EP1442588A2

EP1442588A2 - Digital video recording and reproduction system and method suitable for live-pause playback utilizing intelligent buffer memory allocation

Info

Publication number: EP1442588A2
Application number: EP02789336A
Authority: EP
Inventors: Carlton J. Sparrell; Gordon Landis; David F. Lively; Alexander Vasilevsky
Original assignee: Ucentric Holdings Inc
Current assignee: Arris Technology Inc
Priority date: 2001-11-07
Filing date: 2002-10-31
Publication date: 2004-08-04
Also published as: EP1442588A4; WO2003041387A3; WO2003041387A2; AU2002353935A1

Abstract

A Digital Video Recording (DVR) system (100) and method (200) obviates the need for prior art circular video buffers and their associated problems by using information from a Program Guide Service (102) to specify an appropriate length buffer. As a result, older portions of a program are not erased because of buffer size limitation, and system resources are not inefficiently allocated for small programs. The invention is especially compatible with live-pause recording and playback. At the viewer/user's option any program being played back or recorded can be stored in long-term memory (118).

Description

DIGITAL VIDEO RECORDING AND REPRODUCTION SYSTEM

AND METHOD SUITABLE FOR LIVE-PAUSE PLAYBACK UTILIZING INTELLIGENT BUFFER MEMORY ALLOCATION

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application for Letters Patent is based on and claims pri¬

ority from Provisional Application Serial No. XX/YYY,YYY filed Novem¬

ber 7, 2001, entitled "Digital Video Recording System Supporting Concur¬

rent Playback Using Advanced Program Information" bearing attorney

docket reference "UCNTC/EPGDVR2," hereby incorporated by reference.

The present application also incorporates by reference, the following

other applications:

U.S. Patent Application Serial No. AA/BBB,BBB filed December 14, 2001, entitled "Centralized Digital Video Re- cording And Playback System Accessible To Multiple Reproduction And Control Units Via A Home Area Network" bearing attorney docket number UCN-009; U.S. Provisional Application Serial No. 60/327,627 filed October 5, 2001, entitled "Home Area Network Centralized Digi- tal Video Recorder;"

U. S . Provisional Application Serial Number 60/313 ,209 filed August 17, 2001, entitled "Delivering Multimedia Over Home Area Networks;" U.S. Provisional Application Serial Number 60/313,228 filed August 17, 2001, entitled "Web Services Provisioning Architecture;"

U.S. Provisional Application Serial Number 60/193,813 filed March 31, 2000, entitled "Home Area Network; and" U.S. Patent Application Serial Number 09/365,726 filed Au- gust 3, 1999, entitled "Multi-Service In-Home Network With an Open Interface." BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to digital recording and play-

back systems and methods. More particularly, the present invention relates

to improvements in system resource availability and efficacy for digital re¬

cording and playback systems and methods compatible with "live-pause," or

"elastic" recording/playback.

2. Background

Digital Video Recording and Playback systems are becoming more

commonplace with the advances in technology and the downward trend in

prices. Along with a playback quality that is superior to analog-based sys¬

tems, Digital Video Recorders (DVRs) also allow other features that are not

practical with analog-based systems. Among such features is the ability of a

DVR user to engage in "live-pause" recording and playback.

Also known as "elastic" recording and playback, live-pause recording

and playback allows a viewer/user with such an enabled system to watch a

program live in real time while the program is being recorded, while also al¬

lowing the user to use "trick play" modes or functions such as pausing the

program or rewinding the program. While the recorded program is being paused or rewound, the system continues to record the program in a buffer

memory. The system keeps track of where in memory the user has exited to

perform trick play functions. The user can later return to the previous point

of viewing in the program or skip with a "fast forward" operation up to the

most current point of recording. Live-pause recording and playback allows

the user the flexibility of watching a program live, already recorded, or a

combination of both live and recorded viewing, along with interesting trick

play modes.

Prior art DVRs utilize a fixed-length circular buffer memory to store

programs designated (by choice or by system default) for live-pause re¬

cording and playback. With a circular buffer, frame information (such as

frames of a television broadcast) is written consecutively into the buffer

memory until the end of the buffer memory is reached. Writing continues

by wrapping around to the beginning of the buffer memory and overwriting

as many consecutive memory locations as is needed. That is, when the

buffer is filled, the system begins recording over the oldest information in

the buffer.

