Metadata for Enhanced Electronic Program Guides

Transcription

1 Metadata for Enhanced Electronic Program Guides by Gomer Thomas An increasingly popular feature for TV viewers is an on-screen, interactive, electronic program guide (EPG). The advent of digital television (DTV), with the high digital bandwidth it provides, has the potential to support more and better EPG functions than ever. However, currently the best EPGs are available only in proprietary environments. The reason for this is that the current DTV standards only support data for the most basic EPG functions. To make enhanced EPG functions ubiquitous, enhanced DTV standards are required. One capability that is of great interest to broadcasters and advertisers, if not consumers, is the ability to include general purpose advertising in EPG displays. This paper lays out the vision of future EPGs, describes the standards activities currently underway to support them, and suggests a possible business model for supporting general purpose advertising in EPGs. State of the Art Television program guides have come a long way in recent years. At one time the only TV program guides available were those printed in newspapers and magazines. These typically have a grid with time on one axis and a list of channels on the other axis, showing the programming for all the channels that can be received in the circulation area of the newspaper or magazine, including both terrestrial channels and cable channels for the various cable companies serving the area. They also typically contain synopses of movies and sometimes selected other shows scheduled to be shown. The advent of cable systems brought on-screen, electronic program guides (EPGs). The early versions consist of a dedicated channel displaying a program guide that shows the programming for a couple of hours ahead. Since there is only space to show half a dozen or so channels on the screen at a time, the display automatically scrolls through all the available channels, at a painfully slow pace. At the end of the channel list, the display may also scroll through brief descriptions of movies and sometimes other events that are currently showing. Then many cable companies began utilizing settop boxes to provide interactive EPGs. These support several features: Ability to call up a program guide grid at any time, and scroll up and down through channels and forward and backward in time, via clicks on a remote control. Usually information on programming for some days into the future is available. Display of channel number, program title, and program duration, appearing briefly each time the channel is changed, and at other times by clicking on the remote control. Textual description of any program listed in the program grid, or of the current program being viewed, called up by clicking on the remote control. Ability to switch channels automatically by clicking on a program in the program grid. If it is a current program, the channel changes at once. If it is a future program, the channel changes when the program is scheduled to start. Some of the more advanced cable guides also have a search facility, whereby viewers can search for programs with specified characteristics, such as a specified genre. Satellite systems also provide EPGs, typically of the more advanced variety. What are the options for viewers without cable or satellite service? One option is to go to one of the web sites that provide a program guide service. These are typically tailored to the visitor s geographical area. You enter your zip code, and it shows the programming for the channels you can receive. These services are fully interactive, and usually 1

