`US 20020066106Al
`
`(19) United States
`(12) Patent Application Publication
`Kanojia et al.
`
`(10) Pub. No.: US 2002/0066106 Al
`May 30, 2002
`( 43) Pub. Date:
`
`(54) PROMOTION SERVER USING VIDEO ON
`DEMAND CHANNEL
`
`(75)
`
`Inventors: Chaitanya Kanojia, Newton, MA (US);
`Terri Swartz, Marlboro, MA (US);
`Darren Wetzel, Boston, MA (US);
`Mark Fagnani, Watertown, MA (US)
`
`Correspondence Address:
`HAMILTON, BROOK, SMITH & REYNOLDS,
`P.C.
`530 VIRGINIA ROAD
`P.O. BOX 9133
`CONCORD, MA 01742-9133 (US)
`
`(73) Assignee: Navic Systems, Inc., Newton, MA
`
`(21) Appl. No.:
`
`10/003,079
`
`(22)
`
`Filed:
`
`Nov. 2, 2001
`
`Related U.S. Application Data
`
`(63)
`
`Non-provisional of provisional application No.
`60/253,350, filed on Nov. 28, 2000.
`
`Publication Classification
`
`Int. Cl.7 ............................. H04N 7/10; H04N 7/025
`(51)
`(52) U.S. Cl.
`................................. 725/87; 725/36; 725/93
`
`(57)
`
`ABSTRACT
`
`Idle Video-On-Demand (VOD) channel capacity is used to
`deliver promotional content to selected set-top boxes (STBs)
`
`in a cable television network. Commercial segment cues are
`used to instruct a set-top box to switch away from a
`broadcast program to the VOD channel during a commercial
`segment, and then switch back again to the original broad(cid:173)
`cast program at the end of the segment.
`
`More particularly, a promotion server determines an asset to
`be distributed such as a targeted promotion item (e.g., a
`commercial), and a list of STBs that are to receive it. The
`promotion server causes the video promotion content to be
`stored in VOD servers located at the head ends. A scheduler
`process then delivers schedule messages to head end mes(cid:173)
`sage servers which identify each promotion asset, and an
`STE which is to receive it. The head end message server
`notifies its associated VOD server which then cues the asset
`by loading the asset, starting the asset, but pausing it. Prior
`to the occurrence of a commercial slot in a broadcast
`program, an asset trigger is inserted into the broadcast
`stream at the head end. This asset trigger contains general
`information concerning the asset to be sent, and an idle VOD
`channel number. The STE receives the asset trigger and
`readies itself to tune to the VOD channel when cued for at
`the beginning of a commercial segment, but does not yet
`tune to the VOD channel. Upon detection of a commercial
`cue tone in the broadcast channel, the head end message
`server sends a tune away trigger to the STE, and also
`instructs the VOD server to start playing the cued promo(cid:173)
`tion. When the STE receives a tune away trigger, it switches
`from the broadcast channel being played to the selected idle
`VOD channel, and the promotion is viewed.
