Exam practice

• i.RTF: Rich Text Format
• ii.PNG: Portable Network Graphics
• iii.GIF: Graphics Interchange Format
• iv.JPG (JPEG): 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; MPEG is the Moving Picture Experts Group)
• viii.AAC: Advanced Audio Coding
• ix.MP4: MPEG-4 Part 14
• x.AVI: Audio Video Interleave

Multimedia is information presented with several kinds of media together. It has five components:

• Text: letters, numbers and symbols, used for headings, labels, captions and exact information. It takes little space and can be styled with fonts, sizes and colors.
• Graphics: still pictures such as photos, drawings, charts and logos, stored as raster (pixels) or vector (shapes) graphics. They show in a moment what words take long to explain.
• Audio: sound, such as speech, music and effects, stored as samples of its waveform (MP3, AAC, WAV).
• Video: a series of frames filmed by a camera, shown fast with their sound, to show real movement (MP4, MOV, AVI).
• Animation: pictures that are drawn or made by a computer, not filmed, and shown one after another so that they seem to move (2D or 3D).

A learning app, for example, uses text for the lesson, graphics for diagrams, audio for a teacher’s voice, video of experiments and animation to show processes.

RTF (Rich Text Format) is a file format for text documents, made by Microsoft in 1987. Unlike a plain TXT file, it stores text together with its formatting: fonts, sizes, colors, bold, italic and underline, line spacing, indentation and alignment. The formatting is written as control words in the file (such as \b for bold), so an RTF file is still text that any program can read. Its main use is moving styled documents between different word processors and computers: almost every word processor (Word, WordPad, LibreOffice Writer) can open and save it. RTF files have the extension .rtf. It can’t hold everything a DOCX can, and its files are larger for the same text.

An audio waveform is a graph that shows how a sound changes over time: time runs from left to right, and the height of the line shows how strongly the air (or microphone) is pushed at each moment. It has two main features:

• Amplitude, the height of the wave from the middle line to a peak, shows the loudness: a tall wave is a loud sound, a small one a quiet sound.
• The width of each wave (its period) shows how fast the sound vibrates. The number of waves each second is the frequency (in hertz), which decides the pitch: close-together waves are a high sound, wide ones a low sound.

To store a sound, the computer measures the waveform at equal intervals of time; each measurement is a sample, and the samples are saved as a sound file. In an audio editor the waveform shows where the sound is loud or silent, which helps in cutting and editing it.

Resolution is the number of pixels in each frame of a video, given as width × height. More pixels show more detail and a clearer picture, but make bigger files. Common resolutions: SD 720 × 480 (old TVs and DVDs), HD 1280 × 720 (online video), FHD 1920 × 1080 (TVs, monitors, phones), and 4K 3840 × 2160.
Frame rate is the number of frames (still pictures) shown each second, measured in frames per second (fps). A higher frame rate gives smoother motion; a low one looks jerky. Common frame rates: 24 fps (cinema), 25 fps (TV in Nepal and other PAL countries), 30 fps, and 50 or 60 fps (sport and games).
Both affect the file size: a video of higher resolution and higher frame rate holds more data each second, so it needs more storage and faster internet.

Raster graphics (bitmaps) are made of pixels, a grid of tiny squares, each storing one color. They are best for photos and detailed pictures with smooth changes of color. When enlarged, they become blocky or blurred, because each pixel just gets bigger. The more pixels, the bigger the file. Formats: PNG, GIF, JPG. Edited in programs such as Photoshop and Pixlr.
Vector graphics are made of shapes: lines, Bézier curves, circles and polygons, stored as mathematical formulas (points and numbers). The computer draws them again at any size, so they stay sharp when enlarged, and simple drawings have small files. They are best for logos, icons, fonts and diagrams, but can’t store photos. Format: SVG (also PDF). Edited in programs such as Illustrator and Inkscape.

Animation is pictures that are drawn or made by a computer and shown one after another so that they seem to move.
2D animation is flat: it has only width and height, like a drawing on paper. It is usually drawn frame by frame in an animation program: the animator draws the keyframes (the main positions) and the computer or an assistant fills in the in-betweens. It is used for cartoons, GIF stickers and explainer videos.
3D animation has width, height and depth, so it has perspective, light and shadow and can be seen from any side. It is made by modeling a character in the computer, rigging it with a skeleton, animating the skeleton with keyframes, and rendering every frame. It is used for animated films (such as Toy Story, 1995), video games and adverts. 3D animation looks more real but needs more powerful computers and more time.

Text, graphics, audio, video and animation.

Raster graphics (also called bitmap graphics) are pictures made of a grid of pixels, tiny squares each storing one color. The file stores the color of every pixel, so the more pixels, the more detail (and the bigger the file). They lose quality, becoming blocky, when enlarged. Photos are raster graphics; PNG, GIF and JPG are raster formats.

