Computer Graphics & Multimedia (AD-503 (B)) - Unit 5 Short Notes

How unit 5 is examined

This unit covers multimedia basics, text, audio, video, animation and compression; no past questions were asked, so every topic is short and definition-first.

Basic of multimedia, application of Multimedia

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>Multimedia is the integrated, computer-controlled presentation of text, graphics, audio, video and animation in one interactive product.</mark>

Key points.

1. The five media elements are text, images or graphics, audio, video and animation.
2. Multimedia is interactive when the user controls the flow, for example through hyperlinks and menus.
3. Applications include education and e-learning, entertainment and games, advertising, medicine and simulation.
4. It needs authoring tools, storage such as CD, DVD or servers, and compression because the data is large.

Diagram. <figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u5-01" viewBox="0 0 460 130" width="460" height="130" role="img" aria-label="Five elements of multimedia"><style>#dsfig-u5-01 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u5-01 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u5-01 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u5-01 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u5-01 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u5-01 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u5-01 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u5-01 .t{fill:#16181D;font-weight:500}#dsfig-u5-01 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u5-01 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u5-01 .dot{fill:#16181D}#dsfig-u5-01 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u5-01 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u5-01 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u5-01 .ah{fill:#454C5A}#dsfig-u5-01 .ah.hi{fill:#2340B8}#dsfig-u5-01 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u5-01 .wl .t{font-size:12px;font-weight:700}#dsfig-u5-01 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u5-01 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u5-01 .e{stroke:#B1B7C3}html.dark #dsfig-u5-01 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u5-01 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u5-01 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u5-01 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u5-01 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u5-01 .t{fill:#E6E8ED}html.dark #dsfig-u5-01 .t.inv{fill:#0F1115}html.dark #dsfig-u5-01 .kd{stroke:#E6E8ED}html.dark #dsfig-u5-01 .dot{fill:#E6E8ED}html.dark #dsfig-u5-01 .ann{fill:#8FA3FF}html.dark #dsfig-u5-01 .lbl{fill:#858D9C}html.dark #dsfig-u5-01 .ptr{fill:#8FA3FF}html.dark #dsfig-u5-01 .ah{fill:#B1B7C3}html.dark #dsfig-u5-01 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u5-01 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u5-01 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u5-01 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah2" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah" d="M0,1 L9,5 L0,9 z"/></marker><marker id="ahh2" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah hi" d="M0,1 L9,5 L0,9 z"/></marker></defs><line class="e" x1="208.3" y1="37" x2="40" y2="101"/><line class="e" x1="208.3" y1="37" x2="123.5" y2="101"/><line class="e" x1="208.3" y1="37" x2="210.5" y2="101"/><line class="e" x1="208.3" y1="37" x2="285.5" y2="101"/><line class="e" x1="208.3" y1="37" x2="376.5" y2="101"/><rect class="n" x="159.3" y="22" width="98" height="30" rx="8"/><text class="t" x="208.3" y="37" dy=".35em" text-anchor="middle">Multimedia</text><rect class="n" x="14" y="86" width="52" height="30" rx="8"/><text class="t" x="40" y="101" dy=".35em" text-anchor="middle">Text</text><rect class="n" x="82" y="86" width="83" height="30" rx="8"/><text class="t" x="123.5" y="101" dy=".35em" text-anchor="middle">Graphics</text><rect class="n" x="181" y="86" width="59" height="30" rx="8"/><text class="t" x="210.5" y="101" dy=".35em" text-anchor="middle">Audio</text><rect class="n" x="256" y="86" width="59" height="30" rx="8"/><text class="t" x="285.5" y="101" dy=".35em" text-anchor="middle">Video</text><rect class="n" x="331" y="86" width="91" height="30" rx="8"/><text class="t" x="376.5" y="101" dy=".35em" text-anchor="middle">Animation</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Five elements of multimedia</figcaption></figure>

Text-Types, Unicode Standard, text Compression, Text file formats

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>Unicode is a universal character-encoding standard that gives every character of every language a unique code point.</mark>

Key points.

1. Text types are plain text (no formatting), formatted text (fonts, styles) and hypertext (linked nodes).
2. ASCII uses 7 bits (128 characters) while Unicode covers over a lakh of characters through UTF-8, UTF-16 and UTF-32.
3. Text compression must be lossless, using Huffman coding, run-length coding or the LZW dictionary method.
4. Common formats are TXT, RTF, DOC and PDF; font formats are TrueType (TTF) and OpenType (OTF).

