Multimedia

A science lesson on your phone may show an animated experiment, play a teacher's voice, pop up a quiz and end with a short video — text, pictures, sound, video and animation working together. That combination is multimedia. This unit explains each element: how text is styled, how pictures are stored as pixels or as shapes, how sound and video become numbers in a file, and how animation creates movement. It also shows how to edit images in Pixlr and Canva, sound in Audacity and video in CapCut, the free tools the course uses.

3.1 Introduction to multimedia, its elements and applications

Apps you already know are multimedia: Duolingo mixes text, voice, sound effects and animation to teach languages; TikTok combines video, filters, text and music; YouTube joins video, sound, thumbnails and live chat; and Google Earth layers satellite images, text labels and 3D maps. In Nepal, OLE Nepal's E-Paath lessons and the government's Sikai Chautari portal use multimedia for school subjects.

Element	What it is	Example in a learning app
Text	letters, numbers and symbols	lesson notes, quiz questions
Graphics	still pictures: photos, drawings, charts, icons	a labelled diagram of the heart
Audio	sound: speech, music, effects	the teacher's voice explaining
Video	moving pictures recorded with sound	a recorded experiment
Animation	drawn or computer-made pictures that move	an animated water cycle

Multimedia may be linear, playing from start to end like a film, or interactive, where the user clicks, chooses and answers, as in a game or a learning app.

Applications of multimedia

• Education — e-books, online courses, simulations and quizzes make lessons interactive and easier to understand.
• Entertainment — films, music, video games and virtual reality.
• Business and advertising — advertisements, product videos and presentations capture customers' attention.
• Communication — video calls, video conferencing and social media.
• Content creation — short videos, graphics and podcasts for social media.
• Other fields — medical imaging and surgery training, virtual tours for tourism, maps and navigation, news and journalism.

Advantages of multimedia	Disadvantages of multimedia
holds attention and makes learning interesting	creating good content takes time and skill
explains hard ideas with pictures, sound and motion	cameras, computers and software can be costly
suits learners who learn by seeing, hearing or doing	large files need storage and fast Internet
allows interaction and immediate feedback	too many effects can distract from the message
one presentation can reach a huge audience	may not work on old devices or for people without access

3.2 Text: fonts, typography and text file formats

Text is the characters you see on the screen — letters, digits and symbols, also called alphanumeric characters. It carries most of the exact information in a multimedia product: titles, labels, instructions and explanations. Text is typed in editors such as Notepad and WordPad and word processors such as Microsoft Word and Google Docs.

Fonts

A typeface is a design of letters, such as Arial; a font is one version of it — a particular size, weight and style, such as Arial Bold 14 point. Font size is measured in points (1 point = 1/72 inch).

Font family	Look	Examples	Best for
Serif	small strokes (serifs) at the ends of letters	Times New Roman, Georgia	printed books and long reading
Sans-serif	plain letters without serifs	Arial, Calibri, Noto Sans	screens, slides, signs
Monospace	every letter the same width	Courier New, Consolas	program code
Script and decorative	handwriting or artistic shapes	Brush Script	titles and cards only

Nepali text should be typed in a Unicode font such as Kalimati, Mangal or Noto Sans Devanagari. Older non-Unicode fonts such as Preeti store English letters and only draw them as Devanagari, so Preeti text turns into nonsense on any computer or phone that does not have the font.

Typography

Typography is the art of arranging text so that it is easy to read and pleasant to look at. Its main tools are the choice of font, size and style (bold, italic, underline), colour and contrast with the background, alignment (left, centre, right, justified), line spacing (leading), kerning (the gap between two letters) and hierarchy — making headings larger than body text so the reader sees the structure at a glance.

Text file formats

Format	Full form	Stores	Notes
TXT	Text	plain characters only — no fonts, sizes or colours	opens in any editor; smallest; used for notes and program code
RTF	Rich Text Format	text with formatting: fonts, size, colour, bold, alignment, spacing	readable by almost every word processor (Microsoft, 1987)
DOCX	(Word) Document, XML format	text, formatting, tables, images, comments	Microsoft Word's own format since Word 2007; actually a zipped bundle of XML files
PDF	Portable Document Format	text, fonts, images and layout fixed for printing	looks the same on every device; used to share final documents

A DOCX file differs from a TXT file in that it keeps the formatting, pictures and tables, needs a word processor to open properly and is larger; a TXT file keeps only the characters.