`
`6-----
`._ ___ _
`
`210
`
`DB
`SERVER
`
`220
`
`PROMOTION
`..,_ __ MGR SERVER
`
`•PROFILES
`•VIEWERSHIP
`•DEMOGRAPHICS
`•STB CAPACITY
`•TARGETING DATA
`
`SCHEDULER
`
`ROUTING
`SERVER
`
`240
`
`230
`
`DAT A CENTER 200
`
`i 1B/OOB DATA
`
`BROADCAST
`VOD
`
`RESIDENCE 400-1
`
`TO/FROM
`300-h
`
`F IG /
`
`(DATA NET)
`
`TO/FROM
`310
`FIG.1B
`
`(COAX)
`
`TO/FROM
`300-1
`FIG.1B
`
`BBiTV EX2069
`DISH v. BBiTV
`IPR2020-01267
`
`
`
`205
`
`_210
`
`DB
`i . - - - - - SERVER
`
`I
`
`220
`
`PROMOTION
`MGR SERVER
`
`•PROFILES
`•VIEWERSHIP
`•DEMOGRAPHICS
`•STB CAPACITY
`•TARGETING DATA
`
`SCHEDULER
`
`ROUTING
`SERVER
`
`250
`
`240
`
`230
`
`DATA CENTER 200
`
`BROADCAST
`VOD
`
`m1B/OOB DATA
`MSG ~LIENT rv 420
`0,-. 1
`
`I
`
`\
`
`450
`
`RESIDENCE 400-1
`
`PROMO
`AGENT
`
`rv-430
`
`STB 410
`
`FIG.1A
`
`TO/FROM
`
`300-h FIG/
`
`(DATA NET)
`
`TO/FROM
`310
`FIG.18
`
`(COAX)
`
`TO/FROM
`300-1
`FIG.1B
`
`""C
`
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`
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`>
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`
`
`
`300-h
`
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`END h
`
`~ } 400-y
`
`8TB
`
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`
`TO/FROM
`275
`FIG.1A
`
`TO/FROM
`275
`FIG.1A
`
`TO/FROM
`400-1
`FIG.1A
`(
`
`I
`
`400-2
`
`400-r
`
`FIG.18
`
`""C
`
`~ .... ~ = ....
`~ "Cl -....
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`.... 0 =
`
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`
`
`
`Patent Application Publication May 30, 2002 Sheet 3 of 3
`
`US 2002/0066106 Al
`
`500
`
`PROMO SERVER:
`ASSIGN ASSETS
`TO STBS
`
`SCHEDULER:
`CREATEXMIT
`SCHEDULES
`
`ROUTING SERVER:
`SEND SCHEDULES
`TO HER'S
`
`510
`
`520
`
`530
`
`540
`
`545
`
`548
`
`MSG SERVER:
`NOTIFY VOD/MM
`NOTIFY STB'S
`.
`: COMMERCIAL PRE-SYNC
`
`VOD SERVER:
`LOAD ASSET
`CUE ASSET
`
`STB:
`-----;-..1 GET ASSET INFO
`VODCH#
`
`MSG SERVER:
`ASSET TRIG
`
`550
`
`COMMERCIAL CUE TONE
`
`565
`
`560
`MSG SERVER:
`TUNE AWAY TRIG t----------,~
`NOTIFY VOD/MM
`
`VOD SERVER
`PLAY ASSET
`
`COMMERCIAL END-SYNC
`
`MSG SERVER:
`TUNE BACK TRIG
`
`570
`
`580
`
`FIG. 2
`
`
`
`US 2002/0066106 Al
`
`May 30, 2002
`
`1
`
`PROMOTION SERVER USING VIDEO ON
`DEMAND CHANNEL
`
`RELATED APPLICATION(S)
`
`[0001] This application claims the benefit of U.S. Provi(cid:173)
`sional Application No. 60/253,350 filed on Nov. 28, 2000,
`the entire teachings of which are incorporated herein by
`reference.
`
`BACKGROUND OF THE INVENTION
`[0002] This invention relates generally to broadcast sys(cid:173)
`tems such as cable television networks and more particularly
`to a technique for coordinating the insertion of specific video
`content, including targeted commercial or other promotional
`video content, over idle video-on-demand channels.
`
`[0003] For many years it has been realized that cable
`television (CATV) systems provide numerous advantages as
`compared to over-the-air broadcast systems. First, these
`cable systems were valued for their ability to provide for
`reception of signals in remote rural locations, or where radio
`signals may be blocked, such as in dense high rise apartment
`buildings. Later, it was realized that by incorporating long
`distance communications equipment, such as orbital satellite
`transponder equipment, centralized distribution networks
`could be built that not only could route local channels more
`reliably, but also distribute program content on a nation(cid:173)
`wide basis. This gave rise to broadcast program content
`which is available strictly for the cable television subscriber,
`and the now widely familiar movie, news, weather, music,
`childrens, sports, family and other program-gendre-specific
`cable channels.