2 provide sophisticated search features. While not as convenient as a guide on the television screen, many dedicated computer users find them very useful. Another option is to buy a high end TV set with a built-in EPG. The company behind this service has made an arrangement with one of the national TV networks for each of their affiliates to broadcast programming data for all the TV stations in their viewing area, encoding the data in the vertical blanking interval (VBI) of their analog TV signal. It has also made an arrangement with a number of the TV set manufacturers to include an interactive on-screen program guide facility in their sets that takes advantage of this data. Of course, the data is in a proprietary format, so it is only available to TV sets from a TV manufacturer that is party to the arrangement. Yet another option is to buy a digital television (DTV) set. The DTV standards allow each DTV station to put programming data in the broadcast stream for all the digital and analog channels from that station, so DTV sets can support an interactive on-screen program guide without the need for any proprietary arrangements. Of course, such a guide will only include stations that are broadcasting a DTV signal, but under FCC rules that will include all stations within the next few years. Unfortunately, the current DTV standards do not support the data needed for some of the more sophisticated EPG features available elsewhere, such as a search for programs by genre or other characteristics. Vision for the Future As seen above, the current state of the art for onscreen EPGs is less than ideal. This raises the question: What should the ideal program guide environment of the future look like? At a minimum, EPGs should have the following characteristics: Universally available whether the viewer is a cable subscriber, satellite subscriber, or only receives terrestrial broadcast channels. Automated channel discovery displaying in the EPG all the channels that the TV set can receive and only those (which may include a mix of cable, terrestrial and satellite channels). After channel change display channel and program information for a short time: New channel number, name, and logo New program title, start/end time, and content advisory rating. Current channel and program display on demand: Current channel number, name, and logo. Detailed description of current channel. Current program title, content advisory rating, and start/end times. Detailed description of current program. Grid guide display on demand scrollable program grid, by channels and time. Search facilities search on demand for programs by genre, performer, director, content advisory rating, closed captioning, etc. Future programming grid and search extending at least two weeks into the future. Details in guide detailed description on demand of any program in grid or returned by search. Indicators in guide content advisory ratings, closed captioning indicators, and data enhancement indicators * (as well as title and start/end times) displayed for all programs in grid or returned by search. Multimedia program/channel descriptions ability for displayed program and channel descriptions to include still images, video clips, audio clips. etc. rather like a web page, or collection of linked web pages. Automated channel change by selecting current or future program from the guide. Automated recording in conjunction with a recording device, by selecting current or future program from the guide. Advertising ability of the program guide to include multimedia advertising, of both TV * DTV programs may be data-enhanced. Some viewers may strongly prefer data enhancement for certain types of programs. Thus, the program guide should allow them to identify the data enhanced programs easily. 2

3 programs and other products and services. This advertising could be banner ads, larger still images, sound clips, video clips, or perhaps other forms. (This may or may not appeal directly to viewers, but it will appeal strongly to other players in the industry, who may make it worthwhile to viewers.) The universally available characteristic requires standards. Thus, the challenge is to have DTV standards that support all the other features described above. Current Standards First, let s take a look at the current DTV standards related to program guides: The relevant ATSC standard is the Program and System Information Protocol for Terrestrial Broadcast and Cable. 1 It provides facilities to convey the following information in the DTV broadcast stream for each virtual channel broadcast by the station: Logical channel number (major-minor format) Short channel name (up to 7 characters) Extended channel name (possibly in multiple languages; up to about 250 total bytes of Huffman encoded characters) Extended text description (possibly in multiple languages; up to about 4000 total bytes of Huffman encoded characters) and the following information for each TV program scheduled to be broadcast by that station for up to 16 days in the future: Title (possibly in multiple languages; up to about 250 total bytes of Huffman encoded characters) Start time Duration Content advisory ratings Closed caption indicator (with specification of language(s) in which closed captioning is available) Extended text description (possibly in multiple languages; up to about 4000 total bytes of Huffman encoded characters) The ATSC Data Broadcast Standard 2 specifies how to convey a data enhancement indicator for each TV program. Thus, the ATSC standards support the most basic functions, but do not support channel logos, search facilities, multimedia program and channel descriptions, or advertising. Other relevant DTV standards by DVB 3 and SCTE 4 provide much the same capabilities. Current Standards Activities In recognition of the limitations of the current Program and System Information Protocol (PSIP) standard for the support of enhanced program guides, ATSC has created an Advanced EPG ad hoc group under the T3/S8 Specialist Group on Transport, with the charter to propose appropriate extensions that will provide stronger support for enhanced EPGs. This amounts to defining how to associate more extensive and more highly structured metadata with channels and programs. To avoid reinventing the wheel, the group was specifically directed to take advantage of other metadata efforts, such as MPEG-7, if at all possible. The group is still in an early stage of its work, but the effort may move fairly quickly. There are a number of other standards activities potentially relevant to this effort: ATSC Directed Channel Change amendment ATSC Content Identification ad hoc group (also under T3/S8) SMPTE metadata dictionary MPEG-7 MPEG work on carrying metadata in MPEG-2 transport streams TV-Anytime metadata work W3C Metadata Activity The Directed Channel Change amendment 5 to the ATSC PSIP standard defines specific categories and subcategories of TV programs that could be used as the basis for searching programs by genre. The primary charter of the ATSC Content Identification ad hoc group is to recommend a suitable scheme and registration authority for uniquely identifying content and tracking it as it 3

