Viewer controllable on-demand multimedia service

• US 5,629,732 A
• Filed: 03/29/1994
• Issued: 05/13/1997
• Est. Priority Date: 03/29/1994
• Status: Expired due to Fees

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Rizkalla, Michael, Moskowitz, Alan S.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): GRANT, CHRISTOPHER C
• Application Number:
  US08/219,670
• Time in Patent Office: 1,141 Days
• Field of Search: 348/7, 348/12, 348/13, 455/4.2, 455/5.1, 455/6.1
• US Class Current: 725/102
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

In a multimedia application where movie events are distributed on an on-demand basis, a multimedia server serves a subscriber requesting a movie event through either a high-demand process or a low-demand process. In a low demand process, a data stream representative of the movie is exclusively provided to the subscriber in accordance with a double-buffering technique. The server may switch many low-demand processes serving the same movie event into a high-demand process to effectively utilize limited resources. In the high-demand process, high-demand pointers are launched periodically and are associated with data streams representative of the movie event having different start times. Each data stream associated with a high-demand pointer may be shared by an unlimited number of subscribers. Service alterations of the movie including fast-forwarding, rewinding, and restarting after a pause are achieved by way pointer-hopping.

Claims

1. Apparatus for providing multimedia events comprising:

a memory for storing a plurality of data groups at different memory locations, said data groups representative of a selected multimedia event;

a processing element for retrieving data groups from said memory; and

a transmitter for providing a plurality of data streams, each data stream representative of a version of the selected multimedia event starting at a different time;

said processing element generating a plurality of pointers, each pointer being associated with a different data stream, each pointer indicating memory locations from where data groups are retrieved to form the data stream associated therewith.

2. The apparatus of claim 1 wherein a new pointer is generated every predetermined time period.

3. The apparatus of claim 2 wherein said new pointer when generated indicates a memory location where the first one of said data groups is stored.

4. The apparatus of claim 1 wherein each data stream is provided to at least one receiver capable of deriving the selected event from the data stream.

5. The apparatus of claim 1 wherein each memory location is identified by a base memory address and a memory offset.

6. The apparatus of claim 1 wherein said selected event is a movie event.

7. The apparatus of claim 6 wherein each data group contains data representative of a predetermined number of frames in the movie event.

8. The apparatus of claim 1 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

9. Apparatus for providing a selected multimedia event to a plurality of receivers comprising:

a transmitter for providing a plurality of data streams, each data stream representative of a version of said selected multimedia event having a different start time, number of the data streams provided being a function of number of versions of said selected multimedia event which are currently received by said receivers;

a processing element for assigning each data stream to at least one receiver; and

a receptive element for receiving from a receiver at least a request for service alteration, said processing element responsive to said request for effecting said service alteration by at least removing from said receiver the assignment of the data stream assigned thereto.

10. The apparatus of claim 9 wherein said request is a request for fast-forwarding the selected event, and wherein said service alteration is effected by further assigning to said receiver a second data stream, said second data stream representative of a version of the selected event having an earlier start time than the data stream previously assigned to said receiver.

11. The apparatus of claim 9 wherein said request is a request for rewinding the selected event, and wherein said service alteration is effected by further assigning to said receivers a second data stream, said second data stream representative of a version of the selected event having a later start time than the data stream previously assigned to said receiver.

12. The apparatus of claim 9 wherein said request is a request for a pause during the selected event, and wherein said service alteration is effected by further recording a duration of said pause.

13. The apparatus of claim 9 wherein said request is a request for restarting the selected event after a pause during the selected event, and wherein said service alteration is effected by further assigning to said receiver a selected data stream, said selected data stream representative of a version of the selected event having a later start time than the data stream previously assigned to said receiver, said later start time being a function of a duration of said pause.

14. The apparatus of claim 9 wherein said selected event is a movie event.

15. The apparatus of claim 9 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

16. Apparatus for providing multimedia events to a plurality of receivers comprising:

a processing element, said processing element instructed by first instructions for performing a plurality of first processes to provide said receivers with a selected multimedia event;

a buffer element for storing, in each first process, first data partially representative of the selected event;

said processing element instructed by second instructions for performing a second process;

a memory for storing at a plurality of memory locations second data representative of the selected event in its entirety;

said second process including reading said second data from said memory starting at different memory locations to provide a plurality of data streams; and

a switching mechanism for switching said plurality of first processes into said second process upon detection of a predetermined condition, said switching mechanism including a mechanism for assigning said data streams to said receivers.

17. The apparatus of claim 16 wherein said buffer element includes two individual buffers, and wherein each first process includes writing ones of the first data to said buffer element, and reading the other ones of the first data from said buffer element, in such a way that while said ones of the first data is read from one of the buffers, said other ones of the first data is written to the other buffer.

