iTunes changed the game by offering a legal, user-friendly platform where consumers could purchase and download music. The store initially sold songs in MP3 format but soon transitioned to AAC, a more efficient and higher quality audio codec, especially at similar bitrates. AAC files offered better sound quality and smaller file sizes compared to MP3s, making them an attractive option for digital music distribution. AAC, or Advanced Audio Coding, is an audio compression algorithm designed to provide high-quality audio at bitrates significantly lower than those required by earlier formats. It's an efficient way to compress audio files without sacrificing much quality, which was a significant improvement over MP3.