`
`[0004] The present trend is towards a model where the
`reception devices in the home will include embedded com(cid:173)
`puter systems designed for a particular function or purpose.
`Today, for example, set-top boxes typically have limited
`data communication capabilities. The main function of these
`devices is to handle channel access between residential users
`and a head end or server on the cable TV network. For
`example, these systems are typically deployed to offer
`certain types of premium services, such as video-on-de(cid:173)
`mand. This service allows a viewer to use a menu system to
`select from a variety of typically pre-recorded premium
`programs that may be available, such as movies or sporting
`events. The selected program content is then immediately
`delivered to the viewer over channels dedicated to delivery
`of the video-on-demand content.
`
`[0005]
`In the future, the functionality offered by these
`set-top boxes or other embedded platforms will be expanded
`even further. For example, they may offer Internet browsing
`capabilities and e-commerce serving capabilities. Moreover,
`it is anticipated that common-household appliances will also
`have computer network functionality, in which case the
`set-top boxes may be used to remotely control and automate
`various tasks in the home.
`
`[0006]
`Indeed, millions of digital set-top boxes have
`already been deployed in the United States. It is estimated
`that the worldwide market for Internet appliances such as
`digital set-top boxes and other Internet-connected terminals
`will reach $17.8 billion in 2004. Increasingly, advertisers
`and content providers therefore view the cable set-top as the
`first platform of choice for widespread delivery of a suite of
`intelligent content management and distribution services.
`
`SUMMARY OF THE INVENTION
`
`[0007] The present invention is a system for delivery of
`targeted content such as promotional video content to a cable
`television viewer, where the specific content is under control
`of the a central operator and the viewer is not necessarily
`aware of the targeted nature of the content.
`
`[0008] Consider that the digital set-top box provides inter(cid:173)
`esting functionalities, including the ability to collect data
`such as a log of the channels watched over time. The set top
`box can thus be designed to report this information to a
`central location. At the central location, this data can be
`aggregated for many hundreds of thousands of users. This
`information, when coupled with other information, such as
`viewer demographics, can then be used by advertisers to
`blanket defined market segments with promotional content.
`The delivery of promotions to specific target segments can
`thus allow for
`impulse responses yielding immediate
`increases in product revenues.
`
`[0009] However, a nationwide cable television network
`may have hundreds of thousands, if not millions of set-top
`boxes, each tuned to a different channel. An efficient scheme
`for routing the targeted content to specific set-top boxes is
`therefore not as straightforward as it might appear at first
`glance.
`
`[0010] Some have proposed systems in which the targeted
`content is digitized and sent to the set-top boxes in com(cid:173)
`pressed form, well prior to its display. However, even a
`single promotion may require several hundred megabytes of
`storage. These techniques therefore require each set-top box
`to have a fairly large storage capacity, the cost of which
`might be prohibitive. And if such a distribution network
`were built using strictly standard data network protocols
`such as TCP/IP, the sheer number of require connections
`could overload a central data servers and routers.
`
`[0011] The present invention seeks to overcome these
`limitations by making use of idle video-on-demand channel
`capacity to deliver promotional content to selected set-top
`boxes in the network. The set-top boxes are then enabled to
`switch away during a commercial segment from the broad(cid:173)
`cast program to the available video-on-demand channel. The
`set-top boxes then switch back to the previously selected
`broadcast program at the end of the segment.
`
`[0012] More specifically, a network configured in accor(cid:173)
`dance with the invention includes a promotion server, a
`scheduler process, and a message router located and/or
`controlled at a central location, head end locations that
`include message servers, VOD servers, and trigger insertion
`equipment, and set-top boxes (STBs) located at subscriber
`premises that include at least a message client process and
`a promotion agent process.
