SYSTEM AND METHOD FOR STREAMING AUDIO

• US 20100023638A1
• Filed: 07/22/2009
• Published: 01/28/2010
• Est. Priority Date: 07/22/2008
• Status: Active Grant

• Current Assignee: Snap One LLC (Snap One Holdings Corp.)
• Original Assignee: Control4 Corporation (Snap One Holdings Corp.)
• Inventors: Bowman, Timothy D.
• Granted Patent: US 8,639,830 B2
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

A system and method is provided of synchronizing data streaming. The method can include the operation of receiving an incoming media packet having a timestamp from a media server at a client device. A further operation is synchronizing the clocks for a client device with a clock for a media server. The timestamp can be compared with a next play time for a packet. Another operation can be placing the incoming media packet into a user buffer at a playing position in the user buffer based on the next play time. The incoming media packet can then be played using a media output device accessible to an end user.

Claims

1. A method of synchronizing data streaming, comprising:

synchronizing a clock for a client device with a clock for a media server;

receiving an incoming media packet having a timestamp from the media server at the client device;

comparing the timestamp with a next play time for a packet;

placing the incoming media packet into a user buffer at a playing position in the user buffer based on the next play time; and

playing the incoming media packet using a media output device accessible to an end user.

2. The method of claim 1, wherein placing the incoming media packet into the user buffer further comprises the step of placing the incoming media packet into the user buffer at a time position in the user buffer based on the timestamp of the incoming media packet as compared to the clock for the client device and the next play time.

3. The method as in claim 1, wherein playing the incoming media packet further comprises transferring packets from the user buffer to a kernel buffer to enable the packets to be played using an audio speaker for the client.

4. The method as in claim 1, further comprising:

receiving an announcement media packet into an announcement buffer; and

mixing the announcement media packet with a packet from the user buffer into the kernel buffer at a point where the announcement media packet will be played.

5. The method as in claim 4, further comprising inserting a quiet period before and after the announcement media packet.

6. The method as in claim 4, wherein mixing the announcement further comprises placing data from the announcement media packet into the kernel buffer.

7. The method as in claim 4, wherein mixing the announcement further comprises placing a combination of data from the announcement media packet and the user buffer into the kernel buffer.

8. The method as in claim 1, wherein the media server transmits the media packet to a plurality of client devices.

9. The method as in claim 1, further comprising:

calculating a drift coefficient for the clock of the client device; and

adjusting the timing of the playback of data in the media packet on the client device based on the drift coefficient.

10. The method as in claim 1, wherein a client device is configured to resample data in the media packet to match a sampling rate used by the user buffer and a kernel buffer.

11. The method as in claim 1, wherein a first client device plays audio from the media packet within a pre-defined number of milliseconds of when a second client device plays audio from the media packet.

12. A method of synchronizing audio streaming, comprising:

synchronizing a clock for a client device with a clock for a media server;

receiving an incoming media packet on the client device from the media server, the media packet comprising a timestamp and media data;

comparing the timestamp with a next play time for data in the incoming media packet;

placing the incoming media packet into a user buffer at a playing position in the user buffer based on the comparison of the time stamp with the next play time for the data in the incoming media packet;

transferring the data packet from the user buffer to a kernel buffer, the kernel buffer storing data that will play on an audio device; and

playing the incoming media packet using a media output device accessible to an end user.

13. The method as in claim 12, further comprising:

receiving an announcement media packet into an announcement buffer;

mixing the announcement media packet with a packet from the user buffer to make a mixed announcement packet; and

placing the mixed announcement packet in the kernel buffer at a point where the announcement media packet will be played.

14. The method as in claim 12, further comprising inserting a quiet period before and after the announcement.

15. The method as in claim 12, wherein mixing the announcement further comprises placing only data from the announcement media packet into the kernel buffer.

16. The method as in claim 12, wherein mixing the announcement further comprises placing a combination of data from the announcement media packet and the user buffer into the kernel buffer.

17. The method as in claim 12, wherein the media server transmits the media packet to a plurality of client devices.

18. The method as in claim 12, further comprising:

calculating a drift coefficient for the clock of the client device; and

adjusting the timing of the playback of data in the media packet on the client device based on the drift coefficient.

19. The method as in claim 15, wherein a first client device plays audio from the media packet within a pre-defined number of milliseconds of when a second client device, in the plurality of client devices, plays audio from the media packet.

20. A system for synchronizing audio streaming, the system comprising:

a media server configured to transmit media packets to a client device, the media server comprising;

a media source configured to provide transmittable media to the media server; and

a stream sender configured to send a stream of media packets to the client device; and

a time synchronization module configured to keep a clock of the client device synchronized with a clock of the media server; and

the client device configured to receive media packets from the media server and play them on a media output device, the client device comprising;

a stream acceptor configured to monitor receiving ports for incoming media packets;

a media buffer configured to store the incoming media packets;

an audio device interface configured to send the media packets to the media output device; and

a time synchronization module configured to keep a clock of the client device synchronized with a clock of the media server.