True Audio Quality application detects the music files that have been re-encoded. Many users tend to re-encode files from lossy formats, such as mp3, to lossless like flac. Files like those can reach your collection with the misconception that are truly lossless. Well, it’s time to cleanup your music collection and make it more suitable for your high standards or a club environment in case you’re a professional DJ.
When the reported and true quality are the same, the file has not been re-encoded and it actually has the quality it claims. Otherwise, the audio file has been re-encoded to the reported quality from the more lossy format shown in true quality column.