Scenario: You’ve obtained an audio or video file that’s either in a format unsupported by the device you intend to play it on—an iOS device, traditional iPod, or your Mac, for example—or in a form ...

Digital sound is nothing more than numbers. What separates one container from another is how those numbers are packed, how much data (if any) is thrown away, and which devices understand the result.

Audio files come in a number of different formats. Some are lossy, such as AAC and MP3; they save space compared to the original files, but some of the original data is lost during compression. Some ...