3.3 Graphics: raster and vector, pixels and resolution, formats, and editing

Graphics are the visual elements of multimedia: photographs, drawings, charts, logos, icons and shapes. They are made and edited in programs such as Pixlr, Canva, GIMP and Adobe Photoshop (for photos) and Inkscape and Adobe Illustrator (for drawings and logos). A computer stores a picture in one of two completely different ways.

Raster graphics, pixels and resolution

The resolution of a raster image is its number of pixels, written as width × height, for example 1920 × 1080. More pixels show more detail but make a larger file. For printing, resolution is also given as pixels per inch (ppi) or dots per inch (dpi): about 300 ppi gives a sharp photo print. The colour depth is the number of bits per pixel: 24-bit colour (8 bits each for red, green and blue) gives about 16.7 million colours. When a raster image is enlarged, the pixels become visible as blocks — pixelation.

Vector graphics

Raster (bitmap) graphics	Vector graphics
made of a grid of pixels	made of mathematically described points, lines and curves
blurs or pixelates when enlarged	stays sharp at any size
file size grows with the number of pixels	file size grows with the number of shapes; usually small
best for photographs and realistic images	best for logos, icons, diagrams, fonts, maps
edited pixel by pixel (Pixlr, Photoshop, GIMP)	edited shape by shape (Inkscape, Illustrator)
formats: JPG, PNG, GIF, BMP, WebP	formats: SVG, AI, EPS (and PDF)

Graphics file formats

Most image formats compress the pixel data to make files smaller. Lossless compression rebuilds every pixel exactly; lossy compression throws away detail the eye is unlikely to notice, giving much smaller files.

Format	Full form	Type	Key features	Typical use
JPG / JPEG	Joint Photographic Experts Group	raster, lossy	small files for photographs; quality setting; no transparency	camera photos, web photos
PNG	Portable Network Graphics	raster, lossless	supports transparency; sharp edges and text stay crisp	logos on websites, screenshots, diagrams
GIF	Graphics Interchange Format	raster, lossless but only 256 colours	simple animation; on/off transparency	short animations, stickers
WebP	(Web Picture)	raster, lossy or lossless	smaller than JPG and PNG; transparency and animation	modern websites
BMP	Bitmap	raster, uncompressed	very large files	old Windows programs
SVG	Scalable Vector Graphics	vector	sharp at any size; text-based	icons, logos, maps on websites
PDF	Portable Document Format	document (raster and vector)	fixed layout, prints identically	sharing and printing documents and posters

Editing images in Pixlr

Pixlr is a free online image editor at pixlr.com, with an app for phones. The quick editor the textbook calls Pixlr X is now named Pixlr Express, and the advanced one Pixlr Editor. Its workspace has four areas: the canvas (where the image is shown and edited), the tools panel (left), the layers panel (right) and the navigation tools for zoom, pan and rotate.

Task	Steps in Pixlr
New project	Open pixlr.com → Pixlr Express → Create new → choose a preset or type a name and size (e.g. 1920 × 1080) → Create
Add text	Text tool (T) → Add new text → type → change font, size, colour, alignment and spacing in the left panel; drag the handles to resize, the round dot to rotate
Add a shape	Arrange (or Elements) → Shape → choose square, circle and so on → set fill, outline and shadow
Work with layers	Layers panel → + to add a layer → the ⋯ menu to rename, hide, lock or change opacity and blend mode → drag to reorder
Insert a photo	Element / Add media → choose the file → Open
Cut out an object	Cutout tool → choose shape, softness or the Draw and Lasso cutout → drag over the object → Keep or Remove to refine
Export	Save → choose the name, format (JPG, PNG, WEBP or PXZ) and quality → Save as

PXZ is Pixlr's own layered format: save in PXZ to keep layers for later editing, and export a PNG or JPG for sharing. A higher quality setting gives a sharper image and a bigger file.

Designing in Canva

Canva (canva.com, with a phone app) is a free online design tool built around templates. Choose the kind of design (poster, presentation, Instagram post, certificate), pick a template, then replace its text and pictures by dragging Elements (shapes, icons, stickers, photos) on to the page. Uploads brings in your own images, Text adds headings, and Share → Download exports the design as PNG, JPG, PDF or, for animated designs, MP4. Pixlr is better for editing a photograph itself; Canva is faster for laying out a poster, card or presentation from ready-made parts.