18. The apparatus of claim 17 wherein said two individual buffers are equal in size.

19. The apparatus of claim 16 wherein said processing element generates a plurality of pointers, each pointer being associated with a different one of said data streams, each pointer indicating memory locations of said memory from where ones of said second data are read to form the data stream associated therewith.

20. The apparatus of claim 19 wherein each memory location is identified by a base memory address and a memory offset.

21. The apparatus of claim 16 wherein said predetermined condition is a function of limits of capacities of elements supporting said apparatus.

22. The apparatus of claim 21 connected to said receivers via a network, wherein said limits include limited bandwidth of said network.

23. The apparatus of claim 21 connected to a data storage device comprising said first data, wherein said limits include a limited rate of retrieval by said storage device of said first data.

24. The apparatus of claim 16 wherein said selected event is a movie event.

25. The apparatus of claim 24 wherein said second data is assembled in data groups each representative of a predetermined number of frames in the movie event.

26. The apparatus of claim 16 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

27. A system for providing multimedia events comprising:

a plurality of receivers; and

a multimedia server comprising;

a memory for storing a plurality of data groups at different memory locations, said data groups representative of a selected multimedia event;

a processing element for retrieving data groups from said memory; and

a transmitter for providing a plurality of data streams to said receivers, each data stream representative of a version of the selected multimedia event starting at a different time;

each receiver receiving one of said plurality of data streams, and deriving the selected event from the received data stream;

said processing element in said multimedia server generating a plurality of pointers, each pointer being associated with a different data stream, each pointer indicating memory locations from where data groups are retrieved to form the data stream associated therewith.

28. The system of claim 27 wherein a new pointer is generated every predetermined time period.

29. The system of claim 27 wherein said new pointer when generated indicates a memory location where the first one of said data groups is stored.

30. The system of claim 27 wherein each memory location is identified by a base memory address and a memory offset.

31. The system of claim 27 wherein each receiver is connected to the transmitter through a communications network.

32. The system of claim 31 wherein said communications network is a broadband network.

33. The system of claim 27 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

34. The system of claim 27 wherein each receiver is capable of generating at least a request for service alteration, said processing element effecting said service alteration in response to said request.

35. The system of claim 34 wherein said request is a request for fast-forwarding the selected event, said processing element causing a receiver requesting the fast-forwarding, which said receiver is currently receiving a selected data stream, to receive a second data stream, said second data stream representative of a version of the selected event having an earlier start time than said selected data stream.

36. The system of claim 34 wherein said request is a request for rewinding the selected event, said processing element causing a receiver requesting the rewinding, which said receiver is currently receiving a selected data stream, to receive a second data stream, said second data stream representative of a version of the selected event having a later start time than said selected data stream.

37. The system of claim 34 wherein said request is a request for a pause during the selected event, said processing element causing a receiver requesting said pause, which said receiver is currently receiving a selected data stream, to stop receiving said selected data stream, and causing recordation of a duration of said pause.

38. The system of claim 34 wherein said request is a request for restarting the selected event after a pause during the selected event, said processing element causing a receiver requesting the restart to receive a selected data stream, said selected data stream representative of a version of the selected event having a later start time than the last data stream which said receiver received, said later start time being a function of a duration of said pause.

39. The system of claim 27 wherein said selected event is a movie event.

40. The system of claim 39 wherein each data group contains data representative of a predetermined number of frames in the movie event.

41. A method for providing multimedia events comprising the steps of:

storing a plurality of data groups at different memory locations in a memory, said data groups representative of a selected multimedia event;

retrieving data groups from said memory;

providing a plurality of data streams;

each data stream representative of a version of the selected multimedia event starting at a different time; and

generating a plurality of pointers, each pointer being associated with a different data stream, each pointer indicating memory locations from where data groups are retrieved to form the data stream associated therewith.

42. The method of claim 41 wherein a new pointer is generated every predetermined time period.

43. The method of claim 42 wherein said new pointer when generated indicates a memory location where the first one of said data groups is stored.

44. The method of claim 41 wherein each data stream is provided to at least one receiver capable of deriving the selected event from the data stream.

45. The method of claim 41 wherein each memory location is identified by a base memory address and a memory offset.

46. The method of claim 41 wherein said selected event is a movie event.

47. The method of claim 46 wherein each data group contains data representative of a predetermined number of frames in the movie event.

48. The method of claim 41 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

49. A method for providing a selected multimedia event to a plurality of receivers comprising the steps of:

providing a plurality of data streams, each data stream representative of a version of said selected multimedia event having a different start time, number of said data streams being a function of number of versions of said selected multimedia event which are currently received by said receivers;

assigning each data stream to at least one receiver;

receiving from a receiver at least a request for service alteration; and

effecting said service alteration in response to said request, the effecting step including the step of removing from said receiver the assignment of the data stream assigned thereto.

50. The method of claim 49 wherein said request is a request for fast-forwarding the selected event, and wherein said effecting step further includes the step of assigning to said receiver a second data stream, said second data stream representative of a version of the selected event having an earlier start time than the data stream previously assigned to said receiver.

