System and method for time synchronization between multimedia content and segment metadata

• US 20040267738A1
• Filed: 06/30/2004
• Published: 12/30/2004
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shin, Hyo-seop
• Granted Patent: US 7,428,696 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/4147 PVR [Personal Video Recorder] H04N5/76 takes precedence ; arrangements for broadcast with accumulation-type receivers H04H20/40
• 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 21/43074 of additional data with content streams on the same device, e.g. of EPG data or interactive icon with a TV program
• CPC Class Codes: H04N 21/4345 Extraction or processing of SI, e.g. extracting service information from an MPEG stream
• CPC Class Codes: H04N 21/435 Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
• CPC Class Codes: H04N 21/4622 Retrieving content or additional data from different sources, e.g. from a broadcast channel and the Internet web site content organization and management for information retrieval from the Internet G06F16/958; transmission by internet of broadcast information H04H60/82; stock exchange data over packet-switching network H04L12/1804; push services including data channel over packet-switching network H04L12/1859

Abstract

A system and method for time synchronization between multimedia content and segment metadata. Time synchronization system of the present invention includes a content processor receiving and storing multimedia content containing first segment time information; a metadata processor receiving and storing segment metadata for the content containing second segment time information; a synchronizer extracting the first segment time information from the multimedia content and the second segment time information from the metadata in response to a request of a user, determining respective reference time points from the first and second extracted segment time information, correcting a relative time point of the content using a difference between the determined reference time points, and synchronizing the received content and metadata using the corrected relative time point; and a content segment browser forwarding the content segment request signal to the synchronizer and reproducing a plurality of segments of the content synchronized by the synchronizer.

Claims

1. A time synchronization system, comprising:

a content processor receiving and storing multimedia content containing first segment time information as received content;

a metadata processor receiving and storing segment metadata for the received content containing second segment time information as received metadata;

a synchronizer extracting the first segment time information from the received content and the second segment time information from the received metadata in response to a content segment request signal of a user as first extracted segment time information and as second extracted segment time information, determining a first reference time point and a second reference time point from the first and the second extracted segment time information, respectively, correcting a relative time point of the received content using a difference between the first and the second reference time points as a corrected relative time point, and synchronizing the received content and metadata using the corrected relative time point; and

a content segment browser for forwarding the content segment request signal to the synchronizer and reproducing a plurality of segments of the received content synchronized by the synchronizer.

2. The system as claimed in claim 1, wherein the first and the second extracted segment time information comprises first Global Positioning System (GPS) time information and second GPS time information, respectively, and the first and the second reference time points are the first and the second GPS time information, respectively, and wherein:

if the first GPS time information of the received content is ahead of the second GPS time information of the received metadata, the synchronizer corrects the relative time point of the received content by adding a difference between the first GPS time information of the received content and the second GPS time information of the received metadata to a relative time value in the received metadata;

or

if the first GPS time information of the content is behind the second GPS time information of the received metadata, the synchronizer corrects the relative time point of the received content by subtracting the difference between the first and second GPS time information from the relative time value in the received metadata.

3. The system as claimed in claim 1, wherein the first segment time information comprises a first Global Positioning System (GPS) time information and a first decoding time stamp (DTS) time information, the second segment time information comprises a second GPS time information and a second DTS time information, and the first and the second reference time points are the first and the second DTS time information, respectively, and wherein:

if the first GPS time information of the received content is ahead of the second GPS time information of the received metadata,

the synchronizer causes a difference between the first and the second DTS time information (Δ

T_DTS) to be changed to Δ

T_DTS−

2³³ as a new Δ

T_DTS when the Δ

T_DTS>

0 or the Δ

T_DTS to remain unchanged when the Δ

T_DTS<

0 and then corrects the relative time point of the received content by adding an absolute value of the Δ

T_DTS to a relative time value in the received metadata, where the Δ

T_DTS is a value obtained by subtracting the second DTS time information of the received metadata from the first DTS time information of the received content;

or

if the first GPS time information of the received content is behind the second GPS time information of the received metadata,

the synchronizer causes the Δ

T_DTS to be changed to Δ

T_DTS+2³³ as the new Δ

T_DTS when the Δ

T_DTS<

0 or the Δ

T_DTS to remain unchanged when the Δ

T_DTS>

0 and then corrects the relative time point of the received content by subtracting an absolute value of the Δ

T_DTS from the relative time value in the received metadata, where the Δ

T_DTS is a value obtained by subtracting the second DTS time information value of the received metadata from the first DTS time information value of the received content.

