I've downloaded a file containing videos. The archive was in .rar format. The actual size of the archive was 2.5GB but after decompression it came out as a 10GB folder. I want to know how to compress the folders with lowest possible archive size be in any format i.e. zip, .rar, .7z or any other? Please also tell me which app to use for this purpose? Currently I'm using 7zip but I can't make my folder that small because I don't know the correct setting. Thank you for helping.