Synchronization and automation in an ITV enviroment

• US 20060031914A1
• Filed: 02/04/2005
• Published: 02/09/2006
• Est. Priority Date: 02/04/2004
• Status: Active Grant

• Current Assignee: MK Systems USA Inc.
• Original Assignee: Ericsson Television Incorporated (Telefonaktiebolaget LM Ericsson)
• Inventors: Dakss, Jon, Sarachik, Karen, Milazzo, Paul, Bove, V. Michael Jr., Kotmel, Allan
• Granted Patent: US 8,010,986 B2
• Time in Patent Office: Days
• US Class Current: 725/135
• CPC Class Codes: H04H 60/13 Arrangements for device control affected by the broadcast information
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• 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 21/4348 Demultiplexing of additional data and video streams
• 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 21/6332 directed to client
• CPC Class Codes: H04N 21/654 Transmission by server directed to the client
• CPC Class Codes: H04N 21/6543 for forcing some client operations, e.g. recording remote booting in general G06F9/4416
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content
• CPC Class Codes: H04N 5/04 Synchronising for television systems using pulse code modulation H04N7/56

Abstract

A synchronization mechanism embeds synchronization triggers into a television signal or stream at regular intervals. The triggers include an accurate representation of the time in which the triggers were embedded. A receiving device decodes the triggers and synchronizes its internal timer based on the triggers. In this regard, the receiving device obtains a reference time from the internal timer and computes an offset between the reference time and the trigger time. The computed offset is then applied to the reference time. With the receipt of each new trigger, the application compares the trigger time to a new reference time with the most recently computed offset value applied. If there is any variance between these two values, the application creates a new smoothed offset.

Claims

1. A method for synchronizing an interactive television (ITV) event with a content element received by a receiving device, the method comprising:

receiving a first trigger including a first time value for a first video frame of the content element;

obtaining a second time value recorded by an internal time source upon receipt of the first trigger;

computing a first offset between the first time value and the second time value;

applying the first offset to the second time value; and

retrieving an ITV event based on the second time value with the applied first offset.

2. The method of claim 1, wherein the first trigger is embedded into a video signal associated with the content element.

3. The method of claim 1, wherein the first trigger is embedded into a digital transport stream.

4. The method of claim 1, wherein the internal time source is an internal clock.

5. The method of claim 1, wherein the internal time source is a presentation value of a presented video frame.

6. The method of claim 1, wherein the trigger is received over an out-of-band data path.

7. The method of claim 1 further comprising:

receiving a second trigger including a third time value for a second video frame of the content element;

obtaining a fourth time value recorded by the internal time source upon receipt of the second trigger;

computing a second offset between the third time value and the fourth time value;

deriving a third offset based on the first offset and the second offset; and

applying the third offset to the fourth time value.

8. The method of claim 7, wherein the third offset is an average of the first and second offsets.

9. A receiver synchronizing an interactive television (ITV) event with a received content element, the receiver comprising:

a decoder decoding a plurality of triggers, each trigger including a time value of a corresponding video frame of the content element;

an internal time source recording time; and

a processor coupled to the decoder and the internal time source, the processor executing program instructions which;

obtain from the decoder a decoded first time value included in a first trigger;

obtain from the internal time source a second time value recorded upon receipt of the first trigger;

compute a first offset between the first time value and the second time value;

apply the first offset to the second time value; and

retrieve an ITV event based on the second time value with the applied first offset.

10. The receiver of claim 9, wherein the plurality of triggers are embedded into a video signal associated with the content element.

11. The receiver of claim 9, wherein the plurality of triggers are embedded into a digital transport stream.

12. The receiver of claim 9, wherein the internal time source is an internal clock.

13. The receiver of claim 9, wherein the internal time source is a presentation value of a presented video frame.

14. The receiver of claim 9, wherein the trigger is received over an out-of-band data path.

15. The receiver of claim 9, wherein the processor further executes program instruction which:

obtain from the decoder a decoded third time value included in a second trigger;

obtain from the internal time source a fourth time value recorded upon receipt of the second trigger;

compute a second offset between the third time value and the fourth time value;

derive a third offset based on the first offset and the second offset; and

apply the third offset to the fourth time value.

16. The receiver of claim 15, wherein the third offset is an average of the first and second offsets.