terminal with content of a sending terminal, the content synchronization system includes the sending terminal; the receiving terminal; and a server configured to provide content to the sending terminal and the receiving terminal and to comprise a communication unit configured to communicate the sending terminal and the receiving terminal and to transmit a message and information about time point at which the message is sent, and a content playback time point calculating unit configured to calculate a first content playback start time point of the receiving terminal in an effort to provide the content of the sending terminal that is synchronized with the receiving terminal.

## Claims

### Claim 1

A content synchronization method for providing a receiving terminal with content of a sending terminal in a system that includes the sending terminal, the receiving terminal and a server to provide content to the sending terminal and the receiving terminal, comprising:
receiving, at the server, a session request message from the receiving terminal to request the sending terminal to provide content, that is currently being played back at the sending terminal, to the receiving terminal;
receiving, at the server, session information including identification information of the content, a content playback point at the time of transmitting the session information, and session information transmission point information from the sending terminal;
calculating a first content playback start time point by adding a transmission delay time to a content playback time point of the sending terminal at the time of transmitting the session information that is included in the session information, the transmission delay time including a session information delivery delay time taken by the session information to be transmitted from the sending terminal to the receiving terminal and a content request message delivery time taken by the content request message to be transmitted from the receiving terminal to the server to request the content
calculating, at the receiving terminal, a second content playback start time point by adding a content delivery time taken by the content to be transmitted from the server to the first content playback start time point; and
playing back, at the receiving terminal, the content at the second content playback start time point.

### Claim 2 (depends on 1)

The content synchronization method of claim 1, wherein the session information includes content identification information of the content being currently played back by the sending terminal and a session information transmission time point at which the sending terminal transmits the session information.

### Claim 3 (depends on 2)

The content synchronization method of claim 2, wherein the session information delivery delay time includes a first sub-delay time taken by the session information to be transmitted from the sending terminal to the server and a second sub-delay time taken by the session information to be transmitted from the server to the receiving terminal.

### Claim 4 (depends on 3)

The content synchronization method of claim 3, wherein the server checks a session information receiving time point, at which the server receives the session information, and determines a difference between the session information receiving time point and the session information transmission time point as the first sub-delay time.

### Claim 5 (depends on 3)

The content synchronization method of claim 3, wherein the content request message includes the second sub-delay time and a content request message transmission time point, at which the content request message is sent, and the server checks a content request message receiving time point and determines a difference between the content message receiving time point and the content request message transmission time point as the content request message delivery time taken by the content request message to be transmitted.

### Claim 6

A content synchronization method for providing a receiving terminal with content of a sending terminal in a system that includes the sending terminal, the receiving terminal and a server to provide the content to the sending terminal and the receiving terminal, comprising:
receiving, at the server, a session request message including session information of the sending terminal from the sending terminal to request the server to provide content currently being played back by the sending terminal;
calculating a first content playback start time point by adding a transmission delay time to a content playback start time point of the sending terminal at the time of transmitting the session information that is included in the session information, the transmission delay time including a session information delivery delay time taken by the session information to be transmitted to the receiving terminal and a content request message delivery time taken by a content request message to be transmitted from the receiving terminal to the server to request the content;
calculating, at the receiving terminal, a second content playback start time point by adding a content delivery time taken by the content to be transmitted from the server to the first content playback start time point; and
playing back, at the receiving terminal, the content at the second content playback start time point,
wherein the session information includes identification information of the content, a content playback point at the time of transmitting the session information and session information transmission point information.

### Claim 7 (depends on 6)

The content synchronization method of claim 6, wherein the session information includes content identification information of the content being currently played back by the sending terminal and a session information transmission time point at which the sending terminal transmits the session information.

### Claim 8 (depends on 7)

The content synchronization method of claim 7, wherein the session information delivery delay time includes a first sub-delay time taken by the session information to be transmitted from the sending terminal to the server and a second sub-delay time taken by the session information to be transmitted from the server to the receiving terminal.

### Claim 9 (depends on 8)

The content synchronization method of claim 8, wherein the server checks a session information receiving time point, at which the server receives the session information, and determines a difference between the session information receiving time point and the session information transmission time point as the first sub-delay time.