PNG (Portable Network Graphics), GIF (Graphics Interchange Format) and JPG/JPEG (Joint Photographic Experts Group).

In education: multimedia makes learning more interesting and easier to understand. Diagrams, animations and videos show things words can’t (how the heart pumps, how a seed grows), and seeing and hearing together helps students remember. Interactive lessons, simulations and quizzes let students try things and get feedback, and learn at their own pace. Video lessons let one good teacher reach students all over Nepal, even in remote schools.

In business: multimedia advertisements, with pictures, music and video, catch customers’ attention and make them remember a product, so marketing is more effective. Businesses also use multimedia for presentations, showing products online, training staff and meeting by video call, which saves time and travel.

A TXT file stores only plain characters: no fonts, sizes, colors, pictures or layout. It is small, simple, readable in any editor such as Notepad, and opens on every device.
A DOCX file, Microsoft Word’s format, stores the text together with its formatting (fonts, sizes, colors, bold, alignment, spacing) and also pictures, tables, headers, page layout and comments. It is really a compressed (ZIP) package of several XML files, so it can’t be read properly in Notepad, and needs a word processor such as Word or LibreOffice Writer. A DOCX is bigger than a TXT with the same words.

For a Dashain greeting card to send on a phone, I would use:

• Text: the greeting itself (“शुभ विजया दशमी”), the names of the person it is for and from. Text is clear and exact.
• Graphics: a picture of a kite, tika and jamara, or a family photo, with a colorful border. Pictures carry the festival’s feeling at a glance.
• Animation: the kite flying across the card, or the words appearing one by one, to catch the eye and make it lively.
• Audio: a short piece of festive music, or my own voice saying the greeting, to make it personal.

If it is a printed card, only text and graphics can be used, so I would pick one strong picture and a big, readable greeting.

PNG, if the logo must be a picture of pixels: PNG supports transparency, so the logo has no white box round it and can sit on any background color, and it is lossless, so its sharp edges and flat colors are kept exactly, with no smudges. (JPG can’t be transparent and smudges sharp edges.)
Even better, if the logo is drawn as shapes, is SVG: it is also transparent outside the shapes, and as a vector it stays sharp at any size, from a business card to a signboard.

Vector graphics, for the billboard’s design: its text, logo and shapes. A billboard is enormous, several meters wide, and a vector design is drawn again from its formulas at that size, so the letters and edges stay perfectly sharp; a raster design blown up that big would look blocky. Vector files are also small and easy to change.
If the billboard includes a photo, that part must be raster, so it should be a photo with a very high resolution. Billboards are seen from far away, so a photo of good resolution looks sharp there, but the text and logo should still be vector.

Similarities: both combine several components of multimedia: YouTube and Google Earth both use text (titles, labels, descriptions), graphics (thumbnails; satellite photos and map symbols) and moving pictures. Both are interactive (the user chooses what to watch or where to go), are used for learning as well as fun, work on computers and phones, and need a good internet connection because they send large amounts of data.
Differences:

A simple layout, one screen of a lesson (sketch it as a phone screen, as in Figure 3.1):

• At the top, the title of the lesson, “The Water Cycle”, in large text: it tells the student what the lesson is about.
• Below it, a video of a real experiment (water boiling and condensing on a cold plate), with a play button: real things are best shown filmed.
• Beside or below, an animation of the water cycle, with arrows of water rising from the sea, forming clouds and falling as rain: a process that takes days, shown in seconds.
• A labeled graphic (diagram) of the cycle that stays still, to study and copy into a notebook.
• A speaker button for an audio explanation in Nepali or English, for students who learn better by listening or find reading hard.
• Short lines of text under each part, and a quiz button with questions to tap, with sounds and pictures for right and wrong answers, to check understanding.
• Buttons along the bottom: Back, Next, Home.

Each element is chosen for what it does best: text for exact words, graphics and animation for shapes and processes, video for real events, audio for those who listen better than they read.

Strengths of video:

• It is the richest medium: it shows real movement, faces, expressions and places, with sound, so it explains a skill or an event far better than text or audio alone (how to tie a bandage, what a flood looked like).
• It catches attention and is remembered, so it spreads quickly on social media; most internet traffic today is video.
• It can be understood by people who can’t read, and with captions, by people who can’t hear.

Weaknesses of video:

• Its files are very large: it needs fast internet, costs mobile data and storage, and is hard to watch in places with poor connections, where text and audio still work.
• It takes more time, skill and equipment to make.
• It is slow to search and skim: a reader can scan a page of text in seconds to find one fact, but must watch a video through. Text is also better for exact information (numbers, addresses, instructions to follow step by step).
• Audio is better when the eyes are busy (driving, working) and uses far less data than video.

Conclusion: video has the biggest impact for showing, persuading and engaging, and has become the main form of online communication. But it is not always the best: text is best for exact, searchable information, and audio for listening on the move with little data. Good digital communication chooses the medium that suits the message and the audience, and often combines them.