Sometimes, though not that often, one comes across files that require conversion from one format to another to be able to exploit their full potential, or to make them functional on different hardware types, a good example being converting a DVD movie into Windows Media (.avi) or MPEG (.mpg) format. One can also convert image files, such as conversions from true colour to grayscale. Other file conversions can be applied to office file formats (word-processors) and audio file formats.
Some files are easily converted whilst others are notoriously difficult, and good knowledge of the file converting software would be required. A typical example of a difficult file conversion is a Portable Document File (.pdf) to Word-processor format, such as (.doc) - the core coding of the pdf file does not allow certain feature sets, even with elaborate software and results in a garbled output, with word spacing all over the place!
There are two main forms of format conversions; PIVOTAL format conversion is used when the conversion that changes one format to another is managed by a new file that is called up in memory, when required, and is usually a much more streamlined file than the source code. A typical example is the conversion of a Rich Text File (.rtf) to a Wordperfect file. The pivotal format in this case would be an Open-document format; in this way, memory allocation and file size are kept to an acceptable level.
LOSSY file conversion, on the other hand, results when the target format does not support the same feature sets as the original source files, a good example being a Microsoft Word file converted to Notepad format. The output file would have some features missing or corrupted, such as spacing, text types or fonts. Lossy file conversions result in a lower grade output than the source, this being most evident in bitmap images or video conversions, where the target file would have inferior resolution than the source. Reverse engineering, i.e. to re-convert back to the source is not always possible.
Other file conversions are performed to enable users with less powerful machines with old software to run programs created in a later software version, such as AutoCAD (.dwg) files or Microsoft Office files. Cross platform compatibility nowadays has been improved, and PC software is readily read on a Mac via Microsoft’s Virtual PC and software is available for reading Mac formatted discs on a PC platform.