This section provides an introduction to the Intercast Content Management Software(ICMS), also known as the Intercast "Broadcast Site" or "Head-end" system. The ICMS system takes previously authored content (web pages, associated files such as .GIFs, and what are called "billboards") and inserts it into the outgoing television broadcast signal at the appropriate time.

Customers on the receiving end may view the content on PC's which are equipped with appropriate Intercast hardware and software and connected to either an antenna or standard television cable.

The first step in the production process is to author the HTML content. Authors may create the content using any tools they choose. Once created, the HTML content is transferred to one of several ICMS systems which, under manual or automatic (time-activated) control, send the content to a standard device known as a "VBI Inserter". The VBI inserter then immediately places the HTML data in the video signal. The video signal containing the HTML data is then transmitted on-air or recorded onto video tape. An overview of the process is shown below in Figure 6.

The first step in the process, the creation of the HTML content, is done independently of the Intercast ICMS systems. The HTML pages, JPG / GIF files and other associated files are created using the same tools as those used for creating content for the World Wide Web. Developing Intercast content does not require any special authoring tools; however, delivering content for Intercast technology requires some unique considerations. In particular, the broadcaster must synchronize the delivery of web content related to a specific program. Therefore, the broadcaster must pre-send the web content prior to the desired viewing time. In order to do this, the broadcaster must consider the size of the content and available bandwidth. These two factors affect when the broadcaster needs to send the content. In addition, the content developer should recognize that viewers may join the program mid-stream or change channels during the program. In either case, the viewer may not receive all the content for a specific set of web pages. Each of these issues is discussed below in more detail.

The developer may want to consider whether their content assumes the presence of a back channel modem. Strictly speaking, Intercast technology does not require a modem, but the user experience is significantly enhanced if it is present. The modem also extends and strengthens the hybrid application model applied to Intercast technology. Since Intercast uses a one-way, broadcast connection to the viewer, if the viewer has no Internet connection, HTML elements requiring communication back to a web server will not function. So, for example, server-based CGI scripts will not operate without a back-channel.

Taking this into consideration, if an author chooses to develop content which does not require a back-channel, the content should be complete and compelling by itself and not contain any HTML elements which require interaction with a website. Conversely, if an author decides to assume that a user does have an active Internet connection, items such as CGI scripts and URLs referring to any site on the Web could be included in the Intercast pages.

The developer needs to monitor Intercast content file size to ensure synchronized delivery of the content. The delivery time depends specifically on file size and the available bandwidth (number of VBI lines available). To ensure successful delivery of all content, the developer should minimize file sizes as much as possible.

The next consideration is bandwidth. Intercast content, as mentioned above, is transmitted in the TV signal, or more precisely, in the "Vertical Blanking Interval" (VBI) of the TV signal (to be described in more detail below). Depending on the number of VBI "lines" reserved for Intercast transmissions by the TV station, the throughput could range from about 9,600 baud (for one line of VBI) to 28,000 baud (for three lines of VBI). Some stations could allocate even more than three lines of VBI for use. Given this bandwidth consideration and the fact that the content needs to be received by the viewer in a timely manner, the transmission of large files should be avoided, unless sufficient time to download is provided in advance of use.

Additionally, the developer should consider how the user experience changes if certain page sets do not appear. This may occur when the user changes channels or joins a program midway through an Intercast content transmission. In either case, not all of the page sets will arrive on the client PC. The developer should consider ways to ensure a cohesive and consistent experience in the case of missing page sets. Therefore, the content developer should develop their web page content to support continuity if particular page sets do not arrive because the viewer joined late or changed channels.

Currently, Intercast technology does not support ActiveX controls or Java applets. A future release of the Intercast viewer and authoring tools will provide this support.

Design content that the user can easily view using the smaller Intercast viewer web window. Avoid requiring the user to scroll down through the Intercast viewer web window to view the entire page contents. This is not a requirement, but does make the Intercast technology viewing experience more enjoyable.