`
`[0013] The promotion server determines an asset to be
`distributed such as a targeted promotion item (e.g., a com(cid:173)
`mercial), and a list of STBs that are to receive it. The
`promotion server causes the video promotion to be sent to a
`VOD service so that it is available at the VOD servers at the
`hea ends.
`
`[0014] The scheduler process then delivers schedule mes(cid:173)
`sages to the head end message servers which identify the
`promotion and an STE which is to receive it. Receipt of a
`schedule message by the head end message server causes its
`
`
`
`US 2002/0066106 Al
`
`May 30, 2002
`
`2
`
`associated VOD server to cue the asset by loading the asset,
`and starting the asset, but pausing it so that the asset does not
`yet play.
`[0015] Prior to the occurrence of a commercial slot in a
`broadcast program, an asset trigger is inserted into the
`broadcast stream at the head end. This asset trigger contains
`general information concerning the asset to be sent, and a
`VOD channel number. The STE receives the asset trigger
`and readies itself to tune to the VOD channel when it detects
`a commercial begin cue tone.
`[0016] Upon detection of a commercial begin cue tone in
`the broadcast channel, the head end message server sends a
`tune away trigger to the STE, and also instructs the VOD
`server to start playing the cued promotion. When the STE
`receives the tune away trigger, it switches from the broadcast
`channel being played to the selected VOD channel, and the
`promotion is viewed.
`[0017] When a commercial end cue is detected in the
`broadcast channel, the head end message server instructs the
`STE to tune back be sending a tune back trigger. The tune
`back trigger causes the STE to return to the broadcast
`channel that was being watched prior to delivery of the
`promotion.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0018] The foregoing and other objects, features and
`advantages of the invention will be apparent from the
`following more particular description of preferred embodi(cid:173)
`ments of the invention, as illustrated in the accompanying
`drawings in which like reference characters refer to the same
`parts throughout the different views. The drawings are not
`necessarily to scale, emphasis instead being placed upon
`illustrating the principles of the invention.
`[0019] FIGS. 1A and 1B are a block diagram of a network
`in which promotion is delivered using a video-on-demand
`channel according to the invention.
`[0020] FIG. 2 is a process flow diagram illustrating how
`the various elements and processes in the system deliver the
`promotion.
`
`DETAILED DESCRIPTION OF A PREFERRED
`EMBODIMENT
`
`[0021] 1. The Promotion Delivery System Generally
`[0022] Turning attention now to the drawings, FIGS. 1A
`and 1B illustrate a multimedia content delivery system
`which delivers promotions using a video-on-demand chan(cid:173)
`nel according to one embodiment of the present invention.
`The content delivery system may be any type of Cable
`Television (CATV) network system which may include any
`type of Hybrid Fiber Coax (HFC) physical cabling, or
`satellite equipment, or even digital video content distribu(cid:173)
`tion systems based on Digital Subscriber Line (DSL) or
`broadband wireless technologies such as Microwave Distri(cid:173)
`bution Services (MMDS).
`[0023] The system includes a data center having a pro(cid:173)
`motion server subsystem 200 at which the promotion deliv(cid:173)
`ery process originates, and a cable signal distribution net(cid:173)
`work, including head end locations 300-1, ... , 300-h for
`routing the promotions to a large number of network devices
`or set top boxes (STBs) 410 located at individual residences
`
`locations 400-1,
`and other cable system subscriber
`400-2, ... , 400-,; ... , 200-x, 400-y, where respective video
`displays 450 are located. The promotions include promo(cid:173)
`tional content that may be presented in various multimedia
`formats including compressed digital formats (MPEG 2 and
`4), or praghical images compressed and uncompressed using
`standard formats such as JPEG, GIF or BMP. Promotions are
`used to advertise goods and services, promote events, or
`present other commercial or non-commercial information.
