Compression in Multimedia:
To provide feasible and cost-effective solutions for the problem of the considerable storage capacity of images, most multimedia systems handle compressed
image data. Compression in multimedia is a subject to certain contraints. The quality of the coded, and later on, decoded data should be as good as possible. On the other hand, the costs of the
implementation should be minimal and the algorithm as fast as possible.
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JPEG:
JPEG (Joint Photographic Experts Group) is a standard for compression of still images. The process runs in four steps. It uses DCT to accomplish a
high compression ratio by the following entropy encoding.
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JPEG:
JPEG
coded images are used in many applications with graphical functions, for example in Web browsers. Here, the images are transferred in coded form and are represented in decoded form.
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Use of JPEG:
JPEG is a flexible format, applicable to images of arbitrary size and colour sets. It produces best quality and good compression ratios for natural images.
For graphical images (texts, line drawings) it produce visible artefacts sometimes even for small compression ratios of about 5. For graphical images, other coding formats like GIF or PNG are better
suited.
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Target user |
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Lesson 1: |
Basics |
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Lesson 2: |
Beginner |
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Lesson 3: |
Expert |
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