OVERVIEW OF THE ATSC DATA BROADCAST SERVICE SPECIFICATION Version 1.0 Don Newell, Intel Corporation Regis J. Crinon, Sharp Labs of America Inc. R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 1 ® PRESENTATION OVERVIEW MANDATE OF THE ATSC T3S13 WORKING GROUP A/V/D SERVICES DATA SERVICES SIGNALING • ANNOUNCEMENT, DISCOVERY, BINDING • ADVANTAGES (for broadcast, interactive services) LAYERS AND PROTOCOLS • PACKETIZATION, SYNCHRONIZATION , PROTECTION LAYERS • DOWNLOAD, IP PROTOCOLS • ADVANTAGES TRANSPORT SYTEM TARGET DATA RECEIVER MODEL • DATA SERVICE PROFILES • BUFFER MODEL • DATA SERVICES LEVELS CONCLUSION May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 2 R R ® ATSC T3S13 MANDATE • Define how data associated with a television program is carried, scheduled and announced. • Define how data not associated with a program is carried, scheduled and announced. • Build a foundation for new services (e.g. interactive services). • Define transport mechanisms to support a wide variety of data services: Asynchronous/Synchronous/Synchronized data Multiprotocol data Fixed bandwidth data Opportunistic data. May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 3 R R ® THANK YOU! • T3 members for recognizing importance of data services and starting T3S13 • T3 members trying to promote our work • Active participation of experts from other WGs • Companies who have hosted meetings • MPEG for endorsement of some new aspects of transmission May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 4 R R ® A/V/D SERVICES R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 5 ® DTV = VIDEO + AUDIO + DATA MPEG-2 Transport Streams carrying multiplexed: • Service Information (ATSC PSIP + MPEG-2 SI) • Audio, video and data elementary streams R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 6 ® GENERAL PICTURE * Television Programs * A/V * PSIP/System Info *Associated data such as - HTML-based -New media/graphics Stand-alone Data Services * Subscription Services - Magazines, Music - Targeted info services * Streaming Data (DSM-CC, IP) Broadcast Multiplex MPEG Transport Stream R R Opportunistic data services * Business data services * IP router in the sky *Targeted info services May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 7 ® ATSC T3S13 BENEFITS •Richer presentation model for advertisers/content producers Media object delivery (HTML, JAVA applets, Rich Graphics) •New incremental capabilities based on data •Support for widespread existing data protocols •Basic data services File download Integration with Web content May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. R R 8 ® DATA SERVICES SIGNALING R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 9 ® •ANNOUNCEMENT : PSIP + DIT • DISCOVERY • BINDING SDF R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 10 ® ANNOUNCEMENT (SCHEDULE) Data Services associated with an A/V event: value of service_type is 0x02 or 0x03 Use either > PSIP EIT(s) for a data services sharing same schedule and same title as A/V event OR > DIT(s) for a data service having a separate schedule or title A/V events data service 1 data service 2 Data Services NOT associated with an A/V event: value of service_type is 0x04 Use DIT(s) May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 11 R R ® ANNOUNCEMENT (SCHEDULE) In the descriptor loop of every A/V/D or D event: A Data Broadcast Descriptor is present. service_profile service_level Fields may be used by data receiver to determine whether it can proceed with acquisition of data service or not A PID Count Descriptor is optionally present: total # of PIDs minimum # of PIDs Fields may be used by data receiver to determine whether it can acquire full or “minimal” data service May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 12 R R ® ANNOUNCEMENT (SCHEDULE) Only one data service per virtual channel Possibly multiple data services in a single MPEG-2 Transport Stream (in this case SDF must be on distinct PIDs) R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 13 ® DISCOVERY AND BINDING: SERVICE DESCRIPTION FRAMEWORK SDF: • Describes a data service as an aggregation of applications (discovery) • Provides information for associating an application with broadcast or remote data components (binding) • Is designed based on MPEG-2 DSM-CC mechanisms (Association Tag descriptor, Tap structure). May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 14 R R ® SERVICE DISCOVERY • Main element is the Data Service Table identifying the applications making up a data service • The transmission of a Data Services Table is mandatory for any ATSC Data