4 makes its way from production to broadcast in an ATSC DTV environment. However, there is a strong sentiment within the ad hoc group that the content identification framework also needs to facilitate management of metadata associated with the content. Thus, the draft requirements document developed by the group lists some recommended metadata for TV content, including metadata to support EPG functionality. As reported in the July 2000 issue of the SMPTE Journal, 6 SMPTE has been working on a metadata dictionary for the broadcast industry, and also mechanisms to encode the metadata and associate it with the essence it describes. This has resulted in a number of proposed standards, engineering guidelines, and recommended practices. It may be that a subset of this work can be applied to the EPG problem, although the scope of the SMPTE effort is much broader. As the Overview of the MPEG-7 Standard 7 states: MPEG-7, formally named "Multimedia Content Description Interface", aims to create a standard for describing the multimedia content data that will support some degree of interpretation of the information s meaning, which can be passed onto, or accessed by, a device or a computer code. Work on the standard was begun in November Requirements were developed, and a call for technologies was issued in October A working draft was produced in December A committee draft is expected in October The standard consists of the following parts: MPEG-7 Systems tools needed to prepare MPEG-7 Descriptions for efficient transport and storage, and to allow synchronization between content and descriptions. MPEG-7 Description Definition Language the language for defining new Description Schemes and perhaps eventually also for new Descriptors. MPEG-7 Audio Descriptors and Description Schemes dealing with Audio descriptions MPEG-7 Visual Descriptors and Description Schemes dealing with Visual descriptions MPEG-7 Generic entities and Multimedia Description Schemes Descriptors and Description Schemes dealing with generic features and multimedia descriptions MPEG-7 Reference Software MPEG-7 Conformance The scope of this work is very much broader than needed for EPG support, but the general DDL and a subset of the schemes may be useful for the EPG problem. Work has been initiated in the MPEG Systems Expert Group to produce a technical specification for carriage of metadata in MPEG-2 Transport and MPEG-2 Program streams. Depending on how compatible the result is with the ATSC PSIP and Data Broadcast standards, it could be a candidate for encoding metadata in an ATSC broadcast stream to support EPGs. The objective of the TV-Anytime consortium is to enable searching, selecting, locating, and acquiring content wherever and whenever it is available. A key enabler for this is associating metadata with the content. The consortium has developed a Metadata Requirements document, 8 and is working to develop a solution in harmony with MPEG-7, SMPTE, and others. The scope of the TV-Anytime metadata work is much broader than needed for support of EPGs, but much of the work should still be relevant. The W3C Metadata Activity has been going on for quite some time. The two primary results to come out of this have been RDF (Resource Description Framework) 9 and PICS (Platform for Internet Content Selection). RDF provides a standard way for using XML to represent metadata in the form of statements about properties and relationships of items on the Web. It is clear from these descriptions that there are potential opportunities for harmonization between the ATSC work on Advanced EPGs and these other efforts in two areas: Specific attributes to describe TV programs Representation framework for these attributes The ATSC Advanced EPG ad hoc group intends to take full advantage of these opportunities. Business Model for Advertising The business model for most of the proposed EPG features in the vision for the future is pretty straightforward. They require the broadcasters to provide extra metadata in the broadcast stream, 4