This prior art approach is problematic on several fronts. Chiefly,

when a small circular buffer is chosen, this approach often leads to indis-

criminately and permanently erasing older program information that may be of long-term interest to a user. Alternatively, if a large circular buffer is

used, the system sometimes devotes much more memory space to smaller

programs than is actually needed, causing an inefficient use of limited sys¬

tem resources that could be freed up for other tasks.

The Applicants of this Letters Patent note the following U.S. Patent

numbers as being generally related to live-pause Digital Video Recording,

but having the same problems identified above with respect to circular buff¬

ers: RE 36,801; 5,241,428 and 5,329,320. The following U.S. Patents are

noted as being generally relevant to live-pause recording and playback:

6,233,389 and 5,241,428.

What is desired, but absent in the prior art, and therefore of focus in

this Letters Patent, is a Digital Video Recording system and method capable

of live-pause recording and playback without the drawbacks of circular

buffers.

SUMMARY OF THE INVENTION

In view of the aforementioned problems and deficiencies of the prior

art, the present invention provides a digital video recording and playback

method adapted for "live-pause" recording and playback. The method at

least includes the steps of providing at least one electronic audio-visual pro-

gram source, via a program guide source, at least providing program length information about a program of interest, and converting the program length

information into a corresponding buffer memory size. The method also at

least includes the steps of establishing a buffer memory matching the buffer

memory size determined, and recording a selected program in the buffer

memory established. The buffer memory size matches the size needed to

record the program of interest.

The present invention also provides a digital video recording and

playback system adapted for "live-pause" recording and playback. The sys¬

tem at least includes an electronic audio-visual program source, a program

guide source adapted to at least provide program length information about a

program of interest, and a converter adapted to convert the program length

information into a corresponding buffer memory size. The system further at

least includes at least one buffer memory established and sized to match that

determined by the converter, the buffer memory being adapted to record a

selected program. The buffer memory size matches the size needed to re¬

cord a program of interest.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Features and advantages of the present invention will become appar¬

ent to those skilled in the art from the description below, with reference to

the following drawing figures, in which: Figure 1 is a schematic block diagram of the present-inventive digital

video recording and playback system; and

Figure 2 is a flowchart detailing the present-inventive method for digi¬

tal video recording and playback.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present-inventive digital video recording and playback system

and method obviates the need for circular buffers by the "intelligent" estab¬

lishment of buffers having sizes matching the requirements of programs of

interest, so that it is not necessary to record over portions of the same buffer

for a single program. It is also not necessary to devote a buffer having con¬

siderably more size than is needed for programs of interest. To establish a

buffer of the appropriate size, the system novelly utilizes information from a

program guide service about the start and end times of a currently viewed

program to determine the size of the buffer needed (via a record/playback

service in the preferred embodiment). A video manager establishes a buffer

in the memory area of the system matching the size requirements.

A general schematic diagram of the present-inventive digital video re¬

cording and reproduction system 100 is shown in Figure 1. A program

guide service 102 obtains information used by the system to construct an

electronic program guide (EPG) to present details about programs to the sys- tern and to viewers in the form of a graphical user interface. In the preferred

embodiment, the program guide service 102 obtains programming informa¬

tion via a broadband or wide area network (WAN) connection to a host

computer. Those skilled in the art will appreciate that the programming in-

formation can be obtained through other types of connections, such as, inter

alia, a cable MODEM, xDSL, POTS MODEM, satellite, and fixed terrestrial

wireless.

For programs to be viewed and reproduced by the system 100, the

program guide service provides information such as the program name, start

and end times, channel designation, and additional information about the

program such as the program rating, and a program synopsis. In an alterna¬

tive system, the program guide information can be delivered in a different

manner, such as in the video program stream as is known in the art. That is,

along with the other audio and video information representing a television

channel, for example, headers and other program description information

can be included (e.g., program description information can be inserted in the

vertical blanking interval of an NTSC television signal).

