Method and apparatus for implementing seamless playback of continuous media feeds

• US 6,138,147 A
• Filed: 10/22/1997
• Issued: 10/24/2000
• Est. Priority Date: 07/14/1995
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Oracle Corporation
• Inventors: Weaver, Daniel, Pawson, David J.
• Primary Examiner(s): Lim, Krisna
• Application Number:
  US08/956,262
• Time in Patent Office: 1,098 Days
• Field of Search: 709/203, 709/206, 709/236, 707/104
• US Class Current: 709/206
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/415 Redundant array of inexpensive disks [RAID] systems
• CPC Class Codes: G11B 27/031 Electronic editing of digitised analogue information signals, e.g. audio or video signals
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• 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 21/23113 involving housekeeping operations for stored content, e.g. prioritizing content for deletion because of storage space restrictions storage management, e.g. defragmentation G06F3/0604; snloading stored programs G06F9/445; housekeeping operations in file systems, e.g. deletion policies G06F16/10; buffering arrangements in a network node or in an end terminal in packet networks H04L49/90
• CPC Class Codes: H04N 21/2318 using striping
• CPC Class Codes: H04N 21/232 Content retrieval operation locally within server, e.g. reading video streams from disk arrays storage management G06F3/0604; details of querying and searching of video data from a database G06F16/739
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/236 Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream multiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/23805 Controlling the feeding rate to the network, e.g. by controlling the video pump
• 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 21/2393 involving handling client requests scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/25808 Management of client data terminal profiles in network data switching protocols H04L67/303
• CPC Class Codes: H04N 21/2625 for delaying content or additional data distribution, e.g. because of an extended sport event
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/434 Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/435 Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
• 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 21/6377 : directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/658 : Transmission by the client directed to the server
• CPC Class Codes: H04N 21/6587 : Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 21/8455 : involving pointers to the content, e.g. pointers to the I-frames of the video stream
• CPC Class Codes: H04N 21/8547 : involving timestamps for synchronizing content
• CPC Class Codes: H04N 21/8549 : Creating video summaries, e.g. movie trailer retrieval in video databases by using presentations in form of a video summary G06F16/739
• CPC Class Codes: H04N 7/17336 : Handling of requests in head-ends
• CPC Class Codes: Y10S 707/99945 : Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99948 : Application of database or data structure, e.g. distributed, multimedia, or image

Abstract

A method and system for storing a continuous feed of video is provided. According to one aspect of the invention, the continuous feed is encoded in a digital video format to produce a digital data stream. A series of content files is created by repeatedly performing the steps of (1) storing the digital data stream in a current file, and (2) establishing a new file as the current file when the current file satisfies a predetermined condition. If the series of content files contains more than a predetermined amount of the continuous feed, the oldest content file in the series of content files is deleted. Tag information that indicates information about frames contained in the digital data stream is generated. The tag information includes timestamps that indicate timing of frames relative to a beginning of the digital data stream. An initial time value that indicates an absolute time that corresponds to the beginning of the digital data stream. When a request from a client for playback beginning at a specified absolute time is received, the initial time value is subtracted from the specified absolute time to determine a relative time. The tag information is used to identify a location in the digital data stream that corresponds to the relative time. The digital data stream is then transmitted to the client beginning at the location in the digital data stream that corresponds to the relative time.

Claims

1. A method for storing a continuous feed of video, the method comprising the steps of:

receiving a digital data stream produced by encoding said continuous feed in a digital video format;

creating a series of content files by repeatedly performing the steps of;

storing said digital data stream in a current file; and

establishing a new file as said current file when said current file satisfies a predetermined condition;

if said series of content files contains more than a predetermined amount of said continuous feed, then deleting an oldest content file in said series of content files.

2. The method of claim 1 further comprising the steps of:

determining whether any reader is currently playing information from said oldest content file, and

delaying the step of deleting if a reader is currently playing information from

said oldest content file.

3. The method of claim 2 wherein the step of delaying is performed by delaying the step of deleting until either:

a predetermined period of time has elapsed;

or

no readers are currently playing information from said oldest content file.

4. The method of claim 1 wherein, if said series of content files contains more than a predetermined amount of said continuous feed, then preventing new readers from beginning to access data from said oldest content file in said series of content files.

