Multimedia

If your focus area is Multimedia, Sections I and II of your written paper are about the multimedia industry: 10 multiple-choice marks and about 15 marks of short answers (roughly six items, at least one worth 4–6 marks), 25 of the 40 written marks. They test Industry Related Manufacturing Technology for multimedia: the media, hardware, software, processes and techniques the industry uses, with WHS, legal issues, planning and costing.

• Media elements: text, images (raster and vector), audio, video, animation, 3D and interactivity.
• File formats and compression: lossy and lossless; containers and codecs; choosing formats for print, web and video.
• Calculations: image, audio and video file sizes; print size; frame counts; production costs.
• Production processes: pre-production (scripts, storyboards, flowcharts), production and post-production (editing, sound, effects, rendering, export).
• Animation and 3D: keyframes, tweening, easing, onion skinning, lip sync, rigging, texturing, rendering, motion capture.
• Interactive and emerging media: navigation, user testing, accessibility, VR and AR, AI tools.
• Legal, ethical and WHS issues: copyright, Creative Commons, ethics of manipulation and AI, ergonomics and on-set safety.

Expect Section II questions that ask you to calculate (show the formula and working), describe a process step by step, or explain the difference between two terms.

Raster (bitmap) images are grids of pixels. They suit photographs, but they become pixelated when enlarged. Vector images store shapes as mathematical paths, so they scale to any size with crisp edges; they suit logos, icons and diagrams.

Resolution is the number of pixels. For print it is described in pixels per inch (ppi) in the image file; printers lay down ink in dots per inch (dpi), a property of the printer. About 300 ppi is a common target for quality print. Print size = pixels ÷ ppi (in inches, × 25.4 for mm).

Bit depth is the number of bits stored for each pixel's colour. 8 bits gives 256 colours (or greys); 24 bits ('true colour') gives about 16.7 million.

Colour models: RGB (additive, light) for screens; CMYK (subtractive, inks) for print.

Uncompressed image size:

Worked example: 1280 × 720 pixels at 24-bit colour.

Check which definition of a megabyte the question uses: 1 000 000 bytes, or 1 048 576 bytes (sometimes written MiB).

Lossless compression shrinks a file without discarding data (the original can be rebuilt exactly). Lossy compression permanently discards detail people are unlikely to notice, giving much smaller files. Re-saving lossy files repeatedly causes generation loss: artefacts build up.

A container (MP4, MOV, MKV) wraps the tracks together; a codec (H.264, H.265, AAC) compresses each track. The file extension tells you the container, not the codec.

For the web, resize images to the largest size they will be shown, choose a suitable format (JPEG or WebP for photos, PNG or SVG for graphics) and lower the quality setting only until artefacts start to show.

Sample rate is the number of times per second the sound is measured. The highest frequency recorded is about half the sample rate, so 44.1 kHz (CD) captures up to about 22 kHz, and video normally uses 48 kHz. Bit depth (16 or 24 bits) is how precisely each sample is stored; more bits give a wider dynamic range and less noise.

Uncompressed audio size, with $f$ = sample rate (Hz), $b$ = bit depth, $c$ = number of channels and $t$ = time (s):

Worked example: 10 seconds of mono audio at 48 kHz, 24-bit.

Video: frame rate is frames per second (fps): 24 fps is the film look, 25 fps is the Australian broadcast standard (from the 50 Hz PAL system), about 30 fps is the North American standard, and 50 or 60 fps gives smooth motion. Resolution is commonly 1920 × 1080 (Full HD) or 3840 × 2160 (4K UHD). Aspect ratio is width : height: 16:9 widescreen, 9:16 vertical phone video, 4:3 older TV. Bit rate sets compressed size: size (megabits) = bit rate (Mbps) × seconds; divide by 8 for megabytes.

Shooting and editing

• Shots: extreme long shot (establishing), long shot, medium shot, close-up (emotion), extreme close-up (detail). Angles: high angle (subject looks smaller), low angle (subject looks powerful).
• Composition: rule of thirds; leading lines; headroom and lead room.
• Continuity: the 180-degree rule keeps the camera on one side of the line of action so screen direction stays consistent; the 30-degree rule says successive shots of the same subject should change camera angle by at least about 30°, so the cut does not look like a jarring jump.
• Editing: cuts, cross dissolves, J-cuts (incoming audio leads the picture), L-cuts (outgoing audio continues over the new picture), B-roll, colour correction and grading, chroma key (green screen).
• Sound: dialogue, Foley (everyday effects performed in sync), sound effects, music, ambience. Diegetic sound exists in the story world; non-diegetic sound (score, narration) is for the audience only. ADR re-records dialogue.

Describe processes in order. For example, adding sound effects: spot where effects are needed, source or record them (checking licences), place and synchronise them on separate tracks, then mix levels, panning and fades, and check before export.

