METHOD AND SYSTEM FOR STREAMING DIGITAL VIDEO CONTENT TO A CLIENT IN A DIGITAL VIDEO NETWORK

Abstract

A technique for streaming digital video content to a client involves providing a new stream of digital video content to the client using forward error correction (FEC) for a limited initial period and then ending the use of FEC after the limited initial period has ended. In an embodiment, during the limited initial period, the digital video content is provided to the client at a rate that is slightly higher than the playout rate in order to allow a client buffer to accumulate digital video content. FEC continues to be used until the client buffer is sufficiently populated such that lost or damaged frames can be retransmitted to the client before the corresponding digital video content is needed for playout. Once the client buffer is sufficiently populated, FEC is ended and retransmission is used to maintain the quality of the streamed digital video content.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1F illustrate a technique for servicing channel change requests in accordance with an embodiment of the invention.

FIG. 2 depicts a process flow diagram of the above-described technique for servicing channel change requests in a digital video network that is capable of distributing digital video content to clients via multicasting and unicasting.

FIGS. 3 and 4 depict an embodiment of a channel change server and a client, respectively, which are configured to service channel change requests in accordance with an embodiment of the invention.

FIG. 5 depicts an exemplary process flow diagram that illustrates the interaction between a server system and a client related to servicing a channel change request.

FIG. 6 is an exemplary process flow diagram of surf mode logic in accordance with an embodiment of the invention.

FIGS. 7A-7C depict a process of servicing a channel change request via unicasting.

FIG. 8 illustrates a technique for switching a client from unicasting back to multicasting in accordance with an embodiment of the invention.

FIGS. 9A-9D depict exemplary states of the client's stream buffer with respect to the technique described with reference to FIG. 8.

FIG. 10 illustrates another technique for switching a client from unicasting back to multicasting in accordance with an embodiment of the invention.

FIGS. 11A-11D depict exemplary states of the client's stream buffer with respect to the technique described with reference to FIG. 10.

FIG. 12 is a process flow diagram of a method for servicing a channel change request in a digital video network in accordance with an embodiment of the invention.

FIG. 13 is a process flow diagram of another method for servicing a channel change request in a digital video network in accordance with another embodiment of the invention.

FIG. 14 is a graph of bandwidth usage versus time for a stream that is provided to a client at a rate that supports normal playout at the client and that includes forward error correction.

FIG. 15 illustrates the bandwidth usage when a client buffer is filled by a burst of digital video content that is sent immediately upon detecting a channel change request (CCR).

FIG. 16 is a graph of bandwidth usage versus time for a stream that is provided to a client using forward error correction for a limited initial period in accordance with an embodiment of the invention.

FIG. 17 is a graph of bandwidth usage versus time for a stream that is provided to a client using forward error correction for a limited initial period in accordance with another embodiment of the invention.

FIG. 18 is a graph of bandwidth usage versus time for a stream that is provided to a client using forward error correction for a limited initial period in accordance with another embodiment of the invention.

FIG. 19 is a graph of bandwidth usage versus time for a stream that is provided to a client using forward error correction for a limited initial period in accordance with another embodiment of the invention.

FIG. 20 is a process flow diagram of a method for servicing channel change requests in a digital video network that is capable of distributing digital video content to clients via multicasting and unicasting.

FIG. 21 is a process flow diagram of another method for servicing channel change requests in a digital video network that is capable of distributing digital video content to clients via multicasting and unicasting.

FIG. 22 is a process flow diagram of another method for servicing channel change requests in a digital video network that is capable of distributing digital video content to clients via multicasting and unicasting.

FIG. 23 depicts an embodiment of a stream server transmit module that resides on the stream server side of the digital video network and a client receive module that resides on the client side of the digital video network.

FIG. 24 is a process flow diagram of a method for streaming digital video content to a client in a digital video network.

Claims

1. A method for streaming digital video content to clients in a digital video network, the method comprising: identifying a new stream of digital video content that is intended for a client;providing the new stream to the client using forward error correction for a limited initial period; andending the use of forward error correction after the limited initial period while continuing to provide the new stream to the client.