`
`[0024] The promotion server subsystem 200 located at the
`data center communicates with a promotion agent subsystem
`430 embedded within each of the STBs 410. The promotion
`server subsystem 200 and the promotion agent subsystems
`430 may communicate with each other through the routing
`server 230, data network 275, head end router 310, head end
`message server 320, and message clients 420 by using a
`combination of application-level messaging and serialized
`bulk data transmissions.
`
`In more detail, the promotion server subsystem 200
`[0025]
`includes a database server 210, a promotion manager server
`220, a message routing server 230, a promotion scheduler
`240, and a bank of message routers 250. These components
`are typically located at a central location in the multimedia
`network such as at a data center or head end, or divided
`between the two depending on the density and population of
`STE devices 410.
`
`[0026] The routers 250 communicate with the hea ends
`300 through a data network 275. The data network 275 may
`be a local area network, but depending upon the geographic
`dispersion of the head ends 300, may itself include a wide
`area network having a further hierarchy of routers and bulk
`servers (not shown in FIGS. lA and 1B). Ultimately, each
`of the STE devices 410 is reachable through the data
`network 275 via an associated head end 300. In a typical
`cable television network, there may be many thousands of
`network devices 410 connected to a particular head end 300,
`and there may be many thousands of head ends 300.
`
`[0027] Each head end 300 includes a number of devices
`and processes including a head end message server 320, a
`trigger inserter 330, a Video-on-Demand/Multimedia (VOD/
`media) streaming server 340 and associated storage device
`350, and RF distribution equipment 370, which distributes
`broadcast video channels from a video distribution network
`(not shown).
`
`[0028] The head end router 310 sends and receives data
`messages to and from the promotion server subsystem 200,
`routing them to and from the head end message server 320.
`
`[0029] The head end message server 320 receives sched(cid:173)
`ule messages indicating the schedule of promotions for
`particular STBs 410 connected to its respective head end
`300-1. The hea end message server also transmits and
`receives messages to the STBs 410 using an Out-of-Band
`(OOB), In-Band (IB), or broadcast trigger path over the
`cable network. The signalling used for data communication
`may be narrowband Quadrature Phase Shift Keying
`(QPSK), or if high bandwidths are needs, may be Quadra(cid:173)
`ture Amplitude Modulation (QAM).
`
`[0030] Upon the occurrence of certain events, the head end
`message server 320 also uses the trigger inserter 330 to
`insert trigger signals into the RF cable channel signals
`
`
`
`US 2002/0066106 Al
`
`May 30, 2002
`
`3
`
`generated by the RF equipment 370. The use of trigger
`signals is an additional expedient communication path for
`critical cuing events.
`
`[0031] The VOD/media server 340 is connected to receive
`and store VOD content from a VOD distribution network
`(not shown) provide VOD channels to the RF equipment. It
`should be understood that the VOD content, which typically
`includes premium programs such as movies or sporting
`events, in this instance also include promotions. The VOD
`content can be stored in recorded form. If it originates in
`analog form, it is typically stored in a compressed digital
`format.
`
`[0032] At least three signal paths are
`there present
`between the head end 300 and the STBs 410, including a
`bi-directional data path for data messages, a broadcast video
`stream including data in the VBI spectrum or "stuffed" into
`the private data segments of an MPEG stream, and a
`video-on-demand stream.
`
`[0033] To determine how to deliver targeted promotions to
`the network devices, the promotion server subsystem 200
`generates viewership profiles for each of the STBs 410 from
`data collected using a variety of statistical models. The
`viewership profiles are then used to associate groups of
`STBs 410 with a particular given target promotion.
`
`[0034] More particularly, the promotion server subsystem
`200 periodically collects viewer usage data from the pro(cid:173)
`motion agent subsystem 430 located in each of the STBs 410
`to generate viewership profiles. In television networks, the
`data collected by the promotion server subsystem 200 may
`include tuner data (i.e., a history of channels watched) and
`responses to past promotions. This history is kept on a
`relatively fine time scale, such as five seconds. In this way,
`it can be determined how long a particular promotion was
`deployed, or even which portions of a promotion or video
`program were viewed.
