Computer file formats. Paul . Nieuwenhuysen @vub.ac.be Vrije Universiteit Brussel Informatie- en Bibliotheekwetenschap, Universitaire Instelling Antwerpen België Presented for the SAP project at Katholieke Universiteit Nijmegen , Nederland, 10 May 200 1
Presented for the SAP project atKatholieke Universiteit Nijmegen, Nederland, 10 May 2001
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Introduction to file formats
A program can incorporate only 1, 2, or all 3 of the functions
File formats for text only
File formats for graphics/images
Estimate the typical size of a computer file that contains a bitmap image in colours, that has been obtained by using a typical scanner, and that can cover a complete typical display or projection screen directly at optimal resolution without enlargement, when no compression is applied.
The differences in all the graphics file formats cause the requirement of filter / conversion programs, when a graphics file must be inserted in a document which is managed by an application program which works primarily with another graphics file format.
File formats for documents with text and images
File compression, archiving and conversion
ARC, BOO, CAB, LHZ, ZIP, ZOO,...
GIF, TIFF, ... in various versions
JPEG, ... in various versions
AVI, MPEG, Quicktime, RM, ... in various versions
Select or create an appropriate photograph bitmap file.
Save this file as a JPEG file under a different name.
Repeat this at about 3 very different levels of compression and thus of image quality(always starting from the appropriate original photo file, because JPEG is a final storage format).
Load all the resulting photo files in a program to edit such files; zoom in to 400% for instance;use tiling to display the photo files simultaneously on the screen; compare their quality.
Determine also the file size of each photo file.
Decide finally which compression level is appropriate or your aims.