Different compression levels are used for each type of material being distributed. The reason for this is that some material compresses much better than others. Movies and MP3 files are already compressed with near maximum capacity. Repacking them would just create larger files and increase decompression time. Ripped movies are still packaged due to the large file size, but compression is disallowed and the RAR format is used only as a container. Because of this, modern playback software can easily play a release directly from the packaged files, and even stream it as the release is downloaded (if the network is fast enough).