`
`[0035] The so-called promotion groups are thus collec(cid:173)
`tions of STE devices 410 whose individual viewership
`profiles match membership criterion describing a particular
`demographic or viewership history. For example, a promo(cid:173)
`tion group may be demographically based, i.e., "married
`women in their 30's with more than one school age child and
`a household income of at least $100,0000," or based on
`viewership history, i.e., "tends to watch the Golf Channel on
`Sunday afternoon." Therefore, the promotion delivery sys(cid:173)
`tem 200 is adaptable to changes in viewer usage or view(cid:173)
`ership patterns by making adjustments to promotion groups.
`The process for creation and selection of promotion groups
`is described in more detail in the U.S. Provisional Patent
`Application Serial No. 60/253,488 filed Nov. 28, 2000,
`entitled "Using Viewership Profiles for Targeted Promotion
`Deployment" which is hereby incorporated by reference in
`its entirety.
`
`[0036] Promotions are then scheduled for delivery to
`promotion groups of specific STBs 410 which may not all be
`connected to the same head end 300. A promotion is
`scheduled for delivery to a promotion group by an advertiser
`or service provider entering a scheduling request for a
`promotion such as via the promotion manager 220. The
`promotion manager server 220 packages the promotion for
`delivery and by storing a record of it in the database server
`210, and notifying a video-on-demand service (not shown)
`
`that the promotion content will be needed at the VOD server
`340 locations at the head ends 300. Typically, broadcast
`VOD content, such as movies, is more likely distributed
`using Digital Audio Tape (DAT) which is sent by courier to
`the various head end locations.
`
`[0037] However, if a wide area data network is in place
`between the head end locations and the central location, the
`promotion assets can be distributed to the VOD servers 340
`using such a network. In such a case, the promotion infor(cid:173)
`mation is read from the database 210 by the scheduler 240
`which then creates customized transmission schedules that
`specify when each of the STBs 410 is to receive it. Upon
`receipt of the transmission schedule messages, the promo(cid:173)
`tion agent 430 in each of the STBs 410 processes each
`schedule entry and waits for the delivery of each promotion
`identified in the transmission schedule. For further informa(cid:173)
`tion concerning the use of a wide area network for the
`distribution of promotions, and a specific protocol and
`format for such promotion data, reference should be made to
`U.S. Provisional Patent Application Serial No. 60/253,369
`filed Nov. 28, 2000, entitled "Synchronization of Bulk Data
`Transfers To End Node Devices In A Multimedia Network"
`which is hereby incorporated by reference in its entirety.
`
`[0038] 2. Process for Delivery of Promotion Content
`Using Video-on-Demand Channel
`[0039] Turning attention now to FIG. 2, a preferred
`embodiment of the process for delivery of targeted promo(cid:173)
`tion content will be described. Initially the system is in a idle
`state 500.
`
`[0040] Moving to step 510, the promotion server 220
`assigns promotion assets to specific STBs 410, storing this
`information in the data base server 210.
`
`[0041] Next, in step 520, the scheduler 240 determines
`that promotions are in need of distribution, and reads the
`information in the database 210 to create individual trans(cid:173)
`mission schedules. From the schedules are built a list of
`promotion schedule messages. A promotion schedule mes(cid:173)
`sage is typically created for each instantiation of an expected
`playback of a promotion at a particular STE 410. The
`schedule message contains payload fields identifying a pro(cid:173)
`motion, the network address or other identifier of the indi(cid:173)
`vidual STE which is to receive the promotion, and an
`expected time by which the promotion is to be delivered.
`
`In step 530 the routing server 230 routes the
`[0042]
`schedule messages out over the data network 275 to the
`intended head end 300 via the routers 250 and 310.
