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A technical view of iTV service creation

A technical view of iTV service creation. Sten Law ætz Presentation from October 2000. Presentation overview. 1. Broadcast technology Signal encoding and transmission 2. Set-top box technology Hardware, middleware, applications 3. Service application technology

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A technical view of iTV service creation

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  1. A technical view of iTV service creation Sten Lawætz Presentation from October 2000

  2. Presentation overview • 1. Broadcast technology • Signal encoding and transmission • 2. Set-top box technology • Hardware, middleware, applications • 3. Service application technology • Programming languages, programming models • Service development workflow • 4. Challenges

  3. A warning: • Terminology is similar to traditional networking technology • packets, streams, applications • ...but 80% is slightly different • TLAs abound (and mean different things) • SMS, BAT, PAT, PID, TID, QAM, MUX ...

  4. An iTV service - the big picture Video Audio etc. DVB equpiment Transmission Flow Server STB Database Application Server Modem pool Encryption Host Connection

  5. 1. Broadcast technology • Video/audio compression standard algorithms • Transport layer specification (MPEG2 TS) • Transmission meta-data (PSI/SI)

  6. Video/audio compression • Lossy compression, redundancy elimination • Time-difference coding (frame-based) • Video • DCT (discrete cosine transform) • I/P/B frames • macro-blocks • Audio • MPEG1 layer 3 psycho-acoustical coding • 'mp3' format

  7. Transport streams • TS roughly = 1 analog TV channel • Formatted as MPEG2 packets (188 bytes) • Elementary streams (PES - packetized ES) • Video • Audio • Teletext • Data... • Multiplexed into the transport stream • Merged on packet-level to fill up bandwidth

  8. Transport stream example • Elementary streams merged with each other

  9. Modulation techniques • QPSK - quarternary phase-shift keying (sattelite) • QAM - quadrature amplitude modulation (cable) • COFDM - coded ortogonal frequency division multiplexing (terrestrial)

  10. Transport stream meta-data (MPEG2) • Similar to a directory (FAT for DOS-dinosaurs) • SI (service information) • PSI (program specific information) • Tables of tuples • NIT, PMT, PAT, BAT, TDT, SDT, etc. • Conditional access information

  11. Head-end hardware • Video/audio sources • encoders, video servers, audio servers • Multiplexing • service filtering, re-multiplexing • statistical multiplexing • Distribution • ATM, SDH, satellite relay • Modulation and RF gear • Modulators, up-converters / combiners / filters • Data injection • SI/PSI injection • Application data injection • object carousels

  12. Right, how does it look then? • Tele Danmark iTV servers

  13. The transmission chain revisited

  14. 2. Set-top box technology • Set-top box architecture • Essentially audio/video decoder hardware w. overlay graphics • RTOS (real-time operating system) • Middleware with API and application environment • "The great thing about standards is that there are so many of them"

  15. Set-top box hardware components • CPU • Storage • RAM • EEPROM • Flash RAM • Harddisks • Devices • Smart-card readers • Tuners/demodulators/demuxers • MPEG decoding chipsets w. On-Screen Display (OSD) • Return path modems (PSTN, ISDN, Cable, MMDS) • External buses (par/ser/SCSI/ethernet)

  16. Set-top box schematically

  17. Example STB hardware profile • Tele Danmark Kabel TV 'Selector' • Sagem series 3000 IRD Hardware • 2 MB RAM • 2 MB Flash RAM • 8 KB EEPROM (bootstrap) • single tuner/demodulator/demux • IBM MPEG-decoding chipset • 256 color OSD • PowerPC CPU • Dual smart-card reader • PSTN modem (14400 baud) • RS-232 / Centronics ports • OpenTV EN1 middleware

  18. STB software architecture • JavaTV layered architecture • Applies to most other middleware architectures • E.g.: Swap ‘JavaTV’ for ‘OpenTV’

  19. Middleware / Operating system • Currently deployed systems • OpenTV (OpenTV) • PowerTV (PowerTV) • DigiCypher II (Scientific Atlanta) • JavaTV (Sun) • MediHiway (Canal+ technologies) • Betanova (Beta-research, D-box) • Liberate (Liberate) • WebTV (Microsoft) • MHEG (eg. Philips) • Linux/OS9/VxWorks