The Intercast technology SDK discusses the treatment of all the issues listed above in greater detail. For information on the SDK see : /ial/intercast/

A VBI Inserter, described above, is the device used to place data on specific lines of the VBI. In its basic configuration, an inserter has an "input video", "output video," and a "data input" port. And so, for example, a person responsible for the VBI inserter can program it to "take the data coming in on the Data Input port and insert that data onto VBI lines 12, 13 and 17 of the video signal." In the USA, the format (speed, voltage, etc.) of the data as it appears in the TV signal is specified by the North American Basic Teletext Service (NABTS) standard. In other parts of the world, World Standard Teletext (WST) signaling is used.

The more VBI lines allocated for Intercast content use, the greater the amount of data which can be transmitted per second. The broadcast facility management determines the number of VBI lines allocated to particular Intercast content transmissions.

By law, certain lines in the 10-20 range may not be used for data. For example, line 19 is reserved for the standard TV "ghost canceling" signal. Also, line 21 (which technically is not a part of the Vertical Blanking Interval) is also used to transmit closed captioning data.

Because of the high speed of NABTS VBI data, that data (including Intercast data) cannot be recorded by standard consumer VCR's such as VHS. (Note that closed captioning, however, since it has a much slower data rate can be recorded on consumer VCR's.) More expensive consumer recorders, depending on the manufacturer, may be able to record NABTS data. Almost all professional and broadcast tape machines, if properly configured, are able to record and playback NABTS (and therefore Intercast) data.

Understanding the concept of Pages, Page Sets, and Packages will help explain some of the details of the ICMS systems. See Figure 7.

A "Page" refers to an HTML page along with its required resources (GIF files, JPG files, etc.). A "Page Set" is a hierarchy of pages typically built around a single theme and typically referring to a particular scene or segment of a television show. A "Package" consists of all of the page sets for a single show.

As an example, assume that a broadcaster will transmit Intercast content as part of a 30-minute crime show. Also assume that the first ten minutes of the program show the commission of the crime, the second ten minutes show the investigation of the crime, and the last ten minutes show the capture of the criminal. In this example, an Intercast author/producer might choose to create one page set for each segment. For example, the developer could create a page set for the first ten-minute segment (the "Crime Scene" page set), one for the middle ten minutes ("Investigator's Notebook" page set), and one for the final ten minutes ("Arrest" page set).

Once these pages and page sets are created, the author would use a simple ICMS tool, called the Intercast content "Package Generator", which runs on the authoring station, to gather all the required HTML pages and resources for all page sets into a single directory. The files in that single directory--all the files required for the program--are called the "Package" for that show. This entire package would them be transferred as a unit to other ICMS systems for scheduling and transmission.

As can be seen above, individual pages in page sets can be arranged in a hierarchy. When transmitted, the ICMS system sends the pages from the bottom level (lowest level in the hierarchy) upward. When received by the viewer's PC, the pages are put into a cache. The last file to be sent is the top file in the hierarchy. Once this top page is received, the viewer's system "triggers" this page into view.

Links between the pages in the hierarchy are file links. So, when the user clicks on a file link in the top-level page, the linked-to page is retrieved from the cache and immediately shown to the user. Because the page is cached on the hard drive, the response is nearly immediate (as opposed to retrieving a page from the Internet). As mentioned above, if the page author chooses to place an URL in the page, and the user has a back-channel connection, the page specified in the URL will be retrieved from the specified site on the World Wide Web.

In addition to sending HTML pages, the ICMS systems can also transmit what is called a "Billboard." This is a small 64x64 bitmap which appears in the upper right corner of the Intercast technology user interface. (See the "BB" area of the PC screen in Figure 1.) The broadcaster can use the billboard area for any purpose, but it is most often used to display station or advertising logos.

In all of the explanations below, although not specifically stated, the mechanisms described for sending HTML content can also be used to send billboards.

The ICMS system controls when to transmit Intercast content. The ICMS system supports several methods of transmission. Before describing the system, let us first look at a simplified layout of a typical Broadcast/ Content Provider facility as shown in Figure 8 below.

