Multimedia elements need to be chosen properly depending on the title with the consideration of cost, time and effect.
In the design of multimedia title, designer should consider that the text is
- concise
- appropriate fonts
- readable
- appropriate fonts size
- formatted
- restrain and consistent
Text
ConciseThe amount of text should fill less than half of the screen. Reading volumes of text on computer screen is difficult and tiring. Therefore, the text should be reduced to convey the direct point of the concept.
Appropriate fontsText is boring but appropriate use of fonts and sizes can enliven the audience. Fonts help to
- focus attention
- enhance readability
- set tone (serious or lighthearted)
- project an image (progressive or conservative)
ReadableSerif font is preferred for body text because the serifs create a line across the page. E.g. Times New Roman font. San Serif font does not have the line that it is difficult for reading along the text line. E.g. Arial.
Font sizeFont size is measured in point. There are 72 points per inch. Text used as headings has point size of 48.
The subheadings are half the size of heading size.
The text block is 10 – 12 point size.
FormattingFont format and font color can be used to emphasis a text. Three common font formats are bold, italic and underline.
Restraint and consistentIt is important to exercise restraint, which mean avoid too many different fonts, sizes and styles on the same screen. It is also important to maintain consistency such as each screens have a similar heading font, size, style and color.
Graphics
Visualization is an important part of the communications process. Graphics can be used to
- add emphasis
- direct attention
- illustrate concepts
- provide a background for the content
Two types of graphics used in multimedia titles are
- vector graphics
- bitmap graphics.
Vector Graphics
- Vector graphics is also known draw-type graphics, which represent an image as a geometric shape made up straight lines, oval and arcs.
- Geometric shapes has a set of instructions that describe the size, position, shape and relationship to other shape.
- A vector graphics can be rotated, and resized without affecting the relationship between geometric shapes.
- Applications that use to create vector graphics are such as CorelDraw, Adobe Illustrator, Macromedia Flash and Macromedia Director.
- The advantage of vector graphics are
- graphic can be resize and rotate without distortion
- smaller file size because graphics is stored as a set of instruction.
- The disadvantage of vector graphics are
- the file size is getting larger when the graphics is getting more complex.
- complex graphics take longer time to load
- it cannot displayed in photo quality
Bitmap Graphics
- Bitmap graphic are graphic image represented as an array of dots known as pixels.
- Bitmap graphic only store color information known as color depth.
- Bitmap graphic becomes distorted when resize or placement is changed. Therefore, it need to be redrawn using different resolution setting.
- Applications that use for creating bitmap graphics are such as Corel paint, Adobe Photoshop, and Jasc Paint Shop Pro.
- The advantage of bitmap graphics is the graphic can have a photo quality.
- The disadvantage of bitmap graphics are
- the file size is larger than vector graphics file.
- resizing the graphic will result in distortion.
Graphics image file size
- Graphic image file sizes can become unproductively large depending on the complexity of the images and the way images are developed.
- The multimedia designer must balance the quality of images with the need to keep file sizes small.
- Smaller file size will require less time to download and display on computer screen.
- Screen resolution
- Screen resolution are measured in horizontal and vertical pixels with 640 x 480 being the lowest standard.
- The larger the pixel count and the smaller the pixel diameter are the higher the image resolution.
- A monitor with higher screen resolution will display a much better quality image.
- Image size
The image size is determined by the number of pixels making up the image. The screen resolution and the image size determine how much of the screen is occupied by the image. Image size 640 x 480 will occupy entire screen with resolution 640 X 480.
- Color Depth
Each pixels can display from 1 color to millions of colors. The number of colors is determined by information associated with each pixel. Available number of colors are 16 color (4 bits), 256 color (8 bits), 65,000 color (16 bits) and 16.7 million color (24 bits).
- File size
The size of a bitmap graphic is related to the image size and color depth. It can be estimated by using the formula File Size (B) = Image size (pixels) x Color Depth (bits) / 8
- Given a bitmap image with the
- image size : 1024 (pixels) x 768 (pixels)
- color depth : 3 bytes (24 bits)
- Image file size (Bytes):
- image size x color depth (bits) / 8
- 1024 x 768 x 24 / 8
- 2359296 Bytes
- 2.25 MB
- File formats
Graphics images can be saved in variety of file formats.
The more popular file formats are
- Bitmap (BMP)
- Tagged Image File Format (TIFF)
- Windows Paint (PCX)
- Macintosh Picture Format (PICT)
- Joint Photographer Experts Group (JPEG)
- Graphics Interchange file format (GIF)
- Portable Network Graphics (PNG)
- Different file format has different compression, quality and use.
Sound
•Multimedia playback system is capable of playing music, narration and sound effects.
•Sound waves are created by vibration. It have an analog wave pattern. The pattern has two attributes which are volume and frequency.
•Volume is the height of each peak in the sound wave. The highest the peak, the louder the sound.
•Frequency is the distance between the peaks. The greater the distance, the lower the sound. Frequency is measured in hertz (Hz) . 1KHz is the pattern recurs 1000 times in a second.
Sampling is the process of converting sound waves from analog (sound waves) to digital (bits) form. A sample of the sound is recorded for every fraction of a second.
•The quality of the digitized sound are affected by
•sample rate – the number of sample is taken per second
•sample size – the amount of sample information stored
•channel – the number of track
•Common sample rates are 11.025 KHz, 22.05 KHz, 44.1 KHz.
•The higher the sample rate, the better quality of the digitized sound.
Two common sample size are 8 bits and 16 bits. An 8 bit sample allow 256 values that are used to describe the sound, where as 16 bit sample allows for 65536 values. DVD audio has sample size of 24 bits allows for 17 millions values.
•The higher the sample size, the better the quality of the digitized sound and the larger the file size.
•Common number of sound channels is mono (1 track) and stereo (2 track). Professional audio equipment use up to 4, 8, 16, 32 and higher number of channel.
Sound file size
•Given a audio CD with the
•sample rate : 44.1 KHz (44100 Hz)
•sample size : 2 bytes (16 bits)
•channel : stereo (2 tracks)
•length : 80 minutes (4800 seconds)
•Per second Sound file size (Bytes/s):
•sample rate (Hz) x sample size (bits) x channel / 8
•44100 x 16 x 2 / 8
•176400 B/s
•60 minutes audio is
•Per second Sound file size (Bytes/s) x time (seconds)
•176400 x 4800
•846720000 Bytes
•807.5 Megabytes
Audio File Formats
•One sound has been digitized, it can be easily manipulated using a sound editing program.
•Popular sound formats are
•Window Waveform (WAV) – Microsoft and IBM
•Window Media Audio (WMA) – Microsoft
•Audio Interchange File Format (AIFF) – Apple
•AIFF Compressed (AIFFC) – Apple
•Real Audio (RA)
•MPEG Layer 3 (MP3)
•OGG Vorbis (OGG)
MIDI
•Musical Instrument Digital Interface (MIDI) is a standard format that enables computers and electronic musical instruments to communicate sound information.
•MIDI files contain code instead of the actual digitized sounds, therefore they are hundred times smaller than audio files.
•MIDI requires specialized software and equipment for recording and playback or a MIDI compatible audio card.
•Equipment for recording and playback MIDI are
•electronic keyboard
•synthesizer
•electronic drum