• Frame-by-frame animation draws every frame; working 'on twos' holds each drawing for two frames. At 24 fps, a 10-second animation has 240 frames, or 120 drawings on twos.
• Keyframes set key poses; the software tweens (interpolates) the frames in between. Easing (ease in/out) makes motion accelerate and decelerate naturally.
• Onion skinning shows faint previous and next frames to guide drawing.
• Lip sync breaks dialogue into phonemes and matches each to a mouth shape (viseme) at the right frame.
• Rotoscoping traces over live-action footage. Stop motion photographs physical models moved between frames.
• 3D pipeline: modelling (polygon meshes), UV unwrapping and texture mapping, rigging (a skeleton of joints; inverse kinematics solves joint angles from the position of a hand or foot), animation, lighting and rendering. Ray tracing follows light rays for realistic reflections and shadows but takes more computation, so studios use powerful GPUs or render farms.
• Motion capture records an actor's movement and applies it to a rigged character: realistic and fast for large volumes, but costly and the data needs cleaning.

• Navigation structures: linear, hierarchical (tree from a home page) and webbed (non-linear).
• Design process: brief, research, flowcharts and wireframes, prototype, user testing with real users, revision, release, maintenance.
• Accessibility (Web Content Accessibility Guidelines, WCAG): alt text, captions and transcripts, colour contrast, keyboard operation, clear structure for screen readers.
• VR replaces the user's surroundings with a computer-generated world; AR overlays digital content on the real world; 360° video is viewed in a headset or by panning.
• Virtual production films actors in front of LED walls showing a real-time 3D environment, reducing green-screen compositing.
• Generative AI creates images, video, voice and text. It speeds up production but raises copyright, ethical and employment issues.

Copyright (_Copyright Act 1968_ (Cth)) protects original works automatically once they exist in material form; there is no registration in Australia. Using someone else's images, music or footage needs permission or a licence unless an exception applies. Creative Commons licences combine conditions: BY (credit the creator), NC (non-commercial), ND (no changes) and SA (share alike). Creators also have moral rights: to be attributed and to have their work not treated in a derogatory way.

Legal issues are about what the law requires (copyright, consumer law, privacy, classification). Ethical issues are about what is right: honest representation of people and products, consent, manipulated images and deepfakes, disclosure of AI use and fairness to the artists whose work trained AI tools. Questions often ask you to separate the two.

WHS: at workstations, set the screen top at or slightly below eye level and about an arm's length away, use adjustable chairs and take regular breaks to avoid musculoskeletal and eye strain. On shoots, control trip hazards from cables, manual handling of equipment, electrical hazards (especially outdoors), working at height with lights, sun and heat. Long hours and deadline pressure are psychosocial hazards that employers must also manage.

• Input: cameras, microphones, scanners, graphics tablets, capture cards. Processing: CPU, GPU (rendering, effects) and RAM. Output: monitors (calibrated for colour work), speakers, printers, projectors and headsets.
• Storage: large video projects need fast drives and a backup system (for example the 3-2-1 rule: three copies, on two kinds of media, one off site) and clear file naming and folder structures.
• Design principles: balance, contrast, alignment, repetition, proximity and white space; readable typography (font choice, size, line spacing); consistent colour schemes.

Pre-production documents: the brief, script (words and sounds), storyboard (pictures of each shot), shot list, flowcharts and wireframes for interactive products, and a Gantt chart for the schedule.

Production budget: cost of each line = rate × quantity; add the lines. Worked example: a sound designer for 1.5 days at $600 per day and a studio for 4 hours at $85 per hour.

• Forgetting to divide by 8 to convert bits to bytes, or mixing up Mb (megabits) and MB (megabytes).
• Leaving out the channels (stereo = 2) or converting minutes to seconds in size calculations.
• Calling MP4 a codec, or JPEG lossless.
• Writing ratios backwards (vertical video is 9:16).
• Mixing up J-cuts and L-cuts, or Foley and ADR.
• Treating legal and ethical issues as the same thing.
• Answering 'describe the steps' with a dot-point list. Describe what happens at each step.

• Identify wants the correct term; outline a brief sketch; describe the features or stages; explain cause and effect; evaluate a judgement.
• In calculations, write the formula, substitute with units, and state the answer clearly with the unit asked for.
• Use precise terminology ('lossy compression', 'keyframe', 'inverse kinematics'), which the marking feedback repeatedly rewards.
• For 4–6 mark items, develop two or three points fully and link each to the scenario in the question.

• Industry Study (Section III): use multimedia examples such as virtual production, AI tools, freelance and casual work, the MEAA, ergonomic hazards and e-waste.
• Major Project: the same planning documents (storyboards, Gantt charts, costing) are part of your folio, and good practice there is good evidence here.