`
`[0043] Following that, in step 540 a particular schedule
`message arrives at the message server 320. The message
`server in turn sends a message to its associated local
`VOD/media server 340 that a promotion is to be sent.
`
`In step 545, this causes the VOD/media server 340
`[0044]
`to load the identified asset, and cue the asset for playback,
`but without actually starting the playback at this time. The
`VOD takes other steps at this time, such as to identify a
`VOD channel number on which the asset will be played,
`back to the message server 320.
`
`[0045] At this point, in step 548, the message server 320
`also communicates with the specific STE 410 indicated in
`the schedule message. This message may include informa(cid:173)
`tion about the asset such as an identifier which the promotion
`
`
`
`US 2002/0066106 Al
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`May 30, 2002
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`4
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`agent 430 in the STE may use to record the fact that it was
`played. This message is sent over the OOE/IE data path to
`the STE 410 as previously described.
`
`[0046] After some period of time, a state 550 is entered
`which occurs a short time before a commercial break. In this
`state the message server causes an asset trigger to be inserted
`in the broadcast stream. This trigger, which may typically be
`sent in the Vertical Blanking Interval (VBI) as defined in the
`ATVEF specification, or in other ways. For example, the
`trigger may be placed in the private data sements of an
`MPEG stream, if the VOD content is so formatted. In any
`event, the asset trigger contains text character, or other data
`indicating general information identifying the upcoming
`promotion, and a VOD channel number on which it will be
`played.
`
`[0047] Next, a commercial cue is detected in the broadcast
`signal at the head end 300 as output by a digital ad insertion
`system typically located at the insertion location in the
`broadcast network. Since only a few VOD channels will be
`used for the purpose of distributing promotions, the handful
`of such channels used for this purpose can be monitored at
`the head end for such tones. Detection of commercial cue
`causes a tune away trigger to be sent, in step 560, from the
`head end 300 to the STE 410.
`
`[0048]
`In turn, receipt of the tune away trigger causes the
`promotion agent 430 in the STE 410 to switch to the
`indicated VOD channel. At the same time, the message
`server 320 at the head end signals the VOD/media server
`340 to begin playback of the promotion.
`
`[0049] The STE may include circuits that blank an unde(cid:173)
`sireable "pixelation" effect that may occur during channel
`switchover to the VOD channel. Alternatively, other infor(cid:173)
`mation such as channel information is displayed during
`switchover to the VOD channel.
`
`[0050] The promotion is then viewed at the STE 410 in
`state 565, until a commercial end tone is detected. At this
`
`point, in state 570, the message server 320 instructs the
`promotion agent 430 in the STE 410 to return to the original
`broadcast channel, such as by sending another tune back
`trigger.
`
`What is claimed is:
`1. In a cable television network system that connects
`set-top boxes (STEs) to receive broadcast program content
`from cable network head end distribution points, a method
`for delivery of a promotional content stream comprising the
`steps of:
`
`cueing a promotional content stream at a video-on-de(cid:173)
`mand (VOD) server to be played on a VOD channel for
`a particular STE, the VOD server located at a cable
`network head end;
`
`sending a first trigger to the particular STE indicating the
`VOD channel number, but which does not cause the
`STE to yet switch to the VOD channel;
`
`sensing a commercial cue tone signal in a broadcast
`channel being watched at the STE, the commercial cue
`tone indicating an upcoming start of commercial seg(cid:173)
`ment; sending a second trigger to cause the STE to
`switch to the VOD channel indicated by the first
`trigger; and
`
`beginning playback of the promotional content stream.
`2. A method as in claim 1 wherein the STE stores a
`channel number being watched prior to playback of the
`promotional content stream, and returns to the stored chan(cid:173)
`nel number once the promotional content stream ends.
`3. A method as in claim 1 wherein pixelation that may
`occur during channel switchover to the VOD channel is
`blanked at the STE.
`4. A method as in claim 1 wherein channel information is
`displayed during switchover to the VOD channel.
`
`* * * * *
`
`