### Claim 10 (depends on 8)

The content synchronization method of claim 8, wherein the content request message includes the second sub-delay time and a content request message transmission time point, at which the content request message is sent, and the server checks a content request message receiving time point and determines a difference between the content message receiving time point and the content request message transmission time point as the content request message delivery time taken by the content request message to be transmitted.

### Claim 11

A content synchronization method for providing a receiving terminal with content of a sending terminal in a system that includes the sending terminal, the receiving terminal and a server to provide the content to the sending terminal and the receiving terminal, comprising:
receiving, at the sending terminal, a session request message from the receiving terminal to request the sending terminal to provide content, that is currently being played back at the sending terminal, to the receiving terminal;
transmitting, at the sending terminal, session information including identification information of the content, a content playback point at the time of transmitting the session information and session information transmission point information to the receiving terminal;
calculating, at the server, a first content playback start time point by adding a transmission delay time to a content playback time point of the sending terminal at the time of transmitting the session information that is included in the session information, the transmission delay time including a session information delivery delay time taken by the session information to be transmitted from the sending terminal to the receiving terminal and a content request message delivery time taken by a content request message to be transmitted from the receiving terminal to the server to request the content;
calculating, at the receiving terminal, a second content playback start time point by adding a content transmission time taken by the content to be transmitted from the server to the receiving terminal to the first content playback start time point; and
playing back, at the receiving terminal, the content based on the second content playback start time point.

### Claim 12 (depends on 11)

The content synchronization method of claim 11, wherein the session information further comprises content identification information of the content being currently played back by the sending terminal and a session information transmission time point at which the sending terminal transmits the session information.

### Claim 13 (depends on 12)

The content synchronization method of claim 12, further comprising:
checking, at the receiving terminal, a session information receiving time point at which the session information is received, and determining a difference between the session information receiving time point and the session information transmission time point as the session information delivery delay time; and
transmitting the session information delivery delay time along with the content request message to the server.

### Claim 14

A content synchronization method for providing a receiving terminal with content of a sending terminal in a system that includes the sending terminal, the receiving terminal and a server to provide the content to the sending terminal and the receiving terminal, the content synchronization method comprising:
receiving, at the receiving terminal, a session request message including session information from the sending terminal to request the sending terminal to provide content, that is currently being played back at the sending terminal, to the receiving terminal;
transmitting, at the receiving terminal, a content request message to the server to request the content;
calculating, at the server, a first content playback start time point of the receiving terminal by adding a transmission delay time to a content playback time point of the sending terminal at the time of transmitting the session information, the transmission delay time including a session information delivery delay time taken by the session information to be transmitted from the sending terminal to the receiving terminal and a content request message delivery time taken by a content request message to be transmitted from the receiving terminal to the server to request the content;
calculating, at the receiving terminal, a second content playback start time point by adding a content transmission time taken by the content to be transmitted from the server to the receiving terminal to the first content playback start time point; and
playing back, at the receiving terminal, the content based on the second content playback start time point,
wherein the session information includes identification information of the content, a content playback point at the time of transmitting the session information and session information transmission point information.

### Claim 15

A content synchronization system comprising:
a sending terminal;
a receiving terminal; and
a server configured to provide the receiving terminal with the content of the sending terminal,
wherein the server further comprises:
a communication unit configured to communicate with the sending terminal and the receiving terminal and to transmit a message containing a sending time point of the message, and
a content playback time point calculating unit configured to calculate a first content playback start time point of the receiving terminal in an effort to provide the content of the sending terminal that is synchronized with the receiving terminal, and
wherein the content playback time point calculating unit calculates a first content playback start time point of the receiving terminal by adding a transmission delay time to a content playback time point of the sending terminal at the time of transmitting session information, the transmission delay time including a session information delivery delay time taken by the session information to be transmitted from the sending terminal to the receiving terminal and a content request message delivery time taken by a content request message to be transmitted from the receiving terminal to the server to request the content,
wherein the receiving terminal is configured to calculate a second content playback start time point by adding a content transmission time taken by the content to be transmitted from the server to the receiving terminal to the first content playback start time point and to reproduce the content based on the second content playback start time point,
wherein the session information includes identification information of the content, a content playback point at the time of transmitting the session information and session information transmission point information.

### Claim 16 (depends on 15)

The content synchronization system of claim 15, wherein the session information further comprises content identification information of the content being currently played back by the sending terminal and a session information transmission time point at which the sending terminal transmits the session information.