iTunes 4: Encode From Original Masters
Converting a file from one compressed format to another compressed format can lead to quality loss.
Products Affected
iTunes
Compression algorithms such as MP3 and AAC are intended for use with original source material (audio CD, tape, LP, or AIFF file). They are typically not intended for recompressing a file that was already compressed. A loss of quality can occur if you convert any sound file from one compressed format to another.
If you want to convert your library from MP3 to AAC, for example, you will gets best results by re-encoding songs and other sound files from the original source media.
Important: iTunes software may be used to reproduce materials. It is licensed to you only for reproduction of non-copyrighted materials, materials in which you own the copyright, or materials you are authorized or legally permitted to reproduce. If you are uncertain about your right to copy any material you should contact your legal advisor.
If you want to convert your library from MP3 to AAC, for example, you will gets best results by re-encoding songs and other sound files from the original source media.
Important: iTunes software may be used to reproduce materials. It is licensed to you only for reproduction of non-copyrighted materials, materials in which you own the copyright, or materials you are authorized or legally permitted to reproduce. If you are uncertain about your right to copy any material you should contact your legal advisor.