4. The system as claimed in claim 1, wherein the first segment time information comprises a first Global Positioning System (GPS) time information and a first presentation time stamp (PTS) time information, the second segment time information comprises a second GPS time information and a second PTS time information, and the first and the second reference time points are the first and the second PTS time information, respectively, and wherein:

if the first GPS time information of the received content is ahead of the second GPS time information of the received metadata,

the synchronizer causes a difference between the first and the second PTS (Δ

T_PTS) to be changed to Δ

T_PTS−

2³³ as a new Δ

T_PTS when the Δ

T_PTS>

0 or the Δ

T_PTS to remain unchanged when the Δ

T_PTS<

0 and then corrects the relative time point of the received content by adding an absolute value of the Δ

T_PTS to a relative time value in the received metadata, where the Δ

T_PTS is a value obtained by subtracting the second PTS time information value of the received metadata from the first PTS time information value of the received content;

or

if the first GPS time information of the received content is behind the second GPS time information of the received metadata,

the synchronizer causes the Δ

T_PTS to be changed to Δ

T_PTS+2³³ as the new Δ

T_PTS when the Δ

T_PTS<

0 or the Δ

T_PTS to remain unchanged when the Δ

T_PTS>

0 and then corrects the relative time point of the received content by subtracting an absolute value of the Δ

T_PTS from the relative time value in the received metadata, where the Δ

T_PTS is the value obtained by subtracting the second PTS time information value of the received metadata from the first PTS time information value of the received content.

5. A time synchronization method, comprising:

(1) receiving a multimedia content containing first segment time information as received content and segment metadata for the multimedia content containing second segment time information for the multimedia content as received metadata;

(2) extracting the first segment time information from the received content and the second segment time information from the received metadata to determine a first reference time point and a second reference time point, respectively;

(3) correcting a relative time point of the received content using a difference between the first and the second reference time points to generate a corrected relative time point; and

(4) synchronizing the received content and received metadata received in (1) using the corrected relative time point.

6. The method as claimed in claim 5, wherein the first segment time information comprises a first GPS time information and the second segment time information comprise a second GPS time information and the first and the second reference time points are the first and the second GPS time information, and wherein:

if the first GPS time information of the received content is ahead of the second GPS time information of the received metadata, (3) comprises correcting the relative time point of the received content by adding a difference between the first GPS time information of the received content and the second GPS time information of the received metadata to a relative time value in the received metadata;

or

if the first GPS time information of the received content is behind the second GPS time information of the received metadata, (3) comprises correcting the relative time point of the content by subtracting the difference between the first and the second GPS time information from the relative time value in the received metadata.

7. The method as claimed in claim 5, wherein the first segment time information comprises a first Global Positioning System (GPS) time information and a first decoding time stamp (DTS) time information, the second segment time information comprises a second GPS time information and a second DTS time information, and the first and the second reference time points are the first and the second DTS time information, respectively, and wherein:

if the first GPS time information of the received content is ahead of the second GPS time information of the received metadata,

(3) comprises (3-1) causing a difference between the first and the second DTS time information (Δ

T_DTS) to be changed to Δ

T_DTS−

2³³ as a new Δ

T_DTS when the Δ

T_DTS>

0 or the Δ

T_DTS to remain unchanged when the Δ

T_DTS<

0 and (3-2) correcting the relative time point of the received content by adding an absolute value of the Δ

T_DTS to the relative time value in the received metadata, where the Δ

T_DTS is a value obtained by subtracting the second DTS time information value of the received metadata from the first DTS time information value of the received content;

or

if the first GPS time information of the received content is behind the second GPS time information of the received metadata,

(3) comprises (3-1) causing the Δ

T_DTS to be changed to Δ

T_DTS+2³³ as the new Δ

T_DTS when the Δ

T_DTS<

0 or the Δ

T_DTS to remain unchanged when the Δ

T_DTS>

0 and (3-2) correcting the relative time point of the received content by subtracting an absolute value of the Δ

T_DTS from the relative time value in the received metadata, where the Δ

T_DTS is a value obtained by subtracting the second DTS time information value of the received metadata from the first DTS time information value of the received content.

8. The method as claimed in claim 5, wherein the first segment time information comprises a first Global Positioning System (GPS) time information and a first presentation time stamp (PTS) time information, the second segment time information comprises a second GPS time information and a second PTS time information, and the first and the second reference time points are the first and the second PTS time information, respectively, and wherein:

if the first GPS time information of the received content is ahead of the second GPS time information of the received metadata,

(3) comprises (3-1) causing a difference between the first and the second PTS (Δ

T_PTS) to be changed to Δ

T_PTS−

2³³ as a new Δ

T_PTS when the Δ

T_PTS>

0 or the Δ

T_PTS to remain unchanged when the Δ

T_PTS<

0 and (3-2) correcting the relative time point of the received content by adding an absolute value of the Δ

T_PTS to a relative time value in the received metadata, where the Δ

T_PTS is a value obtained by subtracting the second PTS time information value of the received metadata from the first PTS time information value of the received content;

or

if the first GPS time information of the received content is behind the second GPS time information of the received metadata,

(3) comprises (3-1) causing the Δ

T_PTS to be changed to Δ

T_PTS+2³³ as the new Δ

T_PTS when the Δ

T_PTS<

0 or Δ

T_PTS to remain unchanged when the Δ

T_PTS>

0 and (3-2) correcting the relative time point of the received content by subtracting an absolute value of the Δ

T_PTS from the relative time value in the received metadata, where the Δ

T_PTS is a value obtained by subtracting the second PTS time information value of the received metadata from the first PTS time information value of the received content.