To regulate the speed of compression using the specified digit n, where `-1' indicates the fastest compression method (less compression) and or `-9' indicates the slowest compression method (optimal compression). The default compression level is `-6' (that is, biased towards high compression at expense of speed). | To regulate the speed of compression using the specified digit n, where `-1' indicates the fastest compression method (less compression) and or `-9' indicates the slowest compression method (optimal compression). The default compression level is `-6' (that is, biased towards high compression at expense of speed). |