Service • Data Service Table follows MPEG-2 System section format May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 15 R R ® DATA SERVICE TABLE dataServiceTable(){ for (applications count) { compatibility descriptor application identifier for (tapsCount){ protocol_ encapsulation Tap() } // end tapsCount application parameters descriptors application private information } // end applications count service private information } May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. MPEG-2 packetization, synchronization, protection layers + protocol “pointer” to data element 16 R R ® BINDING TO A COMMUNICATION CHANNEL APP ApplicationCode() { open( TapId ) } TAP IN DST TapId use associationTag selectorLength for(j=0;j<selectorLength; j++){ selectorByte } } } R R associationTag in associationTag descriptor in PMT OR in Network Resource Descriptor May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 17 ® SERVICE BINDING • Main elements are the Network Resources Table and the Association Tag descriptor(s) in the PMT • The Network Resources Table announces any external communication channels used by a data service. • The transmission of a Network Resources Table is optional for any ATSC Data Service R R • Network Resources Table follows MPEG-2 section format May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 18 ® NETWORK RESOURCES TABLE networkResourceTable(){ compatibility descriptor dsmccResourceDescriptor private information } The internet address of a server in an interactive service OR a remote data elementary stream in another MPEG-2 Transport Stream R R includes an association tag May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 19 ® SERVICE BINDING Multiple Taps of one or several applications can reference the same Network Resource !!! AT2 NRT App1 Tap1 Tap2 Tap3 App2 Tap1 Tap2 AT1 PMT DST May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 20 R R ® SDF: GENERAL PICTURE Tap1 Tap 1 (AT1) Application 1 Tap2 Tap 2 (AT4) Network Resources Table Program Map Table Connection 1 (AT1) Matching AT PID 4 ATdescriptor AT 4 Connection 2 (AT2) Connection 3 (AT3) PIDx PIDx PIDx PIDx May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. PIDy PIDy PID4 PID4 21 INTERACTIVE DATA Matching AT BROADCAST DATA COMMUNICATION LAYER APPLICATION LAYER Data Service Table WEB SERVER R R ® SDF ADVANTAGES • promotes responsible usage of bandwidth • flexibility to determine how frequently it is transmitted (impact on accessibility) • designed for broadcast and interactive services • based on basic MPEG section parsing. • direct access to association tags so they can be managed easily in emission station • uses new resource descriptors for broadcast and interactive services (amendment 2 to DSM-CC) May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 22 R R ® LAYERS AND PROTOCOLS R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 23 ® PACKETIZATION, SYNCHRONIZATION, PROTECTION LAYERS Non-flow data controlled carousel DSM-CC download IP SDF PSIP LLC/SNAP checksum CRC32 checksum MPEG-2 PTS checksum CRC32 MPEG-2 addressable sections sections DSM-CC sections A V LLC/ SNAP MPEG-2 PTS PES packets MPEG-2 Transport Stream May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. IP 24 Data Piping R R ® PES Packets • Carry A/V data • Carry data synchronized with A/V • Carries data synchronized with other PES streams • Carries synchronous data A V LLC/ SNAP IP MPEG-2 PTS R R PES packets MPEG-2 T.S. May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 25 ® PES PACKETS • Synchronous data streaming harmonized with SCTE DVS132 • Synchronized data streaming harmonized with DVB • Each type has a defined header • Headers are not the same for Synchronous and Synchronized data elementary streams May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 26 R R ® EXAMPLE OF SYNCHRONOUS DATA SERVICES • Video Games based on 2D/3D graphics and image rendering • Infomercial based on animated computer graphics R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 27 ® DSM-CC SECTIONS • carousel scenario = periodic re-transmission of data module (for increased accessibility) • non-flow controlled scenario = one time download of a data module • Download protocol follows amendment 1 to DSM-CC for directory message numbering • The synchronized download protocol offers capability to transmit non-streaming, error-protected, synchronized data Non-flow data controlled carousel DSM-CC download MPEG-2 PTS checksum CRC32 R R DSM-CC sections MPEG-2 T.S. May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 28 ® EXAMPLES OF ASYNCHRONOUS DATA SERVICES • Stock