2. The method of claim 1 further comprising, while forward error correction is in use, providing digital video content to the client at a rate that is higher than the playout rate at the client in order to populate a buffer at the client.

3. The method of claim 2 wherein the limited initial period ends once the buffer is populated to a pre-established threshold.

4. The method of claim 2 further comprising reducing the rate at which digital video content is provided to the client to the playout rate and initiating a retransmission protocol once the limited initial period ends.

5. The method of claim 1 wherein the limited initial period ends when a buffer at the client is populated to a pre-established threshold.

6. The method of claim 5 wherein the pre-established threshold is a function of the time required to recover a frame at the client using a retransmission protocol.

7. The method of claim 5 wherein the pre-established threshold provides enough buffered digital video content to enable a frame to be recovered at the client before the frame is due for playout at the client.

8. The method of claim 1 wherein the limited initial period ends upon the expiration of a pre-established time interval.

9. A method for servicing channel change requests in a digital video network that is capable of distributing digital video content to clients via multicasting and unicasting, the method comprising: detecting a channel change request related to a client;providing digital video content related to the requested channel to the client in response to the channel change request, wherein providing digital video content to the client comprises using forward error correction for a limited initial period; andending the use of forward error correction after the limited initial period while continuing to provide digital video content related to the requested channel to the client.

10. The method of claim 9 further comprising, while forward error correction is in use, providing digital video content to the client at a rate that is higher than the playout rate at the client in order to populate a buffer at the client.

11. The method of claim 10 wherein the limited initial period ends once the buffer is populated to a pre-established threshold.

12. The method of claim 11 further comprising reducing the rate at which digital video content is provided to the client to the playout rate once the buffer is populated to the pre-established threshold.

13. The method of claim 9 wherein the limited initial period ends when a buffer at the client is populated to a pre-established threshold.

14. The method of claim 13 wherein the pre-established threshold is a function of the time required to recover a frame at the client using a retransmission protocol.

15. The method of claim 13 wherein the pre-established threshold provides enough buffered digital video content to enable a frame to be recovered at the client before the frame is due for playout at the client.

16. The method of claim 10 further comprising initiating a retransmission protocol once the limited initial period ends.

17. The method of claim 9 wherein the limited initial period ends when digital video content related to the requested channel is switched from being provided to the client via unicasting to being provided to the client via multicasting.

18. A method for servicing channel change requests in a digital video network that is capable of distributing digital video content to clients via multicasting and unicasting, the method comprising: detecting a channel change request related to a client;providing digital video content related to the requested channel to the client in response to the channel change request, wherein providing digital video content to the client comprises using forward error correction for a limited initial period to improve the bit error ratio of digital video content received at the client; andafter the limited initial period, using a retransmission protocol to improve the bit error ratio of digital video content received at the client.

19. The method of claim 18 further comprising, before the end of the limited initial period, providing digital video content to the client at a rate that is greater than the playout rate at the client.

20. The method of claim 18 wherein the limited initial period ends when a buffer at the client is populated to a pre-established threshold.

21. The method of claim 18 further comprising ending the use of forward error correction after the limited initial period.

22. The method of claim 18 further comprising reducing the strength of forward error correction after the limited initial period.

23. A system for streaming digital video content to clients in a digital video network, the system comprising: a transmit module configured to; provide digital video content related to a new stream to a client using forward error correction for a limited initial period; andend the use of forward error correction after the limited initial period while continuing to provide digital video content related to the new stream to the client.

24. The system of claim 23 wherein the limited initial period ends when a buffer at the client is populated to a pre-established threshold and wherein the pre-established threshold provides enough buffered digital video content to enable a frame of the new stream to be recovered at the client using a retransmission protocol before the frame is due for playout at the client.

25. The system of claim 24 wherein the transmit module is further configured to reduce the rate at which digital video content is provided to the client to the playout rate once the buffer is populated to the pre-established threshold.

26. The system of claim 23 wherein the transmit module is further configured to provide, while forward error correction is in use, digital video content to the client at rate that is higher than the playout rate at the client in order to populate a buffer at the client.

27. The system of claim 23 wherein the transmit module is configured to use a retransmission protocol once the limited initial period ends.