Information from the program guide service 102 is provided to a user

interface 104 and a record/playback service 106. Accessible via a keyboard,

an infrared remote control device, a pointing device such as a "mouse," or other input means, the user interface is responsible for allowing the user to

direct the operation of the system, as well as allowing the user to view in¬

formation regarding the system operation. The user interface is also respon¬

sible for generating a graphical user interface containing an electronic pro-

gram guide to be generated for display, based upon the program guide in¬

formation, and input from the record/playback service (e.g., icons represent¬

ing recording and playback statuses).

The record/playback service 106 controls the recording and playback

of programs. Under the direction of the user interface 104 and utilizing pro-

gram guide information, the record/playback service 106 establishes buffers

of the appropriate size for recording programs. For example, if during a

live-pause situation, a viewer begins watching an hour-long program at the

scheduled start of the program, a buffer memory capable of storing a one-

hour program is designated. However, if the user begins viewing an hour-

long program ten minutes after its start, the record/playback service 106 de¬

termines that the buffer will need enough capacity to record a fifty-minute

television program. The record/playback service 106 is also responsible for

releasing a buffer memory area for overwriting when the buffer is no longer

needed. This occurs either at the direction of the user, when the user

changes the channel during live-pause recording and playback, or when a buffer stores the oldest program and new buffer memory space is needed to

store new programs. Finally, the record/playback service handles traditional

timer recording common to most video recording systems.

The program signals are delivered to a video manager 116 via tuning

and demodulation circuits 110 and 112. The tuning and demodulation cir¬

cuit 110 tunes the system to the program channel of interest (under the direc¬

tion of the user interface 104 via the video manager 116), and then demodu¬

lates the signal in a manner known in the art. The program signal in this ex¬

ample is a digital television signal. The system 100 is also capable of re-

ceiving analog program signals (such as in the NTSC format), and tuning

and demodulating them with the tuning and demodulating circuit 112.

The analog content signal need not initially be in a modulated form, as

in the example, but may be unmodulated, in which case the tuning and de¬

modulation circuit 112 is bypassed. Such an unmodulated analog content

signal may be coupled to the system 100 via an "S-video" jack. Similarly,

the digital content signal can be received either in a modulated form, or an

unmodulated form (such as a straight ATSC stream), which for the latter

case, the tuning and demodulation circuit 110 is bypassed. It should be ap¬

preciated by those skilled in the art that more than one tuning and demodu- lating circuit for a given type of signal (e.g., digital or analog) can be incor¬

porated without departing from the spirit of the present invention.

As the video manager 116 in the preferred embodiment is configured

to receive a compressed, digitally formatted signal, the output of the circuit

112 is also passed through a video encoder 114. Those skilled in the art will

appreciate that the program signals handled by the video manager 116 can

be encoded using one or more of the Motion Picture Experts Group (MPEG)

digital video standards, as well as others.

In addition to controlling program channel tuning, the video manager

116 also controls the operation of the encoder 114, and controls the direct

allocation and releasing of buffer memories in the system memory 118, as

well as managing, under the direction of the record/playback service 106, the

writing and retrieving (and the manner of writing and retrieving, such as the

recording and playback speeds and trick play modes) of program informa-

tion to the actual buffer memories and long-term memory.

A video decoder 120 performs the function of converting a digital

program signal to a form suitable for display on the system displays 124 and

126. The displays 124 and 126 can be any suitable ones, including, inter

alia, CRTs, projection screens, and solid state displays. Those skilled in the

art will appreciate that the exact method of decoding will depend on the na- ture of the encoding previously used. In the preferred embodiment, the pro¬

gram signals to be displayed are passed through the video manager, whether

they emanate directly from the tuning and demodulating circuits, or from

memory.

The system memory 118 can be of any suitable high-capacity variety,

whether or not moving components are integral to the operation thereof.

As an added security feature to prevent unauthorized system access or

program copying, the programs can be encrypted at some point in the pro¬

gramming stream, whether before storage or after storage, with the encryp-

tion method being a matter of design choice.

A graphics blender 122 performs the function of blending disparate

video input streams into one signal compatible with the displays 124 and

126. Typically, this involves combining an interactive graphical user inter¬

face having the program guide information with the program being viewed.