There is typically what could be called an "Off-line" area in which editing and graphics creation are performed. HTML content development for a station's website might also be performed in this area.

Another area is the "Control Room" where a live program is produced and brought to air. This room contains such tools as the "switcher," "still store," and "Chyron" which are operated live on-air.

Another area could be called the "Master Control/Engineering area" which houses Master Control (the switcher which essentially makes the final selection of what is put on-air), possibly includes a robotic playback automation system (such as a Sony LMS), and usually includes a "rack area" which contains devices such as a VBI Inserter.

With this overview in mind, let us next describe the various transmission methods for Intercast technology, how they fit with current television production processes, and where the ICMS tools may be located in a television facility.

One method to transmit an Intercast Content Page Set is to simply select a page set with a mouse and send it immediately. This method is typically used on a live show in which you cannot know in advance what time the page set should be sent. This is called "Manual" transmission and is accomplished by the ICMS system called the "Air Station." The process flow is shown in Figure 9 below.

A more detailed description of the manual transmission method may best be given using an example--a live evening news program. Assume that, on the morning before the show, the tentative plan is to do news pieces on the following topics: the election, Bosnia, and a flood. Just like a graphics person might pre-compose some "over the shoulder" backgrounds during the day, the Intercast Content HTML author would compose page sets on each topic.

The author would then run the Intercast Content Package Generator on the authoring workstation in order to gather all HTML components (files) for all page sets into a Package. This package would then be placed in a directory with an intuitive name for future retrieval by the operator of the Air Station.

Prior to air time, the operator of the Air Station would access the file system of the authoring station (presumably over an internal LAN) and transfer the package (containing the election, Bosnia, and flood page sets) into the Air Station. Once the package is imported, the operator of the Air Station would see the individual packages on the Air Station's display. During the news program, when the topic of Bosnia is discussed, the Air Station operator merely uses the mouse to select the Bosnia page set and start the transmission of the data to the viewer.

After leaving the Air Station, the data flows into the Intercast Technology Master Encoder PC. The Master Encoder multiplexes (combines) the data streams from other Intercast technology devices elsewhere in the facility (for example other Air Stations) and adds necessary protocol bits (VIP -Vertical Indexing Protocol) to the data. It then sends the data to the VBI inserter. The VBI inserter is an off-the-shelf product from Norpak corporation which can place the data on any VBI line (chosen by the management of the facility) of the TV signal for transmission.

Automatic transmission simply refers to pre-scheduled transmission of page sets based on time of day. This method can be used when the time for airing a page set is known beforehand. Example situations where this may be appropriate are documentaries and situation comedies where a previously-created videotape can be reviewed to determine the exact time in the program when a specific page set should be transmitted.

As mentioned previously, the creation of the page set is done using standard HTML authoring tools. Then time tags are added to the page sets via the Intercast Technology Time Coding Station. These time tagged page sets are then transferred to the Intercast Technology Sequencer which monitors time of day and transmits the page sets at the time specified in their time tags. The process flow is shown in Figure 10 below.

Therefore, four basic steps are required: (1) create the page sets in the authoring station, (2) run the "Package Generator" to gather the page set files into a "Package," (3) transfer the package into the Time Coding Station where each page set can be time tagged, and (4) transfer the package (with the time-tagged page sets) to the Intercast Technology device called the "Sequencer" which monitors time-of-day and transmits each page set at the appropriate time. This is illustrated in Figure 11 below.

Time tagging of the page sets is accomplished using the Intercast Technology Time Coding Station. Once again, the process is best illustrated by an example. Assume that Intercast content is to be produced for NBC's Seinfeld program. Also assume that there are three segments in the program: the "apartment segment," the "restaurant segment," and the "store segment". Finally, assume that the completed videotape of the program has been delivered to NBC, and NBC's next step is to prepare the Intercast content.