3.4 Audio: digital sound, audio file formats, and recording and editing

Audio is the sound in multimedia: speech, music, instruments and sound effects. Sound is a vibration that travels through air as a pressure wave. A microphone turns the wave into a changing electrical voltage (an analogue signal), and the computer's sound card turns that into numbers.

From sound wave to digital audio

An audio waveform is the graph of a sound against time. Its amplitude (height) shows the loudness; the time taken by one complete wave is its period, and the number of waves each second is the frequency, which we hear as pitch (high or low).

To store sound, the computer measures the wave at regular instants — sampling — and stores each measurement as a number:

• the sampling rate is the number of samples per second; music CDs use 44,100 Hz (44.1 kHz) and video uses 48 kHz;
• the bit depth is the number of bits per sample; 16-bit audio has 65,536 possible levels;
• the number of channels: 1 for mono, 2 for stereo.

The size of uncompressed audio follows directly:

Audio file formats

Format	Full form	Compression	Features and use
WAV	Waveform Audio File Format	none (uncompressed)	exact copy of the recording; very large; used for recording and editing
MP3	MPEG-1 Audio Layer III	lossy	small files, plays everywhere; made portable music players and streaming possible
AAC	Advanced Audio Coding	lossy	better quality than MP3 at the same bit rate; used by YouTube, iPhones and Android
M4A	MPEG-4 Audio	lossy (usually AAC)	AAC sound in an MP4 container
FLAC	Free Lossless Audio Codec	lossless	about half the size of WAV with no loss
OGG	Ogg Vorbis	lossy	free, open format used in games

The bit rate (kbps) of a compressed file sets its quality and size: 128 kbps is fine for speech and casual listening; 192–320 kbps sounds close to the original.

Recording and editing audio in Audacity

Audacity is a free, open-source audio editor for Windows, macOS and Linux (audacityteam.org). Its window has a menu bar, a toolbar with the transport buttons, a timeline across the top, one track for each recording showing its waveform, and level meters.

1Menu bar — File (Import, Export Audio), Edit (Cut, Delete, Undo), Effect (fades, Amplify, Normalize, Noise Reduction, Echo)2Transport buttons — play, pause, stop and the red Record button3Time display — the position of the play head4Timeline — time in seconds, used to select parts accurately5Track controls — mute (M), solo (S), volume and the Effects button for that track6Waveform — height is loudness, left to right is time7Level meter — keep the loudest parts below the red zone when recording8Selection toolbar — start, end and length of the selected part

Task	Steps in Audacity
Record	plug in a microphone and choose it in Audio Setup; press the red Record button (or R), speak, and press Stop (or Space)
Import a file	File → Import → Audio, or drag the file into the window
Cut out a part	drag across the unwanted part of the waveform to select it, then Edit → Delete (or press Delete)
Apply an effect	select a part and open the Effect menu, where effects are grouped: Fading → Fade In / Fade Out, Volume and Compression → Amplify / Normalize, Noise Removal and Repair → Noise Reduction, Delay and Reverb → Echo; preview, then apply
Listen	press Play (Space); the play head moves along the timeline
Export	File → Export Audio, give a name, choose MP3 or WAV, the quality (bit rate) and channels, then Export

The textbook uses AudioMass (audiomass.co), a free editor that runs in the browser. It works the same way: its menu bar, waveform display and control panel offer Record (press R and choose the microphone), File → Load from Computer, select-and-scissors to cut, an Effects menu (normalize, fade in, fade out, reverse, pitch shift, and reverb with time, decay and wet settings), and File → Export/Download as MP3 or WAV with a chosen bit rate.

3.5 Video: frames, frame rate and resolution, formats, and editing

A higher frame rate gives smoother motion and a larger file:

Frame rate	Where it is used
24 fps	cinema films
25 fps	television in Nepal, India and Europe (the PAL standard)
30 fps	television in the USA (NTSC), most online video and phones
50–60 fps	sports, video games, slow-motion and smooth phone video

Resolution is the number of pixels in each frame, width × height. The aspect ratio is the ratio of width to height: 16 : 9 for TV and YouTube, 9 : 16 for vertical TikTok and Reels, 4 : 3 for old TVs.

