Open RAR File

RAR Advanced Options

RAR and WinRAR are one of the most popular commercial compression applications. Still most of the time many important and useful features of these applications are not used by users because they either not exposed through interface or may not be easy to find. In this article we will try to cover several interesting features of RAR console application which could help users in their compressions and extraction tasks.

Compression Method

Compression method switch allows choosing between efficiency and performance of compression. Below are options available in RAR:

• m0 (store) - just store file without compressing it
• m1 (fastest) – use the fastest possible compression method by sacrificing efficiency
• m2 (fast) – use fast compression method
• m3 (normal) – use normal compression method. Method m3 is used by default by RAR and WinRAR.
• m4 (good) – provide better compression ratio by sacrificing performance
• m5 (best) – best possible compression but slowest performance

m1 and m2 methods use generic RAR compression algorithm. m3, m4 and m5 also recognize executable, audio and image files and try to use the best possible algorithm for compression of such files. Methods m4 and m5 also use more advanced text compression algorithm from PPM (Prediction by Partial Matching) family.

Compression method is specified via -m<n> switch.

Advanced Compression Parameters

Instead of choosing compression method it is also possible to specifically choose compression algorithm parameters which RAR will use to compress data.

Following algorithm parameters could be set:

• audio compression. Enables algorithm specific to compression of audio data. RAR allows specifying number of audio channels for this algorithm.
• delta compression. Enables algorithm which gives better results in compression of structured table data.
• Text compression. You can customize effectiveness of text predictive compression algorithm by specifying an order of PPM (prediction by partial matching) algorithm.
• Executable compression. Enables compression algorithms specific to x86 or Itanium executable files.
• RGB compression. Enables compression algorithms optimized for compression of 24 bit true color RGB files.
Advanced compression parameters are set using -mc[param1][:param2][module][+ or -] parameter. For more specifics see corresponding section in RAR.exe manual at RAR manual.