5 and they require the TV receiver manufacturers to support the features in their products. The extra metadata requires some effort to prepare, and it takes some extra bandwidth in the broadcast stream, but it helps attract viewers to the broadcaster s programming, which results in extra revenues to the broadcaster. Thus, the broadcasters are likely to do their part. The enhanced EPG features will appeal to viewers, making them more likely to buy TV sets that support them, so the TV set manufacturers will do their part as well. However, the potential display of advertising in EPGs is an exception, at least in the context of terrestrial TV broadcasting. What is the business model by which the broadcasters and TV receiver manufacturers get paid for supporting it? To answer that question, we need to analyze the food chain for advertising in EPGs to see who benefits from the service, who provides the service, and how payment can make its way from those who benefit to those who provide. Suppose a company has a product or service it wants to advertise in a DTV EPG display. The ad copy is prepared and sent to a TV network or station, where it is inserted into the broadcast stream by means of a data encoder. Whenever a TV viewer is using the EPG, the DTV receiver extracts the advertising copy from the broadcast stream and displays it along with the EPG information. There is typically no back connection between the DTV receiver and the station, so there is no way to measure how many viewers see any particular ad, other than statistical sampling techniques of the same kind used to estimate how many viewers see an ordinary TV commercial. Of course, it is not really necessary for the advertising copy to be broadcast on every station. It would be sufficient to broadcast it on one station in each viewing area. While a viewer is looking at a full-screen EPG display, the TV set can switch to any desired channel under the covers, pick up the advertising copy, and switch back later to the channel the viewer was watching. The incentive for the broadcaster to include the ad copy in the broadcast is clear. The advertiser can pay the broadcaster on the basis of the usual statistical estimates of how many viewers saw the ad although one complication is that it is necessary to estimate not just how many viewers are using their EPGs during the time the ad airs, but also how many of their TV receivers have the ability to display ads in the EPG. In the case of cable and satellite operators who provide set-top boxes for their customers, the incentive is also clear. The advertisers can simply pay the cable or satellite operators and in this case it is easy to get an accurate count of how many viewers have complicit receivers. However, the incentive for manufacturers to build this functionality into ordinary TV sets is not nearly so clear. It is not at all likely to be a feature demanded by consumers! One solution may be to have a broker, who can pay manufacturers a fee for each DTV receiver sold with the capability to display ads in their EPGs, and charge advertisers or broadcasters a fee for each ad directed to such receivers. The fee paid to the manufacturers might be a one-time fee, or it might be a continuing royalty based on the ad revenue generated. It would be an easy matter to tag the ads which go through the broker with some kind of service mark, and have the receivers ignore any ad that does not carry the mark, in order to prevent unauthorized advertisers from using the facilities of the receivers. To facilitate multiple brokers, the service marks could represent the TV manufacturers rather than the broker, with the broker being authorized to use the service marks under the fee arrangement. (The problem this solves is that the TV sets would normally have to know what mark(s) to recognize at the time they are manufactured. Consumers would not be keen to update the software on their TV sets to recognize additional brokers.) Summary Interactive, on-screen, electronic program guides with enhanced searching and browsing functions and multimedia displays are definitely the wave of the future. Enhanced DTV standards will be required in order to realize this vision, and work on such standards is currently underway. However, some of the proposed functions may also require creative business models. 5

6 References 1. Program and System Information Protocol for Terrestrial Broadcast and Cable, ATSC doc. A/65, Rev. A, Jul ATSC Data Broadcast Standard, ATSC doc. A/90, Jul Specification for Service Information in DVB Systems, DVB doc. EN v1.3.1 ( ). 4. Service Information Carried Out-of-Band for Digital Cable Television, SCTE doc. DVS 234, revision 2, Mar Amendment No. 1 to Rev. A of Program and System Information Protocol for Terrestrial Broadcast and Cable, ATSC doc. A/65, Jul The SMPTE Data Coding Protocol and Dictionaries, SMPTE Journal, July The Metadata Dictionary, Proposed SMPTE Recommended Practice RP Overview of the MPEG-7 Standard, ISO/IEC JTC1/SC29/WG1 MPEG00/N3349, Mar Req. Series R-3: Metadata Requirements, TV-Anytime Forum doc. TV023r1-3, Mar Resource Description Framework (RDF) Model and Syntax Specification, W3C Recommendation REC-rdf-syntax , Feb