Name	Resolution	Pixels per frame	Common use
SD (Standard Definition)	720 × 480 (720 × 576 in PAL countries)	345,600	old TVs, DVDs
HD	1280 × 720	921,600	online video on slow connections
FHD (Full HD)	1920 × 1080	2,073,600	TVs, laptops, YouTube, phone cameras
4K UHD	3840 × 2160	8,294,400	large TVs, films, high-end phones

Video file formats

A video file is a container that holds the compressed video, the audio and extra data such as subtitles. The way the pictures are compressed is the codec (H.264, H.265, AV1).

Format	Full form	Features and use
MP4	MPEG-4 Part 14	the most widely used; good compression with H.264 or H.265 video and AAC audio; plays on phones, YouTube, Netflix
MOV	QuickTime Movie	Apple's format, compressed or uncompressed; used on iPhones and Macs and in editing
AVI	Audio Video Interleave	Microsoft's older format (1992); large files; compressed or uncompressed
MKV	Matroska Video	free open container; many audio and subtitle tracks
WebM	Web Media	open format for the web, used by YouTube in browsers

Editing and exporting video in CapCut

CapCut is a free video editor from ByteDance, used online at capcut.com, on Windows and Mac, and as a phone app (some effects are paid). Clipchamp, built into Windows 11, and the open-source Shotcut and Kdenlive are free alternatives that work the same way: every editor has a media area, a preview, a timeline and an export button.

1Media area (Project Bin) — the clips, music and pictures you imported2Effects panel — colour, brightness, blur and other effects to drag on to a clip3Preview (monitor) — plays the edited video at the play head4Timeline — video tracks above, audio tracks below; trim, split and arrange clips here

Task	Steps in CapCut
New project	capcut.com → Create new video → choose the aspect ratio (16 : 9 for YouTube, 9 : 16 for TikTok) → click "Untitled project" to rename it
Import	Media → Upload → From this device → select the files → Open; they appear in the media area
Arrange	click a clip, or drag it, on to the timeline; drag clips to change their order; use the zoom slider to see detail
Play	press Space or the play button; the play head (cursor) moves along the timeline
Trim	drag the start or end handle of a clip to shorten it
Split and delete	move the play head to the cut point → Split → select the unwanted piece → Delete
Transition	hover between two clips → Add transition → choose one → drag its edges to change its length
Effects and filters	Effects panel → place the play head → click an effect → double-click it on the timeline to adjust
Text	Text → Add heading → type → set font and colour in Properties → drag the text clip's edges to set how long it shows
Export	Export → Download → choose the resolution (e.g. 1080p), frame rate (e.g. 30 fps) and quality → Export; the file is an MP4

3.6 Concept of animation

Animation is used for cartoons, films, advertisements, video games, websites and learning materials. 2D and 3D describe how the pictures are made; frame-by-frame and keyframe describe how the movement is made.

2D animation is flat: its pictures have only width and height. Each frame is drawn, or characters are built from flat parts that move. Cartoons, explainer videos, animated stickers and many advertisements are 2D. Free 2D tools include Pencil2D, OpenToonz and Krita; Adobe Animate is a common paid one.

3D animation has width, height and depth, so objects have volume and can be seen from any angle with light and shadow. A character is first modelled (built as a 3D mesh), then rigged (given a skeleton of joints), textured, animated by moving the rig, and finally rendered into frames. Pixar's Toy Story (1995) was the first feature film made entirely with computer animation. Blender is a free 3D tool; Maya and 3ds Max are professional ones.

2D animation	3D animation
two dimensions: width and height	three dimensions: width, height and depth
flat look	depth, perspective, light and shadow
drawn frame by frame or built from flat parts	modelled, rigged, textured, animated, rendered
quicker and cheaper to make	needs more skill, time and computing power
cartoons, stickers, explainer videos	animated films, games, architecture walkthroughs
Pencil2D, OpenToonz, Adobe Animate	Blender, Maya, 3ds Max

Frame-by-frame animation: the animator draws every frame separately. It gives full control and a hand-made look, but it is slow: one second of film at 24 fps needs 24 drawings. Keyframe animation: the animator sets only the important positions — the keyframes, such as the start and the end of a movement — and the software calculates the frames in between, called in-betweens or tweens (the process is tweening). Almost all computer animation today is keyframed.

Where animation is used: films and cartoons; video games; advertisements and logos that move; education (an animated heart pumping, the water cycle, E-Paath lessons); websites and apps (loading icons, stickers, emojis); science, medicine and engineering simulations; architecture walkthroughs; and weather maps on television.

