Why is the metadata showing as 'unknown' after ripping a CD?

Many people believe that Audio CDs contain data such as artist name, song title, and album cover image. But this is not true. Audio CDs contain only music data in PCM format.

So how does the Aurender ACS(A30) find metadata?

  • It creates a unique key value (called TOC) by combining the number of songs and the length of each song.
  • It then requests the music database service for metadata corresponding to the key value, and retrieves it if available.
    • (The services used are MusicBrains, Discogs, and FreeDB (GnuDB) in total.)
  • However, if CD information is not registered in these databases, metadata cannot be imported. So, no matter how famous a singer's album is, if you rip it right after its release, it may show up as unknown.
  • There are often albums in the world where the number of songs and the length of each song are the same.
  • In the ACS(A30) Manager, users can select other metadata with the album release selection function, which can help with this. 

What about album covers?

  • Album covers are also pulled from the above databases, but often just metadata and no images.
    • In this case, users can search for an image on Google through the ACS Manager app if there is no image available in the database.
    • This means that sometimes the wrong album cover may be displayed.