Generally speaking, the sound quality of the built-in music apps on mobile phones is better than that of third-party apps. This is especially true for iPhone music. It not only supports local music files, but also integrates Apple Music and provides a large number of genuine iTunes plus aac. The online version, and this iTunes plus aac is a file obtained by Apple compressing and sorting the digital master tape of the record company, and its quality is much better than the mp3 version of various domestic music apps