51. The method of claim 49 wherein said request is a request for rewinding the selected event, and wherein said effecting step further includes the step of assigning to said receiver a second data stream, said second data stream representative of a version of the selected event having a later start time than the data stream previously assigned to said receiver.

52. The method of claim 49 wherein said request is a request for a pause during the selected event, and wherein said effecting step further includes the step of recording a duration of said pause.

53. The method of claim 49 wherein said request is a request for restarting the selected event after a pause during the selected event, and wherein said effecting step further includes the step of assigning to said receiver a selected data stream, said selected data stream representative of a version of the selected event having a later start time than the last data stream which said receiver received, said later start time being a function of a duration of said pause.

54. The method of claim 49 wherein said selected event is a movie event.

55. The method of claim 49 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

56. A method for providing multimedia events to a plurality of receivers comprising:

a first step of performing a plurality of first processes to provide said receivers with a selected multimedia event, said first step including the step of storing, in each first process, first data partially representative of the selected event in a buffer element;

a second step of performing a second process, said second step further comprising the steps of;

storing, in a memory, at a plurality of memory locations second data representative of the selected event in its entirety; and

reading said second data from said memory starting at different memory locations to provide a plurality of data streams; and

a third step of switching said plurality of first processes into said second process upon detection of a predetermined condition, said switching step including the step of assigning said data streams to said receivers.

57. The method of claim 56 wherein said buffer element includes two individual buffers, and wherein said first step further includes the steps of writing ones of the first data to said buffer element, and reading the other ones of the first data from said buffer element, in such a way that while said ones of the first data is read from one of the buffers, said other ones of the first data is written to the other buffer.

58. The method of claim 57 wherein said two individual buffers are equal in size.

59. The method of claim 56 further comprising the step of generating a plurality of pointers, each pointer being associated with a different one of said data streams, each pointer indicating memory locations of said memory where ones of said second data are read to form the data stream associated therewith.

60. The method of claim 59 wherein each memory location is identified by a base memory address and a memory offset.

61. The method of claim 56 wherein said predetermined condition is a function of limits of capacities of elements supporting said apparatus.

62. The method of claim 61 wherein said limits include limited bandwidth of a network connecting said receivers.

63. The method of claim 61 wherein said limits include a limited rate of retrieval of said first data from a storage device comprising said first data.

64. The method of claim 56 wherein said selected event is a movie event.

65. The method of claim 64 wherein said second data is assembled in data groups each representative of a predetermined number of frames in the movie event.

66. The method of claim 56 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

67. A method for use in a system for serving multimedia events, said system comprising a plurality of receivers, said method comprising the steps of:

storing in a memory a plurality of data groups at different memory locations, said data groups representative of a selected multimedia event;

retrieving data groups from said memory;

providing a plurality of data streams to said receivers, each data stream representative of a version of the selected multimedia event starting at a different time;

receiving in each receiver one of said plurality of data streams;

deriving in each receiver the selected event from the received data stream; and

generating a plurality of pointers, each pointer being associated with a different data stream, each pointer indicating memory locations from where data groups are retrieved to form the data stream associated therewith.

68. The method of claim 67 wherein a new pointer is generated every predetermined time period.

69. The method of claim 67 wherein said new pointer when generated indicates a memory location where the first one of said data groups is stored.

70. The method of claim 67 wherein each memory location is identified by a base memory address and a memory offset.

71. The method of claim 67 wherein each data stream is provided in an asynchronous transfer mode (ATM) format.

72. The method of claim 67 further comprising the steps of generating in a receiver at least a request for service alteration, and effecting said service alteration in response to said request.

73. The method of claim 72 wherein said request is a request for fast-forwarding the selected event, and wherein said effecting step includes the step of causing said receiver, which is currently receiving a selected data stream, to receive a second data stream, said second data stream representative of a version of the selected event having an earlier start time than said selected data stream.

74. The method of claim 72 wherein said request is a request for rewinding the selected event, and wherein said effecting step includes the step of causing said receiver, which is currently receiving a selected data stream, to receive a second data stream, said second data stream representative of a version of the selected event having a later start time than said selected data stream.

75. The method of claim 72 wherein said request is a request for a pause during the selected event, and wherein said effecting step includes the step of causing said receiver, which is currently receiving a selected data stream, to stop receiving said selected data stream, and the step of recording a duration of said pause.

76. The method of claim 72 wherein said request is a request for restarting the selected event after a pause during the selected event, and wherein said effecting step includes the step of causing said receiver to receive a selected data stream, said selected data stream representative of a version of the selected event having a later start time than the last data stream which said receiver received, said later start time being a function of a duration of said pause.

77. The method of claim 67 wherein said selected event is a movie event.

78. The method of claim 77 wherein each data group contains data representative of a predetermined number of frames in the movie event.