To answer the first question first: There is basically no difference in the sense of sound between lossless music and genuine CDs. The difference lies in the difference in media (CDs have collection value) and the ownership of copyright. Genuine CDs are directly protected intellectual property rights by law and are not allowed to be rented. Although lossless music is not allowed to be enjoyed in principle, the current situation shows that its enjoyment rate is still very high. In addition, There is a gap in national laws, and everyone acquiesces to its exclusive nature. The second question: Lossless music is mostly captured from CD using related software, and the three formats you mentioned are all available. Among them, WAV is the most direct capture, without any compression, and the sound quality is the same as that of CD. There is no difference, and tags cannot be written (that is, the artist, album, etc. information displayed during playback); APE is second, but tags can be written, but this tag protocol is not very universal. For example, some MP3 players do not recognize APE tags. ; FLAC has the largest compression ratio, but is the most used and has the most mature technology.