CMPD 434 MULTIMEDIA
AUTHORING
Chapter 02
Multimedia Elements
Objective
At the end of this chapter, students should be able to:
• Explain and describe the 5 building blocks of multimedia and Interactivity
• Examining the media elements
• Understanding the various Input and Output Modalities.
Five Multimedia Building
Blocks and Interactivity
Main Elements of Multimedia
Examining Media Elements: Graphics
Bitmapped VS Vector
• Bitmaps images are real images that can be captured from devices such as
cameras or scanners.
• Vector graphics are drawn on the computer and only require a small amount
of memory.
Selecting the correct graphic formats
• Bitmaps have two disadvantages. In terms of the amount of digital storage,
bitmaps are memory intensive, and the higher the resolution, the larger the
file size.
• The other disadvantage with bitmaps is when an image is enlarged, the
individual coloured squares become visible and the illusion of a smooth
image is lost to the viewer. This 'pixelation' makes the image look coarse.
• The advantages of using vector graphics are; a small file size and the ability
to scale the image to any size without loss of quality. They are ideal for logo
designs, as they can be printed very small on business cards or printed large
on a billboard poster.
• Vector graphics, however, cannot reproduce 'continuous tone' photographic
images like bitmaps.
Vector and Bitmapped File format/Uses
DPI vs PPI
• DPI - Dots per Inch
This is the amount of ink dots the printer will put on each pixel of your
image. The DPI is set by the actual printer device.
• PPI - Pixels per Inch
Digital raster images are measured in pixels, or picture elements. How many
pixels per inch is determined by the device you create the digital image
with: camera, scanner, or graphics software and can be modified with a
photo editing software like Photoshop.
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If your image is 1993 pixels wide & printer requires 300 ppi (1993 ÷ 300) can be printed
at 6.643 inches
If your image is 1993 pixels wide & printer requires 240 ppi (1993 ÷ 240) can be printed
at 8.304 inches
Creating and editing vector and bitmapped images
• Bitmap Software
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Features of painting and image-editing programs range from simple to complex across
the platform.
Adobe Photoshop and Lightroom remains the most widely used image-editing tool
among the designer worldwide
Creating and editing vector and bitmapped images
• Vector Software
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Adobe Illustrator or InDesign or Corel’s CorelDRAW uused to create curvy and
complicated looks that they then can be convert to a bitmapped
Examining Media Elements: Sound
• Vibrations in the air create waves of pressure that are perceived as sound.
• Sound waves vary in sound pressure level (amplitude) and in frequency or
pitch.
• ‘Acoustics’ is the branch of physics that studies sound.
• Sound pressure levels (loudness or volume) are measured in decibels (dB).
Digital audio
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Sound into a sequence of numbers, which can then be stored and read back for
reproduction.
Normally, the sound is transduced (as by a microphone) to an analog signal in the same way
as for analog recording, and then the analog signal is digitized, or converted to a digital
signal, through an analog-to-digital converter and then recorded onto a digital storage
medium such as a compact disc or hard disk.
Analog Audio
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An analog recording is one where a property or characteristic of a physical recording
medium is made to vary in a manner analogous to the variations in air pressure of the
original sound.
Generally, the air pressure variations are first converted (by a transducer such as a
microphone) into an electrical analog signal in which either the instantaneous voltage or
current is directly proportional to the instantaneous air pressure (or is a function of the
pressure).
The variations of the electrical signal in turn are converted to variations in the recording
medium by a recording machine such as a tape recorder or record cutter
Preparing Digital Audio Files
• The first step is to digitize the analog material and recording it onto a
computer readable digital media.
• It is necessary to focus on two crucial aspects of preparing digital audio files:
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Balancing the need for sound quality against your available RAM and Hard disk
resources.
Setting proper recording levels to get a good, clean recording.
Editing Digital Recordings
• Multiple Tasks
• Trimming
• Splicing and Assembly
• Volume Adjustments
• Format Conversion
• Resampling or downsampling
• Equalization
• Digital Signal Processing
• Reversing Sounds
• Time Stretching
Synthesizer Sounds
• A sound synthesizer is an electronic musical instrument that generates
electric signals converted to sound through loudspeakers or headphones.
• Synthesizers may either imitate other instruments or generate new timbres.
• They are often played with a keyboard, but they can be controlled via a
variety of other input devices, including music sequencers, instrument
controllers, fingerboards, guitar synthesizers, wind controllers, and
electronic drums.
• Synthesizers without built-in controllers are often called sound modules,
and are controlled via MIDI or CV/Gate.
• A digital audio file format is preferred in the following circumstances:
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When there is no control over the playback hardware
When the computing resources and the bandwidth requirements are high.
When dialogue is required.
Audio File Format
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A file format determines the application that is to be used for opening a file. Following is
the list of different file formats and the software that can be used for opening a specific file.
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*.AIF, *.SDII in Macintosh Systems
*.SND for Macintosh Systems
*.WAV for Windows Systems
MIDI files – used by north Macintosh and Windows
*.WMA –windows media player
*.MP3 – MP3 audio
*.RA – Real Player
*.VOC – VOC Sound
AIFF sound format for Macintosh sound files
*.OGG – Ogg Vorbis
Examining Media Elements: Video
• A video format describes how one device sends video pictures to another
device, such as the way that a DVD player sends pictures to a television or a
computer to a monitor.
• More formally, the video format describes the sequence and structure of
frames that create the moving video image.
• Analog video formats
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NTSC
PAL
SECAM
• Digital Video Formats
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These are MPEG13 based terrestrial broadcast video formats
ATSC Standards
DVB
ISDB
Examining Media Elements: Animation
• Animation is the art of capturing a series of individual movements, whether
on film or in digital form, and replaying them in rapid succession to give the
illusion of movement.
• Each of the images vary slightly from its previous image.
• Illusion of movement in animation is achieved by rapidly displaying many
still images (or frames) in sequence.
Cel Animation VS Computer Animation
Traditional Animation (Cel Animation)
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Traditional animation requires cels and backgrounds to be created separately
The animator draws the character in relation to the background. Each frame is drawn and
then transferred onto a cel, which is a thin, transparent plastic sheet.
Computer Animation
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Computer animation requires more steps.
Animating a film involves modeling (a wireframe representation of the character); rigging
(the "bones" of the character); texturing, layout and animation (character motion and
camera moves are mapped out); lighting and shading, rendering (creating a geometric
"description" of the model); and compositing (combining the elements).
• Key Frames
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In this technique a storyboard is laid out and then the artists draw the major frames of
the animation.
• Cel Animation
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In this technique each character is drawn on a separate piece of opaque paper. Then, at
the time of shooting animation the different characters are overlaid on top of the
background in each frame.
• Rotascoping
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Rotascoping is a technique where images are copied from a moving video into an
animation. The animator draws the motion and shape of the object by referring to the
video as opposed to imagining in his head.
• Computer Animation
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With time the technique of animation has become more and more computer -assisted
and computer- generated. All of such techniques require a trade-off between the level
of control that the animator has over the finer details of the motion and the amount of
work that the computer does on its own.
Interactivity
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Multimedia interactivity describes the set of possible actions a user can do
to change the state of a multimedia system.
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Examining Interactivity
pathways through the interactive multimedia product
additional hyperlinks (internal and external)
use of consistent house style
use of different components
interactive elements
suitability for target audience
purpose of interactive multimedia product
ease of use
Various Input / Output Modalities
• To understand the evolving nature of interactive user interface, we shall first
examine the human sense and their impact on our ability to create interface
in relation to computer inputs/outputs.
• Human Input Output Modalities
• Computer Input Output Modalities