National 5 Computing Science Standard File Formats

2. Proprietary File Formats
Many applications will have their own file formats:
Microsoft Word
OpenOffice Writer
Microsoft Excel
Apple Numbers
May not be possible to open a document created in one application in a
different application

3. Text
TXT Files
Stores plain text (characters) only
No formatting:
 No styles (e.g. bold, underline)
 Only 1 font
Can be opened in any text editor / word processor

4. Text
RTF Files
Rich Text Format
Stores text (characters) and some basic formatting:
 Styles (e.g. bold, underline)
 Font size
All word processors will recognise RTF

5. Graphics
BMP Files
Bitmap Files
Store the colour for each pixel
 8 bits per pixel = 256 colours
 16 bits per pixel = 65,536 colours
 24 bits per pixel = 16,777,216 colours = true colour
Uncompressed meaning file size can be large

6. Graphics
GIF
Graphics Information Interchange
Bit depth: 8 bits = 256 possible colours
Can use transparency
Lossless compression

7. Graphics
JPEG
Joint Photographic Expert Group
Bit depth: 24 bits = 16,777,216 possible colours
Lossy compression
Smaller file size - good for storing files online and on devices

8. Transparency
Graphics
PNG
Portable Network Graphics
Bit depth: 24 bits = 16,777,216 possible colours
Lossless compression
Designed to replace GIF – better compression
Provides degrees of transparency (opacity)

9. Audio
WAV
Waveform Audio Format
Uncompressed
Lossless audio format
Standard for audio CDs

10. Audio
MP3
Motion Pictures Expert Group 1 – Audio Layer 3
Lossy compression
Remove sounds that are inaudible to the human ear - very low and very high
frequencies
Compression results in file sizes 1/10 of original
Used on portable devices and streaming audio

11. Video
MPEG
Motion Pictures Expert Group
Lossy compression
Store only the changes from one frame to the next rather then the entire
frame
Compression impact generally imperceptible to the human eye

12. Video
AVI
Audio Video Interleave
Can provide lossless compression, but large file sizes
Resolution of 320 x 240

13. Spreadsheets
XLS
Microsoft Excel
Industry standard spreadsheet application
Extensive functionality: calculations, graphing tools, pivot tables, and a macro
programming language

14. Spreadsheets
CSV
Comma-separated values
Uses data (comma) to separate the data in each row
Only plain text, no formatting or graphic objects stored

15. Spreadsheets
XML
Extensible Mark-up Language
Flexible way to create information formats and electronically share structured data
Data contained within elements which have a beginning and an end tag

16. PDF
 Portable Document Format
 File format that has captured all the elements (text, formatting, graphics) of a
printed document as an electronic image
 PDF files are created using Adobe Acrobat
 The free program Acrobat Reader needed to view PDF files
 Used for documents, magazine articles, brochures
 PDF files cannot be edited without buying additional software or importing
into other applications