Animation and psychology. Animators use what attracts people's attention: bright colours and movement catch the eye, which is why cartoons for children are colourful and busy; expressive faces help viewers feel for a character; and well-timed, smooth movement makes an animation pleasant and easy to follow.

Textbook exercises: model answers

1. Full forms. (i) RTF — Rich Text Format. (ii) PNG — Portable Network Graphics. (iii) GIF — Graphics Interchange Format. (iv) JPG — Joint Photographic (Experts) Group. (v) SVG — Scalable Vector Graphics. (vi) PDF — Portable Document Format. (vii) MP3 — MPEG-1 Audio Layer III (MPEG Audio Layer 3). (viii) AAC — Advanced Audio Coding. (ix) MP4 — MPEG-4 Part 14. (x) AVI — Audio Video Interleave.

2. Multiple choice — answers

i. (b) — multi means many: many types of media.

ii. (a) — cost and access to hardware and software is a drawback; the others are benefits.

iii. (b) — TXT stores only the characters.

iv. (c) — the characters on screen are text.

v. (b) — vector graphics are built from Bézier curves and scale without loss.

vi. (b) — a PDF can hold raster and vector graphics and is used to share documents.

vii. (c) — amplitude (height) is loudness.

viii. (c) — MP3 is the common compressed format for sharing.

ix. (c) — resolution is the number of pixels, width × height.

x. (b) — MP4 compresses video efficiently.

xi. (a) — width, height and depth.

xii. (d) — 2D animation is usually drawn frame by frame.

3. Short notes — model answers

a. Components of multimedia. Multimedia has five components: text (written information), graphics (still images such as photos, drawings and charts), audio (speech, music, effects), video (recorded moving pictures with sound) and animation (drawn or computer-made pictures that move). Together they make information interesting and easy to understand.

b. Rich Text Format. RTF is a text file format created by Microsoft (1987) that stores text together with its formatting — fonts, sizes, colours, bold and italic, alignment, indentation and line spacing. Almost every word processor can open it, so it is used to exchange formatted documents.

c. Audio waveform. A waveform is the graph of a sound against time. Its height (amplitude) shows loudness and the number of waves per second (frequency) shows pitch. To store it, the computer samples the wave thousands of times a second (44,100 for CD sound) and saves each value as a number.

d. Video resolution and frame rate. Resolution is the number of pixels in each frame, written width × height — SD 720 × 480, HD 1280 × 720, FHD 1920 × 1080; more pixels give a sharper picture and a bigger file. Frame rate is the number of frames shown each second (fps) — 24, 25, 30, 50 or 60; a higher rate gives smoother motion.

e. Raster and vector graphics. Raster graphics are grids of pixels, best for photographs, and they pixelate when enlarged (JPG, PNG, GIF). Vector graphics are shapes described mathematically, best for logos and icons, and stay sharp at any size (SVG, AI, EPS).

f. 2D and 3D animation. 2D animation is flat, with width and height only, and is usually drawn frame by frame (cartoons). 3D animation has width, height and depth; models are built, rigged and moved, then rendered (Toy Story, games).

4. Questions — model answers

a. Text, graphics, audio, video and animation.

b. A raster graphic is an image made of a grid of pixels, each with its own colour; its quality depends on the number of pixels (resolution).

c. JPG (JPEG), PNG and GIF (also BMP and WebP).

d. Raster images are made of pixels and lose quality when enlarged; vector images are made of mathematical shapes and stay sharp at any size. Raster suits photos, vector suits logos and diagrams, and vector files are usually smaller.

e. In education multimedia makes lessons interactive and easier to understand through pictures, sound, video and simulations, and lets students learn at their own pace. In business it attracts customers through advertisements and product videos, explains products clearly, and helps companies communicate through presentations and video meetings.

f. A TXT file stores only plain characters, opens in any editor and is very small. A DOCX file stores text with fonts, colours, tables, images and page layout, needs a word processor, and is larger.

g. For a greeting card: text for the message and names, graphics for a photo, border and decorations, and, for a digital card, a little animation (falling flowers, a glowing diya) and audio (a short tune) to make it lively and personal.

h. PNG — it is lossless and supports a transparent background, so the logo sits cleanly on any colour. (SVG is even better on websites because it stays sharp at every size.)

i. Vector — a billboard is enlarged many times, and a vector design is redrawn sharply at any size, while a raster image would pixelate unless it had an enormous number of pixels.