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u5-02" viewBox="0 0 325 130" width="325" height="130" role="img" aria-label="Types of text"><style>#dsfig-u5-02 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u5-02 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u5-02 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u5-02 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u5-02 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u5-02 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u5-02 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u5-02 .t{fill:#16181D;font-weight:500}#dsfig-u5-02 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u5-02 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u5-02 .dot{fill:#16181D}#dsfig-u5-02 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u5-02 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u5-02 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u5-02 .ah{fill:#454C5A}#dsfig-u5-02 .ah.hi{fill:#2340B8}#dsfig-u5-02 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u5-02 .wl .t{font-size:12px;font-weight:700}#dsfig-u5-02 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u5-02 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u5-02 .e{stroke:#B1B7C3}html.dark #dsfig-u5-02 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u5-02 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u5-02 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u5-02 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u5-02 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u5-02 .t{fill:#E6E8ED}html.dark #dsfig-u5-02 .t.inv{fill:#0F1115}html.dark #dsfig-u5-02 .kd{stroke:#E6E8ED}html.dark #dsfig-u5-02 .dot{fill:#E6E8ED}html.dark #dsfig-u5-02 .ann{fill:#8FA3FF}html.dark #dsfig-u5-02 .lbl{fill:#858D9C}html.dark #dsfig-u5-02 .ptr{fill:#8FA3FF}html.dark #dsfig-u5-02 .ah{fill:#B1B7C3}html.dark #dsfig-u5-02 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u5-02 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u5-02 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u5-02 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah3" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah" d="M0,1 L9,5 L0,9 z"/></marker><marker id="ahh3" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah hi" d="M0,1 L9,5 L0,9 z"/></marker></defs><line class="e" x1="142.5" y1="37" x2="43.5" y2="101"/><line class="e" x1="142.5" y1="37" x2="134.5" y2="101"/><line class="e" x1="142.5" y1="37" x2="241.5" y2="101"/><rect class="n" x="116.5" y="22" width="52" height="30" rx="8"/><text class="t" x="142.5" y="37" dy=".35em" text-anchor="middle">Text</text><rect class="n" x="14" y="86" width="59" height="30" rx="8"/><text class="t" x="43.5" y="101" dy=".35em" text-anchor="middle">Plain</text><rect class="n" x="89" y="86" width="91" height="30" rx="8"/><text class="t" x="134.5" y="101" dy=".35em" text-anchor="middle">Formatted</text><rect class="n" x="196" y="86" width="91" height="30" rx="8"/><text class="t" x="241.5" y="101" dy=".35em" text-anchor="middle">Hypertext</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Types of text</figcaption></figure>

Audio Components, Digital Audio, Digital Audio processing, Sound cards, Audio file formats, Audio Processing software

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>Digital audio is sound converted from an analog wave into numbers by sampling and quantisation.</mark>

Key points.

1. Sampling rate must be at least twice the highest frequency (Nyquist); CD audio uses 44.1 kHz, 16 bits, 2 channels.
2. File size in bytes equals sampling rate $\times$ bits per sample $\times$ channels $\times$ seconds $/ 8$; one minute of CD audio is 10,584,000 bytes, about 10.1 MB.
3. A sound card holds the ADC, DAC and mixer to record and play sound.
4. Formats are WAV (uncompressed), MP3 and AAC (lossy), MIDI (note instructions); Audacity is editing software.

Example. Two minutes of CD-quality stereo: $44100 \times 16 \times 2 \times 120 / 8 = 21{,}168{,}000$ bytes, about 20.2 MB.

