Untitled Quiz

Multimedia Elements

• Multimedia has five basic elements: text, images, video, audio, and animation.

Multimedia Types

• Offline multimedia projects are self-contained and do not interact with external resources.
• Online multimedia projects interact with distant resources across a network.
• Hybrid multimedia projects combine elements of both online and offline projects.
• Interactive (nonlinear) multimedia allows the end user to control how and when multimedia elements are delivered.

Multimedia Applications

• Business: Multimedia is used for presenting information, employee training, marketing, advertising, product demonstrations, simulations, databases, instant messaging, and networked communications. Medical professionals use it to practice complex procedures before actual procedures. Mechanics use it during training or repairs of complex engineering equipment.
• Education: Multimedia is used in learning packages and lab experiments simulations. Specific course aspects that are hard to explain using simple texts and images can be clarified using video clips, animation, 3D modeling, and audio.
• Home Entertainment: Multimedia is used in computer games, interactive encyclopedias, storytelling, cartoons, and other forms of entertainment.
• Public Places: Information is accessed through touchscreens displayed in places like hotels, train stations, and shopping malls, where multimedia terminals are already present.

Multimedia Project Development Stages

• Planning and costing.
• Designing and producing.
• Testing.
• Delivering.

Multimedia Skills

• Executive Producer
• Producer/Project Manager
• Creative Director/Multimedia Designer
• Art Director/Visual Designer
• Artist
• Interface Designer
• Game Designer
• Subject Matter Expert
• Instructional Designer/Training Specialist
• Scriptwriter
• Animator (2D/3D)
• Sound Producer
• Music Composer
• Video Producer
• Multimedia Programmer
• HTML Coder
• Media Acquisition Manager
• Marketing Director

Roles of a Multimedia Project Manager

• Planner: Creates a cost-effective development method based on given schedule and budget.
• Team Builder: Assembles and motivates a team of developers.
• Organizer: Structures the project using the best talent to meet the schedule and technical requirements.
• Negotiator: Balances project, customer, and development team needs.
• Flexible and Assertive Coach: Motivates the team effectively.
• Work Flow Manager: Schedules project activities and tasks for optimal project flow.
• Sales Person: Understands customer needs and delivers the solution on time and within budget.
• Problem Solver: Identifies and resolves technical or management issues.
• Committed to Quality: Ensures error-free multimedia products.
• Goal Setter: Identifies and prioritizes specific tasks with deadlines.
• Positive Attitude: Approach project challenges with optimism and determination.
• Listener: Considers constructive inputs from customers, team members, and management.
• Multi-tasker: Manages multiple factors like technical, management, schedule, and budget issues.

Digital Image

• Image is defined as a two-dimensional function f(x,y) where x and y are spatial coordinates.
• The amplitude of f at any pair of coordinates (x, y) is called the intensity/gray level at that point.
• In grayscale images, intensity values represent shades from black to white.
• In color images, intensity values are represented as combinations of red, green, and blue (RGB).
• An image comprises of elements (pixels).
• Pixel values are proportional to the energy/electromagnetic waves radiated from the source.
• Pixel value range is from 0 to positive infinity and cannot be negative.
• An image function f(x,y) is characterized by illumination (i(x,y)) and reflectance (r(x,y)).

Image Formation

• Digitizing coordinate positions is sampling.
• Digitizing amplitude values is quantization.
• Images have gray levels in integer power of 2, like 2, 4, 8, and 16.
• 8-bit image has 256 gray levels.
• The simplest form of image is the 1-bit monochrome (no color) image.
• Each pixel contains either ON or OFF information (0 or 1)

Image Formation (Continued)

• 24-bit color images use three bytes (RGB) representing colors, each in a range from 0 to 255.
• Color images can be quantized to reduce file space.
• A 256-color palette is good for color reproduction.
• Generating a color quantized image using the median cut algorithm.

Sound

• Sound is a pressure wave with continuous values.
• Increasing or decreasing pressure is called amplitude.
• Measuring the amplitude is called sampling, including using intervals.
• The rate of sampling is called sampling frequency.
• Digitization of sound uses sampling and quantization techniques.

Nyquist Theorem

• Named after Harry Nyquist, a mathematician at Bell Labs.
• For lossless digitization, the sampling rate should be at least twice the maximum frequency response.
• The frequency equal to half the Nyquist rate is called the Nyquist frequency.
• For a band-limited signal, the sampling rate needed is twice the highest frequency present in the signal, determined by f₂ - f₁.
• Signal-to-noise ratio (SNR) measures the signal strength compared to the noise level; measured in decibels.

