Page 149 - DCAP104_EXPOSURE_TO_COMPUTER_DISCPLINES

Exposure to Computer Disciplines

Notes Multimedia represents the convergence of text, pictures, video and sound into a single form.
The power of multimedia and the Internet lies in the way in which information is linked.
Multimedia and the Internet require a completely new approach to writing. The style of writing
that is appropriate for the ‘on-line world’ is highly optimized and designed to be able to be
quickly scanned by readers.
A good site must be made with a specific purpose in mind and a site with good interactivity
and new technology can also be useful for attracting visitors. The site must be attractive and
innovative in its design, function in terms of its purpose, easy to navigate, frequently updated
and fast to download.
When users view a page, they can only view one page at a time. As a result, multimedia users
must create a ‘mental model of information structure.
7.3 Understanding Graphics File Formats

7.3.1 Raster Formats
7.3.1.1 JPEG/JFIF
JPEG (Joint Photographic Experts Group) is a compression method; JPEG-compressed images
are usually stored in the JFIF (JPEG File Interchange Format) file format. JPEG compression is
(in most cases) lossy compression. The JPEG/JFIF filename extension is JPG or JPEG. Nearly
every digital camera can save images in the JPEG/JFIF format, which supports 8 bits per
color (red, green, blue) for a 24-bit total, producing relatively small files. When not too great,
the compression does not noticeably detract from the image’s quality, but JPEG files suffer
generational degradation when repeatedly edited and saved. The JPEG/JFIF format also is
used as the image compression algorithm in many PDF files.
7.3.1.2 JPEG 2000

JPEG 2000 is a compression standard enabling both lossless and lossy storage. The compression
methods used are different from the ones in standard JFIF/JPEG; they improve quality and
compression ratios, but also require more computational power to process. JPEG 2000 also adds
features that are missing in JPEG. It is not nearly as common as JPEG, but it is used currently
in professional movie editing and distribution (e.g., some digital cinemas use JPEG 2000 for
individual movie frames).

7.3.1.3 Exif
The Exif (Exchangeable image file format) format is a file standard similar to the JFIF format
with TIFF extensions; it is incorporated in the JPEG-writing software used in most cameras. Its
purpose is to record and to standardize the exchange of images with image metadata between
digital cameras and editing and viewing software. The metadata are recorded for individual
images and include such things as camera settings, time and date, shutter speed, exposure,
image size, compression, name of camera, color information, etc. When images are viewed or
edited by image editing software, all of this image information can be displayed.

7.3.1.4 TIFF
The TIFF (Tagged Image File Format) format is a flexible format that normally saves 8 bits or 16
bits per color (red, green, blue) for 24-bit and 48-bit totals, respectively, usually using either the
TIFF or TIF filename extension. TIFF’s flexibility can be both an advantage and disadvantage,
since a reader that reads every type of TIFF file does not exist. TIFFs can be lossy and lossless;
some offer relatively good lossless compression for bi-level (black&white) images. Some digital

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