Learning Objectives
- Define multimedia and list the elements of a multimedia system.
- Distinguish linear from non-linear (interactive) multimedia.
- Contrast graphics types and image file formats.
- Relate sound and video to storage, compression, and the Web.
- Identify the hardware and software needed for multimedia.
Next: web-based multimedia, multimedia in business.
What multimedia is
Multimedia combines two or more content types—typically text, graphics, audio, video, and animation—in one presentation, often with interactivity (buttons, links). Hypermedia links those media (the Web is the largest hypermedia system).
Characteristics of a multimedia system
- Computer-controlled — content is created, stored, and played by computers.
- Integrated — different media are combined into one experience.
- Digital — all media are stored as binary data.
- Interactive — users can often choose what to see next.
Linear vs non-linear multimedia
| Linear multimedia | Non-linear (interactive) multimedia |
|---|---|
| Plays from start to end in a fixed order | User controls the order through menus, links, and buttons |
| User has little or no control | User navigates and makes choices |
| Examples: a film, a slideshow on auto-play | Examples: websites, games, e-learning modules, kiosks |
Elements
- Text — headings, body, captions; cheapest to store; accessibility depends on real text, not only pictures of words.
- Graphics — still images. Bitmaps (raster) store pixels (photographs). Vector graphics store shapes and scale cleanly (logos, SVG).
- Sound — sampled audio (WAV, MP3) or MIDI-style instructions. Sampling rate and bit depth affect quality and file size.
- Video — many frames per second plus audio; compressed (MP4/H.264) for the Web.
- Animation — sequenced graphics (GIF, motion graphics, 2D/3D).
flowchart TB
MS[Multimedia System]
MS --> Text
MS --> Graphics
MS --> Sound
MS --> Video
MS --> Animation
Graphics --> Bitmap
Graphics --> Vector
Figure 1: Multimedia Elements Composition
Raster vs vector graphics
| Aspect | Raster (bitmap) | Vector |
|---|---|---|
| Made of | A grid of pixels | Mathematical shapes (lines, curves) |
| Scaling | Becomes blurry or “pixelated” when enlarged | Stays sharp at any size |
| Best for | Photographs, detailed images | Logos, icons, diagrams, illustrations |
| File formats | JPEG, PNG, GIF, BMP, TIFF | SVG, AI, EPS |
| Software | Photoshop, GIMP | Illustrator, Inkscape |
Image file formats (exam table)
| Format | Type | Typical use | Notes |
|---|---|---|---|
| JPEG / JPG | Raster, lossy | Photos | Small files; not ideal for sharp text/logos |
| PNG | Raster, lossless | Screenshots, logos with transparency | Larger than JPEG for photos |
| GIF | Raster, limited color | Simple animation, old web graphics | 256 colors; animation support |
| SVG | Vector | Icons, scalable logos on the Web | Resolution-independent |
| BMP | Raster, often uncompressed | Legacy Windows images | Very large |
| TIFF | Raster | Print / scanning | High quality; large files |
| WebP | Raster, lossy or lossless | Modern websites | Smaller than JPEG/PNG at similar quality |
Choose format by purpose: photo vs logo vs print vs animation.
Audio and video formats
| Format | Media | Notes |
|---|---|---|
| WAV | Audio | Uncompressed; high quality, very large |
| MP3 | Audio | Lossy compression; small files; most common for music |
| AAC | Audio | Better quality than MP3 at the same size; used by streaming |
| MIDI | Audio | Stores musical instructions, not recorded sound; tiny files |
| MP4 | Video | Most common web and mobile format (usually H.264 video) |
| AVI | Video | Older Windows format; often large |
| MOV | Video | Apple QuickTime format |
| WebM | Video | Open format designed for the Web |
Why compression matters: a worked example
CD-quality audio uses a sampling rate of 44,100 samples per second, a bit depth of 16 bits, and 2 channels (stereo):
- 44,100 × 16 × 2 = 1,411,200 bits per second ≈ 176 KB per second
- One minute ≈ 176 KB × 60 ≈ 10.6 MB uncompressed (WAV)
- The same minute as a 128 kbps MP3 ≈ 1 MB, roughly a tenth of the size
Video is far larger still, which is why streaming services and websites always compress it.
Lossy compression (JPEG, MP3, MP4) permanently removes some detail to save space. Lossless compression (PNG, ZIP, FLAC) shrinks files without losing any data.
Hardware and software for multimedia
- Hardware: a fast CPU, enough RAM, a graphics card (GPU), large storage, good display, speakers or headphones, microphone, camera, and scanner.
- Software: image editors (Photoshop, GIMP), audio editors (Audacity), video editors (Premiere Pro, CapCut), animation tools (Blender, Animate), and authoring tools for interactive content.
Nepal / business example
A hotel website that uses uncompressed BMP banners will load slowly on mobile data. JPEG for photos and SVG or PNG for the logo is the practical mix.
Converting the hotel’s 5 MB photos to compressed JPEG or WebP at around 300 KB each can make the page load many times faster for a guest browsing on mobile data, with no visible loss in quality.
Key Takeaways
- Multimedia = multiple media, often interactive.
- Linear multimedia plays in a fixed order; non-linear multimedia lets the user navigate.
- Raster vs vector, and format choice, are standard exam points.
- Sound and video dominate bandwidth; compression is required for the Web.
- Lossy compression saves more space; lossless keeps every detail.
Discussion Questions
- Why is JPEG a poor choice for a company logo with text?
- What does “lossy” mean?
- Name one benefit of SVG over PNG for a responsive website.
Exam-Style Questions
Short answer
- Define multimedia. List its five elements.
- Differentiate between raster and vector graphics.
- Differentiate between lossy and lossless compression with examples.
Long answer
- Explain the elements of a multimedia system with suitable examples.
- Describe common image, audio, and video file formats and explain how a business should choose formats for its website.
