Dealing with DRM

Until recently, most music you downloaded from online music stores was encoded with digital rights management (DRM) technology. DRM was designed to prevent the unlawful distribution, copying, and sharing of copyrighted music. If a track you downloaded is protected with DRM, you're limited as to how you can copy and listen to that song.

DRM works by encoding the audio file in a type of wrapper file format. This wrapper file includes a user key, which is used to decode and play the track-under specified conditions. For example, a DRM license might dictate how many different PCs or portable music players the track can be copied to, whether it can be burned to CD, and so on. If you try to use the song in a way not permitted by the license, the DRM protection keeps it from playing.

Note While DRM technology can be applied to audio files in the AAC and WMA formats, it cannot be applied to MP3 files.This is why most online music stores encode their music as either AAC or WMA formats, to facilitate DRM.

Recently, however, the trend has been away from DRM to selling DRMfree tracks, most often in the MP3 format. (Apple iTunes is an exception to this, selling its DRM-free tracks in its own AAC format.) The benefit to DRM-free music is that once you purchase it, you can use it however you want; you can play it on any number of PCs or portable music players, and burn it onto an unlimited number of custom CDs. It's a much more listener-friendly solution, which is why many online music stores are now offering DRM-free music.

Tip Check with the individual online music store to see if it encodes its tracks with DRM-and if so, what the terms of its DRM license are.