tickers • sports statistics • weather reports • music downloads,... R R SONICS 102 PACERS 90 FINAL ... May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 29 ® EXAMPLES OF NON-STREAMING SYNCHRONIZED SERVICES Just-in-Time transmission of data synchronized with video and/or audio • • • • Pop-up videos Hot-spots, URL links in commercials and documentaries Evening games Triggers born in 1962 R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 30 ® ADDRESSABLE SECTIONS • For tunneling of Internet Protocol • Include a 6-byte MAC address • Default mapping is 28-bit IP multicast address to 23-bit Ethernet MAC multicast address • Agree with Amendment 1 to DSM-CC • checksum protection only for backward compatibility with MPEG section parsers IP LLC/SNAP checksum R R • Note: We need protocols to manage ATSC IP Network (urgent) !!! addressable sections MPEG-2 TS May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 31 ® EXAMPLES OF ADDRESSABLE SECTION -BASED SERVICES Personalized services: • Download of software at night • Subscription to newspaper service Scalable services: • platform-dependent downloads R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 32 ® TRANSPORT SYSTEM TARGET DATA RECEIVER MODEL R R May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 33 ® DATA SERVICE PROFILES Purpose is: • To represent maximum bandwidth allocated to a data service. • Multiple services can be bundled together into the same profile R R • A data service may use less than the transmission bandwidth allowed by the profile May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 34 ® DATA SERVICE PROFILES G1 Guaranteed bandwidth up to 384 kpbs G2 Guaranteed bandwidth up to 3.84 Mbps G3 Guaranteed bandwidth up to 19.39 Mbps R R A1 Opportunistic up to 19.39 Mbps ( NTSC VBI-based Data Services: 180 kbits/sec max ) May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 35 ® OPPORTUNISTIC DATA SERVICES Opportunistic data service = A data service for which no transmission bandwidth has been provisioned in the emission station. Data packets are inserted into the multiplex upon request from multiplexer (see IS DIWG) Opportunistic data services make use of instantaneous bandwidth available in a transport stream. Profile to be used in connection with VBR video encoders . May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 36 R R ® T-STD BUFFER MODEL The T-STD buffer model embodies the timely and controlled delivery of data. Its purpose: • To provide multiplexers with tool to implement synchronization of data with video or audio in a reliable manner. • To define bounds on size of data to be acquired by data receivers • To define bounds on throughput required in data receivers. May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 37 R R ® T-STD BUFFER MODEL FOR ASYNCHRONOUS SERVICES Leak rate specified by sb_leak_rate Data transfer rate specified by RXn Transport buffer TBn Smoothing buffer SBn 512 Bytes R R Size determined by sb_size May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 38 ® T-STD FOR SYNCHRONIZED SERVICES Data transfer rate specified by RXn Transport buffer Smoothing TBn buffer SBn 512 Bytes Leak rate specified by sb_leak_rate Size determined by sb_size Data Access Unit (DAU) taken out at time specified by MPEG-2 PTS associated with DAU, assuming instantaneous decoding Data Elementary buffer DEBn R R Size determined by SDEBn May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 39 ® DATA SERVICE LEVELS 1 4 16 DEBSn = 120120 bytes DEBSn = 480480 bytes DEBSn = 1921920 bytes R R 64 DEBSn = 7687680 bytes May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 40 ® DATA SERVICE LEVELS Purpose to provide reference points for memory and throughput requirements in data receivers DEBn buffer is split uniformly among all data elementary streams so applications of a same service can be run concurrently in a data receiver Nominal Data Access Unit (DAU) size is 40040 bytes = 19.2 Mbits/sec * 1001 / (8 * 60 * 1000) R R DAUs must at least 5.561111 msec apart (172.8 Mbits/sec throughput for level 1 services ) May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 41 ® CONCLUSION • ATSC Data Broadcast Service specification is the result of more than 2 years of successful collaboration between CE, PC and head-end equipment manufacturers. • It has been recorded as DVS 161 by SCTE • The specification opens up new business opportunities (opportunistic data, data service devices, IEEE 1394, personalization,...) • The specification will help accelerate deployment of DTV services. May 6, 1999 SHARP LABORATORIES OF AMERICA, INC. 42 R R ®