The options are lossless such as Apple lossless, ape or FLAC. These lossless compressed formats compress the file to between 50-60% of wav size. Or a lossy format such as mp3. The best converter codec for mp3 is LAME. There's a no. of programs that offer it as a plug-in extra. Or similar is m4a at the higher bit rates (ie- up to 320 kbps.) Also recommended for either mp3 or m4a is VBR (Variable Bit rate) which is a more effective way of converting than CBR (constant bit rate!) It's improves playback quality & is easier on players to read & playback than cbr. ie: Those bits that need the extra bits of info to encode with are used at higher bit rates, but those that are not so important are converted at lower bit rates. Whereas CBR encodes everything at the one rate which results in areas of sound that are not properly represented in sound reproduction due to lack of bit rate afforded to them. Since I'm not a windows user, I could only give you general directions for actual tools to use. So I'll leave it at purely the approach to consider.