  20. API models (as in MHP) • Declarative (high-level) • MHEG • Procedural (low-level) • OpenTV • PowerTV • MediaHiway • JavaTV • Mixed models • Liberate (html, javascript w. extensions) • WebTV

  21. Programming languages • Procedural languages • C/C++ (OpenTV, Betanova, Digicypher II) • Java (JavaTV) • Scripting languages • PanTalk (MediaHiway) • HTML / Javascript (Liberate, WebTV) • Declarative languages • MHEG-5

  22. Application capabilities (OpenTV) • General data processing • OSD rendering • shape control • MPEG decoder control • video/audio playback • MPEG chipset commands • Peripheral control • Return path (modem) • CA system interaction • Tuner/de-mux control • Zapping • SI access

  23. Example: OpenTV programming model • Single-tasking, single threading • API based • Windows API, X Windows • Event driven programming • Don't call us, we'll call you • Display tree manipulation

  24. Example: OpenTV iTV applications • OpenTV iTV service demonstration • Portal • EPG • Games

  25. 3. Service development • Not just an STB application • The components for 'real' interactive services: • STB application (consumer front-end) • Application server (business logic) • Subscriber Management Systems (access control) • Content delivery systems (transmission equipment) • Content management systems (Content authoring)

  26. Service development process • a) Concept specification • b) System architecture design • c) Graphical UI design • d) OpenTV application design/iplementation • Coding, graphic resource creation • e) Content provisioning • Back-end data acquisition and packaging • f) Application server business logic • Legacy system integration • g) Integration work • h) Deployment, operation and maintenance

  27. Development tools used at AGENCY.COM iTV • Resource editing • Graphics editor (e.g Photoshop) • Video editors (e.g. Premiere) • Application development • HTML editors • C/C++ compilers (e.g. GNU, Sun) • XML editors and parsers • Custom processing systems (e.g. LISP, XSL)

  28. Back-end technologies used • Base server platforms • Sun / Solaris UNIX servers • Windows NT PC servers • Application servers • Oracle application server • Custom built systems • Database servers • Oracle RDBMS, SyBase, Informix • Platform specific systems • Streaming servers, flow servers

  29. 4. Challenges • Creating content for the TV • Three-tier vs. two-tier networking • Multi-platform issues • Future direction of the STB

  30. Creating content for the TV • Presentation limitations • Screen size (640 x 480 [720 x 568] interlaced) • Viewer distance > 3 meters • Navigation principle limitations • No pointing device • No 'back'-button • Performance limitations • Limited storage • Limited CPU power • Design limitations • Network operator imposed 'branding'

  31. The fundamental difference between W3 and iTV • The three-tier networking model

  32. The multi-platform issue • Potentially hundreds of different tech profiles • Data delivery path, return path • Bandwidth issues, format issues (DVB/ATSC) • Middleware, APIs and VMs • Programming model, performance, functionality • STB hardware capabilities • Tuners, harddisks, storage • Application servers • Second tier fixed frameworks • The multi-platform challenge: • Single content source, multiple target platforms

  33. Future directions on STBs • TV is still king -> streaming media rules • The interactive bit is still an add-on • Slow convergence on standards (eg. MHP) • Diversity of proprietary systems • Blurring of the STB concept • Games consoles, 'the home entertainment center' • Consumer broadband technology • xDSL, the end of cable TV?

  34. The challenges to change • STB deployment inertia • millions of STBs already out there • software errors have large impact on acceptance • Three-tiered distribution • The network operator's role • Proprietary technology prevails • Extremely complex technology • compared to WWW

  35. Summary • 1. Broadcast technology • Signal encoding and transmission • 2. Set-top box technology • Hardware, middleware, applications • 3. Service application technology • Programming languages, programming models • Service development workflow • 4. Challenges

  36. Questions?

  37. Efterbehandling af Célia Quico’s speciale • Hvad er godt? • Hvad mangler du? • Hvad har du brug for at vi uddyber?

  38. Opgave til næste uge • Start på en matrix over • TDC Selector • Viasat • Canal Digital • (Digitalt jordbaseret tv) • Væsentlige teknologiske træk/begrænsninger ved den enkelte operatørs platform • STB specifikationer • Mulighed for skalering af video/multiple streams osv. • Jeg sender en Excel skabelon ud i aften

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