...By hitting the convert button? Your question doesn't really make sense. What are you trying to do? Also, don't necessarily trust what foobar calls "lossless"; it calls 4-bit ADPCM lossless too, which it isn't.
foobar also calls WAVs lossless, and you can have WAV files that are lossy too (even if PCM), so just ignore what foobar says.
What you want is convert between formats preserving the data itself, this would be a "lossless" conversion. Depending on the format this is possible or not, so you'll have to be more specific. If you convert to WAV then to another format, most of the time you'll have a "lossy" conversion.
Not possible I'm afraid. If some program claims to work, it actually converts to WAV internally (=lossy) first.
See "codec" info in foobar. Generally you can losslessly convert (always with custom tools): - PCM > WAV - MS-IMA/XBOX ADPCM, x-IMA ADPCM, MSADPCM > WAV (but some players may not play it). - Custom Vorbis > Ogg Vorbis - MPEG audio > MP3 (just renaming might work) - EALayer3 > MP3 (with some minor loss of data)
For game formats you can usually convert between two formats if they use the same codec.