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u5-03" viewBox="0 0 596 80" width="596" height="80" role="img" aria-label="Digital audio chain: microphone, analog-to-digital converter, processing, digital-to-analog converter, speaker"><style>#dsfig-u5-03 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u5-03 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u5-03 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u5-03 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u5-03 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u5-03 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u5-03 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u5-03 .t{fill:#16181D;font-weight:500}#dsfig-u5-03 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u5-03 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u5-03 .dot{fill:#16181D}#dsfig-u5-03 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u5-03 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u5-03 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u5-03 .ah{fill:#454C5A}#dsfig-u5-03 .ah.hi{fill:#2340B8}#dsfig-u5-03 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u5-03 .wl .t{font-size:12px;font-weight:700}#dsfig-u5-03 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u5-03 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u5-03 .e{stroke:#B1B7C3}html.dark #dsfig-u5-03 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u5-03 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u5-03 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u5-03 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u5-03 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u5-03 .t{fill:#E6E8ED}html.dark #dsfig-u5-03 .t.inv{fill:#0F1115}html.dark #dsfig-u5-03 .kd{stroke:#E6E8ED}html.dark #dsfig-u5-03 .dot{fill:#E6E8ED}html.dark #dsfig-u5-03 .ann{fill:#8FA3FF}html.dark #dsfig-u5-03 .lbl{fill:#858D9C}html.dark #dsfig-u5-03 .ptr{fill:#8FA3FF}html.dark #dsfig-u5-03 .ah{fill:#B1B7C3}html.dark #dsfig-u5-03 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u5-03 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u5-03 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u5-03 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah4" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah" d="M0,1 L9,5 L0,9 z"/></marker><marker id="ahh4" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah hi" d="M0,1 L9,5 L0,9 z"/></marker></defs><path class="e" d="M59,40 L148,40" marker-end="url(#ah4)"/><path class="e" d="M188,40 L277,40" marker-end="url(#ah4)"/><path class="e" d="M317,40 L406,40" marker-end="url(#ah4)"/><path class="e" d="M446,40 L535,40" marker-end="url(#ah4)"/><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">Mic</text><circle class="n" cx="169" cy="40" r="18"/><text class="t" x="169" y="40" dy=".35em" text-anchor="middle">ADC</text><circle class="n" cx="298" cy="40" r="18"/><text class="t" x="298" y="40" dy=".35em" text-anchor="middle">Pro</text><circle class="n" cx="427" cy="40" r="18"/><text class="t" x="427" y="40" dy=".35em" text-anchor="middle">DAC</text><circle class="n" cx="556" cy="40" r="18"/><text class="t" x="556" y="40" dy=".35em" text-anchor="middle">Spk</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Digital audio chain: microphone, analog-to-digital converter, processing, digital-to-analog converter, speaker</figcaption></figure>

Video-Video color spaces, Digital Video, Digital Video processing, Video file formats

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>Digital video is a sequence of digitised still frames played fast enough (24-30 frames per second) to give the illusion of motion.</mark>

Key points.

1. Colour spaces are RGB for displays, YUV or YCbCr (luminance plus two chrominance) for broadcast, and CMYK for print.
2. Chroma subsampling such as 4:2:0 keeps full luminance but less colour detail, cutting size with little visible loss.
3. Processing includes cutting, transitions, colour correction and compression.
4. Formats are AVI, MP4, MOV, MKV and WMV; they are containers holding codecs like H.264.

Example. Uncompressed 1 second of 640x480 24-bit video at 30 fps is $640 \times 480 \times 3 \times 30 = 27{,}648{,}000$ bytes, about 26.4 MB, which is why video needs compression.

Animation: Uses of Animation, Principles of Animation, Computer based animation, 3D Animation, Animation file formats, Animation software, Special Effects in animation, Storyboarding for Animation

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>Animation is the illusion of movement produced by displaying a series of slightly different images in quick succession.</mark>

Key points.

1. Principles include squash and stretch, anticipation, staging, timing, follow-through and exaggeration.
2. Computer animation uses keyframing with in-betweening, path animation and morphing; 3D adds modelling, rigging, rendering.
3. Formats are GIF, SWF, FLV and MOV; software includes Blender, Maya and Flash.
4. A storyboard is a sequence of sketched panels planning scenes before production; special effects include compositing and particles.

