SYNCHRONIZATION OF MEDIA STREAM COMPONENTS

• US 20110083155A1
• Filed: 06/04/2009
• Published: 04/07/2011
• Est. Priority Date: 06/11/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: VAN GASSEL, Jozef Pieter, De Nijs, Gilein
• Granted Patent: US 8,819,749 B2
• Time in Patent Office: Days
• US Class Current: 725/116
• CPC Class Codes: H04H 20/40 Arrangements for broadcast specially adapted for accumulation-type receivers
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• 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 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/4348 Demultiplexing of additional data and video streams
• CPC Class Codes: H04N 21/4392 involving audio buffer management
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/64315 DVB-H
• CPC Class Codes: H04N 21/6437 Real-time Transport Protocol [RTP]
• CPC Class Codes: H04N 7/56 Synchronising systems therefor

Abstract

There is provided a method for synchronizing a plurality of components of a broadcast media stream, the method comprising buffering (18) streams of data samples for a plurality of components of a broadcast media stream and buffering a plurality of information packets, the stream of data samples for each of the plurality of components including relative timing information, each information packet comprising timing information indicating a relationship between the relative timing information in the components and an absolute time; performing (16) a look-ahead action on the buffered information packets to extract timing information for each of the plurality of components; and using (16) the extracted timing information and relative timing information to synchronize the plurality of components.

Claims

1. A method for synchronizing a plurality of components of a broadcast media stream, the method comprising:

buffering (101) streams of data samples for a plurality of components of a broadcast media stream and buffering a plurality of information packets, the stream of data samples for each of the plurality of components including relative timing information, each information packet comprising timing information indicating a relationship between the relative timing information in the components and an absolute time;

performing (105) a look-ahead action on the buffered information packets to extract timing information for each of the plurality of components; and

using (107) the extracted timing information and relative timing information to synchronize the plurality of components.

2. A method as claimed in claim 1, wherein each information packet is associated with a respective one of the plurality of components, and the timing information indicates a relationship between the relative timing information in their respective components and absolute time.

3. A method as claimed in claim 1, further comprising the step of:

streaming (109) the synchronized data samples in the plurality of components.

4. A method as claimed in claim 1 further comprising the steps of:

storing the information packets in a memory (26); and

using the timing information in the information packets stored in the memory to synchronize the data samples in the plurality of components until further information packets are received.

5. A method as claimed in claim 4, wherein the broadcast media stream comprises a plurality of selectable services, the method further comprising the step of:

receiving (103) information packets for components in each of the selectable services; and

storing the information packets in the memory.

6. A method as claimed in claim 5, wherein the stream of data samples for the plurality of components comprises a first selectable service in the broadcast media stream, and wherein the stored information packets for a second selectable service are used in the event that the second service is selected, and before respective information packets for the second service are received.

7. A method as claimed in claim 1, wherein the data samples are received in bursts, and an information packet is received with each burst.

8. A method as claimed in claim 1, wherein the step of using the extracted timing information and relative timing information comprises determining the data samples in the plurality of components that are to be streamed at the same time.

9. A method as claimed in claim 8, further comprising the steps of:

comparing the determined data samples that are to be streamed at the same time to a previously determined set of data samples that are to be streamed at the same time to identify a drift between the plurality of components; and

adding or omitting data samples from the particular component to correct for the identified drift as the data samples are streamed from the buffer.

10. A method as claimed in claim 9, wherein the drift is corrected by adding or omitting data samples before the one or more data samples received with the information packet used to determine the drift are streamed.

11. A method as claimed in claim 9, wherein adding data samples comprises duplicating data samples.

12. A method as claimed in claim 9, wherein the method further comprises:

storing the results of the step of comparing in a memory.

13. A method as claimed in claim 12, wherein the method further comprises:

calculating an average correction from the results stored in the memory; and

using the calculated average correction to predict a required correction to a particular component.

14. A device for presenting a broadcast media stream to a user, the device comprising:

a buffer (18) for storing a stream of data samples for a plurality of components of the broadcast media stream and a plurality of information packets, each component comprising relative timing information for the data samples within the stream, each information packet comprising timing information indicating a relationship between the relative timing information in the components and an absolute time; and

a processor (16) that is adapted to;

perform a look-ahead action to extract the timing information from the buffered information packets for each of the components; and

use the extracted timing information and relative timing information to synchronize the plurality of components.

15. A device as claimed in claim 14, further comprising a memory (26) for storing the extracted timing information.