After viewing the tape, the HTML author (often at the direction of a producer) would perhaps decide to construct three page sets, one for each segment. After completing the pages and page sets, the author would then run the Intercast Content Package Generator (described above) to gather all file elements into a final Intercast Content "Seinfeld Package." After doing this, the author's job is finished, and the next step is to attach the time tags to the page sets.

To decide on the appropriate times to transmit each page set, the Intercast technology producer or Time Coding Station operator will typically view ("log") the Seinfeld episode to see the timing of the program. Let's say that the first segment (the "apartment" segment) runs from timecode 00:00 (minutes / seconds) to 10:00; the second segment (the "restaurant" segment) runs from 12:00 to 20:00 (note the two minute commercial break between 10:00 and 12:00); and the final "store" segment runs from 20:00 to 28:00. Assume that it makes sense to simply send the appropriate page set at the beginning of its corresponding video segment.

To associate a time tag with each page set, the operator of the Time Coding Station first imports the Intercast technology Seinfeld Package from the authoring station to the Time Coding Station. Once the package is imported, the operator would see a listing of the three page sets previously created by the author. To time tag each page set, the operator merely types in the desired start time (the time at which the operator would like the page set to appear on the viewer's screen) or drags the icon of the page set onto a 30 minute timeline representing the length of the show. Times may be changed by merely editing the desired start time or simply moving the start/end points for a given page set on the timeline. For those familiar with computer-based video editing products such as the Avid™ system, this process is similar to laying down tracks on an Avid Mediacomposer™.

It is important to note that the time tags as entered into the Time Coding Station are offsets from the beginning of the program. That is, rather than specifying that a page should be transmitted at 9:10 PM on Thursday, the operator specifies the time as 0:10--ten minutes into the program. As will be seen later, the absolute start time for the program will be entered into the Sequencer.

Note that to account for the two minute commercial break which occurs between 10:00 and 12:00, the operator of the Time Coding Station is provided with a special icon which specifically reserves time slots for advertisements on the Time Coding Station's display. The operators merely hand-enters the ad time slots or drags the "ad block" onto the timeline to account for this commercial time. The reason for specifically reserving this time slot will be explained in the Sequencer portion of this paper.

Finally, with all time tags entered, the operator re-saves the package.

Therefore, to summarize, the fundamental purpose of the Time Coding Station is to import packages containing non-time-tagged page sets, place time tags on the page sets, and regenerate the package with time tagged page sets.

The next step in the process is to transfer the package (with time tags) from the Time Coding Station to the Sequencer. The Sequencer is described in the next section.

After the "Page sets" (in the "Package") are time tagged via the Time Coding Station, the package is transferred to another ICMS system called the Sequencer. The Sequencer monitors time-of-day and transmits page sets at the time specified in their time tag.

Many people are familiar with TV station automation systems such as the Sony LMS™. The LMS can be described as a large juke box of videotapes which is programmed to play certain tapes at specific times of day. For example, Viacom's "Nick at Nite" LMS is loaded with a several tapes including commercials and shows. It may be programmed, for example, to play the Dick Van Dyke tape at 10:00 PM, the Pepsi commercial at 10:06 PM, etc.

The Intercast Technology Sequencer can be viewed as an "Intercast Technology LMS." That is, Intercast Content "Packages" are loaded into the Sequencer, and the operator programs the Sequencer to, for example, "start the Seinfeld package at 9:00 PM."

The operator of the Sequencer might program it once per day with events for the next 24 hours. To do this, the operator imports Packages into the Sequencer (file transfer over the LAN) and specifies when each Package should start.

Continuing with the Seinfeld example, the Sequencer operator would import the time-tagged Seinfeld package from the Time Coding Station, and program the Sequencer to "play this Seinfeld Package at 9:00 tonight." As a result, at 9:00 PM, the Sequencer would open the Seinfeld package and look at the time tags on each page set in the package. Note that time tags on page sets are relative to the start of the show. Consequently, a page set with a 00:00 time tag would be transmitted at 9:00 PM plus zero offset which simply means 9 PM, and a page set with a time tag of 10:00 would be played at 9:00 PM plus 10 minutes offset or 9:10 PM, etc.

