AN EFFECTIVE ARCHITECTURE OF ADVANCED TV
SET-TOP AND INTERACTIVE SERVICES USING TV-ANYTIME
METADATA
H-K. Lee¹, H-K. Lee¹, B. Bae², K. Kang¹ and J. Kim¹ ¹Electronics and Telecommunications Research Institute, Korea,
²Information and Communication University (ICU), Korea
ABSTRACT
This paper presents the set-top architecture, for metadata processing, based on the TV-Anytime specification. In addition, to verify the above architecture and metadata description scheme, some applications for content browsing and navigation have been implemented using set-top emulation software. In the set-top emulator, metadata is stored and managed by a database tool. The structure of the database tables and their columns is designed according to the TV-Anytime metadata and content referencing specifications. For consistent conversions between XML-based descriptions and database records, the architecture of the database tables retains the semantic and syntactic structure of the TV-Anytime Forum’s description scheme.
Currently, we are considering and implementing some more advanced usage scenarios for broadcast contents with multiple PDRs (Personal Digital Recorder) on home-networks. This includes remote control of the PDR from sub-PDRs, content adaptation and distribution from the main-PDR to sub-main-PDRs with considerations for user preference and terminal capacity information and so on.
INTRODUCTION
Advances in technologies for digital TV and interactive TV provides the user with more content and related data. This rapid increase of information makes it difficult for the user to select or find what he or she wants, and it demands effective methods for selection and management of broadcasted contents, whether distributed or locally stored. To resolve the above issues, international standards and industry consortiums, such as MPEG-7[1] or TV-Anytime Forum[2,3,4], have developed generic or domain-specific metadata standards and their requirements for content description, respectively.
For broadcasting applications, TV-Anytime Forum has extracted application scenarios with proper business models and developed a set of technologies for the intelligent broadcasting environment of PDRs(Personal Digital Recorders).
Metadata takes an important role for advanced TV applications. To verify the usability of metadata especially for broadcast service’s user, research is required on a feasible high level architecture of set-top or client terminals and proper user interaction methods.
This paper presents the architecture for set-top or client terminals, usage of metadata specifications, functional features of an emulator, and concludes with a description of the test environment and future work.
ARCHITECTURE OF SET-TOP
To understand the relationship between functions and the set-top architecture, we draw a conceptual block diagram, as shown at Figure 1, which is based on the TV-Anytime system architecture. In Figure 1, the content or broadcast service provider transmits content and metadata to Clients. Search and Navigation and Location Resolution blocks access metadata and content location information and return a certain part of them in response to the user interaction block. Note that the Search and Navigation and Location Resolution blocks are also located at the outside of the Client. That is, external service providers who serve metadata or content location data are connected to the Client via interactive channels such as the Internet. In addition, the client requires function blocks for content storage, content presentation, and user interaction.
To verify the usefulness of metadata, we developed an emulation system for advanced TV applications based on metadata. To emulate user-centric functions on the set-top, we tried to develop a mostly TV-like user interaction scheme rather than a PC-based one. This is because a simple but intelligent interaction scheme is one of the important issues for successful migration of advanced functionalities to TV.
Figure 2 shows the layered structure for the previous conceptual block construction. Emulator design and implementation is based on this layered structure diagram. For each conceptual block at Figure 1, some more detailed elements are defined and constructed. Most blocks have three types of elementary units; data structure, data access interface, and logical operation engine which has an operation sequence dependent on its specific functionalities.
The data structures for metadata and location resolution shall be used to design the data layer for the Search and Navigation block and Location Resolution block respectively. For emulator development, data structures are implemented by database tables. The structure of these tables matches that of the metadata schema and location resolution data. Consequently, the data access interface is implemented with database access libraries. As intermediate data storage, the database will help to guarantee greater compatibility with various metadata structures such as TV-Anytime, MPEG-7, and so on.
The content presentation block provides content decoding, rendering, and playback control functions. In the emulator, the content presentation block is implemented with a software library. In case of a hardware set-top, the Content Presentation block shall be implemented with hardware components.
Lo c al Stora ge M a na g em en t
U s e r Inte ra c tio n
C o nte nt P res e nta tio n Lo ca tion R es olu tion U s er S ea rc h a n d N av iga tion m e ta d a ta C o ntro l C o nte n t Co n te n t S e rv ic e Prov id er C o nte nt C re ato r C lie nt S e a rc h a n d N a v iga tio n Se rv ic e Prov id er Lo c atio n R e so lu tio n Se rv ic e Prov id er
METADATA SPECIFICATIONS
Metadata is an important data element for advanced functions on the set-top. It is transmitted from the service provider of broadcast content and metadata. The TV-Anytime specification defines 4 types of metadata; instance description metadata, content description metadata, consumer metadata, and segmentation metadata.
Content description metadata describes the content independently of its instantiation. Content description metadata includes a description of a program or a group of programs such as title, synopsis, etc. A group of programs can support various types of group such as series, episodes, and a related set of content. So that you can describe information as a certain group of content, TV-Anytime defines a list of group types in its specification.
Instance description metadata describes information for instantiation of content. For a broadcast service, the broadcast content is a type of instantiation. Using instance description metadata, we describe the program schedule for the content selection application, which is more than just the EPG(Electronic Program Guide).
