The term compression ratio refers to a fraction, percentage or ratio that expresses the difference between the size of a file before it was compressed and after the compression process is complete. This ratio depends on multiple different factors – mostly, the state of the initial file and the algorithm used to compress the file. The higher the compression ratio is, the more resources are needed in order to compress the data in question… or to decompress it.
Technipages Explains Compression Ratio
These ratios are usually either expressed using qualitative terms or in a 1:10 type format. As it happens, compression rates below 1:10 are considered reasonable or good, while ones higher than 1:10, such as 1:12 are instead considered excellent. The other big factor when it comes to the compression ratio is whether or not a compression algorithm is lossy or lossless. The former accepts the loss of parts of the data that is being compressed – it doesn’t noticeably affect the quality of the file in question unless the compression process is repeated hundreds or thousands of times.
The other option – lossless compression preserves all data without any quality loss, but at the price of a lower compression rate. Higher compression rates are only possible with lossy compression, which isn’t always an option – in other words, users have to choose whether they want to prioritize the compression rate or avoid data loss at all costs. Even lower compression rates allow for the reduction of the file’s size – in other words, even a lossless 1:8 compression ratio will still achieve a reduction in file size when the compression process is complete.
Common Uses of Compression Ratio
- Compression ratios are usually described by words – fair, good and excellent, for example.
- The better the compression ratio, the better the resulting file compression will be.
- Although a higher compression rate means that the resulting file is smaller, reinstating and decompressing it will also take more computer resources.
Common Misuses of Compression Ratio
- A good compression ratio means that files are compressed more quickly than what a lower compression ratio can achieve.