j. Similarities: both combine several media, are interactive and are used for learning. Differences: YouTube centres on video with sound, text titles and thumbnails, and is used to watch and share content; Google Earth centres on satellite images and 3D maps with text labels, and is used to explore places. YouTube is mostly linear viewing; Google Earth is exploration the user controls.

k. A learning-app screen could have: a text title and short notes (exact information), a labelled graphic (shows structure at a glance), an audio button to hear the explanation (helps reading and pronunciation), a short video of a real experiment, an animation of the process (makes motion and change clear), and a quiz with instant feedback (interaction). Sketch them as boxes on one screen: title at the top, image and video in the middle, audio and quiz buttons at the bottom.

l. Video combines moving pictures, sound and text, so it shows processes and emotions that text or audio alone cannot, holds attention and is easy to understand for people of every reading level — which is why most Internet traffic today is video. But video files are large, need more data and better devices, take longer to produce and are hard to skim or search; text is quicker to scan and audio can be heard while doing something else. The best choice depends on the message, the audience and their connection.

Chapter summary

• Multimedia combines text, graphics, audio, video and animation; it may be linear or interactive and is used in education, entertainment, business, communication and content creation.
• Text: serif, sans-serif and monospace fonts, size in points; typography arranges text for readability. Formats: TXT (plain), RTF (formatted), DOCX (Word), PDF (fixed layout). Use Unicode fonts for Nepali.
• Raster images are grids of pixels (JPG, PNG, GIF, BMP, WebP) and pixelate when enlarged; vector images are mathematical shapes (SVG, AI, EPS) and stay sharp. Raw size = width × height × bytes per pixel.
• Lossless compression keeps every detail (PNG, FLAC); lossy throws some away for small files (JPG, MP3, MP4).
• Audio: amplitude = loudness, frequency = pitch; sampled at, e.g., 44,100 Hz with 16 bits. Size = rate × bits × channels × seconds. WAV is uncompressed; MP3 and AAC are compressed.
• Video = frames shown at a frame rate (24, 25, 30, 60 fps) with a resolution (SD 720 × 480, HD 1280 × 720, FHD 1920 × 1080). Formats: MP4, MOV, AVI, MKV.
• Tools: Pixlr (photo editing, layers, cutout; JPG/PNG/WEBP/PXZ), Canva (templates), Audacity/AudioMass (record, cut, effects, export), CapCut (timeline, trim, split, transitions, text, export MP4).
• Animation: 2D (width, height) and 3D (with depth: model, rig, animate, render); frame-by-frame draws every frame, keyframe animation draws key poses and the software makes the tweens.

Practice questions

Group A — Multiple choice (1 mark each)

1. Which one is NOT an element of multimedia? [1]atextbanimationccompilerdaudio
2. The smallest unit of a raster image is a [1]abitbpixelcvectordframe
3. Which format is lossless and supports a transparent background? [1]aJPGbPNGcBMPdMP3
4. A school logo that must stay sharp on a large banner should be made as a [1]araster imagebvector imagecGIFdJPEG
5. Which audio format is uncompressed? [1]aMP3bAACcWAVdM4A
6. In an audio waveform, the height of the wave shows [1]apitchbloudnesscdurationdfile size
7. The number of frames shown in one second is called [1]aresolutionbbit ratecframe ratedaspect ratio
8. A resolution of 1920 × 1080 is called [1]aSDbHDcFull HDd4K
9. Which video format was developed by Apple? [1]aAVIbMOVcMKVdWAV
10. In keyframe animation, the frames between two keyframes are [1]adrawn one by onebcalculated by the software as tweenscdeleteddstored as audio
11. A 3D animation has [1]awidth onlybwidth and heightcwidth, height and depthdlength and breadth
12. Which program is used to record and edit sound? [1]aCanvabAudacitycPixlrdMySQL

Answers to Group A

1. (c) — a compiler translates programs; it is not a medium.

2. (b) — a pixel is one picture element.

3. (b) — PNG is lossless with transparency; JPG has no transparency.

4. (b) — vectors are redrawn sharply at any size.

5. (c) — WAV stores the samples without compression.

6. (b) — amplitude is loudness; frequency is pitch.

7. (c) — frames per second.

8. (c) — Full HD is 1920 × 1080; HD is 1280 × 720.

9. (b) — MOV is the QuickTime format.

10. (b) — the software interpolates the in-betweens.