When the appropriate time comes and a page set is transmitted by the Sequencer, the data flows (via LAN) to the Intercast Technology Master Encoder PC (described above) which adds necessary protocol bits to the data and sends it to the VBI inserter for actual insertion into the TV signal.

As packages are imported into the Sequencer and the operator programs the start times, the Sequencer checks for overlap between programs. And so, if the Seinfeld package were programmed to play from 9:00 PM to 9:30 PM on Thursday, any attempt to place another program in this time slot would be prohibited, with one important exception. It was pointed out in the Time Coding Station section above that the operator could reserve slots for "ads". The reason for doing this during the time coding process is as follows: After the operator programs the Sequencer to "play the Seinfeld package at 9 PM", unless small blocks of time are reserved for ads, it would not be possible to, at a later time, import advertising packages into the Seinfeld time period. In the Seinfeld example, by reserving 10:00 to 12:00 as an "ad block" in the Time Coding Station, the Sequencer will permit an operator to drag a Pepsi commercial into this two minute block of time during the Seinfeld playback period.

This is the process by which Intercast content, rather than going directly to air via the Sequencer or Air Station, is placed on a videotape along with the primary video program material. For those familiar with placing closed captioning onto tape, this process is similar. Intercast content is prepared and time tagged, then the original program video tape is played-back through a VBI inserter (where the Intercast content data is added), and the combined video and data are recorded onto a new video tape. As a result, when the new tape is played back, both the video and Intercast content data will be played on-air.

The process flow is shown in Figure 11.

Note that this method eliminates the need for the on-air Sequencer in the Master Control/Engineering Area. The staff in the Master Control/Engineering Area would find this advantageous since there is no change in routine for them. Since the data is placed directly onto the video tape by another group, the LMS operator (or equivalent) merely loads the tape into the LMS and plays it on the air as usual, with no regard to the Intercast content data. This method, however, creates an extra step for the people in the Off-line area since the data needs to be laid to tape.

In this configuration, a limited function Sequencer, called the Lay-to-Tape Sequencer ("LTT Seq" in the figure), is installed in the Time Coding Station. A version of Master Encoder software (labeled ME in the figure) is also installed in the Time Coding Station. Also, a playback VTR, a record VTR, and a product called V-LAN are required. V-LAN (not shown in the figure) is an off-the-shelf product which permits a PC to control a wide variety of professional tape machines via the PC's standard serial port.

In terms of production, the Laying to Tape method is similar to the Automatic method. The HTML pages are composed in the authoring station, and the page sets are time tagged in the Time Coding Station. The difference is that, after time tagging the pages, the Time Coding Station operator presses the "Lay-to-tape" button on the Time Coding Station. This causes the Time Coding Station, via the V-LAN product, to roll the record and playback VTRs. In addition, the Time Coding Station monitors SMPTE time code coming from the playback VTR. At the appropriate time offset into the program, the Time Coding Station sends the corresponding page set to the built-in Master Encoder which then sends the data to the VBI inserter for insertion into the video signal. The combined video and data signals are then recorded on the record VTR.

In addition to the functions described above in the Sequencer section, the Intercast Content Sequencer also has the capability of grabbing pages from a website and transmitting them via Intercast technology. Specifically, the operator may program the Sequencer to "grab URL www.intel.com along with n levels of child pages and send them at 10 AM."

As a result, if you are already maintaining a website and wish to start transmitting Intercast content data with minimal additional authoring effort, you can use the Sequencer to grab your existing pages from your existing website, in many cases without change, and send them at specified times.

This is illustrated in Figure 12 below.

The ICMS systems also have the capability of interfacing with a limited number of station automation systems (including some versions of Sony LMS). This makes it possible to read an LMS play list and automate certain Intercast content programming functions. Contact Intel for additional information. http://www.intel.com/iaweb/intercast/