Thursday, 20 March 2014

Unit 30: Task eight

File format
File format allows you to save various file types with data. Some files are larger than other files and this tend to affect the quality of some of the files. Video files will be larger than documents. Therefore there is a difference in size and the formats will be saved differently. Some of the types of files include .wmv – which is for low quality windows media player videos. Another would be.ppt for PowerPoint files and .raw for unaltered video frames. The higher the quality of the files, the larger the file size will be.


Compression techniques.
There are two types of image compression. Lossy compression is one of them. It has the smallest file size therefore it can cause unwanted distortions in the image. The other type of compression is lossless compression which is the opposite of lossy compression. This has a larger file size and gives a better quality of the image. Lossy image compression techniques could include reducing the colour space to the most common colours in the image. Lossless compression might include entropy encoding or deflation.


Image resolution.
The higher the image resolution is, then the better the quality of the image. Better image resolution does mean an increased file size however this might be unsuitable for websites. For example, with Photoshop files as soon as you export an image you can select the quality of the image from 1-12. The higher number means a larger fie size.

Colour depth.
The greater the colour depth, the more pixels are used to represent the colour of an image in a bitmap image. The average levels of colour depth range from 8-bit to 48-bit. The greater the colour depth, the better the quality of the image’s colour and the definition of the image but the file size would once again be larger due to the complexity of the file.


1 comment:

  1. www: great descriptions of file formats and compression techniques. You have illustrated the points very well with great examples of the quality of these images. D2 achieved.

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