Assam ASSEB HS Multimedia and Web Technology flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Linear vs non-linear multimedia

Linear multimedia plays in a fixed sequence with no user control over order. Non-linear (interactive) multimedia lets the user navigate, branch and choose, as in a website or kiosk.

Lossy vs lossless compression

Lossless compression (PNG, ZIP, FLAC) restores the exact original data. Lossy compression (JPEG, MP3, MPEG) discards perceptual detail for much smaller files and cannot fully reconstruct the original.

Uncompressed audio size formula

Size in bytes equals sample rate times bit depth divided by eight, times number of channels, times duration in seconds. CD-quality stereo for one minute is about 10.6 megabytes.

Raster versus vector graphics

Raster images store a colour per pixel and blur when enlarged. Vector images store mathematical shapes and scale cleanly, but suit logos and diagrams rather than photographs.

Colour depth

The number of bits used per pixel. One bit gives two colours, eight bits give 256, and 24 bits give 16,777,216 true colours. Higher depth means larger files.

Layer mask

A non-destructive grayscale channel attached to a layer. White areas show the layer, black hides it, and grey gives partial transparency, so pixels are never permanently erased.

Tweened animation

An animation technique where the author sets keyframes at the start and end and software interpolates the intermediate frames automatically, greatly reducing file size and authoring effort.

Nyquist sampling rule

To capture a signal faithfully, the sample rate must be at least twice its highest frequency. A 44.1 kHz rate therefore represents frequencies up to about 20 kHz.

Container versus codec

A container such as MP4 or MKV is the wrapper holding video, audio and subtitle tracks. A codec such as H.264 or AAC defines how each track is compressed and decoded.

Progressive versus interlaced video

Progressive video draws every line of each frame in order. Interlaced video splits each frame into two fields of alternate lines, which saves bandwidth but can show combing on motion.

Streaming versus progressive download

Streaming delivers media continuously from a server for immediate playback with buffering. Progressive download saves the file to disk while playing and can be replayed from the local copy.

HTTP status codes

Three-digit server responses grouped by class: 2xx success such as 200 OK, 3xx redirection such as 301, 4xx client errors such as 404, and 5xx server errors such as 500.

DNS

The Domain Name System translates human-readable hostnames into IP addresses through a hierarchical chain of root, top-level domain and authoritative nameservers, with caching controlled by TTL values.

GET versus POST

GET requests data and appends parameters to the URL, making them visible and length-limited. POST sends data in the request body, suits submissions and is not cached by default.

Intranet and extranet

An intranet is a private network restricted to an organisation's members. An extranet extends selected intranet resources to trusted outsiders such as partners or suppliers.

Semantic HTML elements

Tags such as header, nav, main, article, section, aside and footer that describe content meaning rather than appearance, improving accessibility, machine readability and search engine interpretation.

alt attribute

Text alternative on an img element describing the image's content or purpose. It is read by screen readers and shown when the image fails to load; decorative images use an empty alt.

HTML form method and action

The action attribute names the URL that processes submitted data, and method chooses how it is sent, usually GET in the query string or POST in the request body.

CSS specificity

A three-part weight of IDs, classes or attributes or pseudo-classes, and element selectors. Higher specificity wins ties; inline styles beat selectors and !important beats both.

CSS box model

Every element is rendered as content surrounded by padding, then border, then margin. With box-sizing set to border-box, the declared width includes padding and border.

Flexbox versus grid

Flexbox arranges items mainly along one axis with flexible sizing. CSS Grid controls rows and columns simultaneously, making it better for full two-dimensional page layouts.

Media query

A CSS rule wrapped in @media with conditions on viewport width, height or orientation, used to apply different styles for phones, tablets and desktops in responsive design.

var, let and const

var is function-scoped and hoisted with an undefined value. let is block-scoped and reassignable. const is block-scoped and cannot be reassigned, though object contents may still change.

Strict equality operator

The triple-equals operator compares value and type without coercion, so 0 === "0" is false. Double-equals converts types first, so 0 == "0" is true.

DOM

The Document Object Model is the browser's tree representation of an HTML page. JavaScript selects nodes and changes text, attributes, styles and structure through it dynamically.

Event bubbling

An event fired on a nested element first runs its own handler, then propagates upward through ancestors. Calling stopPropagation in a handler prevents further bubbling.

HTTPS and TLS

HTTPS is HTTP carried over Transport Layer Security on port 443. TLS encrypts traffic, detects tampering and proves server identity through a certificate issued by a trusted authority.

Cross-site scripting

An attack injecting malicious script into pages viewed by others, often through unescaped user input. Defence includes output encoding, input validation and a Content-Security-Policy header.

DNS A and CNAME records

An A record maps a hostname to an IPv4 address, and AAAA to IPv6. A CNAME maps one hostname to another hostname, often used for subdomains pointing at a host.

Shared versus VPS hosting

Shared hosting places many websites on one server with pooled resources and low cost. A virtual private server isolates resources and gives administrative control at higher cost.

Project folder structure

Organising a website into index.html plus separate css, js, images and media folders. Relative paths then keep links working when the folder is moved or uploaded.

Viva voce

An oral examination in which the candidate defends the submitted project, explaining tools used, design decisions, code behaviour and answers to technical questions from examiners.