Signal-to-Quantization-Noise Ratio (SQNR)

• Digital signals store only quantized values.
• The precision of digital signals is determined by the number of bits per sample.
• Dividing a fixed range into levels creates quantization round-off errors.

Non-Linear Quantization

• Using Weber's Law, quantizations can be optimized with limited bits by producing more concentrated and compressed quantization near the low end of the stimulus and higher end for the stimulus. This can be better represented into graphs.

Audio Filtering

• Filtering analog to digital audio input is done by low-pass filters.
• Pulse Code Modulation (PCM) takes audio signal samples, quantizes them, and produces digital audio output.
• Standard telephone communication is based on a sampling rate of 8 kHz and 8 bits.
• The bit rate resulting from this is 64 kbps.
• Filtering is performed before digitization to restrict sound frequencies.

Introduction to MIDI (Musical Instrument Digital Interface) and Music Synthesis

• MIDI is an efficient method for representing musical performance information, requiring less storage than audio files.
• MIDI messages do not include sampled audio data. Instead, they contain instructions for synthesizers to recreate sounds.
• MIDI data streams originate from controllers (sequencers, keyboards).
• The recipient is a MIDI sound generator or sound module.
• The output is generated using 16 logical channels, indicated by including 4-bit channel numbers with MIDI messages. MIDI messages include status bytes and data bytes.
• MIDI messages are structured and classified into channel messages and system messages.

Standard MIDI Files (SMF) are a widely used file format for storing musical performance data. They enable devices, such as synthesizers and computers, to communicate specific musical information, including notes, timing, and instrument specifications. SMFs do not contain actual audio data; instead, they convey instructions for playback, allowing different devices to interpret and recreate the original performance. The format is highly versatile, making it ideal for various applications including music production, composition, and education. MIDI files are organized in tracks, with each track representing a different instrument or musical line, and can be easily edited to modify dynamics, expression, and tempo.

• MIDI messages are stored on disks as MIDI files using Standard MIDI Format (SMF).
• SMF files contain the timing information for MIDI messages.
• SMF files organize data using chunks. Each chunk has an ID, indicating the chunk type.
• Chunk IDs, for example, include “MThd,” indicating metadata, and “MTrk,” which represent track information.

Wavetable Synthesis

• Stores high-quality sound samples digitally, enabling playback on demand.
• Uses a table of sound waveforms and reduces memory requirements.

Types of Video Signals

• Video signals can be classified as composite, S-video, and component video.
• Composite video combines luminance and chrominance signals into a single carrier wave. This method can result in interference and dot crawl.
• S-video separates luminance and chrominance signals into two different channels, reducing cross-talk but providing less color information.
• Component video provides separate signals for luminance and chrominance components with high color reproduction quality but requires more bandwidth.

Analog Video

• Analog video signals are time-varying signals.
• Different voltages represent different image components.
• Common components include a white signal (0.714 V), black signal (0.055 V), blank signal (0V), sync signal (-0.286 V).

Analog Video [2]

• Interlaced scanning methods use odd and even lines for time displacement.

NTSC (National Television System Committee)

• Uses the 4:3 aspect ratio.
• Has a sampling rate of 29.97 frames per second.
• Uses interlaced scanning.
• 525 scan lines per frame, separated into two fields with 262.5 lines/field.
• Has specific horizontal sweep and active line signals with timing and duration parameters.
• Has a vertical retrace control.

NTSC [2]

• 20 lines at the start of every field for vertical retrace control.
• 1/6 of the raster on the left side is blanked for horizontal retrace.
• There are 340 visible lines.
• Pixels often appear between lines.

NTSC [3]

• NTSC video is an analog signal without fixed horizontal resolution.
• A pixel clock divides each horizontal line.
• Different sample numbers are provided in different video formats.

NTSC [4]

• The frame frequency of NTSC is 3.58 MHz.
• The composite signal is formed via Y and C components, with center frequencies.

Digital Video

• Advantages over analog: direct random access, repeated recording without issues.
• Almost all digital video uses component video; no need for blanking and sync pulses for digital signal processing.
• High Definition TV (HDTV) has a wider aspect ratio of 16:9 instead of 4:3, using progressive scan for sharper images. HDTV uses more bandwidth and includes more than one channel after compression.

High Definition TV (HDTV) [2]

• Advanced digital TV formats and aspect ratios provide higher resolution with a 16:9 aspect ratio, instead of the conventional 4:3.

High Definition TV (HDTV) [3]

• Interlacing can produce serrated edges in moving objects due to horizontal edges.