A virtual frame buffer 108 holds the graphical user interface informa¬

tion for refreshing the displays 124 and 126. In the preferred embodiment,

video decoding and graphics blending are local to the television sets. There¬

fore, where, as here, the system 100 has multiple television sets (like the

ones 124 and 126), multiple video decoders and graphics blenders exist in

the system. For example, when all or most of the basic system hardware re- sides in one room of a dwelling such as the living room, a television in an¬

other room of the dwelling such as a bedroom will also need to carry out

video decoding and graphics blending functions. The signal from the DVR

to the television will be received over a home are network. The communica-

tion over the home area network includes, for example, communication be¬

tween components 116 and 120, 108 and 122, and 120 and 122.

Figure 2 illustrates an algorithm 200 for executing live-pause opera¬

tions according to the present invention. The live-pause feature can be either

selectively triggered by the user, or set to automatically trigger, as is the

choice of the user. The algorithm 200 is started (Step 202) by the user either

viewing a program or indicating that he or she wishes to record a program

(Step 204).

Next, the program guide service provides program length information

for the currently viewed program to the record/playback service (Step 206).

The record/playback service determines the appropriate buffer memory size

needed to fully record the program in Step 208. Recall that the program

length information includes such things as the start and end times of the pro¬

gram where definitely known, or can either involve an estimate according to

a rule set or standard block sizes. For example, if the program guide infor-

mation indicates that the program currently viewed is a major television network movie that started 30 minutes late than originally scheduled, a

buffer memory capable of storing two hours will be utilized rather than one

for just one and one-half hours.

In Step 210 the video manager designates the actual buffer in the sys-

tem memory. If the user has chosen the current program from long-term

storage, it is so stored in Step 214. All programs are available for live-pause

recording and playback at all stages of the present-inventive process. This

reflected by Steps 215 and 224. The algorithm stops (Step 220) after re¬

cording is complete. Otherwise, the algorithm determines whether the user f has changed the program channel or has halted recording the current pro¬

gram by some other action. If so, the recording is stopped (Step 218). If the

user has not caused recording to be stopped, it is stored in the designated

buffer memory (Step 222) and made available for live-pause viewing (Step

224).

The user can elect at any time to have a program stored in long-term

storage. This is symbolically illustrated by Step 212 and also Step 226. To

summarize, the system 100 allows a user to view any program in live-pause

mode at any time, and allows any program to be stored in long-term memory

prior to the buffer memory being discarded. The following are examples il-

lustrating these basic features. In a first example, the user viewing a program in live-pause mode de¬

cides that the program should be stored in long-term memory. The buffer

memory used to initially store the program can then serve as the long-term

memory. The buffer/long-term memory will continue to record the program

until it is complete. After the program has been designated for long-term

storage, the user can continue to view the current program or tune to a new

program.

In a second example, a user has decided to record a program (e.g., a

sporting event) into long-term storage prior to viewing it. While the pro-

gram is being recorded into memory, it is also available for live-pause play¬

back when the user tunes to the program.

In a third example, the user views an entire program in live-pause

mode without designating it for long-term storage. Upon changing the

channel and thus tuning to a new program, the buffer memory for the previ-

ously-recorded program is released for overwriting by future programs.

Variations and modifications of the present invention are possible,

given the above description. However, all variations and modifications

which are obvious to those skilled in the art to which the present invention pertains are considered to be within the scope of the protection granted by

this Letters Patent.

Claims

CLAIMSWhat is claimed is:

1. A digital video recording and playback method adapted for

"live-pause" recording and playback, said method comprising the steps of:

a) providing at least one electronic audio-visual program source;

b) via a program guide source, at least providing program length in¬

formation about a program of interest;

c) converting said program length information into a corresponding

buffer memory size;

d) establishing a buffer memory matching the buffer memory size de¬

termined in step c); and

e) recording a selected program in the buffer memory established in

step d);

wherein said buffer memory size matches the size needed to record

said program of interest.

2. The method in Claim 1, wherein said program length informa¬

tion comprises the scheduled end time of a program of interest.

3. The method in Claim 1, wherein said program length informa-

tion comprises the scheduled start time of a program of interest.

4. The method in Claim 1 , further comprising the step of:

at the direction of a user, designating a program stored in said buffer

memory for long-term storage.

5. The method in Claim 1, wherein for programs of indefinite

length, said program length information comprises as a default, a fixed

length.

