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Data Compression
Criteria
Survey Formats
Basics
Compression Methods
Data Formats
Files
Audio Data
Image Data
GIF
Colours
Data Compression
Characteristics
GIF87a
GIF89a
Patents
Optimizations
Examples
Drawings
JPEG
Video Data
Glossary
Index
Download
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GIF - Examples
To demonstrate the effects of the different colour tables on the file size, the BinaryEssence logo has been encoded correspondingly.
Examples: File sizes depending on the total number of colours
| Number of Colours |
Index |
Type of the Table |
File Size |
| 4 |
2 bit |
optimized |
1,612 byte |
| 8 |
3 bit |
optimized |
1,994 byte |
| 16 |
4 bit |
optimized |
2,387 byte |
| 256 |
8 bit |
Standard |
5,569 byte |
At the given examples only insignificant deviations result in the subjective quality of the presentation:
optimized, 4 colours, 1,612 byte
optimized, 8 colours, 1,994 byte
optimized, 16 colours, 2,387 byte
Standard table of MS-Paint, 256 colours, 5,569 byte
optimized 4 colours 1,612 byte |
optimized 8 colours 1,994 byte |
optimized 16 colours 2,387 byte |
standard table 256 colours 5,569 byte |
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The savings seem to be small (3,957 byte, 256 versus 4 colours), but for larger files and looking to the entire data volume transferred from a website, a remarkable amount of data results. The maximum reduction potential is approximately 71% in this example.
Beside the total amount of data the access time should be taken into consideration. A large number of users do not have fast internet access, slow modems are still in use. Additionally overloaded servers are not a rare phenomenon. This unnecessary load does not offer any advantage, it only consumes time and money.
Websites with large pictures or a variety of logos and buttons sometimes require intolerable access times. Potential users may break off the page setup, what is definitely not intended especially for commercial websites.
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