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u5-04" viewBox="0 0 632 198" width="632" height="198" role="img" aria-label="Kinds of animation"><style>#dsfig-u5-04 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u5-04 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u5-04 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u5-04 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u5-04 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u5-04 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u5-04 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u5-04 .t{fill:#16181D;font-weight:500}#dsfig-u5-04 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u5-04 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u5-04 .dot{fill:#16181D}#dsfig-u5-04 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u5-04 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u5-04 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u5-04 .ah{fill:#454C5A}#dsfig-u5-04 .ah.hi{fill:#2340B8}#dsfig-u5-04 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u5-04 .wl .t{font-size:12px;font-weight:700}#dsfig-u5-04 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u5-04 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u5-04 .e{stroke:#B1B7C3}html.dark #dsfig-u5-04 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u5-04 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u5-04 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u5-04 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u5-04 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u5-04 .t{fill:#E6E8ED}html.dark #dsfig-u5-04 .t.inv{fill:#0F1115}html.dark #dsfig-u5-04 .kd{stroke:#E6E8ED}html.dark #dsfig-u5-04 .dot{fill:#E6E8ED}html.dark #dsfig-u5-04 .ann{fill:#8FA3FF}html.dark #dsfig-u5-04 .lbl{fill:#858D9C}html.dark #dsfig-u5-04 .ptr{fill:#8FA3FF}html.dark #dsfig-u5-04 .ah{fill:#B1B7C3}html.dark #dsfig-u5-04 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u5-04 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u5-04 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u5-04 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah5" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah" d="M0,1 L9,5 L0,9 z"/></marker><marker id="ahh5" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah hi" d="M0,1 L9,5 L0,9 z"/></marker></defs><line class="e" x1="188" y1="39" x2="72" y2="103"/><line class="e" x1="188" y1="39" x2="420" y2="103"/><line class="e" x1="420" y1="103" x2="304" y2="167"/><line class="e" x1="420" y1="103" x2="536" y2="167"/><rect class="n" x="142.5" y="24" width="91" height="30" rx="8"/><text class="t" x="188" y="39" dy=".35em" text-anchor="middle">Animation</text><rect class="n" x="19" y="88" width="106" height="30" rx="8"/><text class="t" x="72" y="103" dy=".35em" text-anchor="middle">Traditional</text><rect class="n" x="378.5" y="88" width="83" height="30" rx="8"/><text class="t" x="420" y="103" dy=".35em" text-anchor="middle">Computer</text><circle class="n" cx="304" cy="167" r="17"/><text class="t" x="304" y="167" dy=".35em" text-anchor="middle">2D</text><circle class="n" cx="536" cy="167" r="17"/><text class="t" x="536" y="167" dy=".35em" text-anchor="middle">3D</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Kinds of animation</figcaption></figure>

Uses. Animation is used in films, games, advertising, education, simulation and web design.

Compression: Lossless/Lossy Compression techniques, Image, Audio & Video Compression, MPEG Standards, Multimedia Architecture, Multimedia databases

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>Compression reduces data size; lossless restores the original exactly, lossy discards less important data permanently.</mark>

Key points.

1. Lossless methods are Huffman, run-length and LZW; lossy methods are JPEG (DCT-based) and MP3.
2. Compression ratio equals original size divided by compressed size.
3. MPEG-1 targets VCD, MPEG-2 DVD and broadcast, MPEG-4 web and mobile; video uses I, P and B frames.
4. Multimedia databases store and index images, audio and video with content-based retrieval.

Formula. $\text{Compression ratio} = \dfrac{\text{original size}}{\text{compressed size}}$; for 10 MB compressed to 2 MB the ratio is 5:1.

