Method and system for delivering media selections through a network

• US 20020114330A1
• Filed: 11/27/2001
• Published: 08/22/2002
• Est. Priority Date: 12/13/2000
• Status: Abandoned Application

• Current Assignee: Dinastech IPR Limited
• Original Assignee: Dinastech IPR Limited
• Inventors: Chan, Chun Hay, Ng, Chi Ho, Raymond Chan, Kwong Wing, Tam, Cheuk Yin, Chan, Kwun Chung, Cheung, Kwok Wai
• Application Number:
  US09/993,629
• Publication Number:
  US 20020114330A1
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04N 19/88 involving rearrangement of data among different coding units, e.g. shuffling, interleaving, scrambling or permutation of pixel data or permutation of transform coefficient data among different blocks
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 21/2225 Local VOD servers
• CPC Class Codes: H04N 21/23106 involving caching operations prefetching while addressing of a memory level in which the access to the desired data or data block requires associative addressing means within memory systems or architectures G06F12/0862; caching at an intermediate stage in a data network H04L67/568
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/2387 Stream processing in response to a playback request from an end-user, e.g. for trick-play
• CPC Class Codes: H04N 21/26616 for merging a unicast channel into a multicast channel, e.g. in a VOD application, when a client served by unicast channel catches up a multicast channel to save bandwidth data multicast over packet-switching network H04L12/18
• CPC Class Codes: H04N 21/4331 Caching operations, e.g. of an advertisement for later insertion during playback
• CPC Class Codes: H04N 21/6375 for requesting retransmission , e.g. of data packets lost or corrupted during transmission from serverARQ protocols H04L1/18; implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP] H04L69/16
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6408 Unicasting
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

In a large-scale video-on-demand (VOD) system, the scalability and the provision of truly interactive functions are two difficult problems which have not been resolved satisfactorily. It is easy to provide fully interactive functions using unicast streams but these systems are limited in their scalability which affect the cost of service provisioning. Batching systems based on multicast streaming, on the other hand, can increase the scalability but it is difficult to provide interactive functions on these systems. This invention provides a media delivery system having a novel architecture aiming at serving millions of users in a metropolitan area. It features hybrid multicast-unicast streaming to achieve both scalability and full interactivity through the provision of distributed interactive servers, which cached the multicast media streams generated by the media servers. The interactive servers may also provide fault tolerant routing and error recovery.

Claims

1. A method for delivering media to a plurality of media client having a buffer for caching media of a selected media stream within one stream interval and processing capability for playing the media in a multicast media stream through a network, including the steps of:

generating plurality of multicast media streams, wherein each multicast media stream is repeated at regular stream intervals;

joining the media client to a selected multicast media stream in response to a selection request from the media client;

caching the buffer of the media client continuously with unplayed media in the selected multicast media stream; and

caching the selected multicast media streams in at least one interactive server,

such that

interactive requests including any one or more of pause, slow motion, fast forward, rewind, jump forward, and jump backward, and/or errors in playing the media in the media client are handled by the interactive server;

the media client is split from the selected multimedia media stream when an interactive request is submitted by the media client lasting for an interactive time;

the media client is merged to the selected multicast media stream after the interactive request is performed by comparing multiples of the stream intervals with the interactive time.

2. The method of claim 1, wherein the media client is merged to the selected multicast media stream in response to the pause interactive request lasting for a pause time according to the following algorithm:

If m×

stream interval≦

T_pause<

(m+1)×

stream interval, then merge to M(k+m) stream

where M(k) is the selected multicast media stream, T_pause is the pause time, and m is a positive integer.

3. The method of claim 1, wherein media client plays the media at a slower speed in response to the slow motion interactive request, and joins the selected multicast media stream after all of the media in the buffer is played.

4. The method of claim 1, wherein at least one unicast media stream is generated from the interactive server and delivered to the media client in response to a fast forward, rewind, jump forward, or jump backward interactive request from the media client.

5. The method of claim 4, wherein an interactive unicast media stream is generated from the cached and selected multicast media stream in the interactive server to the client containing media at a requested speed in forward or reverse direction in response to a corresponding fast forward or rewind interactive request from the media client, and containing media starting at the time when the interactive request is generated from the media client.

6. The method of claim 5 further including the step of generating a merging unicast media stream from the cached and selected multicast media stream in the interactive server to the client containing media starting at the time when the interactive request is terminated, wherein the merging unicast media stream transmits media at a rate higher than the selected multicast media stream, such that the media client merges to the selected multicast media stream after the interactive request is performed.

7. The method of claim 6, wherein the interactive request is a fast forward interactive request, and the media client is merged to the subsequent selected multicast media stream according to the following algorithm:

If m×

stream interval≦

(P_MC−

P_FF)−

(T_FF+T_Fill)<

(m+1)×

stream interval then merge to M(k−

m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_FF is the play-time to begin fast forward operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the fast forward operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

8. The method of claim 6, wherein the interactive request is a rewind interactive request, and the media client is merged to the subsequent selected multicast media stream according to the following algorithm:

If m×

stream interval≦

T_FF+T_Fill+(P_REW−

P_MC)<

(m+1)×

stream interval then merge to M(k+m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_REW is the play-time to begin rewind operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the rewind operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

9. The method of claim 6 further including the step of terminating the interactive unicast media stream at the time when the interactive request is terminated.

