US 5,720,037 AGranted

Multimedia on-demand server

AssigneeLucent Technologies Inc.

InventorsAlexandros Biliris, Banu Ozden, Rajeev Rastogi, Abraham Silberschatz

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Abstract

A multimedia on-demand server including a randomly accessible library of multimedia programs (such as movies stored on magnetic or optical disks), a limited amount of RAM to buffer and store selected portions of programs retrieved from the library, and an interface that switchably routes program material from the library and RAM buffers to an audience of viewers. The server employs a restricted retrieval strategy and a novel storage allocation scheme that enable different portions of one or more programs to be continuously retrieved and selectively routed to a large number of on-demand viewers, while at the same time minimizing the amount of the RAM required to effect this service. The on-demand server also responds to viewer-generated commands to control the viewing of a program. In a particular embodiment, these commands include video tape player-like operations such as fast-forward, rewind and pause.

Claims36

Dependent claims

A multimedia server comprising:

an addressable memory media including a first addressable memory device and a second addressable memory device where the first addressable memory device has a latency of t.sub.lat1 and a data transfer rate r.sub.t, said first addressable memory device being adapted for storing program information in plurality of sequential data segments, where each of said data segments is partitioned into n portions with each of said portions having d bits of information such that each of said data segments contains (n.multidot.d) bits;
the second addressable memory device having a data transfer rate of r.sub.t and a latency of t.sub.lat2, said second addressable memory device being adapted for storing program information of duration t.sub.lat1 in plurality of sequential data segments, where each of said data segments contains (n.multidot.d) bits and where t.sub.lat2 <<t.sub.lat1 such that the stored information can be completely retrieved from the second addressable memory device within a time period that is less than t.sub.lat1 and
a plurality of buffer memories, each dedicated to continually relaying the data contained within one of said sequential data segments to a communication network, wherein each of said buffer memories receives d bits of program information from a particular one of said sequential data segments at a rate r.sub.t from said addressable memory media, stores said received d bits of information, and then transfers said stored d bits of information to said communication network at a rate r.sub.d, while simultaneously receiving, at a rate r.sub.t, from said addressable memory media, another d bits of program information associated with said particular one of said sequential data segments.

A multimedia server system comprising:

an addressable memory media including a first addressable memory device having a latency of t.sub.lat1 and a data transfer rate of r.sub.t, said first addressable memory device being adapted for storing program information in plurality of sequential data segments, where each of said data segments is partitioned into n portions with each of said portions having d bits of information such that each of said data segments contains (n.multidot.d) bits, and a second addressable memory device having a data transfer rate of r.sub.t and a latency of t.sub.lat2, said second addressable memory device being adapted for storing program information of duration t.sub.lat1 in plurality of sequential data segments, where each of said data segments contains (n.multidot.d) bits and where t.sub.lat2 <<t.sub.lat1 such that the stored information can be completely retrieved from the second addressable memory device within a time period that is less than t.sub.lat1 and
a plurality of buffer memories, each dedicated to continually relaying the data contained within one of said sequential data segments to a switching system, wherein each of said buffer memories receives d bits of program information from a particular one of said sequential data segments at a rate r.sub.t from said addressable memory media, stores said received d bits of information, and then transfers said stored d bits of information to said switching system at a rate r.sub.d, while simultaneously receiving, at a rate r.sub.t, from said addressable memory media, another d bits of program information associated with said particular one of said sequential data segments, said switching system being adapted to selectively connect one or more of said plurality of buffer memories with at least one data interface that is adapted to receive and decode the program information output by said plurality of buffer memories.

A multimedia server system comprising:

an addressable memory media including a first addressable memory device having a latency of t.sub.lat1 and a data transfer rate of r.sub.t, said first addressable memory device being adapted for storing program information in plurality of sequential data segments, where each of said data segments is partitioned into n portions with each of said portions having d bits of information such that each of said data segments contains (n.multidot.d) bits, and a second addressable memory device having a data transfer rate of r.sub.t and a latency of t.sub.lat2, said second addressable memory device being adapted for storing program information of duration t.sub.lat1 in plurality of sequential data segments, where each of said data segments contains (n.multidot.d) bits and where t.sub.lat2 <<t.sub.lat1 such that the stored information can be completely retrieved from the second addressable memory, device within a time period that is less than t.sub.lat1 and
a plurality of buffer memories, each dedicated to continually relaying the data contained within one of said sequential data segments to a programmable switching system, wherein each of said buffer memories receives d bits of program information from a particular one of said sequential data segments at a rate of r.sub.t from said addressable memory media, stores said received d bits of information, and then transfers said stored d bits of information to said programmable switching system at a rate r.sub.d, while simultaneously receiving, at a rate r.sub.t from said addressable memory media, another d bits of program information associated with said particular one of said sequential data segments, said programmable switching system being adapted to selectively connect one or more of said plurality of buffer memories with at least one data interface in response to viewer generated commands, said data interface being adapted to receive and decode the program information output by said plurality of buffer memories, and said data interface being further adapted to receive said viewer generated commands and transmit said commands to said programmable switching system.