6. The method in Claim 1 , further comprising the step of:

releasing said established buffer memory from recording a current

program, and making its memory space available to part of another buffer

memory if needed, when the current program has been recorded.

7. The method in Claim 1 , further comprising the step of:

releasing said established buffer memory from recording a current

program, and making its memory space available to part of another buffer

memory if needed, when a user tunes in to another program.

8. The method in Claim 1 , further comprising the step of:

releasing said established buffer memory from recording a current

program, and making its memory space available to part of another buffer

memory if needed, when a user directs that recording be halted.

9. A digital video recording and playback system adapted for

"live-pause" recording and playback, said system comprising: a) at least one electronic audio-visual program source;

b) a program guide source adapted to at least provide program length

information about a program of interest;

c) a converter adapted to convert said program length information into

a corresponding buffer memory size; and

d) at least one buffer memory established and sized to match that de¬

termined by said converter, said buffer memory being adapted to record a

selected program;

wherein said buffer memory size matches the size needed to record a

program of interest.

10. The system in Claim 9, wherein said program length informa¬

tion comprises the scheduled end time of a program of interest.

11. The system in Claim 9, wherein said program length informa¬

tion comprises the scheduled start time of a program of interest.

12. The system in Claim 9, wherein said established buffer memory

is adapted to become, at the direction of a user, part of a long-term memory

for the long-term storage of a program stored therein.

13. The system in Claim 9, wherein for programs of indefinite

length, said program length information comprises as a default, a fixed

length.

14. The system in Claim 9, wherein said established buffer memory

is adapted to be released from recording a current program, and making its

memory space available to part of another buffer memory if needed, when

the current program has been recorded.

15. The system in Claim 9, wherein said established buffer memory

is adapted to be released from recording a current program, and making its

memory space available to part of another buffer memory if needed, when a

user tunes in to another program.

16. The system in Claim 9, wherein said established buffer memory

is adapted to be released from recording a current program, and making its

memory space available to part of another buffer memory if needed, when a

user directs that recording be halted.

17. A digital video recording and playback method adapted for

"live-pause" recording and playback, said method comprising the steps of:

a) providing at least one electronic audio-visual program source;

b) adaptively establishing a buffer memory having a size adequate to

record a program of interest; and

c) recording a selected program in the buffer memory established in

step b).

18. The method in Claim 17, wherein the size of said buffer mem¬

ory is set to one of a plurality of fixed sizes to match an estimated size of a

program of interest.

19. The method in Claim 17, further comprising the step of:

at the direction of a user, designating a program stored in said buffer

memory for long-term storage.

20. The method in Claim 17, further comprising the step of:

releasing said established buffer memory from recording a current

program, and making its memory space available to part of another buffer

memory if needed, when the current program has been recorded.

21. The method in Claim 17, further comprising the step of:

releasing said established buffer memory from recording a current

program, and making its memory space available to part of another buffer

memory if needed, when a user tunes in to another program.

22. The method in Claim 17, further comprising the step of:

releasing said established buffer memory from recording a current

program, and making its memory space available to part of another buffer

memory if needed, when a user directs that recording be halted.

23. A digital video recording and playback system adapted for

"live-pause" recording and playback, said system comprising: a) at least one electronic audio-visual program source; and

b) at least one adaptively established buffer memory having a size

adequate to record a program of interest;

wherein said buffer memory is adapted to record a selected program.

24. The system in Claim 23, wherein the size of said buffer mem¬

ory is set to one of a plurality of fixed sizes to match an estimated size of a

program of interest.

25. The system in Claim 23, wherein said established buffer mem¬

ory is adapted to become, at the direction of a user, part of a long-term

memory for the long-term storage of a program stored therein.

26. The system in Claim 23, wherein said established buffer mem¬

ory is adapted to be released from recording a current program, and making

its memory space available to part of another buffer memory if needed,

when the current program has been recorded.

27. The system in Claim 23, wherein said established buffer mem¬

ory is adapted to be released from recording a current program, and making

its memory space available to part of another buffer memory if needed,

when a user tunes in to another program.

28. The system in Claim 23, wherein said established buffer mem-

ory is adapted to be released from recording a current program, and making its memory space available to part of another buffer memory if needed,

when a user directs that recording be halted.