Distributed cooperative memory for interactive and scalable video-on-demand system

• US 20030093803A1
• Filed: 09/25/2002
• Published: 05/15/2003
• Est. Priority Date: 03/28/2000
• Status: Active Grant

• Current Assignee: Coppe/Ufrj-Coordenacao Dos Programas de POS Graduacao de Engenharia Da Universidade Federal Do Rio de Janeiro
• Original Assignee: Coppe/Ufrj-Coordenacao Dos Programas de POS Graduacao de Engenharia Da Universidade Federal Do Rio de Janeiro
• Inventors: Ishikawa, Edison, Amorim, Claudio Luis
• Granted Patent: US 7,913,282 B2
• Time in Patent Office: Days
• US Class Current: 725/94
• 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 21/4331 Caching operations, e.g. of an advertisement for later insertion during playback
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/4788 communicating with other users, e.g. chatting arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 21/632 using a connection between clients on a wide area network, e.g. setting up a peer-to-peer communication via Internet for retrieving video segments from the hard-disk of other client devices broadcast-related systems characterised by transmission among terminal devices H04H60/80; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/64322 IP
• 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
• CPC Class Codes: H04N 7/17354 in an intermediate station common to a plurality of user terminals

Abstract

A method is disclosed to improve the scalability of Video on Demand Systems with VCR functions using the client buffers in a cooperative way.

Claims

1. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

characterized by, a centralized method to manage the contents of the client buffers of a Video-on-Demand system, comprising a DCM manager that will receive requests and client notifications, maintaining a table with these client information to calculate the frames that are in the client buffers, or simply clients, a DCM manager that on receiving a request or notification will update the client table, clients that will cooperate with the DCM manager, making available the movie portions that are in their buffers and clients that will reply to the DCM manager requests to send one or more video flows to other clients, obeying the transmission speed and amount of frames specified by the DCM manager, clients that will notify the DCM manager whenever some operation has been accomplished or when something of abnormal happens, such as the buffer level is below or above the work level, clients that always have available a table with the frames that are in their buffers and their positions in the buffers, aiming to answer the DCM manager requests, clients that have supplementary buffers for the use of the DCM VoD system.

4. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

wherein the system of claim 1, 2 and 3 characterized by, a method of fast access to movie portions for fast forward and rewind, with movie visualization using client buffers, comprising, sending movie portions that are necessary to accelerated exhibition (rewind or fast forward), with video bursts or in parallel which are sent by client buffers, the way the DCM manager discovers the buffers that have the requested movie portions, i.e., calculating through the time of initialization of the film the frames that are in the buffer, using the film table to obtain the size of the frames that compose the movie portion that can fit in the client buffer, the form through which the DCM manager discovers the buffers that have the requested movie portions, i.e., calculating through the time initialization of the video the frames that are in the buffer, using for this the video average transmission rate, a fast way to discover the next buffer, to order the video burst through the use of the buffer chain, i.e., if a buffer ordered all of its contents and what comes to proceed it comes from another buffer, it verifies in the table the next buffer and it concatenates the transmission of all of the video bursts or it transmits its video contents in parallel, the use of the supplements to store movie portions in a static or dynamic ways to provide fast access.

5. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

wherein the system of claim 1, 2 and 3 characterized by, a method that allows the implementation of VCR functions in a video-on-demand systems in a economical and scalable manner, comprising a client that, in a pause operation, if it is the last element of the chain, notify the DCM manage so that it ceases the video flow, when the buffer reaches its maximum level of work it updates the client table, with the initial and final frame in its buffer, so that this movie portion can be used by other clients when necessary, in a pause operation, if it is in the middle of the chain, to notify the DCM manager so that it can provide a new flow, for the client(s) that is(are) ahead and while DCM takes providence for that to continue sending what remains in its buffer for the client(s) that is (are) ahead, in a resume operation, to notify the DCM manager so that it can provide a requested flow and meanwhile consuming the contents of its buffer while being prepared to receive a video burst with the missing movie portion to complete the sequence of its contents and the video flow that it will receive, in the fast forward and rewind, notify the DCM manager so it can provide the video bursts with the necessary movie portions for fast exhibition, in the fast forward and rewind without exhibition, notify the DCM manager DCM so it can provide a flow starting from the requested frame.

6. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, comprise a method to solve the problem of a buffer leaving the chain without informing it, provided that when a buffer is below its minimum level of work, it notifies the DCM manager so it can provide another flow source.

7. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, a method to increase safety'"'"'s margin, to guarantee the quality of presentation of the video without stops in the exhibition, understanding that when a buffer is below its minimum level of work, it notifies the DCM manager so that it can provide another flow source.

8. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, a method to build a tree of chains that minimizes the traffic in the communication network backbone, comprising a table in the DCM manager with the place information, a DCM manager uses the place information to build a tree that minimizes the traffic in the backbone.

9. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, servers distributed geographically or with servers in clusters.

10. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, to just use unicast to emulate a multicast.

11. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, video flows with constant transmission rate and/or video flows with variable transmission rate.

12. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, frames with constant size or frames with variable size.

13. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by, to just use the standard buffer and/or to just use the supplementary buffer.

14. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by to use a compressed video stream (MPEG1, MPEG2, MPEG4 or MJPEG or not, in cryptogram or not, using from low resolution video up to high definition standards like HDTV.

15. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

in agreement with the claims 1,2,3,4 and 5 characterized by to use a video frame or a group of video frames as a work unit.

2. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

characterized by, a distributed method to manage the contents of the client buffers of a Video-on-Demand system, comprising, a client that cooperates with the group by sending requests of frames for multicast when necessary, a client that cooperates with the group when receiving requests of frames by multicast and has them in its buffer, sending them to the requester, the use of multicast within the group to request a video flow starting at certain frame and sending this video flow through a client buffer.

3. “

DISTRIBUTED COOPERATIVE MEMORY FOR INTERACTIVE AND SCALABLE VoD SYSTEM”

characterized by, a distributed method to manage the contents of the client buffers of a Video-on-Demand system, comprising, a client who knows where comes from the flow it is receiving and to where it is sending a flow, even in relation to the standard buffer as to the supplementary buffer. A client that knows how to communicate with other clients, to ask where it is sending a video flow or from whom it is receiving a video flow, an intelligent client that using the capacities described above, knows how to walk through the chain trees, with the goal of locating the movie portion that is necessary to execute the operation, avoiding frequent access to the DCM manager and therefore avoiding overload the DCM manager, a client that when executing the video-cassette operations using the chain trees, maintain the DCM manager informed about the final state of the operation.