5. The method of claim 1 wherein the step of establishing a new file as said current file when said current file satisfies a predetermined condition includes the step of establishing a new file as said current file when said current file contains a second predetermined amount of said continuous feed.

6. The method of claim 1 further comprising the step of generating and storing tag information that indicates information about frames contained in said digital data stream.

7. The method of claim 6 wherein the step of storing tag information includes the steps of:

generating a first header for a first tag file;

storing tag information sequentially in said first tag file;

when a set of tags within said first tag file becomes invalid, performing the steps of

generating a second header for a second tag file;

copying all tags in said first tag file, except said set of tags, from said first tag file to said second tag file;

storing new tag information sequentially within said second tag file; and

deleting said first tag file.

8. The method of claim 7 wherein the step of deleting said first tag file comprises the step of renaming said second tag file over said first tag file.

9. A method for providing non-sequential access to video from a continuous feed, the method comprising the steps of:

receiving a digital data stream produced by encoding said continuous feed in a digital video format;

generating tag information that indicates information about frames contained in said digital data stream, said tag information including timestamps that indicate timing of frames relative to a beginning of said digital data stream;

storing an initial time value that indicates an absolute time that corresponds to said beginning of said digital data stream;

receiving a request from a client for playback beginning at a specified absolute time;

subtracting said initial time value from said specified absolute time to determine a relative time;

using said tag information to identify a location in said digital data stream that corresponds to said relative time; and

transmitting said digital data stream to said client beginning at said location in said digital data stream that corresponds to said relative time.

10. The method of claim 9 wherein:

said digital data stream includes timestamp values having a first precision; and

said step of generating tag information includes generating timestamp values that have a second precision, wherein said second precision is higher than said first precision.

11. A computer-readable medium having stored thereon sequences of instructions for storing a continuous feed of video, the sequences of instructions comprising instructions for performing the steps of:

receiving a digital data stream produced by encoding said continuous feed in a digital video format;

creating a series of content files by repeatedly performing the steps of;

storing said digital data stream in a current file; and

establishing a new file as said current file when said current file satisfies a predetermined condition;

if said series of content files contains more than a predetermined amount of said continuous feed, then deleting an oldest content file in said series of content files.

12. The computer-readable medium of claim 11 further comprising sequences of instructions for performing the steps of:

determining whether any reader is currently playing information from said oldest content file, and

delaying the step of deleting if a reader is currently playing information from said oldest content file.

13. The computer-readable medium of claim 12 wherein the step of delaying is performed by delaying the step of deleting until either:

a predetermined period of time has elapsed;

or

no readers are currently playing information from said oldest content file.

14. The computer-readable medium of claim 11 wherein, if said series of content files contains more than a predetermined amount of said continuous feed, then preventing new readers from beginning to access data from said oldest content file in said series of content files.

15. The computer-readable medium of claim 11 wherein the step of establishing a new file as said current file when said current file satisfies a predetermined condition includes the step of establishing a new file as said current file when said current file contains a second predetermined amount of said continuous feed.

16. The computer-readable medium of claim 11 further comprising sequences of instructions for performing the step of generating and storing tag information that indicates information about frames contained in said digital data stream.

17. The computer-readable medium of claim 16 wherein the step of storing tag information includes the steps of:

generating a first header for a first tag file;

storing tag information sequentially in said first tag file;

when a set of tags within said first tag file becomes invalid, performing the steps of

generating a second header for a second tag file;

copying all tags in said first tag file, except said set of tags, from said first tag file to said second tag file;

storing new tag information sequentially within said second tag file; and

deleting said first tag file.

18. The computer-readable medium of claim 17 wherein the step of deleting said first tag file comprises the step of renaming said second tag file over said first tag file.

19. A system for delivering a continuous feed of video, the system comprising:

one or more storage devices;

a video server that stores said continuous feed of video in a series of files on said one or more storage devices;

a threshold detection mechanism configured to detect when said series of files holds more than a predetermined threshold amount of said continuous feed; and

an expiration mechanism that deletes an oldest file of said series of files in response to said threshold detection mechanism detecting that said series of files holds more than said predetermined threshold amount of said continuous feed.

20. The system of claim 19 further comprising a detection mechanism configured to detect whether any reader is currently accessing said oldest file, wherein said expiration mechanism is configured to delay deletion of said oldest file if any reader is currently accessing said oldest file.