ADAPTIVE BIT RATE FOR DATA TRANSMISSION

• US 20120005361A1
• Filed: 06/30/2010
• Published: 01/05/2012
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Knittle, Curtis
• Granted Patent: US 8,904,027 B2
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/6373 for rate control , e.g. request to the server to modify its transmission rate flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/64769 for rate control flow control in packet networks H04L47/10
• CPC Class Codes: H04W 28/0289 Congestion control load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12

Abstract

An adaptive bit rate system for use in transmitting data at adaptable bit rates. The bit rate may be adjusted according to historical behaviors and/or past operational settings, such as but not limited to adjusted a request bit rate to a different bit rate depending the historical behavior.

Claims

1. A method of dynamically adjusting a bit rate at data to be transferred over a network to a client is encoded, the method comprising:

determining a first value reflective of a plurality of bit rates at which data was previously requested to be transferred to the client, the first value being determined at least based in part on one or more prior bit rate requests made by the client;

determining a network congestion of the network;

determining a second value reflective of a bit rate suitable given the network congestion;

determining a third value based on the first and second values; and

requesting adjustment of the bit rate to approximately the third value.

2. The method of claim 1 further comprising determining the third value according to the following equation:

third value=first value*α

+second value*β

wherein 0<

α

<

1, and β

=1−

α

.

3. The method of claim 2 further comprising determining the first value to be an average determined according to a rectangular window function of the plurality of bit rates at which data was previously requested to be transferred to the client.

4. The method of claim 2 further comprising determining the first value to be an average determined according to an exponential window function of the plurality of bit rates at which data was previously requested to be transferred to the client.

5. The method of claim 1 further comprising the client determining the network congestion as a function of network traffic perceived by the client.

6. The method of claim 1 further comprising the server determining the network congestion as a function of messages received form the client marking receipt of data transmitted to the client over the network.

7. A method of dynamically selecting a bit rate used to encode data being transmitted over a network to a client, the method comprising:

determining a current bit rate used to encode data that is currently being transmitted to the client;

determining a first amount by which the current bit is to be adjusted to compensate for network congestion of the network; and

automatically adjusting the bit rate by a second amount, the second amount being equal to a percentage P of the first amount.

8. The method of claim 7 further comprising determining the percentage P as function of a function of past bit rate adjustments.

9. The method of claim 8 further comprising determining the percentage P to be 0% in the event at least N number of bit rate changes occurred within a time period T.

10. The method of claim 7 further comprising determining the percentage P as a function of a time duration of the current bit rate.

11. The method of claim 10 further comprising determining the percentage P to be 0% in the event the time duration is less than a threshold.

12. The method of claim 7 further comprising determining the first amount to be equal to a difference between the current bit rate and a selected bit rate, the selected bit rate being selected from a plurality of bit rates mapped to network congestion values wherein the selected bit rate is the one of the plurality of bit rates mapped to a current level of network congestion.

13. The method of claim 12 further comprising automatically adjusting the bit rate by a third amount instead of the second amount in the event the second amount falls between two of the plurality of bit rates, the third amount corresponding with one of a next higher and lower one of the two of the plurality of bit rates.

14. The method of claim 13 further comprising selecting the one of the first, second, and third next lower and higher bit rate as function of one of a frequency of past bit rate adjustments and a time duration of the current bit rate.

15. A video server comprising:

a transmitting device operable to transmit video over a network to a client at a bit rate;

a controller operable to set the bit rate at which based on the following formula;

bit rate=first value*α

+second value*β

wherein;

(i) the first value equals an average of a plurality of bit rates at which data was previously transferred to the client;

(ii) a second value equals a bit rate currently being requested by the client;

(iii) 0<

α

<

1; and

(iv) β

=1−

α

.

16. The server of claim 15 wherein the first value is an average determined according to a rectangular window function of the plurality of bit rates.

17. The server of claim 15 wherein the first value is an average determined according to an exponential window function of the plurality of bit rates.

18. The server of claim 15 wherein the controller instructions the client to select the requested bit rate from a listing of available bit rates.

19. The server of claim 18 wherein the controller sets the bit rate to the one of the listing of available bit rates that is closest to the bit rate calculated by the formula.

20. The server of claim 15 wherein the controller sets the bit rate to the bit rate currently requested by the client in the event a frequency of past bit rate changes is less than a threshold and a time duration of the currently set bit rate is greater than a threshold.