A multimedia server system comprising:

an addressable memory media including a magnetic disk having a latency of t.sub.lat1 and a data transfer rate of r.sub.t, said magnetic disk being adapted for storing information representative of a video signal in plurality of sequential data segments, where each of said data segments is partitioned into n portions with each portion having d bits such that each of said data segments contains (n.multidot.d) bits, and a random access semiconductor memory having a data transfer rate of r.sub.t and a latency of t.sub.lat2, said random access semiconductor memory being adapted for storing information representative of a video signal of duration t.sub.lat1 in plurality of sequential data segments, where each of said data segments contains (n.multidot.d) bits and where t.sub.lat2 <<t.sub.lat1 such that the stored information can be completely retrieved from the second addressable memory device during a time period that is less than t.sub.lat1 and
a plurality of buffer memories, each dedicated to continually relaying the data contained within one of said sequential data segments to a programmable switching system, wherein each of said buffer memories receives d bits of information representative of a video signal from a particular one of said sequential data segments at a rate of r.sub.t from said addressable memory media, stores said received d bits of information, and then transfers said stored d bits of information to said programmable switching system at a rate r.sub.d, while simultaneously receiving, at a rate r.sub.t from said addressable memory media, another d bits of information associated with said particular one of said sequential data segments, said programmable switching system being adapted to selectively connect one or more of said plurality of buffer memories with at least one data interface in response to viewer commands, said data interface being adapted to receive and decode the program information output by said plurality of buffer memories, and said data interface being further adapted to receive said viewer commands and transmit said viewer commands to said programmable switching system.

In a multimedia server system comprising:

an addressable memory media including a first addressable memory device having a latency of t.sub.lat1 and a data transfer rate of r.sub.t, said first addressable memory device being adapted for storing program information in plurality of sequential data segments, where each of said data segments contains (n.multidot.d) bits;
a second addressable memory device having a data transfer rate of r.sub.t and a latency of t.sub.lat2, said second addressable memory device being adapted for storing program information of duration t.sub.lat1 in plurality of sequential data segments, where t.sub.lat2 <<t.sub.lat1 such that the stored information can be completely retrieved from the second addressable memory during a time period that is less than t.sub.lat1 and where each of said data segments is partitioned into n portions with each portion having d bits of information such that each of said data segments contains (n.multidot.d) bits;
and
a plurality of buffer memories, each dedicated to continually relaying the data contained within one of said sequential data segments to a programmable switching system, wherein each of said buffer memories receives d bits of program information from a particular one of said sequential data segments at a rate of r.sub.t from said addressable memory media, stores said received d bits of information, and then transfers said stored d bits of information to said programmable switching system at a rate r.sub.d, while simultaneously receiving, at a rate r.sub.t form said addressable memory media, another d bits of programming information associated with said particular one of said sequential data segments, said programmable switching system being adapted to selectively connect one or more of said plurality of buffer memories with at least one requesting viewer in response to viewer generated commands;
a method for retrieving multimedia information, comprising the steps of:
receiving a viewer generated command requesting particular information stored within said addressable memory means;
establishing a connection between at least one of said buffer memories and said requesting viewer in response to said received viewer generated command, and
transmitting to said requesting viewer at least one data segment associated with said requested information via a particular one of said buffer memories and said programmable switching system.

5 more elements

In a multimedia server system comprising:

an addressable memory media including a magnetic disk having a latency of t.sub.lat1 and a data transfer rate of r.sub.t, said magnetic disk being adapted for storing information representative of a video signal in plurality of sequential data segments, where each of said data segments is partitioned into n portions with each portion having d bits of information such that each of said data segments contains (n.multidot.d) bits, and a random access semiconductor memory having a data transfer rate of r.sub.t and a latency t.sub.lat2, said random access semiconductor memory being adapted for storing information representative of a video signal of duration t.sub.lat1 in plurality of sequential data segments, where each of said data segments contains (n.multidot.d) bits and where t.sub.lat2 <<t.sub.lat1, such that the stored information can be completely retrieved from the second addressable memory during a time period that is less than t.sub.lat1 and
a plurality of buffer memories, each dedicated to continually relaying the data contained within one of said sequential data segments to a programmable switching system, wherein each of said buffer memories receives d bits of program information from a particular one of said sequential data segments at a rate of r.sub.t from said addressable memory media, stores said received d bits of information, and then transfers said stored d bits of information to said programmable switching system at a rate r.sub.d, while simultaneously receiving, at a rate r.sub.t form said addressable memory media, another d bits of programming information associated with said particular one of said sequential data segments, said programmable switching system being adapted to selectively connect one or more of said plurality of buffer memories with at least one requesting viewer in response to viewer generated commands;
a method for retrieving multimedia information, comprising the steps of:
receiving a viewer generated command requesting information representing a particular video signal stored within said addressable memory means;
establishing a connection between at least one of said buffer memories and said requesting viewer in response to said received viewer generated command, and
transmitting to said requesting viewer at least one data segment associated with said requested information via a particular one of said buffer memories and said programmable switching system.

3 more elements

Dependencies are inferred from the claim text.