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u5-05" viewBox="0 0 413 198" width="413" height="198" role="img" aria-label="Compression techniques"><style>#dsfig-u5-05 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u5-05 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u5-05 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u5-05 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u5-05 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u5-05 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u5-05 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u5-05 .t{fill:#16181D;font-weight:500}#dsfig-u5-05 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u5-05 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u5-05 .dot{fill:#16181D}#dsfig-u5-05 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u5-05 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u5-05 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u5-05 .ah{fill:#454C5A}#dsfig-u5-05 .ah.hi{fill:#2340B8}#dsfig-u5-05 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u5-05 .wl .t{font-size:12px;font-weight:700}#dsfig-u5-05 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u5-05 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u5-05 .e{stroke:#B1B7C3}html.dark #dsfig-u5-05 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u5-05 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u5-05 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u5-05 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u5-05 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u5-05 .t{fill:#E6E8ED}html.dark #dsfig-u5-05 .t.inv{fill:#0F1115}html.dark #dsfig-u5-05 .kd{stroke:#E6E8ED}html.dark #dsfig-u5-05 .dot{fill:#E6E8ED}html.dark #dsfig-u5-05 .ann{fill:#8FA3FF}html.dark #dsfig-u5-05 .lbl{fill:#858D9C}html.dark #dsfig-u5-05 .ptr{fill:#8FA3FF}html.dark #dsfig-u5-05 .ah{fill:#B1B7C3}html.dark #dsfig-u5-05 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u5-05 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u5-05 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u5-05 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah6" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah" d="M0,1 L9,5 L0,9 z"/></marker><marker id="ahh6" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah hi" d="M0,1 L9,5 L0,9 z"/></marker></defs><line class="e" x1="200.9" y1="39" x2="111.8" y2="103"/><line class="e" x1="200.9" y1="39" x2="290" y2="103"/><line class="e" x1="111.8" y1="103" x2="51.5" y2="167"/><line class="e" x1="111.8" y1="103" x2="122" y2="167"/><line class="e" x1="111.8" y1="103" x2="172" y2="167"/><line class="e" x1="290" y1="103" x2="231" y2="167"/><line class="e" x1="290" y1="103" x2="290" y2="167"/><line class="e" x1="290" y1="103" x2="349" y2="167"/><rect class="n" x="147.9" y="24" width="106" height="30" rx="8"/><text class="t" x="200.9" y="39" dy=".35em" text-anchor="middle">Compression</text><rect class="n" x="70.3" y="88" width="83" height="30" rx="8"/><text class="t" x="111.8" y="103" dy=".35em" text-anchor="middle">Lossless</text><rect class="n" x="14" y="152" width="75" height="30" rx="8"/><text class="t" x="51.5" y="167" dy=".35em" text-anchor="middle">Huffman</text><circle class="n" cx="122" cy="167" r="17"/><text class="t" x="122" y="167" dy=".35em" text-anchor="middle">RLE</text><circle class="n" cx="172" cy="167" r="17"/><text class="t" x="172" y="167" dy=".35em" text-anchor="middle">LZW</text><rect class="n" x="260.5" y="88" width="59" height="30" rx="8"/><text class="t" x="290" y="103" dy=".35em" text-anchor="middle">Lossy</text><rect class="n" x="205" y="152" width="52" height="30" rx="8"/><text class="t" x="231" y="167" dy=".35em" text-anchor="middle">JPEG</text><circle class="n" cx="290" cy="167" r="17"/><text class="t" x="290" y="167" dy=".35em" text-anchor="middle">MP3</text><rect class="n" x="323" y="152" width="52" height="30" rx="8"/><text class="t" x="349" y="167" dy=".35em" text-anchor="middle">MPEG</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Compression techniques</figcaption></figure>

Architecture. A multimedia system has input devices, a processor, storage, compression hardware, output devices and a network.

Last-minute revision

• Multimedia combines text, graphics, audio, video and animation interactively.
• ASCII is 7 bits; Unicode gives every character a unique code point (UTF-8, UTF-16, UTF-32).
• Nyquist: sample at least twice the highest frequency.
• CD audio is 44.1 kHz, 16 bit, stereo, about 10.1 MB per minute.
• Video runs at 24-30 frames per second; YCbCr separates luminance from colour.
• Lossless keeps every bit (Huffman, RLE, LZW); lossy discards data (JPEG, MP3, MPEG).
• MPEG frames are I (intra), P (predicted) and B (bidirectional).
• MIDI stores note instructions, not sampled sound.
• A storyboard plans animation scenes as sketched panels.

Memory hooks

• Five media: "T-G-A-V-A" for text, graphics, audio, video, animation.
• Nyquist means "twice the top".
• I, P, B: Intra is complete, Predicted looks back, Bidirectional looks both ways.
• Lossless is like zip; lossy is like a photocopy of a photocopy.

Coverage checklist

• Basic of multimedia, application of Multimedia: definition, elements, applications (no past questions).
• Text-Types, Unicode Standard, text Compression, Text file formats: text types, Unicode, formats (no past questions).
• Audio Components, Digital Audio, Digital Audio processing, Sound cards, Audio file formats, Audio Processing software: sampling, size formula, formats (no past questions).
• Video-Video color spaces, Digital Video, Digital Video processing, Video file formats: colour spaces, subsampling, formats (no past questions).
• Animation: Uses of Animation, Principles of Animation, Computer based animation, 3D Animation, Animation file formats, Animation software, Special Effects in animation, Storyboarding for Animation: principles, methods, storyboard (no past questions).
• Compression: Lossless/Lossy Compression techniques, Image, Audio & Video Compression, MPEG Standards, Multimedia Architecture, Multimedia databases: lossless, lossy, MPEG, databases (no past questions).