10. The method of claim 4, wherein a merging unicast media stream containing media starting at a requested jumping time is generated from the interactive server and delivered to the media client in response to a jump forward of jump backward interactive request such that the media client merges to the selected multicast media stream after the interactive request is performed.

11. The method of claim 10, wherein the interactive request is a jump forward interactive request, and the media client is merged to the selected multicast media stream according to the following algorithm:

If m×

stream interval≦

(P_MC−

P_JF)−

T_Fill<

(m+1)×

stream interval then merge to M(k−

m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_JF is the play-time to begin jump forward operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the jump forward operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

12. The method of claim 10, wherein the interactive request is a jump forward interactive request, and the media client is merged to the selected multicast media stream according to the following algorithm:

If m×

stream interval≦

T_Fill+(P_JB−

P_MC)<

(m+1)×

stream interval then merge to M(k+m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_JB is the play-time to begin jump backward operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the jump backward operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

14. The method of claim 13, wherein the media client is merged to the selected multicast media stream in response to the pause interactive request lasting for a pause time according to the following algorithm:

If m×

stream interval≦

T_Pause<

(m+1)×

stream interval, then merge to M(k+m) stream

where M(k) is the selected multicast media stream, T_pause is the pause time, and m is a positive integer.

15. The method of claim 13, wherein media client plays the media at a slower speed in response to the slow motion interactive request, and joins the selected multicast media stream after all of the media in the buffer is played.

16. The method of claim 13, wherein at least one unicast media stream is generated from the interactive server and delivered to the media client in response to a fast forward, rewind, jump forward, or jump backward interactive request from the media client.

17. The method of claim 16, wherein an interactive unicast media stream is generated from the cached and selected multicast media stream in the interactive server to the client containing media at a requested speed in forward or reverse direction in response to a corresponding fast forward or rewind interactive request from the media client, and containing media starting at the time when the interactive request is generated from the media client.

18. The method of claim 17, wherein a merging unicast media stream is generated from the cached and selected multicast media stream in the interactive server to the client containing media starting at the time when the interactive request is terminated, wherein the merging unicast media stream transmits media at a rate higher than the selected multicast media stream, such that the media client merges to the selected multicast media stream after the interactive request is performed.

19. The method of claim 18, wherein the interactive request is a fast forward interactive request, and the media client is merged to the subsequent selected multicast media stream according to the following algorithm:

If m×

stream interval≦

(P_MC−

P_FF)−

(T_FF+T_Fill)<

(m+1)×

stream interval then merge to M(k−

m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_FF is the play-time to begin fast forward operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the fast forward operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

20. The method of claim 18, wherein the interactive request is a rewind interactive request, and the media client is merged to the subsequent selected multicast media stream according to the following algorithm:

If m×

stream interval≦

T_FF+T_Fill+(P_REW−

P_MC)<

(m+1)×

stream interval then merge to M(k+m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_REW is the play-time to begin rewind operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the rewind operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

21. The method of claim 18 further including the step of terminating the interactive unicast media stream at the time when the interactive request is terminated.

22. The method of claim 16, wherein a merging unicast media stream containing media staring at a requested jumping time is generated from the interactive server and delivered to the media client in response to a jump forward of jump backward interactive request such that the media client merges to the selected multicast media stream after the interactive request is performed.

23. The method of claim 22, wherein the interactive request is a jump forward interactive request, and the media client is merged to the selected multicast media stream according to the following algorithm:

If m×

stream interval≦

(P_MC−

P_JF)−

T_Fill<

(m+1)×

stream interval then merge to M(k−

m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_JF is the play-time to begin jump forward operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the jump forward operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

24. The method of claim 22, wherein the interactive request jump forward interactive request, and the media client is merged to the selected multicast media stream according to the following algorithm:

If m×

stream interval≦

T_Fill+(P_JB−

P_MC)<

(m+1)×

stream interval then merge to M(k+m) stream

where M(k) stream is the selected multicast media stream before the fast forward interactive request is submitted by the media client, P_JB is the play-time to begin jump backward operation, P_MC is the play-time to resume the normal multicast media stream, T_FF is the time for the jump backward operation, T_Fill is the time required to fill the buffer by the merging unicast media stream, and m is a positive integer.

13. A system for delivering media selection to a plurality of media clients having a buffer for caching media of a selected media stream within one stream interval and processing capability for playing the media in a multicast stream through a network, including

at least one media server for generating a plurality of multicast media streams, wherein each multicast media stream is repeated at regular stream intervals, and the media client is joined to a selected multicast media stream in response to a selection request from the media client

at least one interactive server for caching the selected multicast media stream

such that

interactive requests including any one or more of pause, slow motion, fast forward, rewind, jump forward, and jump backward, and/or errors in playing the media in the media client are handled by the interactive server;

the media client is split from the selected multimedia media stream when an interactive request is submitted by the media client lasting for an interactive time;

the media client is merged to the selected multicast media stream after the interactive request is performed by comparing multiples of the stream intervals with the interactive time.