--- title: "Global structure of multimedia system" subject: "Multimedia System" chapter: 1 key: "semester_8/multimedia_system:global-structure-multimedia-system" source: https://www.bctengineer.com/q/semester_8/multimedia_system/global-structure-multimedia-system site: BCT Engineering --- # Global structure of multimedia system Multimedia System · Chapter 1: Introduction - Asked in: 2075 Bhadra, 5 marks; 2072 Asoj, 9 marks; 2071 Bhadra, 9 marks (asked 3 times) - Video: [Global Structure of Multimedia | Multimedia Computing | Bsc CSIT 5th Sem](https://www.youtube.com/watch?v=lPmfHjS-edQ) — CSIT Samay - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_8/multimedia_system/global-structure-multimedia-system - Whole chapter: https://www.bctengineer.com/md/semester_8/multimedia_system/chapter-1 ## Question Explain the global structure (views) of a multimedia system with a diagram. ## Short answer A multimedia system has three layered domains: application domain (user interface and applications), system domain (OS, communication, database), and device domain (capture, storage, output hardware). Each upper layer uses services of the lower layer, enabling portability and separation of concerns. ## Answer A multimedia system can be viewed at three levels, called **domains**: the application domain, the system domain and the device domain. The global structure shows how an application at the top uses system services in the middle, which in turn use the hardware devices at the bottom. ```text +-----------------------------------------+ | APPLICATION DOMAIN | | Applications (e-learning, video conf.) | | User interface | Documents | Toolkits | | Abstractions for programming (API) | +-----------------------------------------+ | SYSTEM DOMAIN | | Operating system (scheduling, I/O) | | Communication system (protocols, QoS) | | Database / file system | +-----------------------------------------+ | DEVICE DOMAIN | | Capture: camera, mic, scanner | | Storage: HDD, CD/DVD, flash | | Output: monitor, speaker, printer | | Network adapters | +-----------------------------------------+ ``` #### Application domain This is the part the user sees. It contains the multimedia applications (video conferencing, video on demand, e-learning, games), the **user interface**, the document and presentation formats, and the programming abstractions (APIs, toolkits, authoring systems) used to build applications. It decides what the user can do, without knowing how the hardware works. #### System domain It gives the services between application and hardware. It has: - **Operating system:** process management and real-time scheduling, resource management, device drivers and file system. - **Communication system:** network protocols, transport of continuous media, quality of service (QoS) guarantees and synchronisation. - **Database system:** storage, indexing and retrieval of large multimedia objects. #### Device domain It covers the physical devices: input devices (microphone, camera, scanner), output devices (monitor, loudspeaker, printer), storage devices (hard disk, optical disc, flash) and network hardware. It also contains the basic concepts of media representation such as sampling, digitisation and compression hardware. #### Flow of operation A user action in the application (play a video) is turned by the API into a request to the system domain. The OS schedules the CPU and disk, the communication system fetches the stream, and finally the device domain decodes and displays it on the screen and speaker. Each upper domain depends only on the interface of the lower one, so devices or protocols can change without rewriting the application. #### Why the layered view is useful - **Separation of concerns:** application designers need not know hardware details; hardware makers need not know the applications. - **Portability:** the same application runs on different devices if the system domain offers the same interface. - **Resource handling at the correct place:** real-time deadlines and QoS are handled in the system domain, because they involve the CPU, disk and network together. #### Example: video on demand - Application domain: the viewer chooses a film from a menu and uses play/pause buttons. - System domain: the server database finds the file, the network protocol streams it with a guaranteed rate, and the client OS schedules the decoder. - Device domain: server disks, network cards, the client's graphics card, monitor and speakers. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which are the three domains in the global structure of a multimedia system, from top to bottom? A. Device, system, application B. Application, device, system C. System, application, device D. Application, system, device Answer: D. The top layer is the application domain, the middle is the system domain and the bottom is the device domain. (Key point: Three domains) 2. Which set belongs to the system domain? A. Operating system, communication system, database system B. Camera, microphone, scanner C. User interface, documents, toolkits D. Monitor, speaker, printer Answer: A. The system domain holds the OS, communication system (protocols, QoS) and database/file system. (Key point: System domain contents) 3. Why are real-time deadlines and QoS handled in the system domain? A. Because the user interface lives there B. Because hardware cannot handle deadlines C. Because they involve the CPU, disk and network together D. Because applications need to know hardware details Answer: C. Deadlines and QoS involve CPU, disk and network together, so they are handled in the system domain. (Key point: Where QoS is handled) 4. What is a benefit of each upper domain depending only on the interface of the lower one? A. Devices or protocols can change without rewriting the application B. The application must be rewritten for each device C. Applications talk directly to hardware faster D. Real-time scheduling is not needed Answer: A. Layering separates concerns and gives portability, so lower layers can change without rewriting applications. (Key point: Benefit of layering) ## Related in Multimedia System - [Abstraction levels of multimedia programming](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Aabstraction-levels-programming) — Multimedia System, chapter 7, asked 6× - [Multimedia UI design guidelines](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Aui-design-guidelines) — Multimedia System, chapter 6, asked 5× - [Multimedia user interface design process](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Aui-design-process) — Multimedia System, chapter 6, asked 2× - [Multimedia application development life cycle](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Aapp-development-life-cycle) — Multimedia System, chapter 1, asked 4× - [Multimedia interface components](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Aui-interface-components) — Multimedia System, chapter 6, asked 2× - [Components to build multimedia systems](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Acomponents-build-multimedia-systems) — Multimedia System, chapter 1 ## Related in other subjects - [Basic structure of power system](https://www.bctengineer.com/question.md?key=semester_4%2Fpower_system_analysis_i%3Abasic-structure-power-system) — Power System Analysis I, chapter 1 - [Three phase system and structure of hcp](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Athree-phase-hcp-structure) — Concrete Technology and Masonry Structure, chapter 2, asked 6× - [Lattice structure of second order pole-zero system](https://www.bctengineer.com/question.md?key=semester_7%2Fdigital_signal_analysis_and_processing%3Alattice-iir-pole-zero-2nd) — Digital Signal Analysis and Processing, chapter 4 - [Block diagram of digital communication system](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Ablock-diagram-digital-comm) — Data Communication, chapter 1, asked 8×