11. (c) — depth is the third dimension.

12. (b) — Audacity is a free audio editor.

Group B — Short answer (2 marks each)

1. Write two differences between raster and vector graphics. [2]
2. What is a pixel? What does a resolution of 1280 × 720 mean? [2]
3. Calculate the size of a 30-second stereo WAV recording at 44.1 kHz and 16 bits. [2]
4. Differentiate between lossy and lossless compression, naming one format of each. [2]
5. What is frame rate? Why are sports often broadcast at 50 or 60 fps? [2]
6. Write two differences between 2D and 3D animation. [2]
7. What is keyframe animation? How does it differ from frame-by-frame animation? [2]
8. Suggest a file format, with a reason, for(a) a song to share on WhatsApp and(b) a scanned certificate to email. [2]

Answers to Group B

1. Raster graphics are made of pixels and lose quality when enlarged; vector graphics are mathematical shapes and stay sharp at any size. Raster suits photographs (JPG, PNG); vector suits logos and diagrams (SVG).

2. A pixel (picture element) is the smallest dot of an image, holding one colour. 1280 × 720 means the image is 1280 pixels wide and 720 pixels high — 921,600 pixels in all (HD).

3. 44,100 × 16 × 2 × 30 = 42,336,000 bits; ÷ 8 = 5,292,000 bytes ≈ 5.3 MB.

4. Lossless compression makes a file smaller without losing any detail, so the original can be rebuilt exactly (PNG, FLAC). Lossy compression throws away detail that is hard to notice, giving much smaller files (JPG, MP3, MP4).

5. Frame rate is the number of frames shown each second (fps). Sports are full of fast movement; 50 or 60 frames per second show each movement in more steps, so the ball and players look smooth instead of jerky.

6. 2D animation has width and height only and looks flat; 3D animation adds depth, perspective, light and shadow. 2D is drawn or built from flat parts; 3D is modelled, rigged and rendered, and needs more time and computing power.

7. In keyframe animation the animator sets only the key positions (start, end, important poses) and the software calculates the frames in between (tweening). In frame-by-frame animation every frame is drawn by hand, which gives full control but takes far longer.

8. (a) MP3 (or AAC) — small file that plays on every phone. (b) PDF — keeps the layout, prints identically and is not easily changed (a JPG is also acceptable for a photo of it).

Group C — Long answer (4 marks each)

1. What is multimedia? Explain its five elements with an example of each. [1+3]
2. Explain the steps to record your voice in Audacity, remove a cough from the recording, add a fade-out at the end and export it as an MP3 file. [4]
3. A 2-minute Full HD video is recorded at 30 fps. Find(a) the number of frames,(b) the uncompressed size of one frame at 24-bit colour,(c) the file size if it is compressed at 8 Mbps, and(d) state why videos are compressed. [4]
4. What is animation? Differentiate between frame-by-frame and keyframe animation, and write four uses of animation. [1+1+2]

Answers to Group C

1. Multimedia is the combined use of text, graphics, audio, video and animation to present information (1). Text — written words, e.g. lesson notes; graphics — still pictures, e.g. a diagram of the heart; audio — sound, e.g. a teacher's recorded voice; video — recorded moving pictures, e.g. an experiment; animation — moving drawn or computer images, e.g. an animated water cycle (3).

2. (1) Connect a microphone, choose it in Audio Setup, press the red Record button, speak, and press Stop. (2) Play the recording, drag across the cough on the waveform to select it, and press Delete. (3) Select the last few seconds and choose Effect → Fading → Fade Out. (4) Choose File → Export Audio, give a file name, select MP3, choose the quality (e.g. 128 kbps) and click Export.

3. (a) 2 × 60 × 30 = 3,600 frames. (b) 1920 × 1080 × 3 = 6,220,800 bytes (about 6.2 MB). (c) 8,000,000 × 120 = 960,000,000 bits; ÷ 8 = 120,000,000 bytes = 120 MB. (d) Uncompressed, the video would need 6.2 MB × 3,600 ≈ 22.4 GB; compression makes it small enough to store, upload and stream.

4. Animation is the illusion of movement made by showing slightly different pictures quickly one after another (1). Frame-by-frame animation draws every frame by hand; keyframe animation sets only key poses and the software calculates the in-between frames (1). Uses (any four, 2): cartoons and films, video games, advertisements, education and simulations, website and app effects, weather maps.