Segmentation metadata describes temporal intervals and their relationships to certain content. The description includes segment locations, key frame locations, segment types, etc. For the emulator implementation, segment-related data is stored with the structure of segment description metadata, and they support random access or browsing functions on segment units.
Consumer metadata is a description related with consumer’s usage history and preference information for content. For the emulator design, we integrate the user’s genre preference into a user interaction scheme and a logical operation for the program guide[5]. It shows that consumer metadata and its recommendations allow the user to select content with less interaction with the set-top.
U SER
U ser Inte ra ction P resenta tion(R e ndering)C onte nts
Loca tion R esolu tion E ngine M eatadata
H an dling E ngine
U ser P referen ce
E ngine C ontents A ccess E ng ine
D ata A ccess A P I based o n X M L P a rser / O D B C A P I M etadata C ontents/ G U I R esource E le m ents Loca tion R esolution R e cords U ser P referen ce related D ata D ire ctS how A P I Pre se ntation La ye r Lo gic L ayer D ata Layer S torage M a nagem ent E ngine
Use r In tera c tion
S e arc h an d
Navigatio n Reso lutio nLoc ation U se r P re f ere nc e M a na ge m en tS to ra g e C o n te nt P re s e ntation
FUNCTIONAL FEATURES OF SET-TOP
To provide the advanced functions for the set-top user with the metadata described in the last section, effective application scenarios and their interaction schemes should be developed. We extracted some critical functions with reference to the TV-Anytime business models. Figure 3 shows a set of screen shots of functions; a content guide with user preferences, a table of content browser, and an event-based summary browser.
The electronic content guide(ECG) is one of the most important functions when a large number of channels must be navigated by the user. However, only providing the list of programs at certain times and channels could not support enough guidance information. Let’s suppose one or two hundred broadcast channels are available at the home, then an efficient guide function becomes vital to select what the user wants to view. Figure 3(a) shows the implementation of the content guide function on the set-top emulator. It shows the weekly timetable, in which each time slot is colored by a user preference. In addition, the program list at the lower half of screen is also ordered by the user’s genre preference.
The table of contents browser provides a navigation control within certain content. The user can easily perceive the overall structure of the content, and has access to any segment of it. As shown in Figure 3(b), with a simple browser interface, the user can view and select a segment after browsing through the hierarchical structure of the content.
For the browsing of content, there are various types of browsing methods, and the efficiency of browsing method is partially dependent on the genre of content. The Event-based summary browser in Figure 3(c) provides a function similar to the index at the end of a book. We found that an informational genre, such as a news or documentary program, is good for browsing with event-based browsing. Therefore, we selected a news program for testing, and built up summary segments for subjects of politics, international, social, and economics. In addition, we have developed some functions for an environment with multiple PDRs. In the future, the user will consume broadcast content in an environment with multiple PDR’s and home devices rather than a simple one with a single set-top. At first, we integrate a remote control function of the main-PDR from the sub-PDR as shown in Figure 3(d). A user of the sub-PDR, currently a portable device in the home, can control all the functions of the main-PDR, mentioned above, on his personal device. Then user can make a connection with his personal device and log into main set-top with his identification information. This identification also makes possible of his preference based program guide information.
CONCLUSIONS
To verify normal operations of each function and their efficiency, we generated test metadata as listed at Table 1. Table 1 shows the metadata tables of the TV-Anytime specification that were used and their physical size. We gathered program guide information for 4 channels over a two week period. Program guide information includes content description and instance description metadata. For segment related functions, we select two types of broadcast content; one is drama and the other is news programs, and each was 35 minutes in length. We found that the measurement and comparison of the efficiency of user preference or the interaction scheme is difficult at this time, but we are developing a methodology for this and will report on this later.
Database Table Description Size
Program Information Table program, relation to group
Group Information Table program group
Program Location Table The location of program
Service Information Table Service Information
Credits List Table Actors, producer etc. About items for creation
578KB
Segment Information Table Segment Information
Segment Group Information
Table Segment Group Information
117KB Table 1 – Metadata tables and size for testing
This paper has presented a study of the metadata required at the user’s side of a broadcast service and its corresponding TV-Anytime’s specification. We have also introduced some current implementation results from the development of metadata extraction and associated technologies.
Currently ETRI have developed an intelligent system on client terminals and an environment with multiple PDRs.
ACKNOWLEDGEMENTS
We faithfully thank the Ministry of Information and Communication (MIC) of the Korean government, who has supported our research under the title of “A Study on MPEG-7 based Broadcasting Contents and Metadata Technology”.
REFERENCES
1. Information Technology – Multimedia Content Description Interface – Part 5: Multimedia Description Schemes, ISO/IEC FDIS 15938-5
2. Requirement Series: R-1 on The TV-Anytime Environment, The TV-Anytime Forum 3. Specification Series: S-3 Metadata, SP0003v1.1, The TV-Anytime Forum
4. Specification Series: S-4 on Content Referencing, The TV-Anytime Forum
5. Munchurl Kim, Geewoong Ryu, Beetnara Bae, Jeho Nam, kyeongok Kang, Jinwoong Kim : Intelligent Program Guide for Digital Broadcasting, IWAIT(2002), Jan. 2002
(a) ECG with User preference (b) Table of contents browser
(c) Event-based summary browser (d) Remote control on sub-PDR Figure 3 – Screens of Functional features on Set-top
